NEUROLOGICAL REVIEW Movement Disorders Emergencies Part 2 Hyperkinetic Disorders Bradley J. Robottom, MD; Stewart A. Factor, DO; William J. Weiner, MD lthough movement disorders do not usually present as neurologic emergencies, there are times when the abrupt onset of an unusual movement abnormality results in emer- gency department or intensive care unit consultations. Part 1 of this review discussed hypokinetic movement disorders emergencies. Part 2 provides a diagnostic approach Ato the recognition and treatment of hyperkinetic movement disorders emergencies by identifying phenomenology and reviewing common etiologies. Arch Neurol. 2011;68(6):719-724 Movement disorders most often have an inflammatory disorders and may be acute insidious onset and a slowly progressive in onset. Sydenham chorea is the most com- course and are not associated with emer- mon cause of acquired, childhood-onset gency situations. In part 1, we addressed chorea.1 Sydenham chorea is the neuro- hypokinetic movement disorders emer- logic manifestation of rheumatic fever and gencies focusing on drug-induced emer- is sufficient to make the diagnosis of rheu- gencies and acute complications of Par- matic fever.2 Its incidence has declined dra- kinson disease. Part 2 focuses on the matically with the widespread availability phenomenology of hyperkinetic move- of penicillin; nevertheless, Sydenham cho- ment disorders (chorea, ballism, myoclo- rea remains prevalent in areas where ac- nus, and dystonia) as the key to appropri- cess to health care is limited.3,4 In addition ate recognition and treatment in the to chorea, which may be generalized or emergent situation. Key clinical features hemichorea, additional features of Syden- of hyperkinetic movement disorders are ham chorea include behavioral changes (ob- presented in Table 1. sessions, compulsions, hyperactivity, and emotional lability), weakness, hypotonia, HYPERKINETIC DISORDERS and, rarely, vocalizations.5 Symptoms may begin abruptly, from 1 to 6 months after Chorea streptococcal pharyngitis.6 The diagnosis is made clinically, though elevated antistrep- Chorea consists of involuntary, irregular, tolysin O antibody titers are supportive. purposeless movements that “flow” into one Treatment with penicillin may prevent the another in a random fashion. Though of- cardiac complications of rheumatic fever ten referred to separately, the distinction and is sometimes continued for several years between chorea, athetosis, ballismus, and as prophylaxis.7 If Sydenham chorea re- dystonia is somewhat arbitrary and relates quires treatment, 1 prospective, nonran- more to speed, amplitude, and duration of domized trial suggested that valproic acid the movement rather than underlying pa- or carbamazepine may be used.1 Based on thology. A combination of these move- observational data, dopamine receptor ments is often encountered in a single blockers or dopamine depleters are also rec- patient. Chorea may result from toxic/ ommended.8 metabolic, vascular, and infectious/ Chorea gravidarum usually begins in the first or early second trimester.9 Chorea may Author Affiliations: Department of Neurology, University of Maryland School of be unilateral or bilateral, often involving the Medicine, Baltimore (Drs Robottom and Weiner); and Movement Disorders face as well as the limbs. Dysarthria is com- Program, Emory University School of Medicine, Atlanta, Georgia (Dr Factor). mon.10 Chorea usually resolves by the third ARCH NEUROL / VOL 68 (NO. 6), JUNE 2011 WWW.ARCHNEUROL.COM 719 ©2011 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/26/2021 Table 1. Clinical Definitions of Hyperkinetic Table 2. Etiologies of Acute-Onset Chorea Movement Disorders Etiology Hyperkinetic Vascular Movement Disorder Clinical Definition Ischemic stroke Chorea Involuntary, irregular, purposeless movements Hemorrhagic stroke that “flow” into one another in a random Cavernous angioma fashion Cerebral anoxia Ballism Rapid, large-amplitude proximal movements Metabolic that are sometimes described as “flinging” Nonketotic hyperglycemia May be present with chorea, representing an Hypoglycemia extreme end of the spectrum of chorea Hyperthyroidism Myoclonus Sudden, brief shocklike movements Pregnancy May be due to muscle contraction (positive Structural myoclonus) or loss of muscle tone (negative Basal ganglia mass lesion myoclonus or asterixis) Cerebellar mass lesion Tics Brief, paroxysmal movements or vocalizations Thalamotomy or subthalamotomy sometimes accompanied by premonitory urge Inflammatory May be stereotyped Multiple sclerosis Unlike other hyperkinetic movements, may be Sarcoidosis voluntarily suppressed for a short period Infectious Dystonia Involuntary, sustained muscle contractions