Download Neuroleptic Malignant Syndrome Synonyms of Neuroleptic

Neuroleptic Malignant Syndrome
Synonyms of Neuroleptic Malignant Syndrome
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Drug-Induced Movement Disorder
Hyperthermia
Neuroleptic-Induced Acute Dystonia
General Discussion
Neuroleptic malignant syndrome is a rare but potentially life-threatening reaction to the
use of almost any of a group of antipsychotic drugs or major tranquilizers (neuroleptics).
These drugs are commonly prescribed for the treatment of schizophrenia and other
neurological, mental, or emotional disorders. Several of the more commonly prescribed
neuroleptics include thioridazine, haloperidol, chlorpromazine, fluphenazine and
perphenazine.
The syndrome is characterized by high fever, stiffness of the muscles, altered mental
status (paranoid behavior), and autonomic dysfunction. Autonomic dysfunction alludes
to defective operations of the components of the involuntary (autonomic) nervous
system, leading to wide swings of blood pressure, excessive sweating and excessive
secretion of saliva.
A genetic basis for the disorder is suspected but not proven. It does appear to be clear
that a defect in the receptors to dopamine (dopamine D2 receptor antagonism) is an
important contributor to the cause of neuroleptic malignant syndrome.
Signs & Symptoms
Symptoms of neuroleptic malignant syndrome usually include very high fever (102 to
104 degrees F), irregular pulse, accelerated heartbeat (tachycardia), increased rate of
respiration (tachypnea), muscle rigidity, altered mental status, autonomic nervous
system dysfunction resulting in high or low blood pressure, profuse perspiration, and
excessive sweating.
Other symptoms may include liver or kidney failure, abnormally high potassium levels
(hyperkalemia), major destruction of skeletal muscle tissue (rhabdo-myolysis) or blood
clots in veins and arteries.
Causes
Neuroleptic malignant syndrome comes about, most likely, as a result of “dopamine D2
receptor antagonism”. Dopamine is a chemical substance (neurotransmitter) found in
the brain and elsewhere in the central nervous system that acts to convey messages
from one cell to another. In some way, the use of a particular drug blocks the receptor in
the brain cell for dopamine.
When the dopamine receptors in the hypothalamus or another bundle of nerve fibers
(nigrostriatal pathways) and/or the spinal cord are blocked, increased muscle rigidity is
the result. The interference with the dopamine receptors in the hypothalamus is also
probably responsible for high body temperature, as well as the swings in blood
pressure.
Some clinicians believe that neuroleptic malignant syndrome may be related to
malignant hyperthermia, a genetic disorder characterized by an abnormal reaction to
anesthesia drugs. (See related disorders section for more information about malignant
hyperthermia.)
Affected Populations
Neuroleptic malignant syndrome may affect any person taking neuroleptic drugs. Men
appear to be at higher risk than women. Some clinicians believe that the stronger
neuroleptic medications are more likely to precipitate an attack of NMS.
Although two-thirds of cases are thought to occur within the first week of start of
treatment, the syndrome may begin at any time during treatment.
Recurrence of an attack of NMS is not uncommon. The risk of recurrence is closely
related to the time elapsed between the end of the original episode of neuroleptic
malignant syndrome and the beginning of renewed administration of an antipsychotic
drug. If the waiting period is two weeks or less, about 63% will have a recurrence. If the
waiting period is more than two weeks, the percentage of patients experiencing a
relapse drops to about 30.
Related Disorders
Symptoms of the following disorders can be similar to those of neuroleptic malignant
syndrome. Comparisons may be useful for a differential diagnosis:
Anaphylaxis is an abnormally severe allergic reaction to a substance. Major symptoms
may include severe itching, hives, flushing, swelling, vomiting, diarrhea, difficulty
breathing and unconsciousness. High fever is not a symptom of this disorder. (For more
information on this disorder, choose “Anaphylaxis” as your search term in the Rare
Disease Database.)
Lethal catatonia is a condition similar to NMS and not infrequently confused with it. A
detailed history may indicate that the patient has endured catatonic states while not on
neuroleptic medications. If so, the chances are that the presenting syndrome is NMS. A
lethal catatonia patient will respond to the administration of neuroleptics. It is, however,
almost impossible to predict whether the patient’s symptoms will worsen or improve.
Patients with lethal catatonia almost invariably endure a period of agitation and
excitement prior to the catatonia. This is in contrast to the patient with NMS in which the
first symptom is usually muscular rigidity.
Heat stroke is a very serious condition characterized by an abrupt and rapid increase in
body temperature that may reach as high as 104 to 106 degrees F. Heat stroke usually
results from exposure to an extremely hot environment. The skin may become hot,
flushed and dry. Rapid loss of fluids may result in the inability to sweat. Sweating is
necessary to cool the body. There may also be an increase in pulse rate and
respiration. The affected individual may become disoriented and eventually experience
convulsions or slip into unconsciousness. Measures such as wrapping the individual in
cold, wet sheets should be taken immediately to lower body temperature. An individual
suffering from heat stroke should be hospitalized as quickly as possible. (For more
information on this disorder, choose “Hyperthermia” as your search term in the Rare
Disease Database.)
