Smoking induced worsening of dystonia a case report

Several biochemical abnormalities have been observed in the brain of patients with primary dystonia, mainly involving norepinephrine, serotonin and dopamine.1 Another neurotransmitter that is also probably involved in dystonia is the cholinergic system, as evidenced by the response to treatment with anticholinergics. However, it is not clear which of these is pathophysiologically related to the development of dystonia.1 There are only three published reports which suggest an association between nicotinic cholinergic system and dystonia, however with conflicting roles.2-4 We report here a patient with multifocal dystonia, predominantly cervical, which used to worsen after smoking and later showed improvement with anticholinergics and cessation of smoking, thus supporting the role of nicotinic cholinergic system in dystonia. Our patient was a 31-years-old man symptomatic for the past 10 years with difficulty in speaking which had increased in severity over the past 2 years. It was characterized by difficulty in pronouncing the words clearly with nasal quality to voice and occasionally he also felt that he had to strain more while speaking. For the past 2 years he also noted abnormal posturing of the neck in the form of turning towards right side, which was associated with neck pain, and difficulty in moving the neck sideward. There was no history suggestive of dystonia affecting other parts of the body, no sleep benefit or diurnal fluctuation, exposure to any toxins or neuroleptics. He did not have any significant family history of neurological illness. The patient was a chronic smoker, smoking cigarette for more than 6 years. However, recently, for the past few months, he noted that after smoking 1 to 2 cigarettes his abnormal movements of neck as well as the neck pain worsened significantly. This used to occur approximately 5 to 10 min after smoking and lasted for an hour. On examination he was found to have involuntary movements in the form of rotation of head to right side, elevation of right shoulder, mild retrocollis, facial grimacing, pouting of lips and increased frequency of blinking. When he spoke these abnormal movements worsened and he had predominantly adductor type of dysphonia. In addition he had mild postural tremors of both hands and minimal dystonia of both hands was noticed on walking. Rest of the neurological and systemic examinations was normal. There was no Kayser-Fleischer ring in the cornea and the MRI of brain was normal. The patient was further evaluated, using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) before and after smoking to objectively confirm the symptomatic worsening of the cervical dystonia reported by him. The TWSTRS score was 36 before smoking (baseline) (Video Segment 1), 45.5 5 minutes after smoking 2 cigarettes (Video Segment 2), and again reduced to 35.5 2 hours after smoking. He also had increased blinking, worsening of facial grimacing, and neck pain after smoking, but no evidence of worsening of hand dystonia. The patient was started on trihexyphenidyl 2 mg/day and slowly increased to 30 mg/day. He was also counseled regarding the benefits of smoking cessation. After 3 weeks of therapy he showed significant improvement in his symptoms both pain and dystonia and the TWSTRS score was 24.5 (Video Segment 3). During this period patient also had stopped smoking completely. He continued to maintain improvement at follow up visit after 4 weeks. There are three previously published reports which had shown a possible role of nicotine in the pathophysiology of dystonia.2-4 These reports had showed that nicotine improved in dystonia in 2 patients and worsened in another 2 patients.2-4 The patients who had worsening with nicotine had primary dystonia in the form of writer's cramp.3 On the contrary, the 2 patients with dystonia who had shown improvement with smoking and subsequently with nicotine had dystonia due to underlying secondary causes. One patient had developed dystonia after an encephalitic illness4 and other had developed dystonia following childhood hemiplegia.2 It is noteworthy that both these patients had associated spasticity, thus having secondary dystonia. The differences in the etiologies of dystonia probably contributed to the difference in the response to nicotine in patients with dystonia. Similar to that reported by Murase et al.3 in writer's cramp which is a form of primary dystonia, our patient who had, predominantly cranial dystonia, also worsened with smoking and subsequently showed improvement with smoking cessation and anticholinergics. The exact mechanism of effect of smoking and nicotine in either improving or worsening dystonia is unknown, primarily because there are only few documented cases. The major component of cigarette smoke that is responsible for addiction and other effects on the central nervous system is nicotine, which acts through nicotinic cholinergic receptors (nAChR).5 Nicotinic receptor activation after smoking facilitates the release of neurotransmitters. Most of this release is believed to occur via modulation by the presynaptic nAChRs. Other neurotransmitters, including norepinephrine, acetylcholine, serotonin, γ-aminobutyric acid, glutamate, and endorphins are released as well, mediating various behaviors of nicotine. There is also evidence of both nicotine and cigarette smoking improving symptoms of Parkinson's disease6 and this may be a result of augmentation of release of dopamine from the basal ganglia.7 Finally, dopamine-depleting agents or blockers have been used in treating dystonias. Therefore, it is not surprising that cigarette smoking or nicotine can aggravate primary dystonias as demonstrated in our patient and that reported by Murase et al.3 Smoking or nicotine induced worsening of dystonia could be also due to facilitation of release of acetylcholine8 or stimulation of nicotinic acetylcholine receptors in the brain. Since our patient also had benefit from trihexyphenidyl, which is only a muscarinic receptor blocker, the former mechanism can at least be implicated in the worsening of dystonia. In summary, our case illustrates a rare and interesting observation, which needs to be studied further. Apart from clinical documentation, functional imaging in dystonic patients before and after smoking may be useful in elucidating the role of smoking in dystonia. Finally, for evaluation of the efficacy of any medical or therapeutic interventions in a patient of dystonia who is also a smoker, concomitants effects of smoking should also be considered. Segment 1. Dystonia before smoking. Segment 2. Worsening of dystonia after smoking. Segment 3. On treatment with trihexiphenidyl; stopped smoking. (1) Research Project: Organization, Conception, Execution, (D.K. Prashantha, P.K. Pal); (2) Statistical Analysis: Not applicable; (3) Manuscript: Writing of the first draft (D.K. Prashantha), Review and Critique (D.K. Prashantha, major contribution by P.K. Pal); (4) Video capturing and editing: (D.K. Prashantha, major contribution by P.K. Pal). Additional Supporting Information may be found in the online version of this article. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. D. K. Prashantha MD*, Pramod Kumar Pal MD, DM*, * Department of Neurology, National Institute of Mental Health & Neurosciences, Bangalore, India.

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