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CLASSIFICATION OF NEWBORN INFANTS
Gestational Age:
 Normal term pregnancy : 40 weeks (280 days)
 Preterm (premature): < 36-37 weeks
 The preterm infant is characterized by
small size,
immature appearance of the face,
thin,
reddish skin,
paucity of subcutaneous fat (fat storage occurs in the third trimester),
scanty hair,
hypotonia.
 Postterm (postmature): > 41-42 weeks
 The posterm infant has
abundant hair,
nails,
thicker skin,
wizened appearance,
wrinkling (decreased subcutaneous fat due to catabolism of stores)
 Preterm infants have problems due to immaturity of many organ systems.
 Postterm infants are handicapped by placental senescence.
 The physical examination of the newborn infant should be performed in a fixed order to ensure that nothing is forgotten.
 First basic measurements are made, then the infant is inspected generally.
 Thereafter the infant is examined by regions starting at the head and ending at the toes.
 Finally the neurological status is assessed.
 The step by step examination given below lists what should be done and gives the normal and abnormal findings.
MEASUREMENTS
|
BIRTHWEIGHT
|
Normal
|
2500g or above
Between 10th and 90th centile for gestational age
|
Abnormal
|
Low birthweight(below 2500g)
Underweight(below 10th centile)
overweight.(above 90th centile) for gestational age
|
HEAD CIRCUMFERENCE
|
Normal
|
Between 10th and 90th centile for gestational age.
|
Abnormal
|
Small head (below 10th centile) or
Large head (above 90th centile) for gestational age
|
CROWN-HEEL LENGTH
|
Normal
|
Between 10th and centile for gestational age. Measure accurately with tape or preferably measuring box.
|
Abnormal
|
Short (below 10th centile or tall (above 90th centile) for gestational age.
|
SKIN TEMPERATURE
|
Normal
|
Abdominal wall 36 - 36.5°C (or axilla 36.5 - 37°C)
|
Abnormal
|
Hypothermia (below 35°C).
|
GENERAL INSPECTION
|
GESTATIONAL AGE
|
Normal
|
Physical and neurological features of term infant.Term (37-41.9 wks).
|
Abnormal
|
Immature features in preterm infant (below 37 weeks).
Postterm infants. (42 weeks and above) have long nails and are often wasted
|
WELLBEING
|
Normal
|
Active, alert.
|
Abnormal
|
Lethargic, appears ill.
|
APPEARANCE
|
Normal
|
No abnormalities.
|
Abnormal
|
Gross abnormalities.
Abnormal faeces.
|
WASTING COLOUR
|
Normal
|
Well nourished. Pink tongue.
|
Abnormal
|
 Soft tissue wasting.
 Cyanosis,
 pallor,
 jaundice,
 plethora.
|
SKIN
|
Normal
|
 Smooth or mildly dry.
 Vernix and lanugo.
 Stork bite,
 mongolian spots,
 milia, erythema toxicum,
 salmon patches.
|
Abnormal
|
 Dry,
 marked peeling
 .Meconium staining.
 Petechiae,
 bruising.
 Large or many pigmented naevi.
 Capillary or cavernous haemangioma.
 Skin infection.
 Oedema.
|
HEAD
|
SHAPE
|
Normal
|
Caput,
moulding.
|
Abnormal
|
 Cephalhaematoma,
 subaponeurotic bleed.
 Asymmetry,
 anencephaly,
 hydrocephaly,
 encephalocoele
|
FONTANELLA
|
Normal
|
Open, soft fontanelle with palpable sutures.
|
Abnormal
|
 Full or sunken anterior fontanelle.
 Large or closed fontanelles.
 Wide or fused
 sutures.
|
HAIR
|
Normal
|
Wide familial variation.
|
Abnormal
|
Low posterior hair line.
|
EYES
|
POSITION
|
Abnormal
|
Hypertelorism or hypotelorism.
|
SIZE
|
Abnormal
|
Microphthalmia or macrocornea (glaucoma).
|
LIDS
|
Normal
|
Mild oedema common.
|
Abnormal
|
 Marked oedema,
 ptosis bruising.
 Narrow palpebral fissures in FAS.
|
CONJUNCTIVAE
|
Normal
|
May have small subconjunctival haemorrhages
|
Abnormal
|
Pale or plethoric.Conjunctivitis.
Excessive tearing when nasolacrimal duct obstructed.
|
CORNEA, IRIS AND LENS
|
Normal
|
Cornea clear, regular pupil, red reflex.
|
Abnormal
|
 Opaque cornea,
 irregular pupil,
 cataracts,
 no red reflex,
 squint,
 abnormal eye
 movements.
|
NOSE
|
SHAPE
|
Normal
|
Small with upturned nostrils.
|
Abnormal
|
Flattened in oligohydramnios.
|
NOSTRILS
|
Normal
|
Both patent. Easy passage of feeding catheter
|
Abnormal
|
Choanal atresia.
Blocked with dry secretions
|
DISCHARGED
|
Abnormal
|
Mucoid,
purulent or bloody secretions
|
MOUTH
|
LIPS
|
Normal
|
Sucking blisters.
|
Abnormal
|
Cleft lip.
Long smooth upper lip,
no philtrum and thin vermillion border in FAS.
|
PALATE
|
Normal
|
Epstein's pearls
|
Abnormal
|
High arched or cleft palate.
|
TONGUE
|
Normal
|
Pink
|
Abnormal
|
Cyanosed, pale, macroglossia. Posteriorly placed (Pierre-Robin anomaly).
|
TEETH
|
Normal
|
None at birth
|
Abnormal
|
Adventitious or primary teeth.
|
GUMS
|
Normal
|
Small cysts.
|
Abnormal
|
Epulis.
|
MUCOUS MEMBRANES
|
Normal
|
Pink, shiny.
|
Abnormal
|
Thrush, ulcers.
|
SALVIA
|
Abnormal
|
Excessive if poor swallowing or oesophageal atresia.
|
JAW
|
Normal
|
Smaller than older child
|
Abnormal
|
Micrognathia in Pierre-Robin anomaly.
|
EARS
|
SITE
|
Normal
|
Pinna vertical at term.
|
Abnormal
|
Ears rotated backwards with poorly formed upper pinna (low set).
|
APPEARANCE
|
Normal
|
Familial variation.
|
Abnormal
|
Pre-auricular skin tag or sinus.
Malformed ears.
Hairy ears in I.D.M.
|
NECK
|
SHAPE
|
Normal
|
Usually short.
|
Abnormal
|
Webbing, torticollis.
|
MASSES
|
Normal
|
No palpable lymph nodes or thyroid
|
Abnormal
|
Cystic hygroma. Goitre.
Sternomastoid tumour.
|
CLAVICLE
|
Abnormal
|
Swelling or crepitus if fractured.
|
BREASTS
|
Normal
|
Palpable breast nodules at term 0.5 to 1 cm. Enlarged, lactating breasts
|
Abnormal
|
Accessory or wide spaced nipples. Mastitis.
|
HEART
|
PULSES
|
Normal
|
Brachial and femoral pulses easily palpable. 120 - 160 beats per minute.
|
Abnormal
|
Pulses weak, collapsing, absent, fast or slow.
|
CAPILLARY FILLING TIME
|
Normal
|
Less than 4 seconds over chest and peripheries.
|
Abnormal
|
Prolonged filling time if infant cold or shocked.
|
BLOOD PRESSURE
|
Normal
|
Systolic 50 to 90mm at term.
|
Abnormal
|
Hypertensive or hypotensive.
|
PRECORDIUM
|
Normal
|
Mild pulsation felt over heart and epigastrium
|
Abnormal
|
Hyperactive precordium.
|
APEX BEAT
|
Normal
|
Heard maximally to left of sternum
|
Abnormal
|
Heard best in right chest in dextrocarida.
|
SOUNDS
|
Normal
|
Loud, single 2nd heart sound on day 1
|
Abnormal
|
Gallop, widely split second sound.
|
MURMURS
|
Normal
|
Soft, short systolic murmur common on day 1.
|
Abnormal
|
Systolic or diastolic murmurs.
|
HEART FAILURE
|
Abnormal
|
Oedema,
hepatomegaly,
tachypnoea or excessive weight gain.
|
LUNGS
|
RESPIRATION RATE
|
Normal
|
40-60 breaths per minute. Irregular in REM sleep. Periodic breathing with no change in heart rate or colour.
|
Abnormal
|
Tachypnoea - above 60 breaths per minute. Gasping. Apnoea with drop in heart rate, pallor or cyanosis
|
CHEST SHAPE
|
Normal
|
Symmetrical.
|
Abnormal
|
Hyperinflated or hypoplastic chest.
|
CHEST MOVEMENT
|
Normal
|
Symmetrical.
|
Abnormal
|
Asymmetrical in pneumothorax and diaphragmatic hernis.
|
RECESSION
|
Normal
|
Mild recession in prems
|
Abnormal
|
Subcostal recession in respiratory distress.
|
GRUNTING
|
Abnormal
|
Expiratory grunt in respiratory distress.
|
STRIDOR
|
Abnormal
|
Inspiratory stridor a sign of upper airway obstruction.
|
PERCUSSION
|
Normal
|
Resonant bilaterally.
|
Abnormal
|
Dull with effusion or haemothorax.
|
AIR ENTRY
|
Normal
|
Egual air entry over both lungs. Bronchovesicular.
|
Abnormal
|
Unegual or decreased.
|
ADVENTITIOUS SOUNDS
|
Normal
|
Transmitted sounds.
|
Abnormal
|
Crackles, wheeze or decreased.
|
ABDOMEN
|
UMBILICUS
|
Normal
|
2 arteries and 1 vein.
|
Abnormal
|
1 artery, 1 vein .Infection. Bleeding or discharge. Hernia. Exomphalos.
|
SKIN
|
Abnormal
|
Periumbilical erythema or oedema.
|
SHAPE
|
Abnormal
|
Distended or hollow.
|
LIVER
|
Normal
|
Palpable 1 cm below costal margin, soft.
|
Abnormal
|
Enlarged, firm, tender.
|
SPLEEN
|
Normal
|
Not easily palpated.
|
Abnormal
|
Enlarged, firm.
|
KIDNEYS
|
Normal
|
Often palpable but normal size.
|
Abnormal
|
Enlarged, firm.
|
MASSES
|
Normal
|
No other masses palpable. Full bladder can be percussed.
|
Abnormal
|
Palpable mass.
|
BOWEL SOUNDS
|
Normal
|
Heard immediately on auscultation.
|
Abnormal
|
Depressed or absent.
|
ANUS
|
Normal
|
Patent. Skin tags.
|
Abnormal
|
Absent or covered. Displaced anteriorly.
|
STOOLS
|
Normal
|
Meconium passed within 48 hours of birth.
