Chapter 10 Part 2 Flashcards
Definition of vertical transmission
infectious agent passed from mother to fetus via three routes: placental-fetal, during birth, postnatal
Definition of placental-fetal transmission
Occurs when mother is infected during pregnancy, interferes with fetal development; effects vary depending on gestational age of fetus
Infection transmission during birth
contact with infectious agent during passage through birth canal
Postnatal transmission of infectious agents
agents transmitted through maternal milk like CMV, HIV, HBV
What are the two major routes of perinatal infections
Transcervical, transplacental
How does a transcervical infection pass to a newborn?
Inhalation of amniotic fluid before delivery or passage through infected birth canal
What is one mechanism responsible for preterm delivery as a result of transcervical infections?
Inflammation causing rupture of amniotic sac and release of prostaglandins from neutrophils
What are the most common conditions associated with bacterial transcervical infections?
Meningitis, sepsis, pneumonia
What type of infections pass transplacentally via the chorionic villi?
Parasites and viruses
Parvovirus B19 mode of infection and clinical outcome
Transplacentally; spontaneous abortion, hydrops fetalis, still birth, congenital anemia; commonly seen in erythroid cells
Clinical manifestations of TORCH infections
fever, encephalitis, chorioretinitis, hepatosplenomegaly, pneumonitis, myocarditis, hemolytic anemia, skin lesions
Long term clinical manifestations of TORCH infections
intellectual disability, growth retardation, cataracts, congenital cardiac anomalies, bone defects
Bacteria of TORCH infection group
Toxoplasmosis, other (syphilis, parvovirus B19), rubella, cytomegalovirus, herpesvirus
Definition of fetal hydrops
accumulation of edema fluid in two or more fetal compartments during intrauterine growth, most commonly pleural, pericardial, peritoneal, skin; can be generalized or local
Cause of immune hyrdrops
blood group antigen compatibility between mother and fetus
Antigens that cause immune hydrops
D Rh and ABO blood groups (Rh- mother and Rh+ father)
Etiology of immune hydrops
Immunization of mother by exposure to other blood type via placenta or birth causes formation of IgM abs, exposure during a second pregnancy leads to an IgG response
What would protect the mom from Rh immunization?
ABO incompatibility, no transplacental bleed during birth
Common treatment for Rh Immunization
RhIg containing anti-D antibodies
Major consequences of hemolysis in immune hydrops
Anemia (cardiac decomp and extramedullary hematopoiesis) and Hgb degradation (kernicterus and jaundice)
Three major etiologies of non-immune hydrops
chromosomal defects, csomal anomalies, fetal anemia (alpha thalassemia, twin-twin transfusion, parvovirus B19)
Gross morphological changes in hydrops
pale fetus and placenta, enlarged liver and spleen, compensatory erythrocyte hyperplasia in bone, extramedullary hematopoiesis,
Where is kernicterus most prominent?
basal ganglia
Mechanism for generalized hydrops
severe hemolysis leads to hypoxic injury to heart and liver, decreasing albumin and leading to heart failure; increased hydrostatic pressure and decreased oncotic pressure
Erythroblastosis fetalis
Alloimmune hemolytic anemia, Rh incompatibility
Microscopically: polychromatophilic macrocytes (CHARACTERISTIC), nucleated RBCs, ejected nuclei
Clinical manifestations of fetal hydrops
pallor, hepatosplenomegaly, jaundice, generalized edema, neuro injury
Definition of inborn errors of metabolism
group of rare genetic diseases resulting from defect in enzyme or transport protein that results in a block of metabolic pathway
Common abnormalities suggesting IEM
deafness, abnormal hair, hydrops, seizures, hypotonia, poor feeding, cataract, cherry red macula, myopathy
Two categories of IEM
disorders that result in toxic accumulation, disorders of energy production and utilization
Goals of IEM treatment
prevent substance accumulation, eliminate toxic metabolite, correct metabolite abnormality
PKU etiology
deficiency of phenylalanine hydroxylase and resultant hyperphenylalanemia
When do PKU signs start to appear?
