levoleucovorin and Encephalitis

Toxoplasmic encephalitis (TE) is the second most common AIDS-related opportunistic infection of the CNS. It occurs in 10%-50% of patients with AIDS who are seropositive for antibodies to Toxoplasma gondii and have CD4+ T lymphocyte counts of < 100/mm3. Primary toxoplasmic infection usually is acquired by ingestion of T. gondii oocysts from soil contaminated by cat feces or by ingestion of tissue cysts present in undercooked red meats. In patients with AIDS, TE probably results from the reactivation of Toxoplasma tissue cysts that remained latent after the primary infection. Detection of IgG antibodies to Toxoplasma indicates prior infection and the possible presence of tissue cysts and, thus, risk for developing TE. A regimen of trimethoprim-sulfamethoxazole or dapsone plus pyrimethamine with leucovorin is recommended for persons infected with the human immunodeficiency virus (HIV) and who are seropositive for IgG to Toxoplasma after their CD4+ T lymphocyte counts fall to < 100/mm3. HIV-infected persons who are seronegative for IgG to Toxoplasma should be counseled to protect themselves from primary toxoplasmic infection by eating only well-cooked meats and washing their hands after outdoor activities involving soil contact; if they have a cat, they should feed it only commercial or well-cooked foods, keep it indoors, and make sure that the litter box is changed daily. HIV-infected persons who are Toxoplasma seropositive may also be advised about these preventive behavioral practices.

Topics: AIDS-Related Opportunistic Infections; Animals; Anti-Infective Agents; Cats; Dapsone; Drug Therapy, Combination; Encephalitis; Humans; Incidence; Leucovorin; Pyrimethamine; Recurrence; Risk Factors; Toxoplasmosis, Animal; Toxoplasmosis, Cerebral; Trimethoprim, Sulfamethoxazole Drug Combination; United States

Pyrimethamine (50 mg) with folinic acid (15 mg) given three times weekly was assessed as primary prophylaxis for toxoplasmic encephalitis (TE) in 554 human immunodeficiency virus-infected patients seropositive for Toxoplasma gondii and with < 200 CD4 cells/mm3. At 1 year, the incidence of TE was similar in pyrimethamine, 12%, and placebo, 13%, groups (relative risk [RR], 0.9; 95% confidence interval [CI], 0.6-1.4), and the survival rate was also similar, 85% and 80%, respectively (RR, 0.9; 95% CI, 0.7-1.2). Rash was the only adverse event that appeared significantly more frequently in the pyrimethamine arm (7% vs. 1%). In the on-treatment analysis, the incidence of TE was lower in the pyrimethamine arm, 4%, than in the placebo arm, 12% (P < .006). Thus, pyrimethamine cannot be recommended as a first-line regimen for primary prophylaxis of TE if the patient can take cotrimoxazole. However, it should be considered for patients who are intolerant to cotrimoxazole, especially in high-risk patients with < 100 CD4 cells/mm3.

Topics: Adult; AIDS-Related Opportunistic Infections; Animals; Anti-Infective Agents; Antibodies, Protozoan; Double-Blind Method; Drug Therapy, Combination; Encephalitis; Female; Follow-Up Studies; Humans; Leucovorin; Male; Multivariate Analysis; Pyrimethamine; Survival Rate; Toxoplasma; Toxoplasmosis; Toxoplasmosis, Cerebral

Topics: Antiprotozoal Agents; Drug Combinations; Drug Interactions; Drug Therapy, Combination; Encephalitis; Humans; Leucovorin; Pyrimethamine; Retrospective Studies; Sulfadiazine; Toxoplasmosis, Cerebral; Treatment Outcome

Although Toxoplasma gondii is the most commonly recognized cause of central nervous system mass lesions in patients with acquired immune deficiency syndrome, published investigations have provided little information about criteria for diagnosis of toxoplasmosis or the response to therapy. In this series the method of diagnosis and response to therapy were assessed in 14 patients who had evidence for toxoplasmosis based on routine histopathology, immunoperoxidase staining, or mouse inoculation. These patients presented with clinical and radiologic findings that did not clearly distinguish them from patients with other infectious or neoplastic processes. Excisional biopsies usually showed tachyzoites on routine histology, but needle biopsies were usually negative unless mouse inoculation or immunoperoxidase staining was employed. Response to pyrimethamine and sulfadiazine therapy was often prompt, but therapy had to be continued for long periods of time to maintain a clinical response, and no alternative regimen of one or more drugs appeared to be effective in patients unable to tolerate both pyrimethamine and sulfadiazine.

Topics: Acquired Immunodeficiency Syndrome; Adult; Antibodies; Drug Therapy, Combination; Encephalitis; Humans; Leucovorin; Male; Middle Aged; Pyrimethamine; Sulfadiazine; Tomography, X-Ray Computed; Toxoplasma; Toxoplasmosis

Topics: Acute Disease; Adult; Drug Therapy, Combination; Encephalitis; Humans; Leucovorin; Male; Pyrimethamine; Sulfadiazine; Toxoplasmosis