Top Tip 7 - Laryngeal Paralysis

Canine acquired laryngeal paralysis is a well-recognised cause of upper respiratory stridor and dyspnoea and is not an uncommon presentation to primary care practitioners. Laryngeal paralysis was once thought to be an isolated problem, however several studies suggest that laryngeal paralysis may be one manifestation of a generalised muscle disorder.

As with all conditions, new information regularly comes to hand that is directly applicable at the general practice coal face. A recent study demonstrated that many dogs with laryngeal paralysis go on to develop generalised polyneuropathy over the course of one year. Clinical signs may include generalised weakness, normal to depressed spinal reflexes, muscle atrophy, ataxia and proprioceptive deficits. These findings highlight the importance of obtaining a thorough history and performing a comprehensive neurologic exam at the time of diagnosis, seeking to identify subtle neurologic deficits. Also, these findings provide important prognostic information for the owner, about the possibility future neurologic disease.

Additionally, the study found that many dogs with acquired laryngeal paralysis have concurrent oesophageal dysfunction. It is well established that the recurrent laryngeal nerves degenerate in idiopathic laryngeal paralysis, and it is possible that this oesophageal dysfunction may be explained by similar degeneration of branches of the recurrent laryngeal nerve supplying the oesophagus. Aspiration pneumonia is a known complication following arytenoid lateralisation, and concurrent oesophageal dysfunction may contribute to this risk. By performing a preoperative contrast oesophagram, we may be able to identify concurrent oesophageal dysfunction, and possibly predict patients at higher risk of aspiration.

For the moment, arytenoid lateralisation remains the mainstay of treatment for laryngeal paralysis. The current focus on increasing our understanding of the pathogenesis of laryngeal paralysis may lead to more sophisticated methods for restoring laryngeal function in the future.

This tip was contributed by Dr Melati Laksito – Residency Trained Small Animal Surgeon

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