Avian Sinusitis

Introduction

This infection can occur in any psittacine with a diet deficient in Vitamin A but is particularly common in imported grey parrots.

Signalment

The specific nutrient deficiency that contributes to a sinus infection in birds is hypovitaminosis A. 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 results in the failure of some cells to differentiate normally. In the sinus, the epithelial lining degenerates into squamous metaplasia resulting in a thickening of the mucus that washes the debris from the sinus. This thickening reduces flow rates and allows bacteria and debris to persist on the sinus lining until infection occurs. This deficiency can also contribute to the development of and rhinoliths, abscesses and conjunctivitis.

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 cloana should be examined for any spread of infection.

Diagnosis

Clinical signs coupled with the history of a vitamin A deficient diet should 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

Proper treatment consists of antibiotic therapy for the infection, ideally with Baytril and a single dose of 20 000 IU vitamin A per kg body weight i.m., followed by supplementation of the diet with vitamin A. Treatment of the infection without this supplementation renders the bird likely to have a recurrence of the infection. Drainage and flushing of the sinus with antibiotics can be attempted in severe cases but due to the anatomy of the sinuses and the nature of the inspissated pus produced, 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 by feeding orange and dark green vegetables long term then infection is unlikely to recurr. Therefore, if the bird recovers well from the original episode of sinusitis the prognosis is good.

References

Lawton, M (1999) Management of respiratory disease in psittacine birds In Practice 1999 21: 76-8

Forbes NA & Altman RB (1998) Self-Assessment Colour Review Avian Medicine Manson Publishing Ltd

Stanford, M (2009) Respiratory Disease in Birds Royal Veterinary College Integrated Course RVC