Toxoplasmic Encephalitis
Prevention of Exposure
HIV-infected persons should be tested for IgG antibody to Toxoplasma
soon after the diagnosis of HIV infection to detect latent infection
with Toxoplasma gondii .
All HIV-infected persons, but particularly those who lack IgG antibody to Toxoplasma, should be counseled about the various sources of toxoplasmic infection. They should be advised not to eat raw or undercooked meat, particularly undercooked pork, lamb, or venison (BIII). Specifically, meat should be cooked to an internal temperature of 150 F (65.5 C); meat cooked until it is no longer pink inside generally has an internal temperature of 165 F (73.8 C) and therefore satisfies this requirement. HIV-infected persons should wash their hands after contact with raw meat and after gardening or other contact with soil; in addition, they should wash fruits and vegetables well before eating them raw (BIII). If the patient owns a cat, the litter box should be changed daily, preferably by an HIV-negative, nonpregnant person; alternatively, the patient should wash the hands thoroughly after changing the litter box (BIII). Patients should be encouraged to keep their cats inside and not to adopt or handle stray cats. Cats should be fed only canned or dried commercial food or well-cooked table food, not raw or undercooked meats (BIII). Patients need not be advised to part with their cats or to have their cats tested for toxoplasmosis.
Prevention of Disease
Toxoplasma -seropositive patients who have a CD4+ T-lymphocyte
count of <100/µL should be administered prophylaxis against toxoplasmic
encephalitis (TE). The doses of TMP-SMZ recommended for PCP prophylaxis
appear to be effective against TE as well. If patients cannot tolerate
TMP-SMZ, the regimens including dapsone plus pyrimethamine that are recommended
for PCP prophylaxis provide protection against TE. Prophylactic monotherapy
with dapsone, pyrimethamine, azithromycin, clarithromycin, or atovaquone
cannot be recommended on the basis of current data. Aerosolized pentamidine
does not afford protection against TE.
Toxoplasma -seronegative persons who are not taking a PCP prophylactic regimen known to be active against TE should be retested for IgG antibody to Toxoplasma when their CD4+ T-lymphocyte count declines below 100/µL to determine whether they have seroconverted and are therefore at risk for TE. Patients who have seroconverted should be administered prophylaxis for TE as described above.
Prevention of Recurrence
Patients who have had TE should be administered lifelong suppressive
therapy with drugs active against Toxoplasma to prevent relapse. The combination of pyrimethamine plus sulfadiazine and leucovorin is
highly effective for this purpose. A commonly used regimen for patients
who cannot tolerate sulfa drugs is pyrimethamine plus clindamycin; however,
only the combination of pyrimethamine plus sulfadiazine appears to provide
protection against PCP as well.
Notes:
Pediatric Note
TMP/SMZ, when administered for PCP prophylaxis, also provides prophylaxis
against toxoplasmosis. Children aged >12 months who qualify for PCP
prophylaxis and who are receiving an agent other than TMP/SMZ should have
serologic testing for Toxoplasma antibody, because alternative
drugs for PCP prophylaxis may not be effective against Toxoplasma. If seropositive for Toxoplasma, children should be
administered prophylaxis for both PCP and toxoplasmosis (i.e, dapsone plus
pyrimethamine).
Notes Regarding Pregnancy
TMP-SMZ can be administered for prophylaxis against TE as described for
PCP. However, because of the low incidence of TE during pregnancy
and the possible risk associated with pyrimethamine treatment, chemoprophylaxis
with pyrimethamine-containing regimens can reasonably be deferred until after
pregnancy. For prophylaxis against recurrent TE, the health-care provider
and clinician should be well informed about the benefit of lifelong therapy
and the concerns about teratogenicity of pyrimethamine. Most clinicians favor
lifelong therapy for the mother, given the high likelihood that disease will
recur promptly if therapy is stopped.
In rare cases, HIV-infected pregnant women who have serologic evidence of remote toxoplasmic infection have transmitted Toxoplasma to the fetus in utero. Pregnant HIV-infected women who have evidence of primary toxoplasmic infection or active toxoplasmosis (including TE) should be evaluated and managed during pregnancy in consultation with appropriate specialists. Infants born to women who have serologic evidence of infections with HIV and Toxoplasma should be evaluated for congenital toxoplasmosis.
Go to the Disease-Specific Recommendations Menu
Go to the USPHS/IDSA Guidelines Menu
Go to the Opportunistic Infections Menu
Go to the HIVpositive.us Main Menu