Yellow stools by day 5.
Breastfed stool may be green and mucoid.
|
Abnormal
|
Blood in or on stool.
White stools in obstructive jaundice.
Offensive watery stools.
|
SPINE
|
Normal
|
Coccygeal dimple or sinus. Straight spine.
|
Abnormal
|
Sacral dimple or sinus. Scoliosis. Meningomyelocoele.
|
GENITALIA
|
PENIS
|
Normal
|
Urethral opeining at centre of glans.
|
Abnormal
|
Hypospadias. Micropenis.
|
TESTES
|
Normal
|
Descended by 37 weeks
|
Abnormal
|
Undescended.
|
SCROTUM
|
Normal
|
Well formed at term.
|
Abnormal
|
Inguinal hernia. Fluid hernia.
|
VULVA
|
Normal
|
Skin tags, mucoid or bloody discharge.
|
Abnormal
|
Fusion of labia.
|
CLITORIS
|
Normal
|
Uncovered in preterm or wasted infants.
|
Abnormal
|
Enlarged in adrenal hyperplasia.
|
URINE
|
Normal
|
Passed in first 12 hours.
|
Abnormal
|
Poor stream suggests posterior urethral valve.
|
ARMS
|
Normal
|
Flexed position in term infant.
|
Abnormal
|
Erb's palsy.
|
HANDS
|
Abnormal
|
Extra, fused or missing digits. Skin stags. Single palmar crease. Hypoplastic nails
|
HIPS
|
Normal
|
Click common. Fully abducted.
|
Abnormal
|
Dislocated or dislacatable. Limited abduction.
|
LEGS
|
Normal
|
Mild bowing of lower legs common
|
Abnormal
|
Dislocatable. Knees in breech.
|
FEET
|
Normal
|
Positional deformation.
|
Abnormal
|
Clubbed feet. Abnormal toes.
|
NEUROLOGICAL STATUS
|
BEHAVIOUR
|
Normal
|
Alert, responsive.
|
Abnormal
|
Drowsy, irritable, jittery.
|
POSTION
|
Normal
|
Flexion of all limbs at term.
|
Abnormal
|
Extended limbs or frog position in preterm and ill infants.
|
MOVEMENT
|
Normal
|
Active. Moves all limbs equally when awake. Stretches, yawns and twists trunk.
|
Abnormal
|
Absent, decreased or asymmetrical movement. Jittery or convulsions
|
TONE
|
Normal
|
Hypotonia in preterm infants.
|
Abnormal
|
Hypotonia or hypertonia. Asymmetrical tone.
|
HANDS
|
Normal
|
Intermittantly clenched.
|
Abnormal
|
Permanently clenched.
|
CRY
|
Normal
|
Good cry when awake
|
Abnormal
|
Weak, high pitch or hoarse cry.
|
VISION
|
Normal
|
Follow a face, bright light or red object.
|
Abnormal
|
Absent or poor following.
|
HEARING
|
Normal
|
Responds to loud noise.
|
Abnormal
|
No response.
|
SUCKING
|
Normal
|
Good suck and rooting reflexes after 36 weeks gestation.
|
Abnormal
|
Weak suck at term.
|
MORO REFLEX
|
Normal
|
Full extension then flexion of arms and hands. Symmetrical.
|
Abnormal
|
Absent, incomplete or asymmetrical response.
|
When the history has been taken and the physical examination completed, an overall assessment of the infant must be made and a list of the problems compiled.
The management of each problem in turn must now be addressed.
Examination of the Hips:
 The hips must be examined in all newborn infants to exclude congenital dislocation or an unstable hip.
 The infant is examined lying on his back with the hips flexed to a right angle and knees flexed.
Ortolani test :
 Both thighs are held so that the examiner's fingers are over the greater trochanters and his thumbs rest on the inner aspects of each thigh.
 The thighs are then abducted: if a hip is dislocated, a 'clunk' can be felt and heard as the femoral head slips forward into its normal position in the acetabulum.
Barlows Test :
 demonstrates an unstable or dislocatable hip.
 One hand immobilizes the pelvis (thumb over pubic ramus, fingers over sacrum) while the other hand moves the opposite thigh into mid-abduction.
 If the hip is unstable, backward pressure on the lesser trochanter with the thumb on the inner side of the thigh causes the femoral head to slip out of the acetabulum.
 Conversely forward pressure on the greater trochanter with the fingers would tend to cause the head to spring back into the acetabulum.
 The same procedure is then carried out for the opposite side.
Birth Weight:
The normal weight of a full term infant is >2500 g.
Small for gestational age (SGA): < 10%ile in weight for the expected duration of pregnancy.
 Despite a small size, the SGA infant has an alert, more mature face, hair, flexed posture, and thicker skin.
 Often the result of factors such as maternal disease, such as high blood pressure, or drug and/or alcohol abuse, autoimmune disorders etc.; with multiple pregnancy; or with intrauterine infection.
 Appropriate for gestational age (AGA): 10-90%ile in weight for the expected duration of pregnancy.
Large for gestational age (LGA): > 90%ile in weight for the expected duration of pregnancy.
 The LGA infant is large and fat ("Campbell's soup" baby).
 This is most often due to maternal diabetes.
 These babies are at risk for injury during delivery because of their unusual size.
APGAR Score:
The APGAR score is a rapid means of evaluating an infant's cardiopulmonary and neurologic function at set intervals after birth (routinely at 1 and 5 minutes). The infants are given scores of 0-2 on each of 5 characteristics categorized according to the letters of Dr. Apgar's name, and a total score is given.
 |
0
|
1
|
2
|
 |
Appearance
|
the baby is blue indicating cyanosis
|
pale/grayish
|
pink /ruddy
|
Pulse
|
absent
|
less than 100
|
strong
|
Grimace*
|
absent
|
weak response
|
cough/sneeze
|
Activity
|
limp/not crying
|
in between
|
vigorous/crying
|
Respirations
|
apneic/not breathing
|
weak breathing
|
good respiration
|
 *a grimace, or reflex grimace, is when the baby coughs and/or sneezes while the doctor suctions out the mouth and nose
 A good APGAR score is 9 or 10, and most normal babies have scores greater than 7 . Low APGAR scores (0-3) require immediate attention in the delivery room to avoid the complications of asphyxia.
PREMATURITY
 Preterm infants have many problems due to immaturity of many organ systems, including pulmonary, hepatic and immune systems.
 Three common disorders of the preterm infant are
Hyaline Membrane Disease (HMD),
Intraventricular Hemorrhage (IVH),
and Necrotizing Enterocolitis (NEC).
 Problems of pulmonary development and adaptation to extrauterine life constitute the major causes of morbidity and mortality in the neonatal period.
 In order to understand the lung pathology and pathophysiology of these premature infants, an understanding of lung development is necessary.
Lung Developement:
First half of gestation :
 The bronchiolar tree is fully developed down to the smallest branches of the conducting airways.
Second half of gestation :
 The major developmental task for the lung is modification of the distal parenchyma.
 During this time the following progressive changes are seen:
 Development and proliferation of alveolar ducts and alveoli
 Attenuation of epithelial lining cells
 Decrease in interstitial connective tissue
 Proliferation of capillaries and their location adjacent to air spaces
 Type II pneumocytes begin to appear at about 22 weeks gestation, but do not produce adequate amounts of surfactant until around 36 weeks.
Hyaline Membrane Disease:
Hyaline Membrane Disease (HMD), also known as Neonatal Respiratory Distress Syndrome(RDS), is a complication of premature birth.
 The more premature the infant, the more likely for HMD to occur. It is rare in full-term infants.
 The basic pathophysiological defect is felt to be deficient surfactant due to poorly functioning type II pneumocytes, with resultant
 high surface tension,
 atelectasis,
 and ventilation- perfusion mismatching.
 This is further complicated by immature pulmonary parenchyma leading to poor ventilation-perfusion matching, and compliant rib cage unable to support collapsed lungs.
Clinical:
The infant with HMD will present with
 respiratory distress at or soon after birth with tachypnea,
 cyanosis,
 grunting,
 and retractions of the chest.
 CXR reveals bilateral ground-glass appearance of the lung fields (atelectasis) and air bronchograms (air in the bronchi standing out against the collapsed parenchyma) .
Pathology:
Gross:
 Lungs are airless,
 dark red,
 liver-like and sink in water
Micro:
 The lungs are immature.
 The characteristic low power appearance is that of widespread collapse of distal air spaces and regularly dispersed, dilated terminal bronchioles.
 The bronchioles are denuded and lined by anuclear eosinophilic hyaline membranes.
 Hyaline membranes are felt to be composed of both necrotic epithelial cells, and fibrin and other proteins leaking out of the capillaries.
NOTE:
 Hyaline membranes can be demonstrated in forms of respiratory distress other than surfactant deficiency,
 such as early pneumonia.
 Although neonatal respiratory distress syndrome and hyaline membrane disease generally imply respiratory distress secondary to surfactant deficiency, the pathological diagnosis requires demonstration of immature pulmonary parenchyma (usually) and the characteristic pattern of atelectasis in addition to the hyaline membranes.
