Understanding Neuroleptic Malignant Syndrome (NMS): Causes, Symptoms, and Treatment

Neuroleptic malignant syndrome (NMS) is a rare but potentially life-threatening reaction to antipsychotic drugs used to treat mental health conditions such as schizophrenia and bipolar disorder. NMS affects the nervous system, causing symptoms like high fever and muscle stiffness. While serious, NMS is treatable, and most people who receive early treatment make a full recovery.

Causes of Neuroleptic Malignant Syndrome

NMS is very rare, affecting only about 1 to 2 out of every 10,000 people who take antipsychotic drugs. All antipsychotic drugs can cause NMS, including older medications like chlorpromazine (Thorazine) and haloperidol (Haldol), as well as newer "atypical antipsychotics" like aripiprazole (Abilify) and quetiapine (Seroquel). These drugs block a brain chemical called dopamine, which can lead to muscle stiffness and rigid movements, particularly in people with Parkinson's disease.

Some factors that may increase the risk of developing NMS include:

• Taking a high dose of the antipsychotic drug

• Quickly increasing the drug dosage

• Receiving the medicine as an injection

• Switching from one antipsychotic drug to another

Certain drugs used to treat nausea and vomiting, such as metoclopramide (Reglan) and prochlorperazine (Compazine), can also cause NMS because they block dopamine. Additionally, people who take drugs for Parkinson's disease, such as levodopa, can develop NMS if they stop taking their medicine too quickly.

Symptoms of Neuroleptic Malignant Syndrome

NMS symptoms often start within 2 weeks of starting the antipsychotic medicine or changing the dosage. Sometimes, symptoms may appear a few days after starting the medication or even months later. The main symptoms of NMS include:

• High fever (102-104°F)

• Muscle stiffness

• Excessive sweating

• Anxiety or other changes in mental state

• Fast or abnormal heartbeat

• Rapid breathing

• Increased saliva production

If left untreated, NMS can lead to serious complications such as kidney failure, heart and lung failure, liver failure, lack of oxygen in the body, aspiration pneumonia, and increased acid levels in the body.

Diagnosing Neuroleptic Malignant Syndrome

To diagnose NMS, your doctor will ask about the medications you take and look for the main symptoms: high temperature, stiff muscles, and an altered mental state. They may also perform tests such as blood and urine tests, brain imaging scans, spinal fluid tests, and an electroencephalogram (EEG) to rule out other conditions with similar symptoms, such as serotonin syndrome and malignant hyperthermia.

Treating Neuroleptic Malignant Syndrome

NMS is treated as a medical emergency to lower the risk of complications. Treatment typically involves stopping the antipsychotic drug that caused the syndrome and providing supportive care in a hospital intensive care unit. This may include:

• Medications to relax tight muscles, such as dantrolene (Dantrium)

• Parkinson's disease drugs that increase dopamine production, such as amantadine (Symmetrel) or bromocriptine (Parlodel)

• Electroconvulsive therapy, if medications are ineffective

NMS usually improves within 1-2 weeks with proper treatment. After recovery, most people can resume taking antipsychotic medication, although the doctor may switch to a different drug. Close monitoring is essential, as NMS can recur. The longer a person waits to restart antipsychotic drugs, the lower the risk of NMS recurrence.

Key Takeaways

• Neuroleptic malignant syndrome is a rare but serious reaction to antipsychotic drugs used to treat mental health conditions.

• Symptoms of NMS include high fever, muscle stiffness, excessive sweating, and changes in mental state.

• Prompt medical attention is crucial if NMS is suspected, as delays in treatment can lead to serious complications.

• With proper treatment, most people recover completely from NMS.