Here is an overview of NMS.
Learning objectives
-Recognize the tetrad of sx of NMS during patient care
-Diagnose NMS in practice
-Make recommendations to the team when suspecting NMS
Definition
- Neurologic emergency
- Syndrome associated with dopamine-blocking medications (especially antipsychotics)
- Can also be from removal of dopaminergic med (carbidopa-levodopa)
- Classic tetrad (diagnostic criteria):
- Mental status change
- Confusion > psychosis, may progress to stupor/coma
- Can see catatonia/mutism
- Rigidity
- Lead-pipe
- Hyperthermia
- Usually >38C, sometimes >40C
- Autonomic instability
- Tachycardia, labile/high BP, tachypnea, diaphoresis
- Mental status change
- NOTE: Some cases don’t have all of these criteria. Consider NMS when ANY 2 of the tetrad occur in the setting of an antidopamine drug.
- Sx usually evolve over 1-3 days after:
- High doses, rapid dose escalation, switching agents, parenteral administration
- Risk factors:
- Lithium or other psychotropics, depot formulations, substance use, neurologic disease, acute medical illness, dehydration, infection, surgery
Typical Labs
- Leukocytosis (10-40K)
- Elevated LDH, ALP, LFT
- Electrolyte abnormalities
- Hypocalcemia, hypomagnesemia, hypo/hypernatremia, hyperkalemia, metabolic acidosis
- Myoglobinuria from rhabdomyolysis
- Low serum iron common
- Elevated CK (1-10,000, can be much higher in severe cases)
Evaluation
- Diagnosis is confirmed by history (exposure to offending drug) and presence of supportive features. There is no single diagnostic test.
- Workup is to:
- Exclude other causes
- Detect complications
- There actually are DSM-TR criteria apparently but no single scoring system used in practice
DDx
- Serotonin syndrome
- More hyperreflexia, clonus, GI symptoms
- Malignant hyperthermia
- Anesthetic, succinylcholine exposure
- Malignant catatonia
- Intrathecal baclofen withdrawal
- Anticholinergic toxicity
- Stimulant intoxication
- Other serious conditions:
- CNS infection
- Sepsis
- Seizures
- Heat stroke
- Tetanus
- Alcohol withdrawal
- Thyrotoxicosis
- Pheochromocytoma
- Autoimmune encephalitis
- Acute porphyria
Management
- Stop offending drug immediately or restart dopaminergic drug
- Often requires ICU care
- Need to:
- Maintain cardiorespiratory stability, give IV fluids, treat rhabdomyolysis-related kidney injury, control hyperthermia, control severe HTN, provide DVT prophylaxis
- Meds that can be used:
- Lorazepam or other benzos
- Lorazepam 1-2mg IM or IV q4-6h
- Diazepam 10mg IV q8h
- Dantrolene: 1-2.5 mg/kg IV, can repeat up to 10 mg/kg/day
- Lorazepam or other benzos
- Bromocriptine: 2.5mg via NG tube q6-8h, titrate up to 40mg/day
- Amantadine: 100mg PO or via gastric tube initially, titrate up to 200mg q12h
- ECT
- Can be considered in refractory cases or when psychotropic tx is needed but can’t use antipsychotics
- Limited evidence
- Has safety risks, including cardiovascular complications
Possible complications
- Dehydration, electrolyte abnormalities, AKI, cardiac arrhythmias, MI, stress cardiomyopathy, respiratory failure, aspiration pneumonia, pulmonary embolism, VTE, sepsis
Prognosis
- Most cases resolve within 2 weeks, mean 4-11 days
- Longer illness in depot antipsychotics or structural brain disease
- Mortality: 5-10%, used to be higher
- Death from systemic complications
Restarting antipsychotics
- There is a risk of recurrence, but unknown degree of risk
- Wait at least 2 weeks, use low-potency agents, start low/go slow, avoid lithium/dehydration
- Monitor carefully
Richa Vijayvargiya, MD
Psychiatry Service Director, UF Shands
Associate Program Director, UF Psychiatry Residency
Assistant Clinical Professor
UF Department of Psychiatry
Consultation-Liaison Division
rvijayvargiya@ufl.edu
Gator Psychiatry 