Neuroleptic malignant syndrome (NMS) is a life-threatening, neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs.
Causes
NMS is caused almost exclusively by antipsychotics, which includes all types of neuroleptic medicines along with newer antipsychotic drugs. The higher the dosage, the more common the occurrence. Rapid and large increases in dosage can also be attributed with the development of NMS. Other drugs, environmental or psychological factors, hereditary conditions, and specific demographics may be at greater risk, but to date no conclusive evidence has been found to support this. The disorder typically develops within two weeks of the initial treatment with the drug, but may develop at any time that the drug is being taken. NMS may also occur in people taking a class of drugs known as
dopaminergics.
Signs and Symptoms
The first symptom to develop is usually muscular rigidity, followed by high
fever and changes in
cognitive functions. Other symptoms can vary, but may be unstable
blood pressure, confusion,
coma,
delirium,
muscle tremors, etc. Once symptoms do appear, they rapidly progress and can reach peak intensity in no more than three days. These symptoms can last as little as eight hours or as long as forty days.
A raised creatine phosphokinase (CK) plasma concentration will be reported due to increased muscular activity. The patient may be hypertensive and suffering from a metabolic acidosis. A non-generalised slowing on an EEG is reported in around 50% of cases.
Mnemonic
A
mnemonic used to remember the features of NMS is:
FEVER.
[Identify neuroleptic malignant syndrome. schizophrenia.com URL: http://www.schizophrenia.com/sznews/archives/002054.html. Accessed: July 2, 2006.]
Prognosis
As with most illnesses, the prognosis is best when identified early and treated aggressively. In these cases NMS is usually not fatal, although there is currently no agreement on the exact mortality rate for the disorder. Studies have given the disorder a mortality rate as low as 5% and as high as 76%, although most studies agree that the correct percentage is in the lower spectrum, perhaps between 10% - 15%. Re-introduction to the drug that originally caused NMS to develop may also trigger a recurrence, although in most cases it does not.
Treatment
Although treatment is not always necessary, it will help to cure the disease and prevent fatal developments from occurring. The first step in treatment is generally to remove the patient from any neuroleptic or antipsychotic drugs being taken and to treat fever aggressively. Many cases require intensive care, or some kind of supportive care at the minimum. Depending on the severity of the case, patients may require other treatments to contend with specific effects of the disorder. These include circulator and ventilatory support, the drugs
dantrolene sodium,
bromocriptine,
apomorphine and
electroconvulsive therapy (ECT) if medication fails.
Differential diagnosis
The clinical features of NMS and serotonergic syndrome are very similar. This can make differentiating them very difficult.
Features, classically present in NMS, that are useful for differentiating the two syndromes are:[ Full Free Text.]
History
NLM was known about as early as
1956, shortly after the introduction of the first
phenothiazines, and is derived from the
French syndrome malin des neuroleptiques.
[Friedberg JM. Neuroleptic malignant syndrome. URL: http://www.idiom.com/~drjohn/biblio.html. Accessed: July 3, 2006.]
References
External links
Still a risk, but which patients may be in danger?] - currentpsychiatry.com.
Antipsychotics | Medical emergencies | Miscellaneous psychiatric disorders | Psychiatry