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ASG Specialties:

  • Hip Dysplasia
  • Patella Luxation
  • Medial Patella Luxation
  • Elbow Dysplasia
  • Fragmented Coronoid Process
  • OCD Osteochondritis Dissecans Fractures
  • Arthritis
  • Ruptured Cruciate Ligament
  • Ruptured Cranial Cruciate Ligament
  • Ruptured Anterior Cruciate Ligament


Addison’s Disease

Poodle: Addison's Disease

Addison’s Disease (also known as adrenal insufficiency, hypocortisolism, and hypoadrenalism) is a rare, chronic endocrine system disorder in which the adrenal glands do not produce sufficient steroid hormones (glucocorticoids and often mineralocorticoids).

by Mickila Collins, DVM,
Diplomate American College of Veterinary Internal Medicine


Symptoms

Addison’s Disease is characterized by a number of relatively nonspecific symptoms, such as abdominal pain, vomiting, diarrhea and weakness, but under certain circumstances, these may progress to Addisonian crisis, a severe illness which may include very low blood pressure, renal failure and hypoglycemia.

The condition arises from problems with the adrenal gland and can be caused by damage by the body’s own immune system, certain infections, or various rarer causes. Addison’s disease is named after Thomas Addison, a graduate of the University of Edinburgh Medical School who first described the condition in 1849. The adjective “Addisonian” is used to describe features of the condition, as well as patients suffering from Addison’s disease.

Presentation

addisons-adrenalThis disease is most common in young to middle-age female dogs. Female dogs account for approximately 70% of cases. The average age of diagnosis is 4-5 years but can range from 4 weeks to 16 years. Mixed breed dogs are reported the most commonly represented breed. However, there are several other breeds that appear to be at an increased risk including the Great Dane, Poodle (Toy, Miniature and Standard) and West Highland White Terrier. This disease is rarely encountered in cats.

Affected Patients

Outward signs of Addison’s may include one or more of the following:

  • Weakness
  • Lethargy; listnessness
  • Lack of appetite
  • Vomiting
  • Regurgitation
  • Slow pulse (bracycardia)
  • Diarrhea (+/- blood in stool)
  • Weight loss (often severe)
  • Abdominal pain
  • Poor skin and coat condition (dry; patchy; flaky; dull)
  • Increased thirst and water intake (polydypsia)
  • Increased volume of urine output (polyuria)
  • Shaking, trembling and shivering (neurological signs; with severe disease)
  • Shock
  • Seizures
  • Collapse
  • Death

Diagnosis

Addison’s disease is typically diagnosed via blood tests. Based on the dog’s symptoms and the results of the initial evaluation and routine blood work a clinical suspicion for the disease may indicate further testing. Suspicious findings may include low blood glucose, low blood sodium levels (hyponatremia), low blood chloride levels (hypochloremia), high blood potassium levels (hyperkalemia) and high levels of circulating blood urea nitrogen (BUN). An initial screening tests (baseline cortisol) may be ran to screen patients and determine if further, more specific testing is indicated.

AA axisThe most conclusive test for Addison’s is an adrenocorticotropic hormone (ACTH) stimulation test. In normal dogs, ACTH is produced by the pituitary gland and stimulates the adrenal glands to produce corticosteroids when the body needs them. The ACTH stimulation test involves measuring a dog’s blood steroid levels, and then administering ACTH. After a prescribed period of time, the levels of circulating corticosteroids will be reassessed. Dogs with Addison’s will have a barely detectable increase in blood steroid levels – or none at all, because their damaged adrenal glands can’t respond to the ATCH stimulus.

Treatment

Treatment involves replacing the absent hormones (oral hydrocortisone and fludrocortisone). Lifelong, continuous steroid replacement therapy is typically required, with regular follow-up treatment and monitoring for other health problems.

Maintenance

Treatment for Addison’s disease involves replacing the missing cortisol, sometimes in the form of prednisone tablets in a dosing regimen that mimics the physiological concentrations of cortisol. In addition, many patients require monthly injections of DOCP (desoxycorticosterone pivalate) or daily oral doses of fludrocortisone acetate for the missing aldosterone.

Crisis

Standard therapy involves intravenous injections of glucocorticoids and large volumes of intravenous saline with dextrose (glucose). This treatment usually brings rapid improvement.

Prognosis

With timely and appropriate treatment for Addison’s disease, dogs can live long and happy lives.


Animal Specialty Group

DVM, Diplomate American College of Veterinary Internal Medicine

Dr. Mickila Collins received her Doctor of Veterinary Medicine degree from Ross University in 2005, completing her clinical year at Louisiana State University. After graduation, she completed a one-year rotating internship, followed by an internal medicine internship, both at ASG.


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