Anti-N-methyl-D-aspartate receptor encephalitis mimics neuroleptic malignant syndrome: case report and literature review

Figures & data

Figure 1 Anti-NMDA receptor antibodies in patient’s cerebrospinal fluid and serum. Anti-NMDA receptor antibodies were positive in cerebrospinal fluid (IgG, 1:32) (A) and serum (IgG, 1:320) (B) before immunotherapy. The level of anti-NMDA receptor antibodies significantly decreased in cerebrospinal fluid (IgG, 1:3.2) (C) and serum (IgG, 1:32) (D) after 5 months of immunotherapy.

Abbreviation: NMDA, N-methyl-D-aspartate.

Table 1 Clinical similarities, differences, and diagnostic features in anti-NMDA receptor encephalitis and NMS

	Anti-NMDA receptor encephalitis	NMS
Diagnostic criteria/features	– Mental status alteration	– Mental status alteration
	– Hyperthermia	– Hyperthermia
	– Rigidity/abnormal postures	– Rigidity
	– Psychiatric behavior
	– Autonomic dysfunction	– Autonomic dysfunction
		– Elevation of CK by at least four times the upper limit of normal
	– Seizures
Prodromal symptoms	Fever or headache	Changes in mental status
Onset	Rapid onset (less than 3 months)	Within 24 hours (16%), within 1 week (66%), within 30 days (96%)
Other reported features	Movement disorder	Tremor, sialorrhea, akinesia, dystonia, trismus, and myoclonus
	Speech dysfunction	Dysarthria and dysphagia
	Central hypoventilation	Leukocytosis
	Cognitive dysfunction	Metabolic acidosis
		Elevated catecholamines electrolyte changes
CK	No related reports	By at least four times the upper limit of normal
CSF	Pleocytosis or oligoclonal bands	Generally normal
Neuroimaging studies	Generally normal	Generally normal
EEG	Focal or diffuse, slow or disorganized activity, epileptic activity, extreme delta brush or nomal	Nonfocal generalized slowing (54%)
Outcome	About 80% patients recovered well (mRS score 0–2)	Mean recovery time is 7–10 days after drug discontinuation, and virtually all patients recover within 30 days

Abbreviations: NMDA, N-methyl-D-aspartate; NMS, neuroleptic malignant syndrome; CK, creatine kinase; CSF, cerebrospinal fluid; EEG, electroencephalography; mRS, modified Rankin Scale.