Diseases of infancy and childhood

Question 1

Major causes of death in infancy and childhood in the first 12 months of life

Answer 1

• congenital anomalies
• short gestation or prematurity
• low birth weight
• sudden infant death syndrome (SIDS)

Question 2

Leading cause of death in the two age groups - 1 to 4 years and 5 to 9 years.

Answer 2

unintentional injuries resulting from accidents

Question 3

Congenital anomalies

Answer 3

• anatomical defects that are present at birth
• most common cause of mortality in the first year
• contribute significantly to morbidity and mortality throughout the early years of life

Question 4

Malformations

Answer 4

• primary errors of morphogenesis
• (+) of intrinsically abnormal developmental process
• single gene or chromosomal defect
• more commonly multifactorial in origin

Question 5

Disruptions

Answer 5

• result from secondary destruction of an organ or body region that was previously normal in development
• arise from an extrinsic disturbance in morphogenesis

Question 6

Amniotic bands

Answer 6

• rupture of amnion with resultant formation of “bands”
• not heritable
• not associated with risk of recurrence in subsequent pregnancies.
• may be caused by environmental agents

“Bands”
- encircle, compress, or attach to parts of the developing fetus

Question 7

Deformations

Answer 7

• extrinsic disturbance of development

- a common problem

Question 8

Fundamental to pathogenesis of deformation

Answer 8

• localized or generalized compression of the growing fetus by abnormal biomechanical forces

Question 9

Most common underlying factor of deformation

Answer 9

• uterine constraint

Question 10

Factors that increase the likehood of excessive compression of the fetus

Answer 10

• maternal factors

- fetal or placental factors

Question 11

Maternal factors

Answer 11

• first pregnancy
• small uterus
• malformed (bicornuate) uterus
• leiomyomas

Question 12

Fetal or placental factors

Answer 12

• oligohydramnios
• multiple fetuses
• abnormal fetal presentation

Question 13

Sequence

Answer 13

• a cascade of anomalies triggered by one initiating aberration.

Question 14

Oligohydramnios

“Potter” sequence

Answer 14

• decreased amniotic fluid

Question 15

Causes of oligohydramnios

Answer 15

• chronic leakage of amniotic fluid d/t rupture of the amnion
• uteroplacental insufficiency secondary to maternal hypertension or severe toxemia
• renal agenesis of fetus

Question 16

Major constituent of amniotic fluid

Answer 16

• fetal urine

Question 17

Classic phenotype of oligohydramnios

Answer 17

• results from fetal compression associated with significant oligohydramnios

Presentation

• flattened facies
• positional abnormalities of hands and feet
• hips may be dislocated
• lungs are frequently hypoplastic (cause of fetal demise)
• amnion nodosum are frequently present

Question 18

Malformation syndrome

Answer 18

• constellation of congenital anomalies
• believed to be pathologically related
• most often caused by a single etiologic agent

Question 19

Agenesis

Answer 19

• complete absence of an organ and its associated primordium

Question 20

Aplasia

Answer 20

• absence of an organ d/t failure of growth of the existing primordium

Question 21

Atresia

Answer 21

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

Question 22

Hypoplasia

Answer 22

• incomplete development or decreased size or an organ with decreased number of cells

Question 23

Hyperplasia

Answer 23

• enlargement of an organ d/t increased number of cells

Question 24

Hypertrophy

Answer 24

• an abnormality in an organ or tissue d/t increase in size of individual cells

Question 25

Dysplasia

Answer 25

- abnormal organization of cells

Question 26

3 major categories of common known causes of congenital anomalies

Answer 26

- genetic - environmental - multifactorial

Question 27

Genetic causes

Answer 27

- all chromosomal syndromes

Question 28

Most chromosomal disorders

Answer 28

- arise during gametogenesis | - not familial

Question 29

Holoprosencephaly

Answer 29

- MC developmental defect of the forebrain and midface

Question 30

Hedgehog signaling pathway

Answer 30

- plays a critical role in the morphogenesis in holoprosencephaly

Question 31

Loss of function mutations of individual components of Hedgehog signaling pathway

Answer 31

- recurrent holoprosencephaly

Question 32

13-cis- retinoic acid

Answer 32

- used in the treatment of severe acne

Question 33

Thalidomide

Answer 33

- used as a tranquilizer | - causes high incidence of limb malformations

Question 34

Alcohol

Answer 34

- important environmental teratogen

Question 35

Fetal alcohol syndrome

Answer 35

Combination of: - prenatal and postnatal growth retardation - facial anomalies (microcephaly, short palpebral fissures, maxillary hypoplasia) - psychomotor disturbances