Infancy Lecture Flashcards
Infant Respiratory Distress Syndrome
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
Causes of Infant RDS
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)
Prematurity leads to what starting what cascade?
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
Erythroblastosis fetalis
- Caused by ABO incompatibility or by Rh incompatibility
ABO incompatibility disease?
Limited to babies with A or B antigens whose mothers have type O blood
Rh incompatibility disease?
Occurs in babies with RBCs having Rh antigen (Rh +ve babies) and mothers who do not contain Rh antigen (Rh -ve mothers)
Father A
Mother O
Child A
Disease?
YES
Father B
Mother O
Child B
Disease?
YES
Father Rh+
Mother Rh-
Child Rh+
Disease?
YES
What happens when the antibody attaches to the Rh+ erythrocytes of the fetus?
Removal and destruction –> anemia –> extramedullary hematopoiesis or cardiac decompensation –> hydrops OR hemoglobin degradation –> bilirubin –> jaundice or kernicterus
What are the causes and symptoms of erythroblastosis fetalis?
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
Phenylketonuria
Autosomal recessive disorder
- Defect in phenylalanine metabolism
- Issue with phenylalanine hydroxylase leading to an accumulation of phenylalanine –> mental retardation
Prevention of PKU
Decrease the amount of phenylalanine in the diet
Sudden Infant Death Syndrome
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
Risk factors to SIDS
Infant sleeping on tummy, prematurity and low birth weight, multiple gestation mother, maternal smoking or drug abuse
Cystic Fibrosis Transmembrane Conductance Regulator
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)
CFTR
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
CF Class 1:
Defective protein synthesis: lack of CFTR
CF Class II
Abnormal protein folding, processing and trafficking–> degraded before it reaches the surface
CF Class III
Defective regulation: Mutations prevent activation of CFTR by preventing ATP binding and hydrolysis (normal expression but nonfunctional)
CF Class IV
Decreased conducatance: Forms ionic pore for chloride transport mutation (transmembrane domain)
CF Class V
Reduced abundance: mutation affects intronic splice sites or the promoter result in reduced protein expression
CF Class VI
Altered regulation of separate ion channels: mutation affects the conductance by CFTR as well as regulation of other ion channels
Neuroblastoma
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
Wilm’s Tumor
Nephroblastoma
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)
