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Laryngeal Paralysis In The Dog
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Laryngeal Paralysis is a partial to complete failure of the arytenoids cartilage (opening into Larynx) and vocal folds to abduct (move to each sire) during inspiration.
Laryngeal Paralysis first described as a disease in a German publication in 1959. Congenital and acquired bilateral Laryngeal Paralysis as caused by neurogenic atrophy of the Laryngeal muscles has been document. Hereditary characteristics (autosomal, dominant passage) in the Bouvier des Flandres was described in a 1981 report. The congenital type has also been reported in Bull Terriers, Siberian Huskies and Dalmatians. Laryngeal Paralysis is most commonly found in older (greater than 10 years) Labrador Retrievers. Males are affected 2-4 times more frequently than females.
Causes for the acquired (non-congenital) disease include trauma, (chain collars), neoplasia and idiopathic (cause unknown), with the idiopathic etiology claiming the majority of the cases.
Laryngeal Paralysis frequently causes progressive inspiratory strido voice change and exercise intolerance. You may also notice cyanosis, coughing, gagging, vomiting, restlessness, and anxiety. In a sever case the animal may actually collapse and on a rare occasion suffocate and die. Some animals are asymptomatic at rest. All animals with Laryngeal Paralysis are at risk for inhalation pneumonia from aspiration of food and saliva. Those dogs that produce thick saliva and have a problem swallowing respond poorly to surgery.
Diagnosis of Laryngeal Paralysis can only be made under direct observation of the artenoid cartilages while the animal is under light sedation. Radiographs of the neck are done to rule out other causes. Nerve conduction studies can be done to rule out generalized neuromuscular disease but is usually not necessary. Hypothyroidism should be ruled out by performing a thyroid profile on the blood.
Medical Management would only be successful in mild cases – This includes weight reduction, exercise restrictions, and Thyroid medication if needed.
In moderate to sever cases, surgery is the recommended treatment. The surgical procedure of choice is unilateral arytenoids cartilage lateralization as it gives consistently good results (greater than 90%). Only on side is operate on because post-operative coughing, severe gagging, pneumonia and death are more frequent when both cartilages are pulled to the outside.
Common Post operative problems including aspiration pneumonia, change in voice (if it has not already occurred), gagging after eating and drinking (temporary) and on a rare occasion the stitches holding the cartilage will tear loose and surgery has to be redone – most commonly seen in very old dogs in which the respiratory stridor has been chronic.
On a rare occasion an animal will be presented in sever respirator distress and emergency treatment has to be done, such as sedation, I.V. corticosteroids, oxygen therapy and tracheotomy.
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