Diseases Related to Feline Diabetes mellitus

Hyperthyroidism

Hyperthyroidism is a common endocrine disorder of middle-aged and older cats. Diabetes mellitus and hyperthyroidism may present concurrently.

Pathophysiology and clinical signs
A thyroid adenoma causes secretion of increased amounts of thyroid hormones (tri-iodothyronine (T3) and thyroxine (T4).

Diagnosis
Hyperthyroidism must be differentiated from diabetes mellitus. This is usually done using laboratory measurement of T4 concentration.

In a few cats the diagnosis may need to be confirmed by additional tests.

Treatment
Once hyperthyroidism has been confirmed, there are several treatment options, including anti-thyroid medications, surgical removal of the gland and radioactive iodine.

The initial choice of treatment is often guided by concern about the cat's kidney function, since treatment may precipitate renal failure.

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Acromegaly

Acromegaly (hypersomatotropism)is an endocrine disease caused by growth hormone excess. It appears to be more common in cats than was thought previously (Niessen et al. 2007). It is characterized by chronic overgrowth of connective tissue, bone and viscera. In cats, acromegaly is due to a growth hormone-secreting pituitary tumor.

Clinical signs include insulin resistant diabetes, enlargement of soft tissue organs and proliferation of gum tissue

Treatment
Currently the best treatment for a cat with a pituitary tumor appears to be radiation therapy or surgery (where available).

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Exocrine pancreatic insufficiency (EPI)

Exocrine pancreatic insufficiency is a congenital or acquired condition that can affect both dogs and cats, although it is more common in dogs.

In cats EPI is usually the end-stage of pancreatitis. It may be seen together with diabetes mellitus if there is damage to both the exocrine and endocrine pancreas.

For more information see EPI in dogs

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Hyperadrenocorticism (Cushing’s syndrome)

Hyperadrenocorticism is rare in cats.
For more information see Hyperadrenocorticism in dogs.

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Pancreatitis

Pancreatitis is an inflammation of the pancreas. Digestive enzymes leak into and damage the surrounding pancreatic tissues.

Etiology
In most cases the cause of pancreatitis is idiopathic. Other predisposing factors may be ahigh fat, low protein diet, other diseases (Cushing's syndrome, Diabetes mellitus) or toxoplasmosis, feline leukaemia virus or feline herpesvirus.

Acute pancreatitis may produce temporary Diabetes mellitus, if there is extensive pancreatic necrosis this may become permanent. A similar situation can arise if there is pancreatic neoplasia.

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References

Niessen SJM., Petrie G., Gaudiano F., et al. Feline acromegaly: An underdiagnosed endocrinopathy? J Vet Intern Med. 2007 ;21(5):899-905.

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