Cleft Palate

Also known as:

Congenital oronasal fistula Palatoschisis

A congenital cleft palate defect (Courtesy of Alun Williams (RVC))

Description

An abnormal communication between the nasal and oral cavities involving the soft and hard palate, premaxilla and or lip. Abnormalities arise from during foetal development where there is incomplete closure of the primary palate, secondary palate or both. The primary palate develops into the premaxilla and lip. If closure is not complete this will result in a primary palate or cleft lip (harelip). The secondary palate forms the hard and soft palate and incomplete closure of either of these results in a secondary palate or cleft palate.

Signalment

Dogs are more commonly affected than cats. In particular brachycephalic breeds are more commonly affected. Other at risk breeds include, Boston terriers, Pekingese, minature schnauzers, beagles and cocker spaniels. Siamese are the most commonly affected cat breed. Present at birth but not always noticed straight away. In large animals, cleft palate has been reported in foals, calves, lambs and kids. The primary cause of this condition is often hereditary but maternal nutritional deficiencies, toxins and viral exposure have also been implemented.

History and Clinical Signs

Failure to thrive with signs such as nasal discharge, nasal milk regurgitation, gagging coughing or sneezing during nursing, and respiratory infection due to aspiration pneumonia or rhinitis.

Diagnosis is made on physical exam. A cleft lip can be easily identified however a full oral examination is needed to diagnose incomplete closure of the premaxilla, hard and soft palate. In some instances anaesthesia may be required to diagnose a soft palate problem. Increased noise over lung fields may be heard if aspiration pneumonia is present. Affected animals often have other concurrent congenital abnormalities and hence a thorough physical exam should be undertaken.

• The commonest structural defect is probably the various forms of cleft palate due to:
  • failure of fusion and the ingrowths of the palatine shelves or
  • frontonasal and maxillary processes.

Also known as Palatoschisis

- aspiration pneumonia is a common sequel