The above described radiological findings are impressive of Herpes simplex encephalitis. The mortality from HSV is high, so commencement of treatment with antiviral drugs (acyclovir) is recommended without delay with the typical radiological findings in the right clinical settings. Moreover, Herpes simplex encephalitis presenting with normal CSF analysis is reported!
The main diiferential diagnosis is:
- MCA infarct: usually involves the basal ganglia (PUTAMEN).
- Limbic encephalitis: paraneoplastic syndrome with non-CNS 1ry malignant tumor; classically small cell carcinoma of the lung. HSV encephalitis in a cancer patient is a big dilemma!
- Gliomatosis cerebri: ill-defined T2 hyerintense lesion involving two or more lobes of the brain with diffuse enlargement of the affected brain. Minimal mass effect and enhancement. Clinical symptoms are usually diconcordant with the radiological manifestations with usually little symptoms. MR spectroscopy may be a problem solving in some cases.