What is the recommended management for toxoplasmosis?

Management of Toxoplasmosis

The recommended management for toxoplasmosis includes screening for anti-Toxoplasma IgG in HIV-infected patients, and treatment with pyrimethamine plus sulfadiazine with leucovorin for active disease, with treatment duration varying based on the type of infection. 1

Screening and Diagnosis

• All HIV-infected patients should be tested for prior exposure to T. gondii by measuring anti-Toxoplasma IgG upon initiation of care (strong recommendation, moderate quality evidence) 1
• A presumptive diagnosis of CNS toxoplasmosis is based on clinical symptoms, serologic evidence of infection, and the presence of space-occupying lesions on brain imaging 1
• Definitive diagnosis of Toxoplasma encephalitis requires histologic or cytologic confirmation by brain biopsy, which should be considered when early neurologic deterioration is present despite empiric treatment or when patients fail to respond to therapy after 10-14 days 1

Treatment Regimens

Congenital Toxoplasmosis

• The preferred treatment is pyrimethamine (loading dose of 2 mg/kg body weight/day for 2 days, then 1 mg/kg/day for 2-6 months, followed by 1 mg/kg three times weekly) combined with sulfadiazine (50 mg/kg/dose twice daily) and supplementary leucovorin 1, 2
• Treatment duration should be 12 months for congenital toxoplasmosis 1, 2
• For children with moderate to severe disease and HIV infection, the full 12-month regimen of pyrimethamine/sulfadiazine should be administered 1

Acquired CNS, Ocular, or Systemic Toxoplasmosis

• Treatment consists of pyrimethamine (2 mg/kg/day for 3 days, followed by 1 mg/kg/day) and leucovorin (10-25 mg/day) plus sulfadiazine (25-50 mg/kg/dose four times daily) 1
• Acute therapy should be continued for 6 weeks, assuming clinical and radiological improvement 1, 2
• Longer courses may be required for extensive disease or poor response after 6 weeks 1, 2

Alternative Regimens

• If patients cannot tolerate TMP-SMZ (co-trimoxazole), the recommended alternative is dapsone-pyrimethamine, which is also effective against PCP 1
• Clindamycin with pyrimethamine is another alternative for patients with sulfonamide hypersensitivity 2, 3
• Atovaquone with or without pyrimethamine may also be considered 1

Prophylaxis

Primary Prophylaxis

• Toxoplasma-seropositive patients with CD4+ T-lymphocyte count <100/µL should receive prophylaxis against toxoplasmic encephalitis 1
• The preferred regimen is TMP-SMZ (co-trimoxazole) double-strength tablet daily, which is also effective against PCP 1
• Prophylaxis can be discontinued in patients whose CD4+ T-lymphocyte counts increase to >200 cells/µL for ≥3 months in response to HAART 1

Secondary Prophylaxis

• Patients who have had toxoplasmic encephalitis should receive lifelong suppressive therapy to prevent relapse 1
• Prophylaxis should be restarted if the CD4 cell count decreases to <100 cells/µL 1

Prevention of Exposure

• Toxoplasma-seronegative adults should be counseled on avoiding new infection 1
• Preventive measures include:
  • Not eating raw or undercooked meat, particularly pork, lamb, or venison 1
  • Washing hands after contact with raw meat, gardening, or other contact with soil 1
  • Washing fruits and vegetables thoroughly before eating them raw 1
  • If owning a cat, changing the litter box daily (preferably by an HIV-negative, non-pregnant person) or washing hands thoroughly after changing it 1
  • Keeping cats inside and not adopting or handling stray cats 1
  • Feeding cats only canned or dried commercial food or well-cooked table food 1

Monitoring During Treatment

• Complete blood count should be performed at least weekly while on daily pyrimethamine and at least monthly while on less than daily dosing to monitor for bone marrow suppression 1, 2
• Leucovorin (folinic acid) should always be administered with pyrimethamine to minimize hematologic toxicity 1, 4

Special Considerations

Pregnancy

• Because of theoretical concerns regarding possible teratogenicity during the first trimester, healthcare providers might choose to withhold prophylaxis during this period 1
• Pregnant women with suspected or confirmed primary toxoplasmosis and newborns with possible or documented congenital toxoplasmosis should be managed in consultation with an appropriate specialist 1

HIV Co-infection

• HIV-infected pregnant women with positive Toxoplasma serology have an increased likelihood of maternal reactivation and congenital transmission 1
• Infants born to women who are seropositive for Toxoplasma should be evaluated for congenital toxoplasmosis 1

Common Pitfalls

• Inadequate duration of therapy may lead to relapse, particularly in immunocompromised patients 2, 3
• Failure to monitor for adverse effects such as rash, fever, leukopenia, hepatitis, and gastrointestinal symptoms 2, 4
• Discontinuation of therapy too early before complete resolution of active infection can lead to recurrence 2, 5
• Aerosolized pentamidine does not protect against toxoplasmic encephalitis and is not recommended 1