Course:
 In the uncomplicated case, respiratory distress continues for 48 to 72 hours.
 At that time the type II pneumocytes increase the production of surfactant.
 As normal surface characteristics begin to reappear in the lung one sees gradual clinical improvement.
 Histologically with recovery there is break-up and phagocytosis of hyaline membranes (seen here), regeneration of bronchiolar epithelium, and reexpansion of the parenchyma.
Intraventricular Hemorrhage (Germinal matrix hemorrhage)
Intraventricular Hemorrhage (IVH), hemorrhage into the ventricular system of the brain, is a particularly serious complication of preterm birth.
Epidemiology:
 seen typically in infants less than 32-33 weeks gestation.
 The more immature the infant is, the higher the risk.
 by sonography it is shown to occur in up to 40-50% of infants less than 1500 g
 rare in mature infants.
Pathology:
 In the developing brain, immature neurons aggregate around the ventricles where they proliferate and eventually migrate out to form the cerebral cortex.
 This periventricular primitive zone is called the germinal matrix.
 During 24-32 weeks gestation (the period of maximum risk of IVH in a preterm infant) much of the germinal matrix is localized bilaterally over the caudate nucleus where it lies just beneath the ependymal lining of the lateral ventricles.
 The vast majority of neonatal intracerebral hemorrhage begins in the germinal matrix. It may remain localized or may rupture through the overlying ependymal cell layer into the lateral ventricles (the red arrow points to the germinal matrix).
 Depending on the extent of the bleeding, the hemorrhage may fill up and expand the ventricular system, follow the course of the CSF to emerge in the subarachnoid space overlying the brainstem and cerebellum, or may occasionally show expansion into the parenchyma.
Etiology and Pathogenesis:
 The exact cause of germinal matrix hemorrhage is unclear.
 Numerous factors have been cited:
 The fragile structure of the germinal matrix and its vessels would appear to predispose to hemorrhage.
 There is poor autoregulation of cerebral blood flow in the preterm infant.
 Sick premies on a respirators frequently experience elevated venous pressures, surges in arterial pressures, and episodic hypotension, all of which may subject an unprotected germinal matrix to injury.
 Once there is hemorrhage, the high fibrinolytic activity that characterizes the germinal matrix allows the hemorrhage to propagate.
Clinical:
 IVH often occurs in the setting of HMD, usually between 6-36 hours of life.
 Infants with large IVH present with
 tense fontanelles,
 apnea,
 seizures,
 cyanosis,
 pallor,
 and decreasing hematocrit.
 Large IVH's are a frequent cause of death.
 Small hemorrhages limited to the germinal matrix or restricted to small accumulations in the ventricles may be clinically silent and appreciated only by sonography.
 A major complication in survivors is post hemorrhagic hydrocephalus or dilatation of the ventricles.
This is due to fibrotic organization of the arachnoid space or plugging of the channels between the fourth ventricle and the subarachnoid space.
Necrotizing Enterocolitis
Necrotizing Enterocolitis (NEC) is a form of spontaneous ischemia of the bowel.
Epidemiology:
 has a propensity to affect preterm infants of very low birth weight
Clinical:
The typical presentation is a preterm infant, particularly one who experienced respiratory distress syndrome (or other causes of perinatal hypoxia), who develops abdominal distension, absent bowel sounds, and bloody stools at several days of age.
Abdominal x-ray may show gas in the wall of the intestines, called pneumatosis intestinalis.
Pathology:
Gross:
 There is multifocal necrosis of the bowel, marked by the segmental dusky, hemorrhagic appearance.
 The most common sites of involvement are the terminal ileum and colon, but any location of the large or small intestine may be affected.
 The bowel is distended, congested, and often frankly necrotic. (Compare the involved segment of intestine below with the more normal segment above.)
 Focal perforations and peritonitis may be seen.
Micro:
 There is necrosis which in its earliest stages affects only the mucosa.
 In this image the necrotic mucosa has sloughed, and the submucosa is hemorrhagic.
 When severe, the necrosis may progressively involve all layers of the bowel through to the serosa (transmural). (This type of involvement, which begins at the luminal aspect of the bowel, is typical of ischemic injury.)
 The necrosis is accompanied by variable amounts of inflammation and hemorrhage.
 Pneumatosis intestinalis, which is present in many but not all cases, is represented by submucosal or subserosal gas-filled cysts.
Pathogenesis:
 The pathogenesis of NEC in most cases is felt to be due to an interaction of three factors:
 bowel ischemia
 bacterial infection
 mucosal damage due to other causes (e.g. hyperosmolar feedings)
 It is felt that in most cases ischemia is primary, perhaps resulting from a decrease in splanchnic circulation in the setting of acute perinatal asphyxia. Injury to the integrity of the mucosa allows access of pathogenic organisms into the bowel wall, where they can cause further injury including the production of gas giving this entity its hallmark x-ray finding, pneumatosis intestinalis.
Course:
 Therapy in many cases is medical, i.e. cessation of feedings, intravenous fluids and antibiotics. Short term complications include perforation and peritonitis which will require surgical intervention.
 If the damage to the bowel wall is not too severe, there can be complete regeneration.
 However with more severe damage, mural fibrosis during the reparative phase may lead to marked narrowing of the lumen with the long term complication of strictures and possible atresia.
 This will cause later-onset intestinal obstruction. If extensive surgical resection is required for strictures, the short bowel syndrome may result with loss of absorptive capacity.
PERINATAL ASPHYXIA
General
 Perinatal asphyxia is a severe hypotensive and hypoxemic insult which the fetus suffers, usually around the time of birth.
Etiology
 Disruption of oxygen delivery to the fetus can originate in:
 the umbilical cord : e.g., knot or prolapse of the cord
 the placenta : e.g., abruption
 the mother's systemic circulation : e.g., pre-eclampsia
 Obstetrical : e.g., difficult delivery
 In addition, postmature infants are more susceptible to asphyxia. One starts to see involution of the placenta after the normal term of gestation.
 To compensate for decreased maternal blood flow the fetus uses up its fat and glycogen stores, leaving it with no reserve of glucose to meet metabolic demands during hypoxia. In addition, the larger size of a postterm infant will make it more susceptible to obstetrical complications arising during delivery.
Pathology:
 Multiple organ systems are affected by acute perinatal asphyxia, and pathologically they are characterized by two main features:
 widespread marked congestion and hemorrhage
 Ischemic necrosis of various organs in a shock-like distribution, if the insult is severe enough.
Lungs:
 The lungs are intensely congested, with variable degrees of interstitial and intra-alveolar hemorrhage that may present clinically as blood welling up from the endotracheal tube. Meconium aspiration is a common association, which is discussed at greater length below.
Liver:
 The liver shows widespread acute hemorrhagic necrosis in the centrilobular regions; this centrilobular distribution is characteristic of shock injury.
Kidney:
 The kidneys may be acutely hemorrhagic, There may be evidence of acute tubular necrosis, or cortical necrosis.
Adrenal:
 Adrenal hemorrhage is commonly present, and microscopically is frequently associated with frank necrosis.
CNS:
 Anoxic-ischemic injury to the brain is the most dreaded sequela or perinatal asphyxia and is discussed in greater detail below.
Meconium Aspiration
 Meconium aspiration syndrome is a frequent cause of respiratory distress in the term and post-term infant and is felt to be a direct consequence of perinatal asphyxia.
 Meconium is the term for the thick, viscous, dark green material which is present in the fetal intestines.
 It consists of both secretions of intestinal mucosal cells as well as amniotic fluid debris that the infant swallows.
Etiology:
 Normally meconium is passed per rectum during the first day of post-natal life. Its passage prior to birth or during delivery is usually felt to be due to a reflex produced by hypoxic stress.
 During anoxia, the fetus first relaxes its anal sphincter and expels meconium into the amniotic fluid.
 Normally the fetus takes shallow breaths of amniotic fluid in utero.
 If the anoxia is severe, the fetus will begin to take deep gasps, which delivers the meconium, now floating in the amniotic fluid, deep into the lungs.
 This placenta is deeply stained with meconium, which was released into the amniotic fluid of a distressed infant.
NOTE: Meconium staining of the amniotic fluid and the infant is not an uncommon occurrence, being present in 10% of all deliveries. Its mere presence in the amniotic fluid in the absence of other signs of asphyxia need not have great clinical significance. Again, it is the deep gasps taken by the fetus with severe perinatal asphyxia that delivers meconium deep into the lungs resulting in respiratory distress.
Pathophysiology:
 Meconium's major effect is on the small airways.
 Complete obstruction - atelectasis results
 Partial obstruction - produces a ball-valve effect with air trapping and overinflation distal to the obstruction which may lead to alveolar rupture and pneumothorax, a frequent complication.
 Meconium may cause a chemically induced spasm of the bronchial tree
 Meconium also serves as a good culture medium predisposing to secondary bacterial infection.
Pathology:
Gross:
 The lungs are firm and bulky. They may show alternating zones of atelectasis and emphysema. On section they may appear green from meconium staining.
 Viscous plugs of meconium may protrude from the bronchi.
Micro:
 There is usually intense congestion.
 The meconium may plug the airways and extensively fill the alveoli.
 Of note is that the underlying parenchyma is mature, unlike the lung in hyaline membrane disease.
Meconium on hematoxylin and eosin stain is a densely eosinophilic, amorphous material with flecks of gold which represent the meconium pigment.
 The skinny eosinophilic profiles marked by the arrow are squames,
 which are desquamated, anucleate surface epithelial cells from the fetus' skin that accumulate in the amniotic fluid during the third trimester.
 The squames are good markers of amniotic fluid. Inflammation is generally unimpressive in uncomplicated meconium aspiration syndrome.
 The presence of numerous neutrophils in the alveoli suggest superimposed bacterial pneumonia.
Clinical:
 Infants who aspirate meconium develop respiratory distress with tachypnea and hypoxia shortly after birth.
