Avian Sinusitis

Introduction

Sinus infection can occur in any psittacine but is particularly common in imported grey parrots. It was largely thought to be associated with a diet deficient in Vitamin A however there is now some controversy surrounding its contribution to the disease .

Signalment

Hypovitaminosis A is a nutritional deficiency thought to predispose birds to sinusitis . This can occur if the bird is fed and all seed diet, which is deficient in vitamin A, iodine and calcium, therefore it is essential that a full dietary history is taken. Vitamin A deficiency causes some cells to differentiate abnormally. This occurs in the sinus, where the epithelial lining degenerates into squamous metaplasia. This causes the mucus to thicken, thus preventing debris from being flushed out of the sinus. This results in a build-up of debris and bacteria, eventually resulting in infection. This deficiency can also contribute to the development of and rhinoliths, abscesses and conjunctivitis. Currently it is thought that sinusitis may not occur as a result of vitamin A deficiency as many parrot diets now have an excess of Vitamin A.

Clinical Signs

Early clinical signs include sneezing, proptosis and clicking. Later, swelling may develop around the eyes or between the eyes and beak over the frontal signs. Excessive secretion of serous or mucous material from the respiratory mucous membranes is often reported. It is common for the bird to be suffering from concurrent disease such as pneumonia and air sacculitis. Respiratory distress may be evident, however this should be observed in a quiet stress-free environment for reliable interpretation. Clinical exam is often better performed under general anaesthesia as the choana should be examined for any spread of infection.

Diagnosis

Clinical signs coupled with the history of a vitamin A deficient diet should be suggestive of sinusitis, however needle biopsy of the swellings is required to make a definitive diagnosis, as it allows for the differentiation from abscesses. Cytology, culture and sensitivity should be performed on the aspirated material to determine the presence and nature of infection. The most common infectious organisms are Pseudomonas and Mycoplasma species. Radiography of the skull can also be performed to confirm the presence of sinusitis.

Treatment

Ideally the bird should be treated with the antibiotic 'Baytril' (enrofloxacin) as it covers the above-mentioned bacteria. Additionally the bird should receive a dose of Vitamin A by intramuscular injection. Subsequent dietary supplementation of Vitamin A by feeding orange and dark green vegetables is necessary to prevent recurrence of infection . Drainage and flushing of the sinus with antibiotics in severe cases is recommended by some but due to the anatomy of the sinuses and the nature of the inspissated pus produced, others report that it is normally unsuccessful. If rhinoliths or choanal abcesses are present they should be removed using a needle or dental instruments.

Prognosis

If the dietary deficiencies are addressed long term then infection is unlikely to recur. Therefore, if the bird recovers well from the original episode of sinusitis the prognosis is good.

References

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