Herpes simplex encephalitis (HSE) is caused by HSV-1 in adults and characteristically involves which brain region, and what is the test of choice for rapid laboratory diagnosis?
- A Brainstem; MRI FLAIR sequences showing bilateral pontine lesions
- B Parietal cortex; electroencephalography showing delta activity
- C Basal ganglia; serum HSV IgM antibody ELISA
- D Temporal lobes and orbitofrontal cortex; CSF HSV PCR ✓
Explanation
HSV-1 encephalitis classically involves the temporal lobes (limbic encephalitis) and orbitofrontal cortex, reflecting the virus's spread along olfactory pathways. Clinical features include personality change, olfactory hallucinations, focal seizures, and temporal lobe features. CSF PCR for HSV DNA is the gold standard diagnostic test with sensitivity >95% and specificity approaching 100% when performed after 72 hours of symptoms; it avoids the need for brain biopsy. MRI shows T2/FLAIR hyperintensity in temporal lobes. Serum antibodies are not useful for acute diagnosis. EEG shows periodic lateralising epileptiform discharges (PLEDs) but is non-specific.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.