Diseases of Infancy and Childhood: Perinatal infections, fetal hydrops

Question 1

Microbes can enter the host by doing what?

Answer 1

breaching epithelial surfaces, inhalation, ingestion, or sexual transmission

Question 2

in general, fetal and perinatal infections are acquired through one of two primary routes. What are these routes?

Answer 2

transcervically (aka ascending) or transplacentally (hematologic)

Question 3

Occasionally, infection occur by a combination of the two routes- how so?

Answer 3

ascending microorganism infects the endometrium and then invades the fetal bloodstream via the chorionic villi

Question 4

perinatal sepsis can be grouped clinically based on what?

Answer 4

early onset (within the first 7 days of life) versus late onset (from 7 days to 3 months)

Question 5

most cases of early-onset sepsis are acquired at or shortly before birth and tend to result in clinical signs and symptoms of what?

Answer 5

PNA, sepsis, and occasionally meningitis within 4-5 days of life

Question 6

what is the most common cause of early onset sepsis as well as early-onset bacterial meningitis?

Answer 6

group B streptococcus

Question 7

what could be the source of perinatal infections?

Answer 7

bacteria, fungus, parasites, viruses, TORCH

Question 8

What are the different routes in which vertical transmission can occur?

Answer 8

placental-fetal transmission, transmission during birth, and postnatal transmission in maternal milk

Question 9

What are 2 examples of infections caused via transmission during birth?

Answer 9

gonococcal and chlamydial conjunctivitis

Question 10

what are 3 examples of infections transmitted via postnatal transmission in maternal milk?

Answer 10

cytomegalovirus (CMV), HIV, and hepatitis B virus

Question 11

what does fetal hydrops refer to?

Answer 11

the accumulation of edema fluid in the fetus during intrauterine growth

Question 12

there are 2 general patterns of fluid accumulation in fetal hydrops, what are they?

Answer 12

hydrops fetalis (generalized) and cystic hygroma (localized)

Question 13

What are the two different etiologies of fetal hydrops?

Answer 13

immune hydrops and non-immune hydrops

Question 14

what is immune hydrops caused by?

Answer 14

a hemolytic disease caused by blood group antigen incompatibility between mother and fetus

Question 15

what are the three major causes of non-immune hydrops?

Answer 15

cardiovascular defects, chromosomal anomalies, and fetal anemia

Question 16

Immune hydrops is what type of reaction?

Answer 16

a type II hypersensitivity reaction (antibodies react with antigens present on cell surfaces or in the extracellular matrix)

Question 17

What happens if there is IgG antibody attachment to Rh+ erythrocytes? and what does this cause/lead to?

Answer 17

removal and destruction of the erythrocyte-antibody complex; causes anemia and hemoglobin degradation

Question 18

what does anemia in the fetus lead to?

Answer 18

extramedullary hematopoiesis and cardiac decompensation

Question 19

what does hemoglobin degradation lead to in the fetus?

Answer 19

an excess of bilirubin; which leads to jaundice and kernicterus

Question 20

What does the cardiac decompensation that results from anemia in the fetus lead to?

Answer 20

hydrops

Question 21

the incidence of maternal Rh isoimmunization has decreased significantly since the use of what?

Answer 21

Rhesis immune globulin (RhIg) containing anti-D antibodies

Question 22

when should administration of RhIg take place?

Answer 22

at 28 weeks of gestation and within 72 hours of delivery to Rh-negative mothers; also administered following abortions because these too can lead to immunization

Question 23

what are some of the cardiovascular defects that could cause non-immune hydrops?

Answer 23

structural and functional anomalies (congenital malformations and arrhythmias)

Question 24

what are some of the chromosomal anomalies that could cause non-immune hydrops?

Answer 24

45, XO (turner syndrome) and trisomes 21 and 18

Question 25

what is an example of fetal anemia that could cause non-immune hydrops?

Answer 25

alpha thalassemia (most common cause), transplacental parovovirus B19 and twin-twin transfusion

Question 26

What are the two consequences of excessive destruction of red cells in the neonate?

Answer 26

anemia and jaundice

Question 27

What is the mechanism for the development of generalized hydrops?

Answer 27

with more severe hemolysis, progressive anemia develops and may result in hypoxic injury to the heart and liver; because of the liver injury, plasma protein synthesis (albumin) decreases. Cardiac hypoxia may lead to cardiac decompensation and failure; the combination of reduced plasma oncotic pressure and increased hydrostatic pressure in the circulation (secondary to cardiac failure) results in generalized edema and anasarca

Question 28

What accounts for the presence in the peripheral circulation of large numbers of immature red blood cells,, including reticulocytes and erythroblasts?

Answer 28

the increased hematopoietic activity