Canine Laryngeal Paralysis Study Guide

Overview and Clinical Importance

Laryngeal paralysis (LP) is a common and potentially life-threatening upper airway disorder in dogs characterized by failure of the arytenoid cartilages to abduct during inspiration. This condition results from dysfunction of the recurrent laryngeal nerve, leading to denervation of the cricoarytenoideus dorsalis (CAD) muscle, the only muscle responsible for opening the glottis. The resultant airway obstruction causes characteristic clinical signs including inspiratory stridor, exercise intolerance, dysphonia, and in severe cases, respiratory distress and cyanosis.

Understanding laryngeal paralysis is essential for the NAVLE as it represents a frequently tested topic that integrates knowledge of neuroanatomy, clinical recognition, diagnostic procedures, and surgical management. The condition is most commonly seen in geriatric large-breed dogs and is increasingly recognized as part of a broader systemic polyneuropathy called Geriatric Onset Laryngeal Paralysis Polyneuropathy (GOLPP).

Anatomy and Neuroanatomy

Laryngeal Structure

The larynx is a semi-rigid organ composed of hyaline cartilage and muscles that connects the pharynx to the trachea. The key cartilaginous structures include the epiglottic cartilage (rostral), thyroid cartilage (lateral walls), cricoid cartilage (complete ring caudally), and the paired arytenoid cartilages. Each arytenoid cartilage has four processes: the cuneiform process (rostral), corniculate process (dorsal), vocal process (attaches to vocal fold), and muscular process (attachment point for CAD muscle).