Diseases of infancy and childhood

Question 1

secondary destruction of an organ or body region that was previously normal in development

Answer 1

Disruption

Example: Amniotic band syndrome

Question 2

consequence of an intrinsically abnormal development process

Answer 2

Malformation

Examples: Holoprosencephaly, spina bifida, anencephaly, cleft lip etc

Question 3

localized or generalized compression of the growing fetus by abnormal biomechanical forces, leading eventually to a variety of structural abnormalities.

Answer 3

Deformation

Clubfeet

Question 4

cascade of anomalies triggered by one initiating aberration

Answer 4

Sequence

Example: Potter (oligohydramnios) sequence

Question 5

renal agenesis–>oligohydramnios–>fetal compression–>pulmonary hypoplasia, club feet, flt nose, recessed chin, epicanthal folds, low-set ears

Answer 5

Potter sequence

Question 6

complete absence of an organ and its associated primordium

Answer 6

Agenesis

Example: renal agenesis

Question 7

absence of an organ due to failure of growth of the existing primordium

Answer 7

aplasia

Example: Thymic aplasia

Question 8

absence of an opening, usually of a hollow visceral organ.

Answer 8

atresia

Example: Esophageal atresia

Question 9

incomplete development or decreased size of an organ with decreased numbers of cells

Answer 9

hypoplasia

Example: Hypoplastic right heart syndrome

Question 10

Microcephaly, long smooth philtrum, thin upper lip, epicanthal folds, hypertelorism
Increased incidence of VSD

Answer 10

Fetal alcohol syndrome

Question 11

2 neonatal problems associated with maternal diabetes mellitus

Answer 11

• Neonatal respiratory distress syndrome (NRDS)
• hypoglycemia
• transposition of the great vessels (TGA)
• macrosomia

Question 12

Morphology of neonatal respiratory distress syndrome (NRDS)

Answer 12

hyaline membranes lining the respiratory bronchioles, alveolar ducts, and alveoli

Question 13

composition of hyaline membranes in NRDS

Answer 13

fibrin + cell debris from necrotic type II pneumocytes

Question 14

Test for fetal lung maturity

Answer 14

Lecithin to sphingomyelin ratio

> 2 is considered mature

Question 15

Pathophysiology of NRDS

Answer 15

Decreased surfactant –>increased surface tension, decreased compliance, increased recoil.

Question 16

Cause for formation of hyaline membranes in NRDS

Answer 16

Leakage of plasma into alveoli from endothelial and epithelial cell damage secondary to pulmonary hypoperfusion

Question 17

signs of respiratory distress in NRDS

Answer 17

nasal flaring, subcostal retraction, tachypnea, expiratory grunting

Question 18

2 complications of NRDS

Answer 18

1. retrolental fibroplasia (retinopathy of prematurity)
2. Bronchopulmonary dysplasia

Question 19

2 morphologic changes in bronchopulmonary dysplasia

Answer 19

1. decreased alveolar septation
2. dysmorphic capillary configuration

Question 20

Retinopathy of prematurity pathophysiology

Answer 20

decreased VEGF–>endothelial cell apoptosis–>retinal ischemia–> upregulation of VEGF–>fibrovascular mass behind the lens.

Question 21

greatest risk factor for necrotizing enterocolitis

Answer 21

prematurity

Question 22

triad of necrotizing enterocolitis

Answer 22

abdominal distension+bloody stools+ pneumatosis intestinalis

linear radiolucencies parallel to the bowel wall

Question 23

Morphologic findings of NEC

Answer 23

• transmural coagulative necrosis
• submucosal gas bubbles

Question 24

This finding is seen in which condition?

