Common Endocrine Diseases in Dogs
An endocrine disease is caused by an imbalance in hormone levels due to the body producing too much or too little of a specific hormone in the body. The health effects are variable, with some endocrine diseases proving fatal if left untreated – but others are more easily managed.
This article will run through the most common endocrine disorders that we see in dogs at Ascot Vet Hospital. But don’t fret – we will move onto our feline friends in our next blog post!
Diabetes mellitus is caused by a deficiency of insulin. All the cells of the body require fuel to function, and glucose is one of the essential fuels. Tissues cannot absorb glucose without insulin. When there is insufficient insulin, the glucose stays in the bloodstream and cannot be taken into the cells and used by the body. The tissues go into starvation mode, resulting in increased appetite and weight loss. Glucose also moves into the urine in high amounts, drawing water with it and causing excessive urination and thirst. All that sugar in the urine also creates a very suitable environment for bacteria to grow, making urinary tract infections common. If high amounts of glucose enter the lens of the eye, cataracts can also develop, leading to blindness.
The main symptoms of diabetes mellitus in dogs are excessive hunger, excessive thirst, excessive urination and weight loss. Diabetes is diagnosed by confirming elevated glucose levels in the blood and the urine.
Nearly every dog will have insulin-dependent diabetes, similar to the human type 1 diabetes. This means that insulin injections will be required. Learning to give these injections can be daunting at first, but virtually all our clients become very proficient at it! Starting dosage is based on weight and glucose readings, so often require some tweaking in the first few weeks. Ongoing blood and urine monitoring will also be required.
High fibre diets are preferred for feeding diabetic dogs, as they slow the absorption of sugars and help maintain blood glucose levels. Diabietic dogs are best fed twice daily 12 hours apart, and injected with insulin after eating meals.
Cushing’s Disease (Hyperadrenocorticism)
Cushing’s Disease is caused by an increase in circulating levels of the hormone cortisol. Cortisol is produced by the adrenal glands, which are located next to the kidneys. The adrenals produce cortisol in response to being stimulated by the pituitary gland, which is located at the base of the brain. Cortisol is normally produced in times of stress to prepare the body for a flight or fight response. It does this by mobilizing fat and sugar stores and retaining sodium and water. If the body is kept in this activated state for prolonged periods of time, it can become debilitating.
There are two ways Cushing’s Disease can develop: by an adrenal gland tumour or by a pituitary tumour. Both lead to the overproduction of cortisol. Clinical signs of the disease include excessive thirst and urination, increased appetite, lethargy, panting, abdominal bloating, hair loss and recurrent infections.
Diagnosis and management of Cushing’s Disease can be tricky and quite involved. Diagnostic tests can include full blood and urine screening, abdominal ultrasounds and specific cortisol blood testing as well. Treatment involves medication to control the overproduction of cortisol by the adrenal glands, and sometimes adrenal gland surgery. Ongoing blood testing for maintenance and medication dose monitoring is required. Once stable and well managed, patients with Cushing’s disease can have years of good quality living ahead of them.
Hypothyroidism (or underactive thyroid) results from a decrease in thyroid hormone production by the thyroid glands. It is more common in middle-aged and older dogs.
A decreased amount of thyroid hormone results in lethargy and sleepiness. Changes in skin and coat are common – the skin often becomes thickened and more pigmented, and the hair coat can become dull, dry and sparse. Often clipped hair will not regrow. Dogs with hypothyroidism can also be prone to skin infections and experience poor wound healing.
Hypothyroidism is diagnosed by a thyroid hormone level blood test. Treatment is by administering oral thyroid supplements. There will normally be an increase in the dogs activity levels very soon after treatment commences, but skin and hair coat improvements can take a few months. Treatment needs to be lifelong and regular blood testing is required to maintain correct dosage.
While they may sound scary, these diseases are all commonly treated and can be easily managed by the staff at Ascot Vet.