ARTICLE IN PRESS Case Studies Acute Onset Dystonia after Infarction of Premotor and Supplementary Motor Cortex Monica B. Dhakar, MD, MS,* Carla Watson, MD,† and Kumar Rajamani, MD* Objective: Poststroke dystonia is the second most common movement disorder after chorea and often has a delayed manifestation. Lesions of the contralateral lenticular nucleus, particularly the putamen, have been implicated in the pathogenesis of dystonia. We present an unusual case of rapid onset of focal dystonia of the left upper extremity, which developed after infarction of the right premotor cortex (PMC) and the supplementary motor area (SMA). Method: A retrospective chart review of the patient was performed. Results and Conclusion: We propose that disruption of the afferents from PMC and SMA in the setting of chronic striatal abnormality can result in acute dystonia due to disinhibition of the thalamocortical circuit. Key Words: Dystonia—supplementary motor area—poststroke—premotor cortex. © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved. Introduction Involuntary movement disorders secondary to cerebrovascular disease are seen in 1%-4% of patients.1 Most of these movement disorders such as ballismus, chorea, tremor, and, dystonia have delayed manifestations, although some of them can present acutely. The most common neuroanatomic location of lesions resulting in From the *Department of Neurology, Wayne State University, Detroit, Michigan; and †Department of Pediatric and Neurology, Wayne State University, Detroit, Michigan. Received June 24, 2015; revision received September 10, 2015; accepted September 17, 2015. Conflict of interest: Drs. Dhakar, Watson, and Rajamani report no disclosures. Authors’ contributions: Dr. Dhakar: manuscript preparation, concept, design, and research. Dr. Watson: image preparation, manuscript design, and revision. Dr. Rajamani: manuscript concept, design, and revision. Address correspondence to Monica B. Dhakar, MD, MS, Yale Neurology, 15 York Street, PO Box 208018, New Haven, CT 06520-8018. E-mail: monica.dhakar@yale.edu. 1052-3057/$ - see front matter © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2015.09.016 abnormal movements involves the caudate, putamen, subthalamic nucleus, and their connections.1,2 We report a unique case of acute onset of focal dystonia in the left upper extremity due to acute infarction of the right premotor cortex (PMC) and the supplementary motor area (SMA). We further discuss the possible mechanism of acute dystonia in frontal lobe infarction. Case Report A 63-year-old woman with history of hypertension, diabetes, dyslipidemia, peripheral vascular disease, and smoking presented to the emergency room after a fall and sudden onset stiffness of the left upper extremity. There was no family history of movement disorders or history of exposure to neuroleptics or antiemetics. She had a flat affect, soft hypophonic speech and left facial upper motor neuron weakness. The left upper extremity had sustained muscle contractions causing flexion at the elbow, wrist, and fingers, and any attempt at voluntary movement worsened the posture (Fig 1, A). Passive movements at the shoulder, elbow, and wrist revealed severe rigidity. She denied any pain at the site. The dystonia did not spread to any other region and was not Journal of Stroke and Cerebrovascular Diseases, Vol. ■■, No. ■■ (■■), 2015: pp ■■–■■ 1 ARTICLE IN PRESS M.B. DHAKAR ET AL. 2 Figure 1. (A) Dystonia of the left upper extremity with flexion of the forearm and wrist. There was severe rigidity on passive movements of the left wrist, elbow, and shoulder. (B) DWI showing restriction in the right premotor and supplementary motor cortices. (C and D) FLAIR sequence showing T2 hyperintensity in the right caudate (arrow) and bilateral thalami (arrow). Abbreviations: DWI, diffusion-weighted image; FLAIR, fluidattenuated inversion recovery. alleviated with distraction. No sensory tricks were tried to alleviate the posture. There was weakness of the left lower extremity without increase in tone. Sensations were all normal. Magnetic resonance imaging of the brain demonstrated restricted diffusion in the right PMC and SMA suggestive of acute infarction (Fig 1, B). It also showed chronic microangiopathic changes in the bilateral thalami, right caudate, right corona radiata, and left cerebellar hemisphere (Fig 1, C,D). Furthermore, magnetic resonance angiography of the head demonstrated a