 Chest x-ray shows patchy bilateral infiltrates and hyperinflation with flattening of the diaphragms. Rapid clinical deterioration may herald the development of a pneumothorax.
 Most infants with meconium aspiration can be supported with artificial ventilation and recover within 4-10 days. A proportion of these patients die, either from massive aspiration causing respiratory failure or secondary bacterial pneumonia.
Anoxic-Ischemic Injury to the Brain
Gray Matter Lesions
 Anoxic-ischemic injury to the brain is the most dreaded sequela of perinatal asphyxia.
 Gray matter lesions are classically seen since neurons are exquisitely sensitive to asphyxia.
 Both the cerebral cortex and deep gray matter (thalamus, basal ganglia, and brain stem) may be involved
 . Involvement of the deep gray matter is seen more often in infants, particularly preterm infants, than in adults suffering from anoxia and/or ischemia.
 This probably reflects the fact that in the infant the neurons in the deep nuclei are more mature and more metabolically active than those in the cortex.
 This makes them more susceptible to ischemia.
Pathology:
 Acute histological changes include acute eosinophilic necrosis of neurons with shrinkage of the cytoplasm, karyorrhexis and pyknosis of the nucleus (blue arrow).
 With time there is loss of neurons and gliosis.
 This image shows the brain some time after a severe case of perinatal asphyxia. The gyri have become thinned, white and firm with loss of the demarcation between the gray and white matter (ulegyria). If necrosis has been extensive, cystic lesions may develop.
Clinical:
The child with such extensive atrophy will show severe mental retardation and other profound neurological handicaps.
White Matter Lesions
Not infrequently, premature infants suffering a hypotensive episode will also develop white matter infarcts called periventricular leukomalacia.
Pathology:
Gross:
 Fairly well demarcated yellow-white chalky lesions which are typically located bilaterally in the white matter, typically at the corners of the lateral ventricles (red arrow).
Micro:
 Dissolution of the white matter, macrophages digesting debris, and astrocytic proliferation are seen.
Clinical:
 Because of their location in the region of the corticospinal tracts, the neurological sequelae of severe white matter damage may be spastic diplegia or quadriplegia (which is often given the label of cerebral palsy).
PERINATAL INFECTION
 Infections are an important cause of morbidity and mortality in the fetal and neonatal period, causing approximately 20% of perinatal disease.
Immaturity of Neonatal Immune System
 In utero, the fetus is afforded protection by several mechanisms:
 Physical barrier of the cervical mucus plug
 Physical barriers of the placental membranes and placental villi
 Bacteriostatic nature of amniotic fluid
 Maternal immune system
 Transfer of maternal IgG across the placenta.
 Neonates are at greater risk of developing systemic infection due to immature immune defense mechanisms.
Routes of Fetal/Neonatal Infection
 The fetus and newborn infant can acquire infection via several routes:
Hematogenous spread
 This route of infection occurs via the placenta. It is typical of viruses, (e.g. CMV and rubella), but may also be seen with such organisms as syphilis, toxoplasmosis, and Listeria. Historically these organisms have been described by the acronym TORCH.
 T - Toxoplasmosis
 O - Other (syphilis, HIV, etc.)
 R - Rubella
 C - Cytomegalovirus
 H - Herpes
 The "other" category is becoming much larger, making this acronym less useful.
Example: Cytomegalic Inclusion Disease:
 The most commonly identified transplacental infection is caused by cytomegalovirus.
Clinical:
 The vast majority of these infections are asymptomatic. The severe clinical syndrome which is called Cytomegalic Inclusion Disease (CID) is fairly uncommon. The greatest risk to the fetus is if a woman develops a primary infection in the first half of pregnancy. In this setting there is about a 33% risk of the fetus acquiring the disease.
 Cytomegalic inclusion disease is characterized by multiorgan involvement. One typically sees intrauterine growth retardation, hepatosplenomegaly, microcephaly, chorioretinitis, thrombocytopenia, periventricular cerebral calcifications, and severe intellectual and sensory deficits. This constellation of findings, with particular reference to low birth weight, hepatosplenomegaly, and cerebral impairment, is typical of many severe transplacental intrauterine infections.
Pathology:
 Depending on the organ involved, cytomegaloviral infection may be associated with focal necrosis +/- dystrophic calcification and a variable degree of lymphocytic and plasma cell inflammatory infiltrates.
Microscopically, infected cells demonstrate large nuclei with basophilic inclusions (arrow).The nuclear inclusions are surrounded by a halo and a thin rim of compressed chromatin
Cytoplasmic inclusions may sometimes be observed.
Ascending infection
 In this route of infection microorganisms travel up to the fetus from the vagina and cervix.
 This route of infection is often referred to as the Amniotic Fluid Infection Syndrome.
This mechanism is typical of most bacterial infections, particularly
Group B streptococcus
and E. coli,
and of Herpes virus infection.
Although it was originally thought that pathogenic agents caused infection only after premature rupture of membranes occurred, it is now being recognized with greater frequency that microorganisms may breach intact membranes, and the resulting infection itself can cause premature labor.
Example: Group B Streptococcus:
Infection by Group B Streptococcus (GBS) is the prototype of Amniotic Fluid Infection Syndrome.
Epidemiology:
 The most common cause of neonatal sepsis in the U.S., but rarely a pathogen in adults.
 15-25% of females have asymptomatic colonization of their genitals by Group B strep ; only about 1% of their babies will acquire the infection through vertical transmission (from mother to neonate)
 Incidence of serious group B strep infection is 2-3 cases/1000 live births (approximately 7200 cases per year in the U.S.)
Clinical:
Symptoms of "Early onset" Group B streptococcus usually occur within the first few hours after delivery. These infants develop pneumonia, become bacteremic, and evolve into respiratory distress syndrome and shock. The mortality averages 50%. Fatal cases are marked by rapid deterioration and death, often within 24 hours.
Risk Factors:
The presence of GBS in the mother does not predict severe neonatal infection. Factors felt to predispose to infection are:
 Premature labor
 Prolonged rupture of membranes
 Heavy maternal colonization
 Obstetrical complications
Therapy:
Although streptococci are very sensitive to antibiotic therapy, the rapidity of the course of early onset GBS is such that by the time the patient becomes symptomatic, it is often too late for antibiotic therapy to be effective.
Pathology:
Gross:
 The lungs in GBS are generally congested and airless. They may appear full and be somewhat heavy (i.e., consolidated instead of atelectatic).
Micro:
 The appearance varies depending upon how long the child lives after the onset of infection.
 If death occurs within the first few hours one may see only marked congestion.
 Diagnosis in this case would depend on the clinical history and isolation of the organism in the blood. By 10-12 hours, often the pattern is one of fluffy hyaline membranes lining the terminal bronchioles and alveoli.
Clusters of gram positive cocci may be seen.
 Acute inflammatory infiltrates appear in the interstitium and membranes, differentiating this condition from HMD. By about 12 hours, the lungs may show widespread intra-alveolar infiltrates of neutrophils.
Direct Contact
Infection can be acquired as the fetus descends through the birth canal during delivery. This is what lends the rationale to doing cesarean sections in women with proven active Herpes simplex infections of the vagina.
Post-partum
These infections are acquired from the environment usually via the respiratory tract, gastrointestinal tract or skin. In addition the umbilical cord stump and circumcision site represent sources of access to pathogenic organisms; infections at these sites are skin pathogens, such as Staphylococcus aureus, or nosocomial organisms.
Pediatric AIDS
Epidemiology:
 The rate of of pediatric AIDS is increasing.
 Pediatric AIDS represents about 2% of total AIDS cases in the U.S.
 From the start of the AIDS epidemic through 1991, there were approximately 3400 cases of AIDS reported.
Definition:
Pediatric AIDS involves children less than 13 years old at the time of diagnosis.
Transmission:
 Perinatally-acquired (vertical transmission) accounts for approximately 80% of cases of pediatric AIDS. There are three mechanisms:
 Hematogenous, transplacental (in utero) (30-40% perinatally-acquired cases)
 Contact with blood and secretions at the time of delivery (60% of cases)
 T hrough breast milk. (This is fairly uncommon in the U.S. where HIV-positive women are discouraged from breast feeding.)
 Without medical internvention, approximately 25% of HIV- positive women will transmit the virus to their offspring.
 The drug zidovudine, when administered during pregnancy, had been shown to decrease the risk of HIV transmission from 25% to 8%.
 Transfusion of contaminated blood or coagulation factors.
 Since national screening of the blood supply was instituted, there has been a sharp drop in numbers of these cases.
 The more traditional routes for transmission of AIDS -- sexual contact and intravenous drug abuse -- are rare in children less than 13 years of age.
Clinical:
 Perinatally-acquired HIV infection in infants and young children is different than in adults in several ways:
 The incubation period before diagnosis of AIDS after infection with HIV is shorter in children (median 2 years vs. adult 8 - 11 years). This assumes that infection occurred at delivery. (NB: Some children do not develop sympotoms for 7 - 10 years).
 The course of the disease in children after diagnosis of AIDS is much shorter, with a median survival of 14 months
 . Fifty percent of children are dead by 3 years of age.
 Signs and symptoms of AIDS are different:
 The infant typically presents with
 failure to thrive,
 hepatosplenomegaly,
 diffuse lymphadenopathy,
 diarrhea,
 chronic thrush.
Pneumocystis carinii is a common pathogen in children with AIDS,
 but other opportunistic infections commonly seen in adults ( eg., cryptococcus, toxoplasmosis),
 and HIV-related malignancies are less common (lymphoma rare, Kaposis's sarcoma almost never).
 Multiple more routine bacterial infections predominate early in the disease.
 Typical types of infections are
 pneumonia,
 bone and joint infections,
 meningitis.
 Typical organisms are
 S. pneumoniae,
 H. influenza,
 and Salmonella.
 HIV encephalopathy is a common finding in children.
