Developmental Disorders Flashcards
Define disruptions.
-disturbances in otherwise normal morphogenetic processes
Define deformations.
-disturbances in otherwise normal morphogenetic processes. These are typically caused by abnormal biomechanic all forces such as uterine constraints.
Define sequences.
- a sequence is a series of events triggered by one initiating factor.
- example: oligohydramnios which leads to a variety of events including fetal compression and other problems
Define syndrome.
-constellations of congenital anomalies that are thought to be pathologically related but cannot be explained on the basis of a single local event. They are often caused by a single event such as a viral infection.
What is the critical period?
-a maturation stage in which the organism is especially sensitive to certain environmental stimuli
What are the three groups of causes of congenital anomalies?
- genetic (18%)
- environmental (7%)
- multifactorial (25%)
How can genetics create a disorder?
- inborn errors of metabolism (rare)
- inherited most commonly as autosomal recessive or X-linked diseases. Some are dominant.
- often affect enzymes and biochemical pathways
What are some examples of diseases from genetic mutations?
- phenylketonuria
- galactosemia
- cystic fibrosis
What changes can happen in the chromosomes that can result in genetic disorders?
- aneuploidy (80-90% die in utero)
- deletions
- duplications
- inversion
- trans locations
What is euploidy?
- involves the addition of a complete set of chromosomes in addition to the diploid stage
- often the result of a retention of a polar body or by fertilization by more than one sperm
- typically results in early spontaneous abortion
What types of infections may causes birth defects?
- viruses
- bacterial
- protozoan
What kinds of viruses may contribute to birth defects?
- rubella
- cytomegalic inclusion disease
- herpes simplex
- varicella-zoster
- influenza
- mumps
What other environmental factors may result in birth defects?
- drugs and other chemicals: thalidomide, alcohol, RA,folic acid
- radiation
- maternal diabetes
What are some additional developmental problems?
- prematurity and growth restrictions
- neonatal respiratory distress syndrome
- hydrops
- eclampsia
What is the second most common cause of neonatal mortality?
-prematurity and fetal growth restrictions
What are some major risk factors for prematurity?
- preterm premature rupture of placental membranes
- intrauterine infections
- uterine, cervical, and placental structural abnormalities
- multiple gestation
What are some of the hazards of prematurity?
- hyaline membrane disease
- necrotizing entercolitis
- sepsis
- interventricular hemorrhage
- long term complications including developmental delay
What are some fetal factors resulting in fetal growth restriction?
- chromosome disorders
- congenital anomalies
- congenital infections
What are some placental factors resulting in fetal growth restriction?
- umbilical-placental vascular anomalies
- placenta previa
- placental thrombosis and infarction
- multiple gestations
- placental genetic mosaicism
What are some maternal factors resulting in fetal growth restriction?
- preeclampsia
- chronic hypertension
- maternal use of drugs, narcotics, alcohol, nicotine
- maternal malnutrition
What is respiratory distress syndrome?
- related to the immaturity of the lungs and related to premature birth
- deficiency in pulmonary surfactant
What is the incidence of respiratory distress syndrome?
-incidence is inversely proportional to gestational age
- 60% of infants born at less than 28 weeks
- 30% of infants born between 28-34 weeks
- 5% or less of infants after 34 weeks
What is fetal hydrops? Most common cause?
- accumulation of edema fluid in the fetus during intrauterine growth
- most common causes was hemolysis by blood group incompatibility between mother and fetus
What are the causes of fetal hydrops?
- immune hydrops
- nonimmune hydrops
What is immune hydrops?
- caused by blood group incompatibility between mother and fetus
- fetal red cells reach the maternal blood stream during last trimester or during childbirth itself
- major factor is the D antigen of Rh group
- ABO incompatibility is generally not a problem because maternal Ab remove any incompatible fetal RBCs that cross the placenta
What are the major causes of nonimmune hydrops?
-cardiovascular defects such as congenital cardiac defects and arrhythmias
-chromosomal anomalies
+Turner syndrome and trisomies 21 and 18 -> due to cardiac aberrations with these anomalies
What is kericterus?
- a bilirubin induced brain dysfunction (highly neurotoxic)
- newborns are especially vulnerable
What is pregnancy induced hypertension?
-persistent elevated bp that develops after 20 weeks of gestation and returns to normal after birth
What are the symptoms of preeclampsia?
- bp is high
- proteinuria
- weight gain
- edema
What is eclampsia?
- extremely serious condition
- extremely high bp
- grand meal seizures or coma
Define malformation.
-primary errors of mophogenesis. They are usually multifactorial, involving a number of etiological agents including genetic and environmental