cutoff of the M1 segment of the right middle cerebral artery and severe stenosis of the A2-3 segment of the right anterior cerebral artery, suggesting intracranial atherosclerotic disease as etiology for stroke. The patient was subsequently placed on dual antiplatelet therapy and statins. She was admitted to rehabilitation for further therapy where she continued to have gradual improvement in dystonia of the left upper extremity over the next 2 weeks. Discussion To our knowledge, acute ischemic stroke presenting with sudden dystonia is very uncommon and deserves attention on several accounts.3 Dystonia is the second most common movement disorder after stroke and is often a delayed manifestation with a median duration of onset of 9.5 months ranging from 3 months to 3 years.2,4 Lesion in the lentiform nucleus, particularly in the putamen, is most frequently associated with dystonia.1 Dystonia occurs due to increased thalamocortical excitation as a consequence of reduced inhibitory output from the globus pallidus interna and the subthalamic nucleus to the thalamus.1 Our patient had prior ischemic lesions in bilateral thalami, right caudate, and right cerebellum predisposing her to develop dystonia due to chronic striatal– thalamic dysfunction. The SMA and PMC have reciprocal connections with the striatum and thalamus.5 Prior reports indicate that poststroke movement disorders are rare even with marked basal ganglia damage, suggesting that these disorders do not result from lesions in a single location but rather from dysfunction of networks and abnormal functional connectivity.6,7 This is possibly because of the plasticity in basal ganglia circuits and the compensatory mechanism of parallel processing, which prevent the manifestation of abnormal movements.7 We speculate that acute infarction of the right premotor and supplementary motor cortices disrupted the compensatory mechanism due to loss of afferent input from SMA and PMC resulting in disinhibition of the thalamocortical circuit and acute onset dystonia. The disruption of the frontal–subcortical circuit also potentially explains the behavioral manifestations of our patient. The sudden nature of dystonia could be argued for the functional etiology of the case. However, the phenomenology described here favors organic dystonia. ARTICLE IN PRESS ACUTE DYSTONIA AFTER INFARCTION OF PMC AND SMA Organic dystonia is often mobile and less overt at rest and worse with any movements,8 as seen in our patient, whereas functional dystonia is more often fixed. Functional dystonia is often associated with peripheral injury, usually involves the lower limbs, and is painful; however, our patient did not have any evidence of such precipitating trauma or complaint of pain.9 There was no variability in her symptoms with distractibility or spread of symptoms to other areas, which is more often a sign of functional dystonia.10 Moreover, she did not fulfill criteria for functional dystonia as proposed by Williams et al11 Our findings are consistent with 2 prior reports of patients with acute onset dystonia after infarction of the SMA and pons, respectively.3,12 Both of these patients had prior lesions of the basal ganglia, suggesting chronic striatal insufficiency, which supports our hypothesis. In conclusion, we present an unusual case of a patient with acute ischemic stroke presenting with sudden onset of dystonia of the upper extremity. The ischemic infarction in the PMC and SMA in the setting of chronic striatal abnormality likely precipitated the dystonia in the opposite upper extremity, thus illustrating the mechanism underlying the pathogenesis of the movement disorder in this patient. Acknowledgments: We thank Dr. Edwin George, specialist in movement disorder at Wayne State University, for his expert advice and critical review of the case and manuscript. 3 References 1. Mehanna R, Jankovic J. Movement disorders in cerebrovascular disease. Lancet Neurol 2013;12:597-608. 2. Alarcon F, Zijlmans JC, Duenas G, et al. Post-stroke movement disorders: report of 56 patients. J Neurol Neurosurg Psychiatry 2004;75:1568-1574. 3. Nishimura K, Uehara T, Toyoda K. Early-onset dystonia after supplementary motor area infarction. J Stroke Cerebrovasc Dis 2014;23:1267-1268. 4. Chuang C, Fahn S, Frucht SJ. The natural history and treatment of acquired hemidystonia: report of 33 cases and review of the literature. 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