 It presents with failure to develop or loss of developmental milestones,
 progressive motor deficits,
 deterioration in intellectual function.
 Pathologically one sees
 microcephaly,
 micro-glial nodules,
 multinucleated cells,
 perivascular inflammation,
 perivascular mineralization of the basal ganglia.
 A pulmonary lesion known as lymphocytic interstitial pneumonitis/pulmonary lymphoid hyperplasia is fairly common in children, but is almost never seen in adults.
 This is a slowly progressive pulmonary disorder, characterized histologically by interstitial and/or peribronchial infiltrates of lymphocytes, plasma cells and immunoblasts. Epstein-Barr virus has been implicated in the pathogenesis.
Diagnosis:
 Diagnosis of HIV infection in children is also more challenging.
 A primary (congenital) immunodeficiency, or severe malnutrition must be ruled out in infants presenting recurrent infections.
 Serological diagnosis in the first year is difficult,
 since a positive serologic test may reflect the presence of passively transmitted maternal antibody (which takes months to disappear) rather than true fetal infection.
 In questionable cases, more definitive methods of diagnosis, such as viral isolation, detection of HIV nucleic acids by polymerase chain reaction, or demonstration of the p24 core antigen, may be necessary.
CONGENITAL ABNORMALITIES
 Major congenital malformations occur in approximately 3% of livebirths, and account for up to 20% of neonatal deaths. The actual incidence of congenital malformations is greatly underrepresented by the figure of 3% since many malformations terminate in spontaneous abortions.
 ETIOLOGY
 The causes of congenital malformations fall into several broad areas:
 Single mutant genes (7%). These are malformations in which familial involvement can be seen to fall into a standard Mendelian mode of inheritance (e .g., autosomal recessive, autosomal dominant, X-linked).
 Chromosomal abnormalities (6%), involving gross abnormalities of the chromosomes in either number or structure (e.g., trisomy 21 {Down's}, monosomy X {Turner's}). These are frequently associated with a constellation of external and visceral abnormalities.
 Environmental (5%) This includes known injurious agents such as infections, therapeutic drugs, drugs of abuse (such as alcohol), radiation, and environmental pollutants.
 Multifactorial (20%) This group reflects a postulated interaction between a genetic predisposition and an environmental insult which occurs at just the right time to cause defective organogenesis. One not infrequently sees malformations occurring in families at rates higher than the risk in the population in general, but lower than the rate seen in pure genetic inheritance. Congenital heart disease often falls into this category.
 Unidentified (62%) Note that this represents the majority of cases.
STRUCTURAL DISORDERS
Congenital Heart Disease
Introduction
Incidence:
Cardiac malformations occur at a rate of 8 per 1000 live births or 0.8%.
Malformation
|
% of all CHD at birth (i.e. the proportion of patients with CHD who have each lesion)
|
 |
 |
 Ventricular septal defect (VSD)
|
 31%
|
 Atrial septal defect (ASD)
|
 10%
|
 Persistent ductus arteriosus (PDA)
|
 10%
|
 Pulmonic stenosis
|
 7%
|
 Coarctation of the aorta
|
 7%
|
 Aortic stenosis
|
 6%
|
 Tetralogy of Fallot
|
 6%
|
 Transposition of the great arteries
|
 4%
|
 Truncus arteriosus
|
 2%
|
 Tricuspid atresia
|
 1%
|
 All others
|
 16%
|
Note: Bicuspid aortic valve is actually the most common CHD, affecting 1-2% of the entire population, but it is rarely recognized until adulthood.
Etiology:
 8% = Genetic
 5% Chromosomal:
 Trisomy 21 -- 50% present with CHD
 Trisomy 18 -- >90% present with CHD
 Trisomy 13 -- >90% present with CHD
 Turner's Syndrome -- 10-20% present with CHD
 3% Single mutant gene
 3% = Environmental
 Drugs: Alcohol, amphetamines, anticonvulsants, anticoagulants, lithalidamide, etc.
 Infections: e.g., Rubella (greatest incidence first trimester) - as many as 35% will present with CHD, particularly pulmonic stenosis and persistent ductus arteriosus
 Maternal Conditions : e.g., Diabetes
 Radiation
 Environmental insults must occur during development of the heart, which occurs early in pregnancy (3rd to 8th week), and hence the mother may not even know that she is pregnant while exposed to these risks.
 90% = Unknown
 The most likely etiology for most CHD is a multifactorial one, where a genetic predisposition in the fetus is acted upon by an environmental trigger occurring at the right time to produce a cardiac malformation.
Classification of Congenital Heart Malformations:
Acyanotic Defects (normal skin color)
 Outflow Obstruction:
 Examples:
 Coarctation of the aorta
 Aortic stenosis (AS)
 Pulmonic stenosis (PS) (with intact interventricular septum)
 Here the outflow obstruction results in a pressure overload on the left or right ventricle.
 Left to Right Shunts:
 Examples:
 Ventricular septal defect(VSD)
 Atrial septal defect(ASD)
 Patent ductus arteriosus(PDA)
 Atrio-ventricular septal defect(AVSD)
 Blood is shunted from the higher pressure left side of the heart to the lower pressure right side of the heart through an anatomic defect resulting in:
 -increased volume of blood entering the lungs
Cyanotic Defects (skin a blue color)
 Examples:
 Tetralogy of Fallot
 Transposition of the Great Arteries
 Hypoplastic Left Heart Syndrome
 Tricuspid Atresia
 Truncus Arteriosus
 These defects are effectively Right to Left Shunts, resulting in:
 -abnormal mixing of deoxygenated venous blood with the oxygenated blood coming from the lungs (resulting in cyanosis).
General Complications of Congenital Heart Disease:
Retardation of growth and development
This is more commonly seen in cyanotic CHD.
Congestive heart failure
CHF results from intolerable work loads imposed either from volume overload in the shunts or pressure overload in the outflow obstructions.
Bacterial endocarditis
Hemodynamic injury from turbulent flow over an anatomic shunt, a malformed valve, or prosthetic repair predisposes to bacterial seeding.
Paradoxical thromboemboli
Deep vein thromboses may embolize and enter the systemic circulation via right to left shunt and cause systemic infarcts.
Pulmonary hypertension
 In response to a volume overload in left-to-right shunts, chronic vasoconstriction leads to anatomic changes in the small muscular arteries of the pulmonary vasculature. This causes a fixed vascular resistance resulting in pulmonary hypertension. These anatomic changes are referred to as Pulmonary Hypertensive Angiopathy and are graded on a scale from I to VI depending upon the severity of changes.
Selected examples of these include (progressing in severity):
 Medial hypertrophy
 Intimal proliferation
 Plexiform lesions.
 In this last example there is a local dilatation of the artery; within the widened lumen there is a plexus of small vascular channels (arrow).
 The pulmonary pressures may increase to the point of equalizing with and then exceeding the systemic pressure, reversing the shunt to right-to-left (i.e. pink baby --> blue baby).
 "Post-tricuspid" lesions (e.g.,VSD, PDA, AVSD ) with higher pressure as well as greater volume of pulmonary blood flow cause earlier and more severe pulmonary hypertension than pre-tricuspid lesions (ASD) which are characterized by high volume alone.
 Some of the more common congenital heart lesions will be discussed in more detail.
Acyanotic Congenital Heart Disease
Outflow Obstruction
Coarctation of the Aorta
 Stenosis of the aorta usually occurring around the region of the ductus arteriosus.
 Pathology:
 The stenosis consists of a discrete intimal "shelf" and/or a hypoplastic segment of the isthmus of the aorta. The location of obstruction can often be divided into preductal or postductal.
 Preductal coarctation, proximal to the ductus arteriosus (pink arrow points to ductus arteriosus; red arrow points to hypoplastic isthmus; green arrow points to site of discrete coarctation)
 This image shows the internal view of a coarctation "shelf" (arrow) interposed between the aortic arch (to its left) and the descending aorta (to its right). The pulmonary artery and ductus arteriosus are spread by the clamps.
 In utero, circulation to the lower body is supplied via the ductus arteriosus. There is no collateral circulation developed.
 Clinical:
 With closure of the ductus arteriosus after birth, circulation to the lower body is compromised and the infant becomes acutely ill and shocky.
 Postductal coarctation, distal to the ductus arteriosus. In utero, circulation to the lower body is compromised, so collateral circulation develops and compensates for the coarctation. The lesion is often not apparent for some time after birth.
 Clinical:
 Physical exam:
 Blood pressure in the lower extremities is lower than the upper extremities. The child often presents with hypertension.
 Chest x-ray:
 Rib notching is seen, representing large, coiled, tortuous collateral vessels (internal mammary, intercostal)
 Aortogram:
 Reveals the coarctation (red arrow) and the tortuous collateral vessels.
Treatment for both types of coarctation:
Surgical intervention is required. The stenotic segment is removed and the aorta reanastomosed. In the preductal type, prostaglandins are given in an attempt to maintain patency of the ductus arteriosus prior to surgery.
Aortic Stenosis
 This condition is a congenital narrowing of the left ventricular outflow tract near the aortic valve. 75% of cases involve the valve itself.
 Pathology:
 The most common anomaly is a bicuspid, rather than tricuspid valve seen in this image in an operative picture This predisposes to secondary calcifications, causing stiffening and thickening of the valve in adult life, usually after the 5th decade
 When presenting in children, the most common anomaly is a maldevelopment and fusion of the cusps or single cusp.
 Clinical:
 Obstruction of outflow from left ventricle creates a pressure load, causing hypertrophy of the left ventricle which may ultimately lead to failure.
Pulmonic Stenosis
This condition is a congenital narrowing of the pulmonic out-flow tract.
Pathology:
The most common anomaly is a dome shaped pulmonic valve formed by fusion of all 3 cusps. Note that the commissures are still identifiable.
Clinical:
Obstruction of right ventricular outflow causes right ventricular hypertrophy.
