Path: Pediatric disorders of immunity and infection

Question 1

On what three factors is an infant’s ability to thrive postnatally primarily dependent?

Answer 1

1. maternal health
2. placental function
3. degree of maturity of the infant at birth

Question 2

What are some maternal diseases that can affect both placental and fetal growth?

Answer 2

diabetes, systemic lupus erythematosus, and pre-eclampsia

Question 3

What are some systems that are most underdeveloped in preterm infants?

Answer 3

lungs, liver, GI, brainste,, immune system

Question 4

What is the definition of acute chorioamnionitis?

Answer 4

acute chorioamnionitis describes the maternal inflammatory response to an ascending intrauterine infection. This can cause preterm birth.

Question 5

What causes acute chorioamnionitis?

Answer 5

usually caused by vaginal bacterial flora that penetrate the amnionic sac. may also be caused by other intrauterine infections like CMV and parvovirus.

Question 6

In what trimesters is acute chorioamnionitis and CMV/parvovirus most dangerous for fetal health?

Answer 6

first two trimesters

Question 7

What factors contribute to maternal tolerance of foreign genetic material during pregnancy?

Answer 7

the syncytiotrophoblast acts as a fetal-maternal barrier between mom and fetus. Also, there is an absence of the MHC class II molecules in this area, so it is harder to trigger T-cells.

Question 8

What happens if the syncytiotrophoblast is broken?

Answer 8

maternal inflammatory cells can invade placental tissue (aka chorionic villi), which can cause uteroplacental insufficiency over time.

Question 9

What is the histologic correlate to chorioamnionitis/uteroplacental insufficiency?

Answer 9

chorionic villitis. there are intravillous maternal T-lymphocytes and increased fetal histiocytes/ hofbauer cells.

Question 10

What are the two kinds of chorionic villitis?

Answer 10

• villitis caused by infectious TORCH organisms
• chorionic villitis of unknown etiology (CVUE) in which there are no infectious organisms and we think the pathology is due to an alloimmune reaction to fetal tissue

Question 11

What is hydrops fetalis?

Answer 11

disease in which the need for tissue oxygenation exceeds cardiac output in the fetus. often leads to fetal demise in utero.

Question 12

What are some of the etiologies for hydrops fetalis? 8 causes

Answer 12

generally catergorized as immune or non-immune. immune hydrops is due to blood group incompatibility and is now rare due to Rhogam. Non-immune may be cardiogenic, chromosomal, thoracic (congentital cystic airway malformation), diaphragmatic hernia, twin-to-twin transfusion syndrome, fetal anemia due to parvovivurs, or CMV infection.

Question 13

What are some molecules that freely pass between maternal and fetal circulation and can cause problems for the fetus?

Answer 13

immune products- antibodies to fetal red cells (hydrops fetalis), autoimmune antibodies as part of maternal lupus or Sjogrens disease, and hyperglycemia secondary to maternal diabetes leading to macrosomia and hypertrophic cardiomyopathy

Question 14

What component of the fetal pulmonary system is immature and what are the clinical sequelae?

Answer 14

alveoli type II pneumocytes

sequelae: incomplete expansion, respiratory distress syndrome

Question 15

What component of the fetal hepatic system may be immature in neonates and what are the clinical sequelae?

Answer 15

physiologic jaundice; hepatocyte

Question 16

What compoent of the fetal GI system may be immature in neonates and what are the clinical sequelae?

Answer 16

mucosa. necrotizing enterocolitis

Question 17

What component of the fetal CNS may be immature in neonates and what are the clinical sequelae?

Answer 17

myelination and brainstem. leads to immaturity of the higher brain, temperature instability, and irregular respirations

Question 18

What fetal system do we worry about the least in pre-term babies?

Answer 18

renal. there may be some glomerular immaturity but minimal clinical sequeale

Question 19

What four factors contribute to the development of necrotizing enterocolitis?

