(P74) Why Is My Arm Jerking?

Chief Complaint : Right Arm Jerking

History of Present Illness : A 32-year-old male with a past medical history of alcohol and substance abuse presents to the emergency department with his partner at the bedside for several hours of right arm jerking at rest and associated arm pain. He states this arm jerking happened once before and went away on its own without intervention. The patient also endorses difficulty walking. The patient states he drinks ten pints of liquor a day, the last drink being four hours prior. The patient denies a history of withdrawal seizures, delirium tremens, or prior hospitalization for his alcohol use. The patient currently denies chest pain, shortness of breath, abdominal pain, nausea or vomiting, fever, or chills.

Pertinent Physical Exam: GENERAL: Awake, alert, and fully oriented, in mild acute distress
HEAD: No signs of trauma, normocephalic, atraumatic
EYES: PERRLA, EOMI, sclera anicteric, conjunctiva clear
NECK: Normal ROM, supple, no lymphadenopathy, JVD, or masses
LUNGS: speaks full sentences, clear to auscultation bilaterally
HEART: Regular rate and rhythm, peripheral pulses normal and equal bilaterally.
ABDOMEN: Soft, non-tender. No guarding, and no rebound.
EXTREMITIES: contracted, adducted, and flexed right arm/elbow, with intermittent myoclonus, no edema. No clubbing or cyanosis.
NEUROLOGICAL: Horizontal and vertical nystagmus noted. Normal speech, unsteady gait, intermittent unprovoked right upper extremity spastic contractions
SKIN: no rashes or lesions noted

Pertinent Laboratory Data: CBC within normal limits
CMP reveals
elevated AST/ALT 96/67(normal range 15-37/13-61)
elevated creatinine kinase 1430 (normal range 26-308)
Elevated CKMB 8.5 (normal range 0.5-3.6)
UA neg
Urine Toxicology reveals positive for amphetamines
Quantitative Alcohol: 299.4
[ranges: subject drinking (100-150), intoxication (150-500), comatose(>500)]

Head CT reveals no acute pathology

Case Discussion: We present a case of a 32-year-old male with a history of alcohol and substance abuse who presented to the emergency department with new onset myoclonus. The patient was admitted to regular heavy drinking, and likely functions normally at the detected ethanol level. However, the patient adamantly denies drug use despite a positive urine toxicology screen for amphetamines, raising suspicion of amphetamine-associated myoclonus. Myoclonus/ true muscle pathology is further supported by the elevation in creatinine kinase. There have been some prior evidence and case reports with the association of amphetamine and its derivatives such as methamphetamine with movement disorders and myoclonus. Myoclonus is the act of involuntary movement of one or more limbs and can be elicited spontaneously or by a trigger such as a loud noise. There have been prior reports of myoclonus and choreoathetosis associated with amphetamine and methamphetamine use (1). In addition, there have been reports of these substances worsening underlying movement disorders such as Parkinson's' or Huntington’s disease (2). These movements may resolve with time with or without abstinence and can be treated with benzodiazepines (3). This case highlights the association between acute amphetamine use and myoclonus. the patient was experiencing discomfort and pain from the right arm myoclonus he had been experiencing for several hours. In this case, the patient’s myoclonus improved with lorazepam treatment that enhances the inhibitory transmitter GABA, the myoclonus resolved, and the patient was discharged. It is important for healthcare providers to be aware of the potential neurological complications of acute amphetamine or methamphetamine use, as early recognition and treatment improve patient outcomes.

References and Acknowledgements (Optional): 1) Ellinwood EH. Amphetamine Psychosis: I. Description of the individuals and process. J Nerv Ment Dis. 1967;144:273–83.

2) Klawans HL, Weiner WJ. The effect of d-amphetamine on choreiform movement disorders. Neurology. 1974;24:312–8.

3) Asser A, Taba P. Psychostimulants and movement disorders. Front Neurol. 2015 Apr 20;6:75. doi: 10.3389/fneur.2015.00075. PMID: 25941511; PMCID: PMC4403511.