Answer 24

Necrotizing enterocolitis

submucosal gas bubbles

Question 25

3 major factors in pathogenesis of NEC in premature neonates

Answer 25

1. Immature intestinal mucosal barrier 2. Immature immune system 3. Microbial dysbiosis

Question 26

2 complications of Rh hemolytic disease of the newborn

Answer 26

Kernicterus Hydrops fetalis

Question 27

# Identify this condition Rh+ baby unconjugated hyperbilirubinemia Lethargy, high-pitched cry, opisthotonus, seizures

Answer 27

Kernicterus

Question 28

Edematous appearance in hydrops fetalis is due to which 2 factors

Answer 28

cardiac failure--> increased hydrosatic pressure Liver injury-->decreased albumin-->reduced oncotic pressure

Question 29

Why is ABO hemolytic disease of newborn associated with minimal jaundice?

Answer 29

1. Neonatal red cells express blood group antigens A and B poorly. 2. Many cells other than red cells express A and B antigens and thus absorb some of the transferred antibody

Question 30

most common CFTR gene mutation

Answer 30

deletion of three nucleotides coding for phenylalanine at amino acid position 508

Question 32

Consequence of deletion of three nucleotides coding for phenylalanine at amino acid position 508 in the CFTR gene

Answer 32

abnormal protein folding, impaired post-translational processing

Question 33

Important clinical consequence of hypertonic sweat in cystic fibrosis

Answer 33

hyponatremia due to excessive salt wasting

Question 34

Basis of sweat chloride test

Answer 34

In sweat gland ducts, Mutated CFTR--> decreased reabsorption of sodium chloride--> hypertonic sweat--> positive sweat chloride test

Question 35

Mechanism of dehydration of mucus lining airways in cystic fibrosis

Answer 35

Mutated CFTR loss/reduction of chloride secretion into the lumen and increased active luminal sodium absorption -->increased passive water reabsorption from the lumen--> lowered water content of the surface fluid layer coating mucosal cells (dehydration), defective mucociliary transport--> viscous secretions

Question 36

Nasal transepithelial potential difference result in cystic fibrosis

Answer 36

The higher relative amounts of negatively charged chloride on the epithelial surface result in a **more negative** transepithelial voltage difference.

Question 37

This pulmonary condition is common in cystic fibrosis

Answer 37

Bronchiectasis

Question 38

Cause of small bowel obstruction in neonates with cystic fibrosis

Answer 38

Meconium ileus | viscid meconium -->obstructs the terminal ileum

Question 39

Clinical presentation of meconium ileus

Answer 39

Abdominal distension, bilious emesis, failure to pass meconium in the first 12-24 hours

Question 40

Radiologic findings of meconium ileus

Answer 40

dilated bowel loops, soap bubble appearance of inspissated meconium in the RLQ, microcolon

Question 41

Cause for pancreatic insufficiency in cystic fibrosis

Answer 41

mutated CFTR-->abnormal bicarbonate transport-->decreased luminal pH-->increased mucin precipitation and plugging of ducts.

Question 42

2 clinical consequences of pancreatic involvement in cystic fibrosis

Answer 42

* chronic pancreatic insufficiency * diabetes mellitus

Question 43

What does low fecal elastase in an individual with cystic fibrosis indicate?

Answer 43

chronic pancreatic insufficiency

Question 44

Why does male infertility occur in cystic fibrosis?

Answer 44

Congenital absence of bilateral vas deferens leading to obstructive azoospermia

Question 45

Underlying defect in primary ciliary dyskinesia

Answer 45

Dynein arm defect → abnormal ciliary motion & impaired mucociliary clearance

Question 46

triad of situs inversus, chronic sinusitis, and bronchiectasis

Answer 46

Kartagener syndrome

Question 47

Definition of SIDS

Answer 47

sudden death of an infant under 1 year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history

Question 48

most compelling hypothesis for mechanism of SIDS

Answer 48

delayed development of “arousal” and cardiorespiratory control

Question 49

Which sleeping position is advocated to reduce the incidence of SIDS?

Answer 49

Supine

Question 50

Which maternal risk factor is said to increase the risk of occurence of SIDS by two-fold?

Answer 50

Maternal smoking