Answer 19

1. immaturity of the gut
2. introduction of feeds and colonization of the gut with bacteria
3. gut ischemia
4. recruitement of inflammatory mediators

Question 20

What are the dangerous sequelae of necrotizing enterocolitis in babies?

Answer 20

sepsis and shock

Question 21

What are five primary consequences of CF?

Answer 21

1. decr. ability to clear infections i nthe resp. tract due to mucus production
2. meconium ileus and obstruction of the GI tract
3. pancreatic enzyme insufficiency due to plugged exocrine ducts
4. liver dysfunction due to bile duct obstruction
5. infertility in males due to blocked ducts

Question 22

What is celiac disease?

Answer 22

inflammatory disease of the small intestine. may arise in kids who develop sensitivity to foods containing gluten. Malabsorption ensues- chronic diarrhea and abdominal pain/cramping.

Question 23

What three factors lead to increased risk of celiac’s disease?

Answer 23

1. cross-reactivity btw gliadin and a microbial antigen
2. presence of specific HLA type on host cells
3. inflammatory mediators
   environmental factors?

Question 24

What factors contribute to material immune tolerance of a fetus (ie. what changes in the MOM)?

Answer 24

shift from Th1 to Th2 helper cells- more humoral protection instead of cell-mediated protection. therefore, cell-mediated diseases like MS get better during pregnancy, while antibody-mediated diseases like lupus get worse.

Question 25

When is CVUE common?

Answer 25

in small for gestational age pregnancies (up to 25%) and in women who have had chronic villitis of unknown etiology in past pregnancies (recurrence up to 25%)

Question 26

How does parvovirus lead to non-immune hypdrops?

Answer 26

nucleared RBCs are infected
increased RBC lysis is observed
increased RBC production
anemia
increased cardiac workload/hypoxia
hydrops and cardiac failure

Question 27

How does diaphragmatic hernia lead to non-immune hydrops?

Answer 27

it causes increased intrathoracic pressure and hypoplastic lungs. that leads to increased pulmonary vascular resistance, increased cardiac workload, and hypoxia. eventual hydrpos and Right heart failure.

Question 28

What is twin-twin transfusion syndrome?

Answer 28

there are placental vascular anastomoses in monochorionic placentas. the dono twin becomes anemic and has restricted growth, hypovolemia, hypotension, oligohydramnios, and cardiac hypoxia
the recipeint twin gets hypervolemic, hypertensive, polyhydramnios, and congestive heart failure.

Question 29

What is cystic hygroma?

Answer 29

it is abnormal lymphatic drainage and may be associated with fetal hydrops.

Question 30

What are some congenital causes of hydrops fetalis?

Answer 30

trisomy 18, trisomy 21, Turner syndrome,

Question 31

What congenital complete heart block with maternal SLE?

Answer 31

this condition is due to circulating maternal antibodies that cross the placenta, enter the fetla circulation. they target fetal cardiac conduction system leading to potential hemorrhage, necrosis, fibrosis, and calcification.

Question 32

What are five potential complications associated with congenital complete heart block with maternal sle?

Answer 32

fetal hydrops, dilated cardiomyopathy, neonatal infection, necrotizing eneterocolitis, intraventricular hemorrhage

Question 33

What are some histologic findings of neonatal necrotizing enterocolitis?

Answer 33

coagulative necrosis, hemorrhage, acute and chronic inflammation, pneumatosis intestinalis, transmural necrosis, focal reparative epithelial changes like formation of granulation tissue, giant cells, or crypt distortion, and bacterial overgrowth

Question 34

What are some problems associated with the GI tract in cystic fibrosis/

Answer 34

obstruction/meconium ileus
steatorrhea (fat in stool)
pancreatic insufficiency
malnutrition

Question 35

What are two major clinical kinds of CF?

Answer 35

pancreatic insufficient vs. sufficient.

Question 36

What are some histological features of celiac’s disease?

Answer 36

villous atrophy/blunting
surface intraepithelial lymphocytes
crypt elongation in the biopsy