Left to Right Shunts
Atrial Septal Defect (ASD)
 An abnormal communication between the left and right atria.
 The patent foramen ovale (PFO) is not an atrial septal defect since it remains closed under physiological conditions.
 The probe is inserted from the right atrium into a probe-patent foramen ovale. This lesion was clinically insignificant, as it should be in any patient with normal right atrial pressures.
 Pathology:
 Two major types of ASD's (We will not discuss less common forms):
 Ostium Secundum (ASD II) : over 70% of ASD's
 In this defect there is an opening in the region of what would be the fossa ovalis in the mid atrial septum. The atrial septum completely surrounds the defect .
 Ostium Primum (ASD I) : 5-15% of ASD's
 The red arrow points to the ostium primum defect. In this type of defect there is an opening just above the annulus of the tricuspid valve. There is no septal tissue inferior to it. It results from incomplete descent of the septum primum.
 The green arrow points to an ostium secundum defect.
Clinical:
 Often not found at birth because most isolated cases of ASD are asymptomatic in infancy and may not have a murmur (associated with increased pulmonary flow).
 Treatment:
 ASD's do not close spontaneously.
 It is recommended that all of these defects should be closed to prevent the late adolescent/early adult sequelae:
 Pulmonary hypertension
 Right ventricular overload with right sided heart failure
 Paradoxical embolisms
Ventricular Septal Defect
This is the most common congenital heart defect after bicuspid aortic valves.
Pathology:
May be classified according to location:
Perimembranous VSD : 65% of VSD's
3538
This is a perimembranous VSD as viewed from the left ventricle.
- found directly under the aortic valve in the left ventricle, and under the septal leaflet of the tricuspid valve in the right ventricle. The conducting system travels around the rim of the perimembranous VSD in the right ventricle. Surgical repair is more difficult since heart block must be avoided.
Muscular VSD : 35-40% of VSD's
4456
This is also a view from the left ventricle.
- The defect is completely surrounded by muscular septum
- There is less concern about the conducting system during surgical repair.
Course:
Spontaneous closure is common in infancy with an estimated 25-50% believed to close prior to age 4.
Small defects may be hemodynamically unimportant, just causing a murmur and requiring prophylactic antibiotics before some procedures (e.g. dental procedures). However large defects may lead to congestive failure in infancy and/or pulmonary hypertension and its sequelae.
Patent Ductus Arteriosus
4457
The ductus arteriosus is the fetal link between the pulmonary artery and aorta which allows circulatory bypass of the lung in utero. In this image, the root of the aorta is to the patientÍs right of the probe and the root of the pulmonary artery is to the patientÍs left. The descending aorta is extending vertically up to the top of the image. The arrow points to the short ductus arteriosus.
Physiological closure of the ductus arteriosis occurs in two ways:
Functional closure - occurs within 10-20 hours after birth, and this represents a constriction of the wall of the ductus
Anatomic closure - occurs within a few weeks to a couple of months to become the ligamentum arteriosum
A pathological problem is defined as no functional closure within a week or no anatomic closure within 3 months in a full term infant.
Clinical:
Pulmonary hypertension may result.
Treatment:
Surgical ligation of the ductus. This is one of the first malformations of the heart to be treated surgically. The operation is very effective.
Cyanotic Congenital Heart Defects
Tetralogy of Fallot
This is the most common cyanotic heart disease.
Pathology:
Tetralogy of Fallot is characterized by the following:
Pulmonic stenosis which almost always occurs below the pulmonic valve (subvalvular, infundibular) with or without a valvular component.
Right ventricular hypertrophy
4459 This image shows a prominent right ventricle and hypoplastic pulmonary artery (arrow) due to pulmonic stenosis.
Ventricular septal defect, typically large and perimembranous
4458 looking at the subaortic VSD (arrow) from the left ventricle
Overriding aorta, overriding the ventricular septum with part of the outflow coming directly from the right ventricle
Pathophysiology:
The pulmonic stenosis causes elevated right-sided pressures, so the flow across the large ventricular septal defect is right-to-left, causing cyanosis.
Clinical:
Physical exam: The child presents with cyanosis and shortness of breath on exertion.
Transposition of the Great Arteries
Pathology:
4460
The red arrow is on the aorta and the green arrow is on the pulmonary artery.There is discordance between the ventricles and arteries, with the pulmonary artery arising from the left ventricle and the aorta arising from the right ventricle. The base of the aorta is anterior to the pulmonary artery (normally posterior). The two fully parallel, rather than sequential, circulations, systemic and pulmonic, require the persistence of fetal shunts (patent ductus arteriosus, patent foramen ovale) or the presence of pathological shunts (VSD,ASD) for short-term survival.
Clinical:
This condition is an absolute medical emergency with a 98% mortality rate within the first few days of life if left untreated.
Treatment:
Surgical switch of either the great arteries themselves or of the venous return to the atria.
OTHER STRUCTURAL MALFORMATIONS
Congenital Diaphragmatic Hernia
Congenital diaphragmatic hernia results from a defect in the diaphragm due to an error in development.
Pathology:
2187
This defect is characteristically unilateral, posterior, and on the left. Through this defect the stomach , intestines, and occasionally the liver and spleen, are able to herniate and compress the contents of the left pleural cavity. With a large defect the heart and mediastinum are shifted to the right side where they compress the right lung as well.
25265
These infants present in severe respiratory distress with bowel sounds audible in the chest. Chest x-ray shows bowel gas pattern in the chest.
2188
The space occupying effect of the intestines in the chest during intrauterine life can interfere with the development of the lungs and may lead to pulmonary hypoplasia. Note that the left side is more hypoplastic than the right. This asymmetrical hypoplasia is typical of that caused by congenital diaphragmatic hernia. The success of corrective surgery ultimately depends on the degree of hypoplasia.
Hirschsprung's Disease (Aganglionic megacolon)
Definition: Congenital aganglionosis of the colon which may also involve portions of the small intestine.
Epidemiology:
 male:female = 4:1
 1 in 5,000 live births
 familial cases exist, with 4-6% of male siblings affected
 may be associated with Down's Syndrome
Pathogenesis:
Pathogenesis appears to be failure during the 5th to 12th weeks of gestation of the normal sequential migration from esophagus to anus of the primitive neuroblasts, derived from the neural crest, down to the gut to form the myenteric and submucosal plexus. Interruption at any point will result in complete absence of ganglion cells distally. Possible causes of disruption are infection , vascular compromise or genetic error.
Pathology:
Gross:
2666
The sequela of aganglionosis is a functional obstruction of the colon. The denervated segment is unable to participate in peristalsis and will go into spasm. The proximal innervated portion of colon becomes distended (megacolon) with intestinal contents and will hypertrophy in its efforts to overcome the obstruction.
Micro:
2477
Definitive diagnosis is by biopsy.
There are no ganglion cells in either the myenteric or submucosal plexuses. Additionally thicker preganglionic fibers often replace the usual thinner nerve twigs in these areas (in this image, the submucosal plexus). [see control Image at a higher power 2476].
Many of these fibers are cholinergic and contain increased amounts of acetylcholinesterase. When biopsies are evaluated for the presence of acetylcholinesterase, not only does one see an increased amount of staining in the fibers, but AchE-containing fibers are also present in regions where they are normally not found, such as in the muscularis mucosae.
Clinical:
The most common presentation of Hirschsprung's disease is delayed passage of meconium or frank obstruction in a neonate, although the disorder may not be suspected until an older infant presents with chronic constipation.
Therapy for Hirschsprung's disease is surgical resection of the denervated segment. A complication of an untreated case is enterocolitis with focal necrosis in the proximal megacolon.
Extrahepatic Biliary Atresia
Complete luminal obliteration or discontinuity of the hepatic or common bile ducts.
Epidemiology:
 1 in 10,000 live births
 Male=Female (in Caucasian population)
 rarely familial : has been associated with trisomy 17, trisomy 18, polysplenia, cardiovascular malformations.
Pathogenesis:
Thought to result from an exogenous insult occurring after initial normal development since:
Rarely seen in stillbirths.
Inflammation and fibrosis are often seen in the excised duct remnant.
Acholic stools may follow an initial short period of bile passage.Viral infection is the most likely etiology, probably initiating an inflammatory, fibrosing process in late gestation or early postnatal life. Reovirus 3 and less commonly, rubella and CMV, have been proposed.
Pathology:
Gross:
May be segmental, but in the majority of cases the entire duct system is obliterated.
Micro:
5035
Obliteration of the duct lumen by granulation tissue or fibrosis, often accompanied by an inflammatory infiltrate.
4462
Changes of the liver reflect the duration of disease. By two months, ductal and ductular proliferation affects every portal area accompanied by variable degrees of fibrosis.
Clinical:
Direct (conjugated) hyperbilirubinemia with jaundice, at or shortly after birth.
Natural History:
Untreated extrahepatic biliary atresia leads to biliary cirrhosis.
4461
Treatment:
Palliative surgery (the Kasai procedure, which anastomoses jejunum directly to the porta hepatis) should be done within 3 months to avoid irreversible hepatic fibrosis. Definitive therapy is liver transplantation.
Autosomal Recessive Polycystic Kidney Disease
There are two forms of polycystic kidney disease:
Adult Polycystic Kidney Disease Also known as Autosomal Dominant Polycystic Kidney disease, this form of genetic polycystic kidney disease generally presents in adults and will not be further discussed here.
Infantile Polycystic Kidney Disease Also known as Autosomal Recessive Polycystic Kidney Disease, this form of genetic polcystic kidney disease generally presents in infancy and childhood.
Pathology:
In situ: The kidneys are greatly enlarged.
1672
Gross:
2924
The enlarged kidneys retain their reniform shape and have smooth surfaces.
2925
On cut section the kidneys appear spongelike and contain innumerable elongated cysts which extend in radial fashion out from the medulla to the cortical surface.
