Microbiology-Congenital Viral Infections Flashcards Preview

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Flashcards in Microbiology-Congenital Viral Infections Deck (22):
1

Clinical manifestations of toxoplasmosis in 1st trimester? 2nd? 3rd?

1st = death, CNS calcifications. 2nd = hydrocephalus, CNS calcifications, chorioretinitis. 3rd = asymptomatic.

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2

A child presents with microcephaly, intracranial calcifications, rash, intrauterine growth restriction, jaundice, hepatosplenomegaly, elevated transaminases and thrombocytopenia. Labs show chorioretinitis, hydrocephaly and CNS calcifications. How is this disease spread?

Toxoplasmosis is spread via the fecal-oral route. The most common way it is ingested is via oocysts in cat feces in a litter box, water, soil or inappropriately prepared meat.

3

What are the ToRCH infections.

Toxoplasmosis, Other (syphilis, HIV), Rubella, CMV and Herpes

4

How does a baby get ToRCH infections?

Mother gets the virus -> Virus crosses the placental and infects the fetus or the child is infected on the way out. Note that the transplacental infections are the most common.

5

How long are toxoplasmosis cysts viable for in soil? What is the definitive host of toxoplasmosis?

18 hours. The cat.

6

When is the worst time for a pregnant woman to get toxoplasmosis?

Worst malformations (death) come w/1st trimester infections. 3rd trimester infections has a higher fetal transmission rate.

7

A child presents with microcephaly, intracranial calcifications, rash, intrauterine growth restriction, jaundice, hepatosplenomegaly, elevated transaminases and thrombocytopenia. Labs show chorioretinitis, hydrocephaly and CNS calcifications. How do you confirm your diagnosis of toxoplasmosis? How do you treat?

Diagnose with infant IgG persistence over 6 months. For symptomatic infants: pyrimethamine w/leucovorin rescue and sulfadiazine for 12 months. For pregnant women give spiramycin daily.

8

A 4-month old Vietnamese girl presents because her child needs eye surgery. PMH reveals maternal fever in 1st trimester. The child was born < 3rd percentile and a purpuric rash on her face and trunk. Her child has been hospitalized at 1 and 3 months for pulmonary inflammation and failure to thrive. The mom has never been vaccinated. PE shows bilateral leucocoria and heart murmur. CXR shows mild cardiomegaly and CBC shows anemia. What is your diagnosis?

Note the heart lesion and leukocoria (from cataracts) typical of rubella. Note the rash similar of CMV, but there is no hepatosplenomegaly. IgG and IgM for rubella are likely to be elevated in this baby.

9

What type of virus is rubella?

Single-stranded RNA

10

When does rubella viral infection cause cardiac (PDA, stenosis), opthalmologic (cataracts), hearing impairment, growth retardation and neurologic symptoms?

1st trimester infection.

11

A 4-month old Vietnamese girl presents because her child needs eye surgery. PMH reveals maternal fever in 1st trimester. The child was born < 3rd percentile and a purpuric rash on her face and trunk. Her child has been hospitalized at 1 and 3 months for pulmonary inflammation and failure to thrive. The mom has never been vaccinated. PE shows bilateral leucocoria and heart murmur. CXR shows mild cardiomegaly and CBC shows anemia. How do you confirm your diagnosis?

Confirm with serology (IgG over several months) and nasal culture.

12

A 35 week AGA female delivered via C/S due to non-reassuring fetal heart rhythm. The child had an initial blood sugar of 12 and petechia on face, torso and thighs and was 5th percentile. Platelets 10, PT 21.4, aPTT 35.4, fibrinogen 88, LP negative for WBCs, LFTs elevated.  Physical exam shows hepatosplenomegaly and jaundice. The baby had an apneic event while testing. The mother had maternal hypothyroidism, works as a nurse and had a viral illness early in pregnancy and one in the last month of pregnancy. She does not hang around cats, hasn't traveled, denies HSV and GBS is unknown. Urine culture is shown below. What is your diagnosis?

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Note the liver findings, skin findings and symmetric growth restriction. These findings narrow it down to CMV and toxoplasmosis. Note the paraventricular calcifications typical of CMV. Babies secrete CMV in their urine when acquired in utero.

13

What babies are particularly susceptible to in utero CMV?

They have mothers that are particularly susceptible to it (like a nurse)

14

What do you need to check in all patients with congenital CMV even though 90% of cases resolve on their own and are asymptomatic?

Sensorineural hearing loss can occur 6 months after birth. CMV retinitis can also occur and both can be prevented with ganciclovir.

15

Most common congenital viral infection

CMV

16

Blueberry muffin lesions

Petechial rashes and thrombocytopenia from CMV in babies. This is because marrow is suppressed and extramedullary hematopoiesis is going on everywhere.

17

Confirming diagnosis of CMV

Isolating virus from child’s urine.

18

A girl was born at 36 weeks with a vesicular lesion on her neck, arm and shoulder. All cultures were negative and her rash improved after a few days and she was sent home. 10 days later the child came back with more vesicular lesions on her back and feet. Physical exam shows strabismus, bilateral optic atrophy and retinal scarring. What is causing her condition?

HSV. This is primarily transmitted through an infected vaginal canal. This is why babies tend to present 7-21 days after birth.

19

What type of virus is HSV?

dsDNA

20

What type of HSV infection increases risk for fetal transmission?

Primary

21

Disease patterns of congenital HSV?

Only affects skin (45%), CNS disease (33%) and disseminated disease. Note that not all kids will present with vesicular lesions.

22

HSV detection and treatment?

Detect with PCR and aciclovir to treat and prevent relapses.