Endocrine Diseases

Endocrine diseases in older birds are not common. T. Lightfoot states that African grey parrots develop a moderate number of neoplasms, and these often cause sudden deaths. Pancreatic hyperplasia is often found at the same time as hyperglycemia in psittacines. Hyperglycemia is often seen in older, obese psittacines, and it is the cause of avian diabetes mellitus. "Hypertrophy of the parathyroid glands may be seen in birds whose diets are chronically insufficient in calcium. These birds will develop bony lesions which may be seen at necropsy." ³⁷
 

7.1 Diabetes Mellitus

According to K. Joyner, diabetes is more common in psittacines than one might think. Glucagon, not insulin, is the regulatory hormone in psittacines. Senior birds, especially females, and usually cockatiels, frequently fall ill to this disease. "Signs include polyuria and polydipsia, which are linked to pancreatic dysfunction. Some birds develop diabetes after having egg-yolk peritonitis, which explains why cockatiels are found with it so often; they have the misfortune of being chronic egg layers." ³² The inflammatory response to this extends into the pancreas, resulting in damage to the organ. Some birds respond to medical therapy; however, many eventually die from the condition. ³²

7.2 Thyroid Disease: Thyroid Hyperplasia or Dysplasia (Goiter)

The presence of goiter in birds is due to thyroid enlargement, and it is most often seen in older birds, particularly pigeons and chickens. It has been found in psittacines as well, mostly budgies. Iodine-deficient foods, usually from all-seed, poor-quality diets, are the cause. "In budgerigars with goiter, clinical changes are limited to regurgitation and dyspnea caused by gland pressure on the trachea and esophagus. The glands can swell to five times their normal size and cause circulatory problems due to compression of the heart and great vessels." ³⁹ Medication will improve the condition.
 

It has been known for many years that budgerigars and parakeets (Melopsittacus undulatus) develop goiters when they have been on seed diets which are, by their nature, low in iodine. The birds may appear to only be obese, but other signs may be seen as well. These include:

• Regurgitation due to crop-mucous accumulation and resulting thick mucus that accumulates on the feathers of the head
• Swelling of he thyroid gland to five times its normal size and cause circulatory problems due to compression of the heart and great vessels.
• Dyspnea (difficulty breathing), caused by gland pressure on the trachea and esophagus. The thyroid gland can swell to five times its normal size and cause circulatory problems due to compression of the heart and great vessels.
• Respiratory sounds such as squeaking from pressure on the syrinx by the swollen thyroid, and dyspnea. ³⁹

Diagnosis is usually easy to make, and the disease is treatable. Dietary changes, the addition of iodine to the water or seeds, and the use of dexamethasone to speed up the response to injectable iodine by decreasing thyroid swelling are the usual treatments for geriatric birds. This treatment has saved the lives of many birds with severe dyspnea. ^22,39