Toxoplasmosis

Question 1

Recent toxo infection blood results

Answer 1

IgG + or -ve
High IgM +
IgA +ve
Low IgG avidity

IgA, rising IgG, and/or low avidity are more specific for “recent” infection (within 3 months)

High IgG avidity after 16/40 does not exclude infection in early pregnancy

Question 2

Advice to pregnant women

Answer 2

Avoid raw/undercooked meat
Wash raw vegetables
Minimize contact with young kittens and their litter

Question 3

Risk in first trimester

Answer 3

Low risk (4-15%)
If infected, damage high risk (34-85%) and likely to be severe

Question 4

Risk in second trimester

Answer 4

Intermediate risk (25-44%)
If infected, damage intermediate (18-33%); likely to be less severe

Question 5

Risk third trimester

Answer 5

Infection high risk (30-75%)
If infected, damage low risk (4-17%)
Usually asymptomatic at birth

Question 6

Intrauterine dx

Answer 6

USS +/- fetal MRI (limited sensitivity and specificity

T.gondii PCR on amniotic fluid at 18-20 weeks gestation or > 4/52 post maternal infection

Question 7

Treatment

Answer 7

Pyrimethamine &sulfadiazine + folinic acid from >18/40

Question 8

US findings

Answer 8

Hydrocephalus
Brain or hepatic calcification
Ascites
Splenomegaly
Ventriculomegaly
Echogenic bowel

Question 9

Risks to baby

Answer 9

Chorioretinitis/retinal scarring
Intracranial calcification
Hydrocephalus
Hepatosplenomegaly
Pneumonia
Thrombocytopenia
Lymphadenopathy
Myocarditis

Question 10

Toxo serology 9/40 of pregnancy - IgM + IgG +

Answer 10

Arrange avidity testing and then discuss risks of toxo in pregnancy depending on avidity

Question 11

Acquired toxo

Answer 11

Eating raw or undercooked meat or ingesting soil contaminated with toxo locusts, which are excreted in the farces of infected cats

Question 12

Amniocentesis

Answer 12

> 4 weeks from infection - PCR