In anti-NMDAR encephalitis (the most common autoimmune encephalitis), the characteristic CSF finding and initial clinical phase are:
- A Lymphocytic pleocytosis; initial psychiatric symptoms progressing to seizures, movement disorders, and autonomic instability ✓
- B Purulent CSF; early coma
- C Xanthochromic CSF; focal deficits mimicking stroke
- D Normal CSF; pure Parkinsonism without psychiatric features
Correct answer: A. Lymphocytic pleocytosis; initial psychiatric symptoms progressing to seizures, movement disorders, and autonomic instability
Explanation
Anti-NMDAR encephalitis typically begins with a prodromal viral illness followed by a psychiatric phase (psychosis, behavioural change), then progresses to seizures, movement disorders (orofacial dyskinesias, choreiform movements), decreased consciousness, and autonomic instability (hyperthermia, tachycardia, labile BP). CSF shows lymphocytic pleocytosis and elevated protein in most cases. Anti-NMDAR IgG antibodies are diagnostic. It is associated with ovarian teratoma in women (requires tumour removal) and is treatable with immunotherapy.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.