Malignant hyperthermia is a genetic disorder characterized by an abnormal response to
muscle relaxants and general anesthesia drugs. Symptoms of Malignant Hyperthermia
are apparent only after the patient has been placed under general anesthesia. Along
with rapidly elevating body temperature that may rise as high as 110 degrees, muscle
rigidity and/or muscle twitching occurs. The patient may also exhibit a very rapid and
irregular heartbeat, abnormally low blood pressure, sickly sweet breath, headache,
nausea and vomiting. It is not known whether neuroleptic malignant hyperthermia is a
variant form of Malignant Hyperthermia, but some researchers have suggested that
these disorders may be related. (For more information on this disorder, choose
“Malignant Hyperthermia” as your search term in the Rare Disease Database.)
The serotonin syndrome mimics neuroleptic malignant hyperthermia. If the use of
selective serotonin reuptake inhibitors (SSRIs) results in symptoms such as altered
mental state, autonomic dysfunction (see above), and neuromuscular defects, then the
condition is likely to be serotonin syndrome. Since SSRIs are being used in increasing
amounts, it is not unreasonable to expect that the incidence of serotonin syndrome will
increase as well. The serotonin syndrome may be distinguished from NMS in most
cases by a detailed history in which any changes in medication and/or dosages are
clarified. In addition, serotonin syndrome usually is not accompanied by severe muscle
rigidity.
The following disorder may be associated with the extended use of neuroleptic drugs. It
is not necessary for a differential diagnosis:
Tardive dyskinesia is a disorder that results from the long-term use of neuroleptic drugs
and is characterized by involuntary and abnormal movements of the jaw, lips and
tongue. Typical symptoms include grimacing, sticking out the tongue, and sucking or
fishlike movements of the mouth. A high percentage of schizophrenic people who have
spent long periods of time in mental hospitals taking neuroleptic drugs have a high risk
of developing tardive dyskinesia. (For more information on this disorder, choose “tardive
dyskinesia” for your search term in the Rare Disease Database.)
Diagnosis
The diagnosis of neuroleptic malignant syndrome is based on the presence of
characteristics that include treatment with neuroleptic drugs within the past 1-4 weeks.
high body temperature (greater than 38 degrees centigrade); muscle rigidity; and at
least five of the following:
Change in mental status
Rapid heart beat (tachycardia)
Low or high blood pressure (hypo- or hypertension)
Excessive sweating (diaphoresis)
Excessive saliva production (sialorrhea)
Tremor
Incontinence
Increased creatine phosphokinase, or increased urinary myoglobin
Increased number of white blood cells (leukocytosis)
Increased concentrations of metabolic acids in blood and urine
Exclusion of other drug-induced psychiatric or systemic illness.
Standard Therapies
Treatment
Treatment of neuroleptic malignant syndrome consists of withdrawal of
neuroleptic medications under a doctor's supervision, immediate measures to restore
appropriate water and nutrient levels, and steps to lower the individual's body
temperature. Medications prescribed as treatment may include skeletal muscle
relaxants, such as dantrolene; stimulators of dopamine production and activity, such as
bromocriptine; and/or continuous perfusion of central nervous system depressants,
such as diazepam.
Complications that may result from neuroleptic malignant syndrome, such as kidney
(renal) insufficiency, deficiency of oxygen reaching the tissues (hypoxia), and/or
decreased alkalinity of the blood and tissues (acidosis) can be extremely serious and
must be treated immediately. Once patients have recovered from neuroleptic malignant
syndrome, about 87% will be able to tolerate an antipsychotic at some point in the
future. Physicians usually switch to a different antipsychotic class and to an atypical
antipsychotic. Such patients must be carefully monitored since recurrences of
neuroleptic malignant syndrome are not infrequent.
Electroconvulsive treatments have been prescribed for patients with neuroleptic
malignant syndrome with varied results.
Investigational Therapies
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All
studies receiving U.S. government funding, and some supported by private industry, are
posted on this government website.
For information about clinical trials being conducted at the National Institutes of Health
(NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com
Supporting Organizations
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Malignant Hyperthermia Association of the United States
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MedicAlert Foundation International
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3803 N. Fairfax Drive
Suite 100
Arlington, VA 22203Phone: (703) 524-7600
Toll-free: (800) 999-6264
Email: [email protected]
Website: http://www.nami.org
National Mental Health Consumers’ Self-Help Clearinghouse
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2000 N. Beauregard Street, 6th Floor
Alexandria, VA 22314-2971 USA
Phone: (703) 684-7722
Toll-free: (800) 969-6642
Email: [email protected]
Website: http://www.mentalhealthamerica.net/
National Alliance on Mental Illness
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2323 Colorado Avenue
Turlock, CA 95382 USA
Phone: (209) 669-2401
Toll-free: (888) 633-4298
Email: [email protected]
Website: http://www.medicalert.org
Mental Health America
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1 North Main St
PO Box 1069
Sherburne, NY 13460 USA
Phone: (607) 674-7901
Email: [email protected]
Website: http://www.mhaus.org
1211 Chestnut Street
Suite 1207
Philadelphia, PA 19107-6312 USA
Phone: (215) 751-1810
Toll-free: (800) 553-4539
Email: [email protected]
Website: http://www.mhselfhelp.org
NIH/National Institute of Mental Health
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Health Science Writing, Press and Dissemination Branch
6001 Executive Boulevard
Bethesda, MD 20892-9663
Phone: (301) 443-4513
Toll-free: (866) 615-6464
Email: [email protected]
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Website: http://www.nimh.nih.gov/index.shtml
North American Malignant Hyperthermia Registry
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Penn State University
Dept. of Anesthesiology
Hershey, PA 17033-0850 USA
Phone: (412) 692-6390
Toll-free: (888) 274-7899
Email: [email protected]
Website: http://www.mhreg.org