Diseases Related to Canine Diabetes Mellitus

Acromegaly

Acromegaly is an endocrine disease caused by growth hormone excess. It is characterized by chronic overgrowth of connective tissue, bone and viscera. Insulin resistant diabetes, enlargement of soft tissue organs and proliferation of gum tissue are seen.

Dogs generally develop acromegaly due to progesterone secretion and growth hormone production by the mammary glands. Acromegaly may rarely be caused by pituitary or hypothalamic neoplasia.

Spaying of bitches is usually curative, although the concurrent diabetes may be permanent, depending on the remaining ability of the pancreas to secrete insulin.

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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. Young adult dogs, especially German Shepherds, are usually affected.

EPI is usually due to pancreatic acinar atrophy (PAA). It may be seen together with diabetes mellitus if there is damage to both the exocrine and endocrine pancreas.

Diagnosis and treatment
EPI is diagnosed on the basis of blood tests and is treated with pancreatic enzyme replacements. Enzyme replacements usually result in improvement of the clinical signs, and dietary management.

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Hyperadrenocorticism (Cushing’s disease)

Hyperadrenocorticism is a relatively common endocrine disease of dogs but is less common in cats.

Aetiology
Excessive endogenous cortisol production is due to a pituitary tumour (85% of cases) producing excessive adrenocorticotrophic hormone (ACTH) or an adrenal (15% of cases) tumour producing excessive cortisol Iatrogenic administration of exogenous glucocorticoids can result in iatrogenic   hyperadrenocorticism.

Clinical signs
Hyperadrenocorticism is a slowly progressive disease with signs that vary in severity depending on the duration and degree of cortisol excess.Clinical signs are similar to diabetes mellitus.

In addition dogs frequently have a pot-bellied appearance and alopecia or other skin and/or coat changes. Diabetes mellitus may develop secondary to hyperadrenocorticism, due to insulin resistance caused by cortisol excess.

Treatment
Hyperadrenocorticism can be treated medically or surgically. Concurrent diabetes mellitus requires insulin treatment.

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Pancreatitis

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

Aetiology
In most cases the cause of pancreatitis is idiopathic. Other predisposing factors may be a high fat, low protein diet and other diseases (Cushing's disease, diabetes mellitus)

Risk factors for pancreatitis include breed - Miniature Schnauzer, Miniature poodle and Cocker spaniel are at higher risk - obesity, diabetes mellitus, Cushing's disease and chronic renal failure.

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

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Diseases Related to Canine Diabetes Mellitus

Pathophysiology of EPI

  • Digestive enzymes are not secreted normally by the pancreas
  • Food is not sufficiently digested and processed
  • Diarrhoea and weight loss in spite of a normal or increased appetite

Certain diseases may contribute to the development of diabetes.