Micro:
2916
The cysts represent dilated collecting tubules. Between the cysts can be seen normal glomeruli and tubules.
2910
A virtually invariable associated finding is the presence of tortuous, dilated bile ducts in the liver, which are accompanied by portal fibrosis, giving this finding the name congenital hepatic fibrosis.
Clinical:
Autosomal recessive polycystic kidney disease (ARPKD) is fairly rare. Typically it presents at birth with huge, bilateral abdominal masses. (See 1672 above)
ARPKD, which is associated with oliguria, also causes oligohydramnios in utero. Oligohydramnios is a deficiency of amniotic fluid. Later in gestation, fetal urine is a large component of amniotic fluid. Adequate amounts of amniotic fluid are required for proper lung growth for at least 2 reasons:
amniotic fluid protects the fetus' thorax from being compressed by the uterus, which would physically restrict pulmonary growth,
it appears that a normal amount of amniotic fluid is required to maintain a proper equilibrium with intrapulmonary secretions, which seem to be required for normal pulmonary growth. So a secondary effect of ARPKD is symmetrically hypoplastic lungs.
15305
In fact the natural history of ARPKD is for death to occur within a few days from respiratory insufficiency.
Less extensive renal disease is compatible with longer survival, but in these cases progressive hepatic fibrosis may cause more serious clinical problems.
Therapy:
The only definitive therapy for the renal disease is transplantation, for it has been shown that cysts will not develop in the transplanted kidney.
METABOLIC DISORDERS
Phenylketonuria
The inborn errors of metabolism are the result of genetic mutations. The prototypic example of this category of disease is phenylketonuria (PKU), which results from a well defined enzymatic defect.
Etiology:
 Inborn error of amino acid metabolism
 Autosomal recessive inheritance
 Ancidence 1 in 15,000
 Approximately 1% of the population carries the gene
Phenylalanine + O2
|
------------------->
|
Tyrosine + H2O
|
 |
Phenylalanine
hydroxylase
|
 |
 Results from an almost total lack of the enzyme phenylalanine hydroxylase, which converts phenylalanine to tyrosine
 As a result of this metabolic block, phenylalanine and its metabolites accumulate in the blood and urine.
Clinical:
 Virtually asymptomatic in the neonatal period with no recognizable morphologic features
 Severe neurologic damage and mental retardation may begin to develop within a few months
 Direct or indirect toxic effects of phenylalanine or one of its metabolites presumably responsible for neurologic deterioration
 Every newborn is screened for elevated levels of phenylalanine in the blood
Therapy:
If the diagnosis of PKU is confirmed, the infant is given a low phenylalanine diet, which will prevent serious neurologic injury if initiated within the first few weeks of life.
Cystic Fibrosis
Cystic fibrosis (CF) is a systemic disorder of exocrine glands involving both mucus-secreting and eccrine sweat glands throughout the body. The defects in CF involve electrolyte abnormalities and abnormally thick mucous that can cause obstruction of excretory ducts with subsequent parenchymatous destruction of organs, most commonly the lungs and pancreas.
Epidemiology:
 U.S., whites : 1:2,000 live births, blacks : 1:17,000 live births
 The most common fatal autosomal recessive disease affecting the Caucasian population
Pathophysiology:
Pathophysiological lesion is a defect in c-AMP-regulated chloride transport across apical membranes of affected epithelial cells.
Sweat glands:
The impairment of transport is failure of resorption of chloride through the duct epithelial cells. The result is a pathologically elevated level of chloride in the sweat. This serves as the basis for the pilocarpine sweat test in which a value of sweat chloride above 60 meq/L (normal being 10 meq/L) along with symptoms consistent with CF is essentially diagnostic.
Respiratory airway and pancreatic duct cells:
In these systems there is a failure to transport chloride into the lumen of the airways and ducts. This is coupled with increased sodium resorption, the combination of which greatly decreases the water content in the lumens of these systems resulting in thick, viscid secretions which are difficult to clear. In both organ systems the viscid secretions lead to obstruction with parenchymal destruction. In the lungs the obstruction also predisposes to infection; these patients in particular show a propensity to become infected with mucoid strains of Pseudomonas.
Etiology:
 Autosomal recessive inheritance
 The CF gene has been localized to a single locus on the long arm of chromosome 7.
 The gene product is a protein called CF transmembrane conductance regulator (CFTR), which is a chloride channel that fails to be activated by cAMP.
 Over 300 CF mutations that have been identified. The most common mutation, found in approximately 70% of cases, is a deletion of a 3 base pair which causes elimination of phenylalanine in the protein product. This mutation is called delta F508 (so called because it occurs at the 508th amino acid). Those homozygous for this mutation will have the most severe form of the disease.
Pathology:
This disease is characterized, pathologically, by thick, viscid secretions in mucous glands, leading to proximal obstruction and parechymal destruction. Numerous organ systems are affected in the body.
Lungs:
5030
This shows plugging of the submucosal tracheal mucous glands and ducts. The bronchioles often become distended with thick mucus, often associated with marked hyperplasia and hypertrophy of the mucus-secreting cells.
2697
Atelectasis and emphysema ensue. Superimposed infections give rise to severe chronic bronchitis and bronchiectasis, and in many cases lung abscesses develop.
Pancreas:
2483
Early on there is cystic dilatation and direct plugging of the exocrine glands and ducts with insipissated eosinophilic secretions. Acinar atrophy with rupture, inflammation and progressive fibrosis ensues. Later there is fatty and fibrous replacement of the exocrine pancreas with relative sparing of the islet cells, although they may ultimately become involved as well.
Liver:
Liver involvement follows the same basic pattern of pancreatic involvement. Early on there is bile duct hyperplasia with mucus plugging of the bile canaliculi. Focal biliary cirrhosis is characteristic. 5031 Diffuse hepatic nodularity is seen only in a small percentage of patients.
Other:
The salivary glands frequently show glandular dilatation and atrophy. Obstruction of Wolffian duct derivatives, i.e., the epididymis and vas deferens, leads to azoospermia and infertility in 95% of the males who survive to adulthood.
Clinical:
15% of infants with CF present with meconium ileus 4465, a condition in which viscous meconium impacts in the terminal ileum causing obstruction with the risk of perforation and peritonitis.
Typically CF is discovered between age 2 and 12 months when the child presents with symptoms of malabsorption (malodorous steatorrhea and malnutrition) secondary to pancreatic insufficiency.
If the infant or child survives long enough, chronic cough, obstructive pulmonary disease and persistent pulmonary infections develop and are responsible for 80 to 90% of deaths.
Therapy:
Attention to the nutritional status of the patient with supplements of pancreatic enzymes and fat-soluble vitamins, as well as antibiotic control of pulmonary infections with physical therapy can prolong the survival of these patients if diagnosed early. 50% of patients with CF now survive beyond age 25. An active line of current research is gene therapy, whereby normal DNA is introduced into the repiratory epithelia by a recombinant viral vector.
PEDIATRIC TUMORS
Introduction
Incidence:
There are approximately 1,700 cancer deaths per year in the U.S. in children under the age of 15 years. Although fairly rare, cancer is the second most common killer, and the top killer from disease in childhood. The most common malignancies in U.S. children are leukemias, tumors of the central nervous system, lymphomas, neuroblastoma, sarcomas (e.g., embryonal rhabodomyosarcoma), and Wilms tumor.
INCIDENCE OF MALIGNANT TUMORS IN U.S. CHILDREN
Diagnosis
|
Incidence (New cases/yr)
|
 |
 |
Leukemia
|
2000
|
CNS
|
1230
|
Lymphoma
|
780
|
Neuroblastoma
|
525
|
Sarcomas
|
420
|
Wilms
|
410
|
Bone Tumors
|
320
|
Retinoblastoma
|
200
|
(from Young, et. al., Cancer 58:598, 1986)
Taken together leukemias and lymphomas constitute nearly one-half of all pediatric tumors. Many of these malignancies, particularly leukemias, neuroblastomas, Wilms tumor, and retinoblastoma, will present before the age of 5. Others, such as bone tumors, lymphomas and testicular tumors, tend to present with a later peak after the age of 10.
Adult versus Pediatric Cancer:
Incidence:
The magnitude of pediatric malignancy is much less -- compare annual mortality of 1,700 children vs. 477,000 adults.
Tumor type:
Most adult malignancies tend to be epithelial-derived, i.e., carcinomas. A large proportion of pediatric cancers are termed"embryonal", where the appearance of the tumor seems to recapitulate embryological development. The most common adult cancers, e.g., lung, breast, prostate, bladder, are extremely rare in childhood.
Prognosis:
Pediatric cancers are generally more responsive to therapy than adult cancers. Considering all pediatric malignancies together, the survival rate falls around 60%. Postulated reasons for this better prognosis include the difference in tumor type and perhaps an increased ability of children to tolerate therapy.
Special predispositions:
There are certain conditions peculiar to childhood which increase the susceptibility of developing cancer.
Chromosomal and genetic syndromes : more than 200 genetic syndromes are associated with an increased susceptibility.
These include:
 Down syndrome (Trisomy 21) -- acute leukemia
 Bloom's syndrome (increased chromosomal fragility in culture) -- leukemia, lymphoma, carcinoma
 Deletion 13q -- retinoblastoma
Congenital Immunodeficiency syndromes :
 Wiscott Aldridge syndrome -- lymphoma
 Agammaglobulinemia -- acute lymphocytic leukemia
Special considerations: Given the young age of the patient and the high survival rate, one has to worry about effects of therapy on the future of the survivor.
Toxicity of treatment may:
Have effects on future growth
Increase the risk of second malignancies and
Interfere with fertility
Small, Round Blue Cell Tumors:
Many of the solid tumors of childhood fall into a category referred to by pathologists as the "small round blue cell tumor." This refers to the relatively homogeneous, densely cellular appearance. The tumor cells are characterized by small size, paucity of cytoplasm, and dark, round nuclei (which stain dark blue on H&E). This appearance reflects the "embryonal" origin of many of these tumors.
