Infancy Lecture

Question 1

Infant Respiratory Distress Syndrome

Answer 1

66% of incidence in infants born at less than 28 weeks

- Primarily in the immature lung and is associated with a deficiency of pulmonary surfactant

Question 2

Causes of Infant RDS

Answer 2

Aspiration during birth of blood and amniotic fluid
Brain injury with failure in the central respiratory center
Asphyxiating coils of umbilical cord around neck
Excessive maternal sedation
Idiopathic RDS (deficiency in surfactants)

Question 3

Prematurity leads to what starting what cascade?

Answer 3

Reduced surfactant synthesis, storage and release –> decreasing alveolar surfactant and increasing aveolar surface tension –> either uneven perfusion or hyperventilation –> hypoexmia + CO2 retention –> acidosis –> pulmonary vasoconstriction (bc lack of pressure) –> pulmonary hypoerfusion –> either endothelial damage or epithelial damage –> plasma leakage into alveoli –> fibrin + necrotic cells (hyaline membrane) –> increased diffusion gradient –> hypoxemia + CO2 retention

Question 4

Erythroblastosis fetalis

Answer 4

• Caused by ABO incompatibility or by Rh incompatibility

Question 5

ABO incompatibility disease?

Answer 5

Limited to babies with A or B antigens whose mothers have type O blood

Question 6

Rh incompatibility disease?

Answer 6

Occurs in babies with RBCs having Rh antigen (Rh +ve babies) and mothers who do not contain Rh antigen (Rh -ve mothers)

Question 7

Father A
Mother O
Child A
Disease?

Answer 7

YES

Question 8

Father B
Mother O
Child B
Disease?

Answer 8

YES

Question 9

Father Rh+
Mother Rh-
Child Rh+
Disease?

Answer 9

YES

Question 10

What happens when the antibody attaches to the Rh+ erythrocytes of the fetus?

Answer 10

Removal and destruction –> anemia –> extramedullary hematopoiesis or cardiac decompensation –> hydrops OR hemoglobin degradation –> bilirubin –> jaundice or kernicterus

Question 11

What are the causes and symptoms of erythroblastosis fetalis?

Answer 11

First pregnancy, Rh incompatibility is not a problem because very few fetal blood cells reach the mother’s blood until delivery –> antibodies can’t hurt the fetus after delivery but can affect any later pregnancies –> destory the fetus’s RBCs –> anemia and jaundice

Question 12

Phenylketonuria

Answer 12

Autosomal recessive disorder

• Defect in phenylalanine metabolism
• Issue with phenylalanine hydroxylase leading to an accumulation of phenylalanine –> mental retardation

Question 13

Prevention of PKU

Answer 13

Decrease the amount of phenylalanine in the diet

Question 14

Sudden Infant Death Syndrome

Answer 14

Under 1 year of age

• 2-4 months: while sleeping bc of symptoms of minor upper respiratory infections
• Usually multifactorial disorder –> immaturiety of critical hypothalamic centers

Question 15

Risk factors to SIDS

Answer 15

Infant sleeping on tummy, prematurity and low birth weight, multiple gestation mother, maternal smoking or drug abuse

Question 16

Cystic Fibrosis Transmembrane Conductance Regulator

Answer 16

Autosomal Recessive Disorders

• Due to dehydrated mucus in the airways because the chlorine stops moving out so water and sodium come to the lumen as well
• No chlorine getting into the sweat ducts, requiring the sodium to stay in the lumen of the sweat ducts (salty sweat)

Question 17

CFTR

Answer 17

Two transmebrane domains with two nucleotide-binding domains and a regulatory R domain

• Agonists binds and increase cAMP which activates PKA which phosphorylates teh R domain resulting in opening of the Cl channel
• Mutation result in defective folding and degradation before it reaches the surface
• Others effect syntehsis of the domains of CFTR

Question 18

CF Class 1:

Answer 18

Defective protein synthesis: lack of CFTR

Question 19

CF Class II

Answer 19

Abnormal protein folding, processing and trafficking–> degraded before it reaches the surface

Question 20

CF Class III

Answer 20

Defective regulation: Mutations prevent activation of CFTR by preventing ATP binding and hydrolysis (normal expression but nonfunctional)

Question 21

CF Class IV

Answer 21

Decreased conducatance: Forms ionic pore for chloride transport mutation (transmembrane domain)

Question 22

CF Class V

Answer 22

Reduced abundance: mutation affects intronic splice sites or the promoter result in reduced protein expression

Question 23

CF Class VI

Answer 23

Altered regulation of separate ion channels: mutation affects the conductance by CFTR as well as regulation of other ion channels

Question 24

Neuroblastoma

Answer 24

Tumor of the adrenal medulla
Usually in children under 5
Deminstrates spontaneous inhibition
- High levels of Trk A
- Caused by loss of tumor-suppressor gene function, amplification of the n-myc oncogene (increased cell proliferation), over expression of telomerase

Question 25

Wilm’s Tumor

Nephroblastoma

Answer 25

Tumor of the kidney
Between 2-5 yo
- Within wilm’s tumor I
- Genomic imprinting (one copy is mutated and that leads to silencing of the other copy)