Laryngeal paralysis is a common and well-documented disorder in both dogs and horses, but little has been characterized about the disease in cats. Common clinical signs are similar in dogs and cats and include increased inspiratory noise, inspiratory stridor, dysphonia, exercise intolerance, inappropriate respiratory effort, coughing, and aspiration pneumonia. Laryngeal paralysis can be caused by recurrent laryngeal nerve injury; cervical or thoracic masses; neuromuscular, metabolic, or toxic diseases; congenital disease; and idiopathic causes.
This article describes the clinical outcome of 10 cats, aged 2 to 18 years, that underwent arytenoid lateralization to treat bilateral or unilateral laryngeal paralysis. Paralysis was considered idiopathic in 7 cats and iatrogenic in 3 cats that had undergone thyroidectomy; it was diagnosed by direct observation of the arytenoid cartilages during multiple respiratory cycles.
The goal of surgery was to relieve airway obstruction and enlarge the rima glottidis.A suture was placed between the cricoid and arytenoid cartilages to facilitate abduction of the arytenoid cartilage.One cat required sutures between the thyroid and arytenoid cartilages. Seven cats had unilateral arytenoid lateralization, 1 had bilateral lateralization, and 2 had 2 separate unilateral (staged bilateral) lateralization procedures.
All cats recovered from lateralization of the arytenoids.However, 1 that underwent bilateral lateralization died after developing aspiration pneumonia immediately after surgery.Two cats required temporary tracheostomies after unilateral lateralization.Overall, 3 cats died of aspiration pneumonia, and 3 of the 7 remaining cats died of concurrent or unknown causes.
The authors concluded that arytenoid lateralization is a viable technique for relieving upper airway obstruction due to laryngeal paralysis in cats but that bilateral procedures should be avoided or performed with considerable caution due to risk of aspiration pneumonia.
COMMENTARY: This paper describes a disorder that most practitioners have never seen or diagnosed in cats.Of note, the treatment for cats is the same as for dogs, and the risk of aspiration pneumonia also seems to be the same. It is easy to speculate from this study that the risk for upper airway obstruction from swelling after surgery is greater in cats because of their small airway lumen.Therefore, oxygen and 24-hour critical care should be available for these patients postoperatively.
Arytenoid lateralization for treatment of laryngeal paralysis in 10 cats.Hardie RJ, Gunby J, DE Bjorling.VET SURG 38: 445-451, 2009.