Tardive dyskinesia

Tardive dyskinesia
Classification and external resources
File:Dopamine-3d-CPK.png Dopamine
ICD-10	G24.0
ICD-9	333.85
OMIM	272620
DiseasesDB	12909
eMedicine	neuro/362

Tardive dyskinesia (pronunciation) is a difficult-to-treat form of dyskinesia (disorder resulting in involuntary, repetitive body movements) that can be tardive (having a slow or belated onset). It is often seen as a side effect of long-term or high-dose use of certain antipsychotic medicines.

Features

Tardive dyskinesia is characterized by repetitive, involuntary, purposeless movements, such as grimacing, tongue protrusion, lip smacking, puckering and pursing of the lips, and rapid eye blinking. Rapid movements of the extremities may also occur. Impaired movements of the fingers may also appear. For comparison, patients with Parkinson's disease have difficulty moving, while patients with tardive dyskinesia have difficulty not moving.

Other closely related neurological disorders have been recognized as variants of tardive dyskinesia. Tardive dystonia is similar to standard dystonia but permanent. Tardive akathisia involves painful feelings of inner tension and anxiety and a compulsive drive to move the body. In the extreme, the individual undergoes internal torture and can no longer sit still. Tardive tourettism is a tic disorder that can closely mimic Tourette Syndrome, sometimes to the point where the two can only be distinguished by the details of their onsets. Tardive myoclonus, a rare disorder, presents as brief jerks of muscles in the face, neck, trunk, and extremities.

Cause

Despite the fact that tardive dyskinesia was described 50 years ago, its mechanism is poorly understood. The most compelling line of evidence suggests that tardive dyskinesia may result primarily from neuroleptic-induced dopamine supersensitivity in the nigrostriatal pathway, with the D2 dopamine receptor being most affected. Neuroleptics act primarily on this dopamine system, and older neuroleptics, which have greater affinity for the D2 binding site, are associated with high risk for tardive dyskinesia. The D2 hypersensitivity hypothesis is also supported by evidence of a dose-response relationship, withdrawal effects, studies on D2 agonists and antagonists, animal studies, and genetic polymorphism research.

Given similar doses of the same neuroleptic, differences among individuals still exist in the likelihood of developing tardive dyskinesia. Such individual differences may be due to genetic polymorphisms, which code for D2 receptor binding site affinity, or prior exposure to environmental toxins. Decreased functional reserve or cognitive dysfunction, associated with aging, mental retardation, alcohol and drug abuse, or traumatic head injuries, has also been shown to increase risk of developing the disorder among those treated with neuroleptics.

Other dopamine antagonists can cause tardive dyskinesia, such as metoclopramide, used to treat gastrointestinal disorders. While newer atypical antipsychotics such as olanzapine and risperidone appear to have fewer dystonic effects, only clozapine has been shown to have a lower risk of tardive dyskinesia than older antipsychotics.

The available research seems to suggest that the concurrent prophylactic use of a neuroleptic and an antiparkinsonian drug is useless to avoid early extrapyramidal side-effects and may render the patient more sensitive to tardive dyskinesia. Since 1973 the use of these drugs has been found to be associated with the development of tardive dyskinesia (Crane, 1973). Since some of the symptoms of tardive dyskinesia can be interpreted as schizophrenia by doctors, they may prescribe additional neuroleptic drugs to treat it, leading to increased risk of more prevalent tardive dyskinesia. Several studies have indicated that long-term neuroleptic use is associated with both cognitive deterioration and atrophy of the brain.

Treatment

Primary prevention of tardive dyskinesia is achieved by using the lowest effective dose of a neuroleptic for the shortest time. If tardive dyskinesia is diagnosed, the causative drug should be discontinued. Tardive dyskinesia may persist after withdrawal of the drug for months, years or even permanently.

The dopamine-depleting drug tetrabenazine has been used to treat tardive dyskinesia and other movement disorders.

