Neuroleptic malignant syndrome (NMS) is a rare neurological condition associated with the use of antipsychotic medications. Autonomic dysfunction, or damage to the nerves that control involuntary bodily functions, is a key feature of the condition.
The condition can lead to life threatening complications in people who do not receive treatment quickly enough, but most who receive immediate treatment recover.
In this article, we look at the symptoms of NMS, along with its causes, treatment options, and risk factors.
NMS is a rare and potentially deadly reaction to the use of antipsychotic medications. These medications, also called neuroleptics, prevent the overactivity of dopamine. Dopamine is a neurotransmitter that carries messages between cells.
NMS affects approximately
People typically develop symptoms of NMS within
- muscle rigidity
- autonomic dysfunction
- altered mental status
According to the Diagnostic and Statistical Manual of Mental Disorders: Fifth Edition (DSM-5), a person must have all three of the following for a doctor to diagnose NMS:
- exposure to a dopamine-blocking medication
- extreme muscle rigidity
The DSM-5 states that they should also exhibit a minimum of two of the following:
- excessive sweating
- difficulty swallowing
- altered level of consciousness
- fast resting heart rate
- elevated blood pressure, or blood pressure that fluctuates between normal and high
- high white blood cell count
- elevated levels of the enzyme creatine phosphokinase (CPK)
A doctor may take a blood test and urine sample to check for altered levels of white blood cells, CPK, blood pH, electrolytes, and liver enzymes.
A normal white blood cell count is
NMS is a rare condition that can occur as a result of exposure to antipsychotic drugs. Doctors use these drugs, which decrease dopamine activity, to treat various neurological disorders.
Abruptly stopping medication that increases dopamine activity, such as the medications for Parkinson’s disease, can also cause NMS.
While NMS treatment is highly individualized and differs in each case, a doctor will first try to stabilize the person by correcting their blood pressure, heart rate, electrolyte levels, and blood pH. They will also ensure that the individual is properly hydrated.
People with NMS are at a greater risk of abnormal heart rates due to autonomic dysfunction and may need treatment in the form of
In some rare situations, doctors may also prescribe electroconvulsive therapy (ECT). In these cases, the doctor will admit a small electric current to the brain when the person is asleep. ECT
Malignant hyperthermia (MH) is a potentially fatal condition that is similar to NMS. MH is a severe reaction to an inhalation anesthetic or muscle relaxer. It occurs due to a rare genetic mutation that a person inherits from one or both parents.
MH affects approximately
NMS and MH produce similar symptoms, including fever, muscle rigidity, and an elevated heart rate.
NMS also has similarities to an acute dystonic reaction, a side effect of antipsychotic medications that causes severe muscle spasms. However, an acute dystonic reaction will not cause autonomic dysfunction, fevers, or mental status changes.
The main difference between NMS and MH is the cause of symptoms. NMS is a reaction to antipsychotic medication, whereas MH is a reaction to an anesthetic or muscle relaxer that occurs due to a genetic abnormality.
The main risk factor for developing NMS is taking antipsychotic medication. While some more potent drugs may increase a person’s risk, all antipsychotic medications can cause this condition. Taking more than one antipsychotic drug can also increase a person’s risk of developing NMS.
- high temperature
- physical restraint
- previous NMS
- a family history of catatonia
- muscle channelopathy, which is an inherited muscle fiber disorder
Men are also
With treatment, most individuals with NMS will recover within
If a person does not receive treatment for NMS quickly enough, they can develop serious
While NMS can be life threatening, fewer than
NMS is a rare reaction to antipsychotic medications. The symptoms include an altered mental status, muscle rigidity, autonomic dysfunction, and fever.
Although some people with NMS can develop fatal complications, most people recover after a few days of receiving the correct treatment.