Diagnosis of central nervous system Toxoplasma gondii from the cerebrospinal fluid in a patient with acquired immunodeficiency syndrome.

The cytologic diagnosis of central nervous system (CNS) Toxoplasma gondii was established from the cerebrospinal fluid (CSF) in a patient with acquired immunodeficiency syndrome (AIDS) who presented with obstructive hydrocephalus and progressive obtundation. Free extracellular tachyzoites, phagocytized tachyzoites, and cyst forms were identified with Wright staining of cytocentrifuge preparations. Diagnosis was confirmed with indirect immunofluorescent antibody studies. Initial CSF examination was remarkable for low cellularity (24 wbc/mm3) with 42% neutrophils and 58% mononuclear cells on differential examination. Subsequent differential counts of CSF showed persistence of a mixed inflammatory pattern until day 10 at which time a mononuclear pleocytosis was observed. Cerebrospinal chemistries were notable for a low glucose (20 mg/dl), which persisted for 10 days. The cytocentrifuge Wright stain preparation was found to be superior to routine millipore filter Papanicolaou stain preparation for the identification of free tachyzoites and is recommended in the setting of immunodeficient patients with suspected CNS toxoplasmosis.