Toxoplasma gondii Encephalitis

Primary Prophylaxis

Start: if CD4 count < 200 cells/μL, or CD4 percentage < 14%, oral thrush, or relevant concomitant immunosuppression, see Primary prophylaxis of OIs
Stop: if CD4 count > 100 cells/μL and HIV-VL undetectable over 3 months

	Drug / Dose	Comments
Preferred prophylaxis	TMP-SMX 400/80 mg qd po or 800/160 mg qd po or 800/160 mg x 3/week po	All regimens are also effective against PcP
Alternative prophylaxis	atovaquone suspension 1500 mg qd po (with food)
	dapsone 200 mg/week po + pyrimethamine 75 mg/week po + folinic acid 25-30 mg/week po	Check for G6PD-deficiency
	atovaquone suspension 1500 mg qd po (with food) + pyrimethamine 75 mg/week po + folinic acid 25-30 mg/week po

Treatment

Treat 6 weeks, then secondary prophylaxis until CD4 count > 200 cells/μL and HIV-VL undetectable over 6 months
Diagnosis:

Definitive diagnosis: clinical symptoms, typical radiology of the cerebrum AND cytological / histological detection of organism in tissue
Presumptive diagnosis: clinical symptoms, typical radiology AND response to empirical treatment. This is the standard in most clinical settings

	Drug / Dose	Comments
Preferred therapy	pyrimethamine Day 1: 200 mg qd po, then If ≥ 60 kg: 75 mg qd po; If < 60 kg: 50 mg qd po + sulfadiazine If ≥ 60 kg: 3000 mg bid po/iv; If < 60 kg: 2000 mg bid po/iv + folinic acid 10-15 mg/day po	Monitor for myelotoxicity of pyrimethamine, mostly neutropenia Sulfadiazine is associated with crystalluria and may lead to renal failure and urolithiasis. Good hydration is essential. Check renal function and urine sediment for microhematuria and crystalluria
Alternative therapy	pyrimethamine Day 1: 200 mg qd po, then If ≥ 60 kg: 75 mg qd po; If < 60 kg: 50 mg qd po + clindamycin 600-900 mg qid po/iv + folinic acid 10-15 mg qd po	Monitor for myelotoxicity of pyrimethamine, mostly neutropenia Additional PcP prophylaxis is necessary
	OR TMP-SMX 5 mg TMP/kg bid iv/po, 25 mg SMX/kg bid iv/po	Preferred intravenous regimen if oral route not possible
	OR pyrimethamine Day 1: 200 mg qd po, then If ≥ 60 kg: 75 mg qd po; If < 60 kg: 50 mg qd po + atovaquone 1500 mg bid po (with food) + folinic acid 10-15 mg qd po	Monitor for myelotoxicity of pyrimethamine, mostly neutropenia
	OR sulfadiazine If ≥ 60 kg: 3000 mg bid po/iv; If < 60 kg: 2000 mg bid po/iv + atovaquone 1500 mg bid po (with food)	Sulfadiazine is associated with crystalluria and may lead to renal failure and urolithiasis. Good hydration is essential. Check renal function and urine sediment for microhematuria and crystalluria
	OR pyrimethamine Day 1: 200 mg qd po, then If ≥ 60 kg: 75 mg qd po; If < 60 kg: 50 mg qd po + azitromycin 900-1200 mg qd po + folinic acid 10-15 mg qd po	Monitor for myelotoxicity of pyrimethamine, mostly neutropenia

Drug / Dose

Comments

Preferred therapy

pyrimethamine
Day 1: 200 mg qd po,
then
If ≥ 60 kg: 75 mg qd po;
If < 60 kg: 50 mg qd po

+ sulfadiazine
If ≥ 60 kg: 3000 mg bid po/iv;
If < 60 kg: 2000 mg bid po/iv

+ folinic acid
10-15 mg/day po

Monitor for myelotoxicity of pyrimethamine, mostly neutropenia

Sulfadiazine is associated with crystalluria and may lead to renal failure and urolithiasis. Good hydration is essential. Check renal function and urine sediment for microhematuria and crystalluria

Alternative therapy

pyrimethamine
Day 1: 200 mg qd po,
then
If ≥ 60 kg: 75 mg qd po;
If < 60 kg: 50 mg qd po

+ clindamycin
600-900 mg qid po/iv

+ folinic acid
10-15 mg qd po

Monitor for myelotoxicity of pyrimethamine, mostly neutropenia

Additional PcP prophylaxis is necessary

OR TMP-SMX
5 mg TMP/kg bid iv/po,
25 mg SMX/kg bid iv/po

Preferred intravenous regimen if oral route not possible

OR pyrimethamine
Day 1: 200 mg qd po,
then
If ≥ 60 kg: 75 mg qd po;
If < 60 kg: 50 mg qd po

+ atovaquone
1500 mg bid po (with food)

+ folinic acid
10-15 mg qd po

Monitor for myelotoxicity of pyrimethamine, mostly neutropenia

OR sulfadiazine
If ≥ 60 kg: 3000 mg bid po/iv;
If < 60 kg: 2000 mg bid po/iv

+ atovaquone
1500 mg bid po (with food)

OR pyrimethamine
Day 1: 200 mg qd po,
then
If ≥ 60 kg: 75 mg qd po;
If < 60 kg: 50 mg qd po

+ azitromycin
900-1200 mg qd po

+ folinic acid
10-15 mg qd po

Monitor for myelotoxicity of pyrimethamine, mostly neutropenia

Secondary Prophylaxis, Maintenance Therapy

Stop: if CD4 count > 200 cells/μL and HIV-VL undetectable over 6 months

Regimens listed are alternatives

Drug / Dose	Comments
sulfadiazine 2000-3000 mg bid - qid po + pyrimethamine 25-50 mg qd po + folinic acid 10-15 mg qd po
OR clindamycin 600 mg tid po + pyrimethamine 25-50 mg qd po + folinic acid 10-15 mg qd po	Additional PCP prophylaxis is necessary
OR atovaquone suspension 750-1500 mg bid po (with food) + pyrimethamine 25-50 mg qd po + folinic acid 10-15 mg qd po
OR atovaquone suspension 750-1500 mg bid po (with food)
OR TMP-SMX 800/160 mg bid po

Drug / Dose

Comments

sulfadiazine
2000-3000 mg bid - qid po
+ pyrimethamine
25-50 mg qd po
+ folinic acid
10-15 mg qd po

OR clindamycin
600 mg tid po
+ pyrimethamine
25-50 mg qd po
+ folinic acid
10-15 mg qd po

Additional PCP prophylaxis is necessary

OR atovaquone suspension
750-1500 mg bid po (with food)
+ pyrimethamine
25-50 mg qd po
+ folinic acid
10-15 mg qd po

OR atovaquone suspension
750-1500 mg bid po (with food)

OR TMP-SMX
800/160 mg bid po