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Toxoplasma gundii

Definition: Damage to the CNS by T gondii is characterised by many foci of enlarging necrosis and microglia nodules. In infants, periaqueductal and periventricular vasculitis and necrosis are distinctive of toxoplasmosis. Necrotic areas can calcify and lead to striking radiographic findings suggestive—but not pathognomonic—of the disease. Hydrocephalus can result from obstruction of the aqueduct of Sylvius or foramen of Monro. Tachyzoites and cysts are seen in and adjacent to necrotic foci near or in glial nodules, perivascular regions, and cerebral tissue uninvolved by inflammatory change. Presence of many brain abscesses is the most characteristic feature of toxoplasmic encephalitis in severely immunodeficient patients and is especially characteristic in people with AIDS. Identification of tachyzoites is pathognomonic of active infection At autopsy in AIDS patients with toxoplasmic encephalitis, almost universal involvement of the cerebral hemispheres is noted, as is a remarkable predilection for the basal ganglia.In cases


  • congenital Toxoplasma gondii infection