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Case 2: Prophylaxis for Toxoplasma Encephalitis

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C The patient should add atovaquone (Mepron) to the dapsone to provide adequate prophylaxis for both Pneumocystis pneumonia and Toxoplasma encephalitis.

This answer is incorrect. For patients who cannot take trimethoprim-sulfamethoxazole, three regimens are considered acceptable alternatives for primary prophylaxis against Toxoplasma encephalitis: (1) dapsone plus pyrimethamine, (2) atovaquone plus pyrimethamine, or (3) atovaquone alone. The regimen of dapsone plus atovaquone has not been adequately studied and is not recommended as an alternative prophylaxis regimen for Toxoplasma encephalitis.

A The patient's positive IgG antibody to Toxoplasma shows evidence of immunity to Toxoplasma and thus she does not need prophylaxis against Toxoplasma encephalitis.
B The patient should receive prophylaxis for Toxoplasma encephalitis and the dapsone she takes for Pneumocystis prophylaxis will provide adequate prophylaxis against Toxoplasma encephalitis.
D The patient should receive prophylaxis for Toxoplasma encephalitis. Dapsone alone does not provide sufficient protection against reactivation of Toxoplasma; she should take pyrimethamine in addition to dapsone.

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