Zofran has shown some benefit in experimental studies on tardive dyskinesia and a variety of anti-Parkinsonian medications are used such as Aricept, Baclofen, Requip and Mirapex. Clonidine is used for dystonic spasms and can be of help. Botox injections are used for minor focal dystonia, but not in more advanced tardive dyskinesia.

A review paper found benzodiazepines to be effective in alleviating the symptoms of tardive dyskinesia. Examples of benzodiazepine drugs include lorazepam (Ativan), diazepam (Valium), or clonazepam (Klonopin).

Natural remedies, such as vitamin E (Alpha-Tocopherol), rhodiola, omega 3 fatty acids or melatonin are unproven since they are seldom tested in a controlled setting such as a drug trial.

Epidemiology

Tardive dyskinesia most commonly occurs in patients with psychiatric conditions who are treated with antipsychotic medications for many years. One study reported that within the first four years of using antipsychotic medications, 18.5 percent of young adults develop symptoms. Furthermore, 31 percent of those over 55 years of age develop tardive dyskinesia symptoms in the same time frame . Other estimates suggest that it occurs in 15-30% of patients receiving treatment with antipsychotic neuroleptic medications for 3 months or longer. “A study being conducted at the Yale University School of Medicine has estimated that 32% of patients develop persistent tics after 5 years on major tranquilizers, 57% by 15 years, and 68% by 25 years.” Other estimates suggest that with each year of neuroleptic use, 5% of the patients will show signs of tardive dyskinesia, i.e., 5% after one year, 10% after two years, 15% after three years with no clear upper limit. Eventually, according to these estimates, if on the drugs long enough, the majority of patients will develop the disorder. The incidence of tardive dyskinesia varies with the type of neuroleptic (e.g., haloperidol (Haldol) more often than perphenazine (Trilafon)), daily dose and duration of treatment (the higher the daily dose and the longer the duration of treatment, the higher the risk).

The elderly and female patients are more prone to develop tardive dyskinesia. Cigarette smokers also have a higher prevalence of tardive dyskinesia. Children and adolescents are much more sensitive to the early and late extrapyramidal side-effects of neuroleptics than adults. Because of this, treatment of youngsters with neuroleptics may be contraindicated, and many authorities believe that they should be initiated only as a last resort, using the lowest dose regime possible and the shortest duration of treatment in accordance with good patient management.

Tardive dyskinesia can become disabling socially and cause people to self isolate, due to the societal stigma as well. Patients and/or their families (guardians and/or caregivers/nurses) should receive full information about the neuroleptic before starting treatment (informed consent).The benefits need to be weighed by the individual patient/guardian and their physician. However, the antipsychotic clozapine is not known to cause tardive dyskinesia and can be an option and is not used on a more widespread basis because of blood dyscrasias as well as other side effects of concern.

The still hypothetical conditions Tardive Psychosis, tardive dysphrenia and tardive dysmentia remain little understood and as yet unconfirmed. New classes of antipsychotics in study such as glycine and other NMDA Receptor Modulators in not affecting the dopaminergic system in Phase II FDA studies have been shown not to cause tardive dyskinesia and may, once realized as FDA approved antipsychotics, be a new treatment modality that will not create this condition.

See also

• Primary ciliary dyskinesia
• Athetosis
• Asterixis

External links

• tardive at NINDS
• Jenelle's story report on a patient at antipsychiatry.org.
• Tardive Dyskinesia at Psyweb.com at psyweb.com
• Photographs and Video of TD (biased view of psychiatry) at yoism.org
• Practical Gastroenterology article with Plain English description of all symptoms of EPS-TD and links to testing guidelines. at reflux.org
• http://emedicine.medscape.com/article/1151826-overview
• http://emedicine.medscape.com/article/1151826-treatment
• http://www.wemove.org/td/
• http://www.bcm.edu/neurology/patient_education/pdcmdc/td.html
• http://www.nslij.com/body.cfm?id=4458ar:تارديف ديسكنيزيا

sv:Tardiv dyskinesi