Cricopharyngeal Achalasia in Dogs

Cricopharyngeal achalasia is an uncommon developmental myopathy of young dogs in which the cricopharyngeal muscle fails to relax during the oropharyngeal phase of swallowing. The underlying reason for this failure to relax is unknown (1).

The disorder has been associated with hypothyroidism in one dog; in that dog, the myopathy resolved with appropriate thyroid supplementation.

Cricopharyngeal achalasia occurs in many dog breeds; however, Spaniel breeds appear to be overrepresented.

Clinical signs of cricopharyngeal achalasia typically become apparent at the time of weaning and remain static. They include the following:

• dysphagia (hallmark clinical sign)

• regurgitation

• nasal reflux of ingested food

• coughing

• weight loss or failure to gain weight

For dogs with cricopharyngeal achalasia, liquid food may be easier to ingest but increases the risk of nasal reflux. Aspiration pneumonia is an important concern.

Diagnosis is by ruling out other causes of dysphagia and regurgitation (eg, idiopathic megaesophagus, myasthenia gravis, vascular ring anomalies) and evaluation of swallowing using contrast fluoroscopy.

Treatment is myotomy or myectomy of the cricopharyngeal muscle.Onabotulinumtoxin A injections have been administered to patients with cricopharyngeal achalasia and may help to prognosticate the success of permanent myectomy.

See also Cricopharyngeal Achalasia in Small Animals.

For other degenerative/developmental myopathies in dogs, see the Overview for this chapter.