that Cryptococcal granuloma produce twisting or squeezing movements Toxoplasmosis Often accompanied by abnormal posture Tuberculoma Human immunodeficiency virus encephalitis Sydenham chorea trimester or disappears within hours after delivery.11 Al- Autoimmune though chorea gravidarum is rarely an emergency, it is likely Systemic lupus erythematosus Antiphospholipid antibody syndrome that neurologists will encounter this entity in the context Scleroderma of an emergent inpatient consultation on a maternity ward. Behc¸et disease The antiphospholipid syndrome may result in acute Iatrogenic generalized chorea. Antiphospholipid syndrome may be Anticonvulsants primary or secondary to systemic lupus erythematosus. Oral contraceptives Antiphospholipid syndrome is thought to be the most Levodopa common cause of chorea gravidarum in industrialized na- Cocaine 12 Amphetamines tions. Rarely is chorea the sole manifestation of an- Alchohol, intoxication and withdrawal tiphospholipid syndrome, but a high index of suspicion is important because of the other potentially cata- strophic manifestations (eg, deep venous thrombosis, pul- (Figure 1). Magnetic resonance imaging findings re- monary emboli, stroke, thrombotic microangiopathy, sult from ischemic injury due to hyperviscosity and re- thrombocytopenia, and hemolytic anemia) that could oc- gional metabolic failure. Like hemiballism secondary to cur with failure to diagnose and treat antiphospholipid stroke, the movements typically subside over a period of syndrome.12 Other metabolic causes include hyperthy- months. In some patients, abnormal movements re- roidism and hyperglycemia (Table 2). verse when the glucose level is normalized. Resolution of magnetic resonance imaging signal change correlates Hemichorea-Hemiballism with clinical improvement in chorea.17 If treatment is re- quired (eg, violent, self-injurious, exhausting, or dis- Hemiballism refers to large-amplitude, flinging move- tressing movements), dopamine receptor blockers or ments of one side of the body that can be violent. As hemi- dopamine depleters such as tetrabenazine or reserpine ballismus resolves over days to weeks, the movements are used (Table 3). Because the movements usually re- often become choreiform. Historically, the most com- solve over time,18 medication should be tapered after 3 mon cause of hemiballism was stroke involving the sub- months and the patient, reevaluated. thalamic nucleus. However, this etiology is rare, with an annual incidence of less than 1 per 100 000 in a popu- Myoclonus lation-based study from Belgrade, Serbia.13 Although stroke remains the most common cause, only a minor- Myoclonus consists of sudden, brief shocklike move- ity of cases have lesions within the contralateral subtha- ments that may be due to muscle contraction (positive lamic nucleus.14-16 The second most commonly re- myoclonus) or loss of muscle tone (negative myoclonus ported cause of hemiballism is nonketotic hyperglycemia. or asterixis). Neurologists are often emergently con- With this disorder, chorea, or ballism, may be unilateral sulted in the intensive care unit to see patients with my- or bilateral. It occurs more in women,17 and it may be oclonus as a result of toxic/metabolic derangements or the initial presentation of diabetes mellitus. Magnetic reso- cerebral anoxia. It is also seen in serotonin syndrome and nance T1-weighted images demonstrate hyperintensity neuroleptic malignant syndrome. Medications includ- in the putamen, caudate nucleus, and globus pallidus17 ing monoamine oxidase inhibitors, selective serotonin ARCH NEUROL / VOL 68 (NO. 6), JUNE 2011 WWW.ARCHNEUROL.COM 720 ©2011 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/26/2021 reuptake inhibitors, serotonin-norepinephrine reup- lenting, generalized multifocal myoclonus involving the face, take inhibitors, tricyclic antidepressants, opiates, le- limbs, and axial musculature in comatose patients,” is omi- vodopa, gabapentin, triptans, lysergic acid diethylam- nous.22 The chance of good recovery in this setting is ex- ide (LSD), amphetamines, cocaine, and 3,4- ceedingly low,23 and the likelihood of any outcome other methylenedioxymethamphetamine (MDMA or ecstasy) than a poor one is 0% (95% confidence interval, 0%-8.8%).22 may cause myoclonus. Hepatic and uremic encephalopa- A “poor outcome” is defined as death or persisting uncon- thies are the most common metabolic derangements re- sciousness after 1 month or death, persisting unconscious- sulting in myoclonus and asterixis.19,20 ness, or severe disability requiring full nursing care after 6 Cerebral anoxia may result in 2 distinct myoclonic syn- months. Postanoxic myoclonus (Lance-Adams syn- dromes, myoclonus status epilepticus