about 6 mo after birth - mental disability; will eventually lead to seizures, decreased pigmentation, eczema
Maternal PKU etiology
hyperphenylalanemia in asymptomatic mothers leading to teratogenic effects of phenylalanine on developing fetus
Clinical signs of PKU
musty odor to urine, light hair and skin, brain damage
Diagnosis of PKU
not determined with screening tests because of significant number of genes involved, must use blood test to differentiate benign hyperphenylalanemia from PKU
What form of PKU cannot be treated by dietary restriction?
abnormalities in recycling BH4 (cofactor for PAH)
Etiology of galactosemia
Lack of galactose-1-phosphate uridyl transferase or galactokinase (rare)
Pathogenesis of galactosemia
Build up of glactose-1-phosphate in liver, spleen, eye lens, kidney, heart, cerebral cortex leading to build up of galactitol and galactonate
Clinical features of galactosemia
hepatomegaly, lens opacification, CNS alterations due to loss of nerve cells
Clinical features of galactosemia in infants
failure to thrive, vomiting, diarrhea, jaundice, hepatomegaly, mental retardation, cataracts, hemolysis, coagulopathy
Etiology of cystic fibrosis
inherited disorder of ion transport that affects fluid secretion in exocrine glands, repro, GI, and resp epithelia
Clinical features of CF
chronic lung disease secondary to recurrent infections, pancreatic insufficiency, steatorrhea, malnutrition, hepatic cirrhosis, intestinal obstruction, male infertility
Primary defect in CF
epithelial chloride channel coded on chromosome 7q31.2
CFTR structure
two transmembrane domains, two nucleotide binding domains, regulatory domain that contains PKA and PKC phosphorylation sites
What other channels does CFTR regulate
rectified chloride channels, rectified potassium channels, gap junction channels, bicarb transport, ENaC (most significant)
Effect of loss of CFTR in sweat ducts
hypertonic sweat
Pathogenesis of resp and intestinal complications in CF
isotonic but low volume surface fluid layer, defective mucociliary action and viscid secretions
Class I CF
defective protein synthesis, complete CFTR lack
Class II CF
abnormal protein folding, processing, or trafficking; MOST COMMON
Class III CF
defective regulation, normal amt of CFTR but non functional
Class IV CF
decreased conductance, mutation in transmembrane domain
Class V CF
reduced abundance, reduced amount of normal protein
Class VI CF
altered regulation of ion channels
Clinical signs associated with atypical CF
idiopathic chronic pancreatitis, late-onset chronic pulmonary disease, idiopathic bronchiectasis, obstructive azoospermia
Environmental modifiers of CF
virulence of organisms, therapeutic efficacy, concurrent infections, tobacco or allergen exposure
Genetic modifiers of CF
gene polymorphisms in MBL2, TGFB1, IFRD1 (all modify lungs ability to resist infection
Common gross morphological changes in CF
pancreatic insufficiency, defective mucociliary action; SWEAT GLANDS morphologically UNaffected
Morphological changes of pancreas in CF
atrophy of exocrine portion of pancreas, impaired absorption, squamous metaplasia of pancreatic ducts, meconium ileus
Morphological changes of liver in CF
bile canaliculi plugged by mucus, steatosis
Morphological changes of salivary glands in CF
progressive ductual dilation, squamous metaplasia, glandular atrophy and fibrosis
Pulmonary changes in CF
viscous secretions lead to obstruction and infection, distended bronchioles, hyperplasia and hypertrophy of goblet cells, abscesses
Common organisms responsible for lung infections in CF
Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, Burkholderia cepacia
Clinical features of CF
meconium ileus, intussusception, persistent colonization, exocrine pancreatic insufficiency, recurrent nasal polyps, infertility, liver disease, malabsorption, fatty stools
What is necessary for CF diagnosis?
Classical charcteristics, sweat chloride test, immunoreactive trypsinogen, CFTR gene sequencing
