Treatment of Laryngeal Paralysis

Introduction:
Acquired laryngeal paralysis is a common diagnosis in middle aged large breed dogs with respiratory dys-function. This disease is described as idiopathic when no other disease (laryngeal neoplasia, accidental or surgical trauma, cervical or mediastinal neoplasia) is identified. Paralysis of the intrinsic muscles of the larynx, secondary to degeneration or infiltration of the recurrent laryngeal nerves, causes muscle atrophy and dysfunction. Recent information suggests that patients with what was previously described as “idiopathic” disease have evidence of peripheral neuropathy at other sites in their body. Typically, to be affected clinically, dogs must have bilateral disease causing a fixed upper airway obstruction at the rima glottidis. This lack of control of the rima and vocalis muscle causes the clinical signs of inspiratory stridor and altered phonation. In addition it predisposes affected dogs to aspiration pneumonia. Since restoration of normal function is not a realistic goal currently, the treatment option that has gained the most universal acceptance for dogs with “idiopathic” disease is unilateral arytenoid lateralization.

Diagnosis:
Diagnosis of laryngeal paralysis has traditionally been based upon identifying dogs with the appropriate history (exercise intolerance, loss of bark, inspiratory stridor, chronic cough) and clinical signs (inspiratory stridor) and demonstrating poor arytenoid function during laryn- goscopy performed with the dog under a light plane of anaesthesia. If paralysis is present, if any movement is seen it may be either an ineffective flutter or paradoxical adduction of the arytenoids (and vocal folds) during inspiration. It is a good idea to examine some NORMAL dogs under light anaesthesia so that the abnormal can be identified more easily. This laryngeal examination is subjective at best. Laryngeal ultrasound in a conscious dog will allow dynamic evaluation without the effects of drug administration, in compliant patients. [...]