Toxoplasmosis

Background

• Most common cause of focal encephalitis in patients with AIDS
• Risk at CD4 < 100 and not on prophylaxis

Clinical Features

• Headache
• Fever
• Focal neurologic deficits
• altered mental status
• Seizures

Differential Diagnosis

• Lymphoma
  • More commonly single lesion in the periventricular white matter or corpus callosum
• Cerebral TB
  • Characteristic inflammatory appearance with isodense exudate filling basal cisterns
• Fungal infection

HIV associated conditions

• HIV neurologic complications
  • Toxoplasmosis
  • Cryptococcosis
  • AIDS Dementia
  • Seizures in patients with HIV-AIDS
  • Primary CNS lymphoma
• HIV pulmonary complications
  • Pneumocystis jirovecii pneumonia (PCP)
  • Tuberculosis (TB)
  • CMV pneumonia
• Ophthalmologic complications
  • CMV Retinitis
  • Herpes Zoster Ophthalmicus
• Other
  • AIDS fever of unknown origin
  • Immune reconstitution inflammatory syndrome
  • HIV diarrhea
  • Esophageal candidiasis
  • Kaposi's sarcoma
  • Pruritic papular eruption of HIV
  • Hairy oral leukoplakia
• HAART medication side effects
  • HAART-induced lactic acidosis
  • Neuropyschiatric effects
  • Hepatic toxicity
  • Renal toxicity
  • Steven-Johnson's
  • Cytopenias
  • GI symptoms
  • Endocrine abnormalities

Evaluation

• Head CT without contrast
  • Shows multiple subcortical lesions with predilection for basal ganglia
  • Contrast usually not needed; if obtained, will show ring enhancing lesions
• CSF
  • Helpful but high rate of false negatives
• Serology not generally helpful since antibodies common in general population

Management

Antibiotics

Immunocompetent

Antibiotics only needed if patient has severe symptoms

• Pyrimethamine 200mg PO load then 50mg PO q24hrs x 4 weeks AND
  • Leucovorin 10mg PO q24hrs AND
  • Sulfadiazine 1g PO q6hrs

Immunosprepressed

• Pyrimethamine 200mg PO load then 75mg PO q24hrs x 4-8 weeks AND Leucovorin 25mg PO q24hrs PLUS
  • Sulfadiazine 1500mg PO q6hrs OR
  • Clindamycin 600mg PO or IV q6hrs OR
  • Azithromycin 1200mg PO q24hrs OR
  • Atovaquone 1500mg PO q12hrs

OR

• TMP/SMX 5mg/kg IV q12hrs

Pregnant

• Spiramycin 1g PO q8hrs
  • If amniotic fluid is positive treat with 3 weeks of pyrimethamine (50 mg/day orally) + sulfadiazine (3 g/day orally in 2-3 divided doses)
  • Alternate with a 3-week course of Spiramycin 1 g 3 times daily OR
• Pyrimethamine (25 mg/day orally) and sulfadiazine (4 g/day orally) divided 2 or 4 times daily until delivery AND
  • Leucovorin 10-25 mg/day orally to prevent bone marrow suppression
• Dapsone 50mg PO QD; Off label use

Congenital/Pediatric

• Pyrimethamine 2mg/kg/day PO x 2 days then 1mg/kg/day x 2-6 months, then 1mg/kg MWF AND
  • Sulfadiazine 50mg/kg PO BID AND
  • Leucovorin 10mg PO 3x/week
• Duration: 12 months for congenital toxoplasmosis
• Alternative: TMP/SMX 5mg/kg (TMP) PO/IV q12hrs
• Clindamycin 20-30mg/kg/day PO/IV divided q6hrs (max 2.4g/day) if sulfa allergic
• Spiramycin 50-100mg/kg/day PO divided q8hrs

Steroids

• Consider dexamethasone 4mg IV q6hr for significant edema or mass effect

Folinic Acid

Administer if the treatment regimen includes Leucovorin

• Folinic acid 10mg PO QD x6–8wk

Disposition

• Admit