Cystoisosporiasis

Cystoisospora belli, formerly Isospora belli

Diagnosis and treatment

Diagnosis:
detection of oocysts by UV fluorescence or microscopy of stools, duodenal aspirates or intestinal tissue biopsy in persons with chronic, mostly watery diarrhea. If the diarrhea lasts > 4 weeks, the diagnosis of cystoisosporiasis is an AIDS defining illness

Notes on treatment:
besides antiprotozoal treatment, additional measures are symptomatic treatment, rehydration and electrolyte management. see also Anti-infective/ART interaction table for treatment optimization

  Drug / Dose Comments
Preferred therapy

TMP-SMX
320/1600 mg bid po
OR
160/800 mg bid po

Treat minimally 10 days, increase duration to 3-4 weeks if symptoms worsen or persist.

Treat minimally 10 days, Increase dose to 2 x 2 tablet/day, if symptoms worsen or persist
Alternative therapy, if TMP-SMX is not tolerated 

pyrimethamine
50-75 mg qd po
+ folinic acid
10-15 mg qd po

10 days
Monitor for myelotoxicity, mostly neutropenia, for pyrimethamine
OR
ciprofloxacin
500 mg bid po		 7 days

Secondary Prophylaxis / Maintenance Therapy

Stop: if CD4 count > 200 cells/μL and HIV-VL undetectable over 6 months and no signs of persistent cystoisosporiasis

  Drug / Dose Comments
Preferred therapy

TMP-SMX
160/800 mg three times weekly po
OR
160/800 mg qd po
OR
320/1600 mg three times weekly po

  
Alternative therapy, if TMP-SMX is not
tolerated

pyrimethamine
25 mg qd po
+ folinic acid 10-15 mg qd po

Monitor for myelotoxicity, mostly neutropenia, for pyrimethamine