Congenital toxoplasmosis: Difference between revisions
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β | == |
+ | ==Background== |
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β | * Often no history of illness during pregnancy |
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β | ** Symptoms, if present, tend to be mild with low-grade fever, malaise, and lymphadenopathy |
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+ | *See also [[toxoplasmosis in pregnancy]] |
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β | == Diagnosis == |
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β | === In pregnancy === |
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β | * Molecular |
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β | ** Definitive diagnosis is based on PCR of amniotic fluid around 18 months, usually done after maternal serology to confirm intrauterine infection |
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β | *** Sensitivity is 64 to 92% and specificity 100% (NPR around 88 to 98%) |
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β | *** Earlier than 18 weeks has unknown sensitivity and specificity, and has a higher risk of spontaneous abortion |
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β | ** Can also be done on fetal blood |
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β | * Serology |
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β | ** Can check maternal IgM and IgG |
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β | ** IgM is not specific to recent infection, however, as it can be present for more than a year |
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β | ** IgG avidity testing is used to determine recency of infection |
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β | *** Low avidity is 35-50% and high is >60% |
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β | *** Low avidity is unhelpful, as avidity can remain low for more than a year |
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β | *** High avidity, on the other hand, suggests infected at least 3-4 months prior |
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β | ** Therefore, if infection is suspected in the first 16 weeks of gestation, avidity testing may be able to rule out infection during pregnancy |
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β | * Needs serial head ultrasound to monitor for hydrocephalus and intraparenchymal brain calcifications |
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β | ** May also see hepatic calcifications, splenomegaly, and ascites |
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β | === In children === |
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β | * Serology |
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β | * Molecular testing |
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β | * Other |
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β | == |
+ | ==Diagnosis== |
β | === In pregnancy === |
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β | * If infected < 14 weeks gestation, [[Is treated by::spiramycin]] 3 g/day until delivery |
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β | ** However, it doesn't cross the placenta and it's unclear whether it affects outcomes in the baby |
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β | ** Likely most effective if given within 8 weeks of maternal infection |
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β | ** Second-line would be monotherapy with [[Is treated by::sulfadiazine]] or [[Is treated by::clindamycin]] |
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β | * If age β₯ 14 weeks gestation and documented fetal infection, or if suspected infection was β₯14 weeks gestation, use standard therapy |
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β | ** Standard therapy is: [[Is treated by::pyrimethamine]] 50 mg q12h for 2 days followed by 50 mg daily (plus [[folinic acid]] 10-20 mg daily until 1 week after stopping pyrimethamine), and [[Is treated by::sulfadiazine]] 75 mg/kg load followed by 50 mg/kg q12h (maximum 4 g/day) |
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β | ** This treatment crosses the placenta, which is why it is used in cases of documented or suspected fetal infection, as well as in later-term infections when the risk of fetal infection is higher |
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β | ** Therefore, if initially started on [[spiramycin]], then switch to standard therapy if amniotic fluid PCR is positive or ultrasound is abnormal |
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β | ** However, it is teratogenic until 14 weeks gestation so [[spiramycin]] is used until then |
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β | === In children === |
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+ | ==Management== |
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β | ** [[Is treated by::Sulfadiazine]] 75 mg/kg load, followed by 50 mg/kg q12h (max 4 g/day) |
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β | ** |
+ | **[[Is treated by::Pyrimethamine]] 1 mg/kg q12h for 2 days (load), followed by 1 mg/kg for 2 to 6 months, followed by 1 mg/kg qMWF |
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+ | **Can add [[prednisone]] for severe chorioretinits at 1 mg/kg/day divided bid (max 40 mg/day), followed by a rapid taper |
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+ | *For prevention, refer to [[Toxoplasmosis in pregnancy#Management|the management of toxoplasmosis in pregnancy]] |
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[[Category:Obstetrical infectionsββ]] |
[[Category:Obstetrical infectionsββ]] |
Revision as of 13:11, 30 July 2020
Background
- Can be acquired during maternal parasitemia associated with primary infection
- However, it is possible to acquire from reactivation of latent toxoplasmosis in an HIV-infected mother
- Risk of transplacental infection of fetus is lowest in first trimester and highest in third
- See also toxoplasmosis in pregnancy
Clinical Manifestations
- At birth, 85% of infected babies are asymptomatic and only 15% are symptomatic
- Risk of infection is related to trimester of infection: 6% in first, 40% in second, and 72% in third
- Risk of signs of congenital infection is inversely related to trimester of infection: 61% in first, 25% in second, and 9% in third
- Classic triad of chorioretinitis (most common), intraparenchymal cerebral calcifications, and hydrocephalus
- Others: thrombocytopenia, hepatitis, hepatosplenomegaly, cataracts, strabismus, microphthalmia
Diagnosis
- Standard workup starts with serology, then adds PCR and other investigations if clinical suspicion is high
- Serology: in neonates, IgG serology reflects maternal status, so use IgM and IgA instead
- Molecular testing: if clinical suspicion is high, add PCR of the peripheral blood, urine, and CSF to the serology
- If clinical suspicion is high, also get ophthalmologic evaluation, hearing assessment, ultrasound or CT of the brain, and lumbar puncture
Management
- Postnatal treatment of neonates is with standard therapy for at least 12 months
- Sulfadiazine 50 mg/kg q12h
- Pyrimethamine 1 mg/kg q12h for 2 days (load), followed by 1 mg/kg for 2 to 6 months, followed by 1 mg/kg qMWF
- Folinic acid 10 mg PO thrice weekly until 1 week after pyrimethamine is stopped
- Treatment of congenital infection in older children is standard therapy until 1 to 2 weeks after resolution of signs or symptoms
- Pyrimethamine 1 mg/kg q12h (max 50 mg) for 2 days, followed by 1 mg/kg/day (max 25 mg)
- Sulfadiazine 75 mg/kg load, followed by 50 mg/kg q12h (max 4 g/day)
- Folinic acid 10-20 mg po thrice weekly
- Can add prednisone for severe chorioretinits at 1 mg/kg/day divided bid (max 40 mg/day), followed by a rapid taper
- Serial evaluations with a clinical assessment, neuroradiology, ophthalmology, and CSF analysis
- For prevention, refer to the management of toxoplasmosis in pregnancy
References
- ^ Effectiveness of prenatal treatment for congenital toxoplasmosis: a meta-analysis of individual patients' data. The Lancet. 2007;369(9556):115-122. doi:10.1016/s0140-6736(07)60072-5.