Temporal lobe involvement on CT is most characteristic of infection with which virus?

Temporal lobe involvement on CT is most characteristic of infection with which virus?

• A. Herpes simplex encephalitis
• B. Varicella
• C. West Nile virus
• D. Influenza

Answer: (A)

Temporal lobe involvement on CT points to herpes simplex encephalitis. HSV has a strong preference for the temporal lobes, leading to edema and often hemorrhagic necrosis in one or both medial/inferior temporal regions. On imaging, you’ll commonly see edema in the temporal lobes, and MRI is even more sensitive for these changes, with T2/FLAIR hyperintensity and diffusion restriction in the affected areas. Clinically, HSV encephalitis presents with fever, rapidly evolving altered mental status, and focal neurologic signs such as aphasia or memory disturbance, which is why urgent antiviral therapy is started while CSF PCR confirms HSV. Other viruses may cause encephalitis but do not show this temporal-lobe predilection: varicella-zoster can cause multifocal involvement, West Nile often affects the thalamus, brainstem, or cortex in a more diffuse pattern, and influenza encephalopathy is not specifically tied to temporal lobe lesions.

Temporal lobe involvement on CT points to herpes simplex encephalitis. HSV has a strong preference for the temporal lobes, leading to edema and often hemorrhagic necrosis in one or both medial/inferior temporal regions. On imaging, you’ll commonly see edema in the temporal lobes, and MRI is even more sensitive for these changes, with T2/FLAIR hyperintensity and diffusion restriction in the affected areas. Clinically, HSV encephalitis presents with fever, rapidly evolving altered mental status, and focal neurologic signs such as aphasia or memory disturbance, which is why urgent antiviral therapy is started while CSF PCR confirms HSV. Other viruses may cause encephalitis but do not show this temporal-lobe predilection: varicella-zoster can cause multifocal involvement, West Nile often affects the thalamus, brainstem, or cortex in a more diffuse pattern, and influenza encephalopathy is not specifically tied to temporal lobe lesions.