Abstract:Introduction:Choreaform movements provoked by opiates is an infrequent adverse event. Buprenorphine induction of chorea has not heretofore been described. Such a case is presented.METHOD:Case Study: A 38-year-old female presented with a decade long history of alcohol, cocaine, benzodiazepine, and heroin abuse. The patient was insufflating 1.5 grams of heroin daily. On presentation, she was actively withdrawing, scoring 17 on the Clinical Opioid Withdrawal Scale. Urine toxicology screening was positive for opiates, cocaine, and cannabinoids. Buprenorphine 4 mg sublingual was initiated. Within one hour, she observed, “My legs were moving uncontrollably as if I was a marionette.” These dance-like movements were isolated to both legs and gradually resolved after discontinuation of buprenorphine: most of the movements manifested in the first 8 hours, and dissipated over the next 2 days. She did have similar movements after treatment with quetiapine during a previous hospitalization, years earlier.RESULTS:Abnormalities in physical examination: General: goiter, bilateral palmar erythema. Neurological examination: Cranial Nerve (CN) Examination: CN I: Alcohol Sniff Test: 2 (anosmia). Motor Examination: Drift testing: mild right pronator drift. Reflexes: 3+ bilateral lower extremities. Neuropsychiatric Examination: Clock Drawing Test: 3 (abnormal). Animal Fluency Test: 18 (normal). Go-No-Go Test 6/6 (normal).DISCUSSION:Buprenorphine induced chorea could be a result of partial mu-opioid agonism, or kappa and delta receptor antagonism (Burke, 2018; Cowan, 1977). Mu-opioid receptor activation causes increased dopamine turnover in the nigrostriatum, which is responsible for locomotor sensitization (Campos-Jurado, 2017). With the addition of mu-opioid receptor modulation of dopamine release, kappa-opioid receptor alters various neurotransmitters in the basal ganglia, potentiating hyperkinetic movements. Buprenorphine’s choreiformogenic action may be due to kappa-opioid receptors ability to augment neurotransmission in the striatum (Escobar, 2017; Bonnet, 1998). The combination of simultaneous activity of these three opioid receptors may cause chorea, since they act to modulate dopamine, glutamate, and GABA in the direct and indirect pathways within the basal ganglia (Abin, 1989; Cui, 2013; Allouche, 2014; Trifilieff, 2013). This patient’s history of heroin and cocaine use may have caused supersensitization of dopamine receptors (Memo, 1981), provoking hyperkinesia. Involvement of substance-induced sensitization with concurrent kappa-opioid receptor neurotransmitter augmentation in direct and indirect pathways in the basal ganglia may have primed our patient to the development of chorea after buprenorphine administration. Further investigation for the presence of extrapyramidal movements in those undergoing buprenorphine treatment is warranted.
A novel nanobody-based bio-assay using functional complementation of a split nanoluciferase to monitor Mu- opioid receptor activation