Tetrabenazine treatment for Huntington's disease-associated chorea

Tetrabenazine (TBZ), a monoamine depleter and dopamine receptor blocker, is used to treat a variety of hyperkinetic movement disorders. The objective was to study the efficacy and tolerability of TBZ for chorea associated with Huntington's disease (HD). Nineteen patients (12 female), mean age 56.3 +/- 12.4 years (range 37-76 years) diagnosed with HD were prospectively evaluated at initial and follow-up visits using a modified Abnormal Involuntary Movement Scale (AIMS). Patients were videotaped, and the randomized videotapes were rated with the motor subset of the AIMS by two investigators who were blinded to treatment assignment. Eighteen patients completed and were rated after 5.9 +/- 3.3 months (range 2-11) at a final mean TBZ dose of 62.5 +/- 37.4 mg/day (range 25-150). The blinded videotaped motor scores showed that 15 were better on TBZ, 2 were better before TBZ, and 1 was unchanged (p < 0.001, Wilcoxon signed rank test). The mean score improved from 16.2 +/- 4.8 to 12.8 +/- 4.4. Adverse events included akathisia, insomnia, constipation, depression, drooling, and subjective weakness. All 18 of these patients have continued to take TBZ since completion of the study. TBZ was well tolerated and resulted in a significant improvement in modified AIMS scores in HD patients. These results support the use of TBZ for chorea in patients with HD.     

Huntington's chorea and tryptophan

Daily use of 7 g l-tryptophan and 70 mg pyridoxine for 14 days led to no deterioration of objectively measured manual motor skills in a small group of patients with Huntington''s chorea.     

Iatrogenic parkinsonism in Huntington's chorea

This case report describes a 63 year old woman with a nineteen year history of Huntington's Chorea who had been successfully treated with tetrabenazine for 9 years. During a hospital admission for an unrelated medical illness, she was given two doses of chlorpromazine 25 mg for a vascular headache and within hours became mute, extremely rigid, and unable to move or swallow. The consultation psychiatrist confirmed the diagnosis of severe drug-induced parkinsonism by intramuscular injection of benztropine mesylate which resulted in a dramatic immediate improvement. Both chlorpromazine and tetrabenazine were discontinued and the patient's severe parkinsonian symptoms completely abated on oral benztropine mesylate. Tetrabenazine alone, was restarted after 48 hours to control her Huntington's Chorea and there was no recurrence of parkinsonism. (Past history revealed the patient to have tolerated the same doses of chlorpromazine and tetrabenazine when given separately.) Previous literature reports concurrent safe use of antipsychotics with tetrabenazine, but this case report would suggest caution, and early discontinuance in the event of parkinsonism.     

Kluver-Bucy syndrome in Huntington's chorea

In this paper the first case of Kluver-Bucy syndrome (KBS) in Huntington's chorea is reported. The patient, a 46-year-old man with advanced Huntington's disease, displayed prosopagnosia, oral tendencies, emotional changes, hypersexual behavior, and hyperphagia associated with severe dementia. Haloperidol in moderate doses controlled both the KBS and the chorea, suggesting a possible role for the dopaminergic system in the pathogenesis of KBS in Huntington's disease. The presence of profound dementia in our patient supports the previous assertion that human cases of KBS are invariably associated with severe cognitive dysfunction. Since KBS was established as an entity, a great deal of attention has been directed to its neuroanatomical basis. However, due to the multidetermined nature of human behavior, the role of physiological, psychological, and environmental factors should also be taken into consideration with regard to the pathogenesis of this syndrome.