Status Epilepticus – 5-Minute Threshold — SCE Neurology MCQ

Correct answer: D — Paired CSF and serum neuronal-surface antibody testing

The best answer is “Paired CSF and serum neuronal-surface antibody testing”. A delayed neuropsychiatric and movement syndrome after treated HSV encephalitis is a recognised trigger for autoimmune encephalitis, commonly anti-NMDAR, and requires paired antibody testing after excluding viral relapse. “Restart indefinite aciclovir without obtaining new immune studies” is less appropriate because negative repeat viral studies and the characteristic delayed phenotype argue against assuming persistent viral replication “Perform dopamine-transporter SPECT to diagnose a degenerative movement disorder” is less appropriate because dopamine-transporter imaging does not evaluate an acute post-encephalitic antibody syndrome “Arrange muscle biopsy for an inflammatory myopathy” is less appropriate because the abnormal movements and autonomic features localise to brain rather than muscle “Diagnose a primary psychiatric disorder without repeat neurological assessment” is less appropriate because the temporal neurological syndrome and dyskinesia require an organic assessment before psychiatric attribution

Reference: Autoimmune encephalitis after herpes simplex encephalitis. https://pmc.ncbi.nlm.nih.gov/articles/PMC4653102/ A clinical approach to diagnosis of autoimmune encephalitis. https://pmc.ncbi.nlm.nih.gov/articles/PMC5066574/