74-year old female with chronic low back pain and Parkinson’s Disease (on medical therapy) had onset of excessive involuntary movements. Patient retained awareness while having involuntary, nonsuppressible writhing motion of the face, trunk and all limbs. Symptoms were nonpatterned– variable in timing, speed and direction. This lasted a day and self-resolved. Patient reported no changes to her Parkinson’s medication regimen. She recently started a fentanyl patch (25mcg) the day prior and it was removed at the onset of her symptoms. 

Patient reported a similar episode one month prior during a minor procedure. Medication list from the facility included a dose of fentanyl for sedation. Her doctor noted she had involuntary writhing motions of her entire body that resolved a few hours later when anesthesia wore off. 

Laboratory studies did not reveal significant signs of inflammation, metabolic abnormalities, systemic infections or toxins. She underwent neurodiagnostic work-up: MRI brain with and without contrast did not reveal any signal changes or structural lesions in the basal ganglia; electroencephalogram was normal. 

In patients with preexisting basal ganglia dysfunction, a multidisciplinary approach should be considered when new medications are introduced. This case cautions the use of a common sedative in patients with Parkinson’s Disease, which may cause generalized dyskinesias.