COMMON SMALL, ROUND "BLUE" CELL TUMORS OF CHILDHOOD
4467 Neuroblastoma
2659 Wilms tumor
1213 Lymphoma
5022 Embryonal Rhabdomyosarcoma
2784 Medulloblastoma
3711 Ewing's sarcoma
3015 Small cell osteosarcoma
Despite histological similarities, therapy and prognosis differ. One must utilize the clinical information about site, age, presentation, and laboratory data to make the diagnosis. Other techniques available to aid in an uncertain diagnosis of "small cell tumor of childhood" are electron microscopy, immunohistochemistry, tissue culture, cytogenetics and molecular genetics.
Leukemia
General:
Leukemia is the most common malignancy in children, and acute lymphocytic leukemia (ALL) is by far the most common type of leukemia in children.
LEUKEMIA IN CHILDHOOD
|
Acute Lymphocytic
|
80-85%
|
Acute Non-Lymphocytic
|
15%
|
Chronic Myelogenous
|
1-3%
|
Chronic Lymphocytic
|
0%
|
Virtually all childhood leukemias are acute, and the majority are lymphocytic. The most common adult leukemia, CLL, virtually never appears in childhood.
Clinical:
The peak incidence of ALL occurs between 2 and 6 years of age.
The child usually presents with fever, pallor, petechiae or purpura, bone pain.
Hepatosplenomegaly, is present in about two-thirds of patients, and lymphadenopathy in about one-half.
Pathology:
1191
The peripheral blood smear will show predominantly blast forms in the peripheral blood. Pancytopenia with a normochromic, normocytic anemia may be apparent.
1190
The bone marrow aspirate will show a monotonous population of blast forms.
1189
Bone marrow biopsy will show replacement of the marrow with blast forms.
Classification of acute leukemia is aided by biochemical markers (e.g., Tdt), monoclonal antibodies for immunotyping (e.g., pre-B cells, pre-T cells, or so-called common ALL or CALLA), and cytogenetic analysis.
 Greater than 90% of childhood ALL is Tdt positive.
 The majority of childhood ALL expresses CALLA.
 Not only do the monoclonal antibodies help in the differential diagnosis with acute non-lymphocytic leukemia, but in the ALL group, some of these categories seem to have prognostic significance.
Course:
A long-term course of ALL usually shows widespread dissemination with liver and spleen involvement. Meningeal involvement is a common form of relapse. However with current therapy the survival from ALL has shown a spectacular improvement from 4% in 1960-1963 to 73% in 1977-1980.
Lymphoma
General:
In contrast to the leukemias:
 Lymphoma in children infrequently occurs before the age of 5 years old.
 The peak incidence of Non-Hodgkin's Lymphoma (NHL) is 7 to 11 years old,
 Hodgkin's Disease most typically occurs after the age of 10.
However, like ALL:
 The prognosis of childhood lymphoma is generally good.
 70% 5-year survival for NHL
 85% 5-year survival for Hodgkin's Disease.
LYMPHOMA IN CHILDHOOD
|
 |
Incidence
|
Non-Hodgkin's Lymphoma
|
 |
Lymphoblastic
|
20%
|
Undifferentiated (Burkitt's)
|
25%
|
Large cell, diffuse
|
10%
|
 |
 |
 |
55%
|
Hodgkin's Lymphoma
|
 |
Lymphocyte predominant
|
5%
|
Nodular sclerosis
|
30%
|
Mixed cellularity
|
9%
|
Lymphocyte depleted
|
1%
|
 |
 |
 |
45%
|
Non-Hodgkin's Lymphoma:
The major types of childhood NHL tend to be "high grade" lymphomas. Follicular patterns are virtually never seen in children.
 |
Lymphoblastic
|
Burkitt's
|
 |
 |
 |
Primary Site
|
Chest
|
Abdomen
|
Marrow/CNS Involvement
|
Common
|
Uncommon
|
Age
|
Older
|
Younger
|
Phenotype
|
T cell (80%)
|
B cell
|
Pathology:
Lymphoblastic:
4605
Cytologically, these cells are indistinguishable from those of ALL. Note the rounded nuclei with delicate, dusty nuclear chromatin and indistinct nucleoli. Mitoses are usually common.
Tdt positive in greater than 90% of cases
This lymphoma characteristically presents above the diaphragm and is frequently associated with a mediastinal mass.
Burkitt's:
3631
The cells are monotonous, small and non-cleaved. The chromatin is irregular and often coarse. One or more prominent nucleoli are present. Mitoses are numerous. On low power there is a "starry-sky" appearance due to macrophages engulfing nuclear debris.
This is a B cell lymphoma.
This has a characteristic 8;14 translocation.
Although in Africa children present most often with Burkitt's lymphoma in the jaw or orbit, in the U.S. Burkitt's lymphoma presents most often in the abdomen. Also, the association with Ebstein Barr virus is less common in U.S. Burkitt's.
Clinical:
In contrast to NHL in adults, childhood NHL is more likely to:
Present in an extranodal site
Be rapidly proliferative
Present with wide spread hematogenous dissemination
Undergo leukemic transformation:
3632
It is often impossible to determine whether involvement of the marrow is primary or secondary. Such disease is called lymphoma/leukemia and is treated as one entity.
Hodgkin's Lymphoma:
Like Hodgkin's disease in adults, Hodgkin's in children:
Has a predominance of the Nodular sclerosing type 683 and 687.
Tends to present with lymph node involvement, most commonly in the neck
Progresses slowly by contiguous spread
Unlike adults, children:
Present at an earlier stage of disease
Less commonly have constitutional symptoms.
Neuroblastoma
Neuroblastoma is a poorly differentiated tumor arising from primitive neural crest cells that normally give rise to the adrenal medulla and sympathetic ganglia.
Epidemiology:
 7-10% of all childhood malignancies
 one of the most common solid malignant tumors in children and the most common congenital tumor
 most occur < 5 years of age
Pathology:
Gross:
4466
Typically seen within the adrenal medulla. The surface is generally lobulated and soft with a reddish-gray appearance on cut surface. Areas of hemorrhage, necrosis and cyst formation are typical with increasing size, and gross calcification is evident in 40-50%.
Micro:
4467
This tumor is typical of the small, round blue cell tumor with sheets of undifferentiated cells (with an indistinct neuropil background seen here). Some evidence of neural differentiation,neurofibrillary stroma, and 3540 pseudorosette formation (Homer-Wright pseudorosettes), is helpful in diagnosing these tumors as neuroblastomas. Other diagnostic tools include demonstrating the presence of neurosecretory granules on EM and the demonstration of neuron specific enolase and other markers with immunoperoxidase stains.
Clinical:
The clinical manifestations depend upon the site of primary disease and the extent of spread.
 2/3 arise within the abdomen, the majority of which arise within the adrenal medulla.
 1/5 arise within the posterior mediastinum along the sympathetic ganglia.
 In a small but significant percentage, the primary site is never established.
Children with neuroblastoma may present with a mass or appear systemically ill or present with signs of metastatic disease. Characteristically neuroblastoma metastasizes early, showing a special predilection for:
 bone
 lymph nodes
 liver
 bone marrow
 subcutaneous tissue.
Laboratory :Catecholamines and their metabolites are elevated in the urine in more than 90% of patients.
Prognostic factors include:
 age (younger age [particularly < 1.5 years] more favorable)
 site
 stage
 the level of serum biochemical markers ferritin and neuron-specific enolase (elevated levels correspond with poorer prognosis)
 N-myc oncogene: Increased amplification of the n-myc oncogene is inversely related to good prognosis
 cytogenetics (aneuplod tumors have better prognosis)
 histology (a grading system called the Shimada classification has been correlated with prognosis).
Course:
There are two possible courses taken by neuroblastomas:
Widespread dissemination (majority)
Spontaneous regression (3-7%) either by necrosis, or spontaneous or therapy-induced differentiation, possibly with complete maturation to a benign ganglioneuroma
2114
Although there has been some improvement in survival, the results of therapy are still disappointing with an overall 56% survival.
Wilms Tumor
Wilms tumor is a poorly differentiated renal tumor arising from embryonic metanephric blastema.
Epidemiology:
 mean age 3-4 years old (80% < 5 years)
 second commonest intra-abdominal malignancy
 associated disorders may be aniridia, hemihypertrophy, and genitourinary anomalies (hypospadias, cryptorchidism, horseshoe kidneys, etc)
Pathology:
Gross:
3541
This tumor usually presents as a solitary, round, intra-renal tumor with a sharply defined pseudo-capsule. Color is characteristically pale tan or gray on cut section (in contrast to the yellow color of renal adenocarcinoma). Unlike neuroblastoma, Wilms tumor is typically not calcified and is bilateral in 5% of cases.
Micro:
The classic histologic description is that of a triphasic appearance, comprising:
Blastema - primitive, undifferentiated cells
2659
Epithelial differentiation -
tubular 5039 and glomerular 2660
Stroma
This triphasic appearance is not essential for the diagnosis as there are monophasic and biphasic forms. The monophasic blastema may create problems in differential diagnosis. Unlike neuroblastoma, EM and immunoperoxidase studies are nonspecific and not helpful in the positive diagnosis of Wilm's tumor. The only histologic feature which is associated with poor prognosis is anaplasia. This is defined as marked nuclear enlargement and hyperchromatism with multipolar mitotic figures.
5037
Clinical:
These children typically present with an asymptomatic abdominal mass that has been identified by the patient's parent or doctor.
Course:
 initially spreads locally through the renal capsule
 shows a propensity to extend into the renal vein and inferior vena cava
 metastasizes preferentially to regional lymph nodes and lung. Bone marrow involvement is unusual.
Wilms tumor is another pediatric malignancy which has shown great advances in therapy. The prognosis of patients with Wilms tumor is excellent for those with early stages, and good even for those with more advanced stages, yielding an overall survival of 84%.
|