Balance impairment caused by diazepam in 2 dogs with vestibular disease: case reports

Abstract

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial license (http://creativecommons. org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The vestibular system generates neurological signals containing information about the forces of gravity and movement [1]. Based on these signals, the brain maintains balance and coordinates movements [1]. Vestibular system disease induces signs including nystagmus, head tilt, leaning, falling, and rolling [2]. Magnetic resonance imaging (MRI) is considered a valuable diagnostic tool for vestibular disease [2]. In veterinary medicine, general anesthesia is required for MRI scan, and diazepam is one of the options of premedication for anesthesia in sick patients to reduce the dose of general anesthetics and minimize hemodynamic changes [3]. It is suggested that benzodiazepine may impair postural control in humans medicine [4], however only balance impairment cases after midazolam injection were reported in veterinary medicine [5,6]. Here, the authors present 2 canine cases of sudden onset of leaning, falling, and rolling after diazepam premedication. Case 1. An 11-year-old 3.1 kg castrated male Maltese suffering from acute left head tilt was referred to the diagnostic imaging center for MRI (Magnetom Essenza; Siemens Healthcare, Germany) scan of the brain. The owner noticed that the symptom had begun 2 days earlier. There were no abnormalities on complete blood count, serum chemistry, and thoracic radiography. The dog was bright, alert, and responsive. The neurological examination revealed a left-sided head tilt and horizontal nystagmus (fast phase to the right), and there were no detectable proprioceptive deficits and paresis. The heart rate (HR) of the patient was 102 bpm, and the respiratory rate (RR) was 30 rpm. The systolic blood pressure (BP) measured by Doppler (811-B; Parks Medical Electronics, USA) ultrasonic method was 136 mmHg. The dog was premedicated with intravenous (IV) 0.2 mg/kg diazepam (Diazepam; Samjin Pharm, South Korea). Immediately following the injection, an abrupt balance impairment characterized by leaning, falling, and rolling Following intravenous (IV) administration of diazepam as a preanesthetic agent, sudden balance impairment, such as falling, leaning, and rolling, was identified in 2 canine cases. The 2 dogs were anesthetized for brain magnetic resonance scan to diagnose about a history of head tilt. After end of the diagnostic procedures, during the anesthetic recovery period, balance impairment was also observed. However, the symptoms gradually ceased by IV administration of flumazenil. These 2 canine cases indicated that diazepam premedication was responsible for the acute balance impairment.