Nervous System- Infection & Inflammation I
Question No. 15. The Answer is: (A) Plasmodium falciparum.
Discussion: The characteristic macroscopic pathologic finding of malaria involving the central nervous system is generalized petechial hemorrhages of the brain. Although the distribution of the petechial hemorrhages is global, the white matter is more affected. In addition, there are also dusky discoloration, opacity of the leptomeninges, edema and congestion. Toxplasma gondii infection in a previously healthy and immunocompetent adult can manifest as meningoencephalitis, non-specific encephalopathy, and space occupying. The last presentation often lead to resection as these lesions tend to mimic brain tumors. Macroscopically, these lesions consists of a necrotic core surrounded by viable tissue. Viable organism are frequently found at the interface between the viable and necrotic tissue. Paragonimus westermani is a trematode that goes to the lung. In the central nervous system, they would manifest as space occupying lesions and cause papilloedema. Herpes simplex typically causes bilateral infarction of the temporal lobes. Involvement of the CNS by Entamoeba histolytica is a rare event and is usually but not always co-exists with hepatic and/or pulmonary involvement. The lesion is usually solitary and located in richly vascularized tissue such as the cortex and basal ganglia. In most cases, it is cavitated lesion containing necrotic debris and lined by congested and hyperemic tissue. Meningoencephalitis can also occur.
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