Which of the following statements regarding (NMS) is correct?

A. The syndrome usually occurs after the first dose of a medication.
B. Resolution of symptoms usually occurs within 24 hours.
C. No routine laboratory test is diagnostic for NMS.
D. Symptoms associated with injectable (depot) neuroleptics are not usually prolonged.
E. Risk factors for the development of NMS have not been identified.
 

• Answer C is correct.

• Laboratory findings are not diagnostic for NMS.

• They are useful to rule out other disorders.
• There is some work with CSF monoamine and metabolite levels, which may prove to be useful.  This is still experimental and warrants much further investigation.

• Laboratory features of NMS include:

• Leukocytosis (15,000 – 30,000) in > 90% of patients
• Elevation of serum creatinine phosphokinase (up to 15,400 IU) in > 90% of patients
• Elevated liver transaminase enzyme levels in > 75% of patients

• The syndrome may occur after the first dose of a drug or after many years of exposure to the drug.

• The syndrome is usually seen within two weeks of initiating antipsychotic treatment, but there have been cases of late onset reported (up to years later).

• Neuroleptic malignant syndrome lasts from 5 to 10 days except in the event that long-acting depot injections (e.g., fluphenazine or haloperidol) are involved.

• When neuroleptic depot injections are involved, the course of NMS may last 2 to 3 times longer.

• Risk factors for the development of NMS include organic brain syndrome, physical dehydration, and exhaustion.  Additionally, NMS is more commonly seen in young males. Over 80% of all cases have been seen with patients less than 40 years of age, the average age being 35.

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