Which brain lobe is most involved in herpes simplex encephalitis?

• A. Frontal lobe
• B. Parietal lobe
• C. Temporal lobe
• D. Occipital lobe

Answer: (D)

Herpes simplex encephalitis classically targets the temporal lobe, especially the inferior and medial regions, due to HSV-1 spreading to the limbic system via the trigeminal pathways. This leads to a rapid clinical course with fever, altered mental status or coma, seizures, and focal deficits such as aphasia when the dominant temporal lobe is involved. Imaging typically shows edema and often hemorrhagic necrosis in the temporal lobes, which can be unilateral or bilateral. While other lobes can be affected, the temporal lobe involvement is the defining feature of HSV encephalitis, making it the most likely site. Occipital lobe involvement is not characteristic of this condition.