title: Myoclonus and urinary retention following subarachnoid morphine injection in a dog.
abstract: A 5-year-old German Shepherd dog which presented for total hip replacement developed myoclonus and urinary retention after the subarachnoid injection of preservative-free morphine. Myoclonus was resistant to treatment, except pentobarbital anesthesia. Urinary retention was treated with bethanechol and subsided within a few days. Involuntary muscular activity can result from the epidural, subarachnoid or systemic injection of various opioid drugs, or as a result of the toxic or irritant effect of preservatives or autologous blood. The latter were not causative factors in this case. Opioid agonist inhibition of central inhibitory neurotransmitter action may have explained the myoclonus. Postoperative urinary retention was attributed to the spinal action of morphine inhibiting efferent parasympathetic nervous activity.
authors.affiliation: Department of Clinical Sciences (Anesthesiology), Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada. konabouj@yahoo.com
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Kona-Boun
authors.forename: Philippe
authors.initials: P
authors.lastname: Pibarot
authors.forename: Andrée
authors.initials: A
authors.lastname: Quesnel
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D019644:Arthroplasty, Replacement, Hip / Q000662:veterinary*; D004285:Dogs; D007268:Injections, Epidural / Q000662:veterinary; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects*; D009207:Myoclonus / Q000139:chemically induced / Q000662:veterinary*; D011183:Postoperative Complications / Q000662:veterinary; D013346:Subarachnoid Space; D016055:Urinary Retention / Q000139:chemically induced / Q000662:veterinary*
chemical_list: D000701:Analgesics, Opioid; D009020:Morphine