Sudden onset of arm movements in a diabetic patient

A 71-year-old female patient presented with sudden onset of involuntary and uncontrolled movements in her right arm and leg. Symptoms began approximately 24 hours after an intramuscular betamethasone injection administered a few days earlier for shoulder pain. She had a 25-year history of type 2 diabetes and hypertension. There was no history of any neurological or psychiatric illness. Neurological examination revealed normal cognitive function, cranial nerve examination, muscle strength, sensory examination, and cerebellar assessment. Irregular movements were observed in the right upper and lower extremities, particularly when the patient was sitting and distracted. The patient did not report pain in the affected extremities. The movements were recorded on video (Video 1), demonstrating continuous, irregular and involuntary movements of the right upper and lower limbs. …