Central Nervous System- Basic Neuropathology
Question No. 14. The Answer is: (C). The followings are true:
2. Encephalitis caused by a protozoal infection.
4. This lesion is an AIDS-defining disease.
Discussion: This picture shows a Toxoplasma gondii cyst in brain tissue stained with hematoxylin and eosin. Toxoplasma gondii is a protozoan parasite that infects most species of warm blooded animals, including humans, causing the disease toxoplasmosis. Acquired infection with Toxoplasma in immunocompetent persons is generally an asymptomatic infection. However, 10% to 20% of patients with acute infection may develop cervical lymphadenopathy and/or a flu-like illness. The clinical course is benign and self-limited; symptoms usually resolve within a few months to a year. Immunodeficient patients often have central nervous system (CNS) disease and also retinochoroiditis, or pneumonitis. In patients with HIV infection, toxoplasmic encephalitis is the most common cause of intracerebral mass lesions and is thought to be caused by reactivation of chronic infection. Toxoplasmosis of the CNS is an AIDS-defining disease.