Addisons Disease in Dogs

Studies have shown that 75% to 80% of dogs found to have Addison’s disease are females of young to middle age, with the age of four being a common time to develop the affliction. Hypoadrenocorticism is the reduction in corticosteroid secretions from the adrenal glands, which are located near the kidneys and have the function of aiding the body in regulating necessary tasks. Day to day function will be altered by lower than normal production of hormones required to control salt, blood cell activity and more.

Addison’s disease, also known as canine hypoadrenocorticism, occurs when the adrenal glands stop or reduce production of their normal hormones. While some dogs are diagnosed in the early stages of the disease, most cases are discovered in a crisis situation. If you notice any changes to your pet’s health it is important to consult a veterinarian for advice as soon as possible.

Symptoms of Addison’s disease can be intermittent, making the urgency of a veterinary visit seem less urgent to some pet owners. Because of the often intermittent nature of signs, dogs are often not seen by the veterinarian until a crisis has developed, leaving the dog with a low pulse, slow heart rate, cold extremities and collapse. Symptoms before crisis are as follows:

• Weakness
• Depression
• Loss of appetite
• Thirst
• Frequent urination
• Trembling
• Abdominal pain
• Excessive vomiting and diarrhea which can cause dehydration

Types

Addison’s disease is characterized mainly by two classes of steroidal hormone interruption. Mineralocorticoids are important to glucose regulation, fat and protein breakdown, maintenance of blood pressure levels, as well as red blood cell formation. Glucocorticoids play a major role in balancing water, potassium and salt levels in the body. Irregularities in these areas due to low secretion of hormones from the adrenal glands points to Addison’s disease.

While the lack of hormonal secretions by the adrenal glands is the most common cause for Addison’s disease, there are other explanations for the development of the syndrome though they occur much less frequently:

• Infection or inflammation
• Cancer
• Physical trauma to glands
• Rapid withdrawal of prescribed steroids
• Drug therapy
• Abnormal blood supply to adrenal glands
• Adrenal gland failure due to issues with the hypothalamus or pituitary gland

Do not attempt to self diagnose any health problem your pet may be experiencing. Prompt veterinary care is necessary when your dog is suffering from a disorder such as Addison’s disease.

Relay to the veterinarian the timeline of symptoms, the behavioral changes you have noticed and any other information you feel may be helpful to the investigation into your dog’s health. Because renal failure is a definite consideration, taking your dog to the veterinarian and communicating your concerns is the best way to aid in a quick diagnosis of symptoms, no matter how intermittent.

The veterinarian will check for signs of weakness such as low pulse and irregular heartbeat, which are two signs that a crisis point in Addison’s disease may be imminent. A blood test to check for low sodium or sugar, and high potassium will be performed. A urinalysis is also an important step in diagnosis, because diluted urine may mean Addison’s disease. An electrocardiogram will indicate if the heart rhythm of your dog is abnormal. The final test in diagnosing Addison’s disease is the ACTH test, which is additional blood work involving a delay of one hour between tests, and measures how well the adrenal gland responds to adrenocorticotropic hormone.

While treatment for Addison’s disease depends on the severity of clinical signs, it is noted that most often the diagnosis of Addison’s disease is made when the dog is already critically ill. Unfortunately, this is the nature of this illness. However, the prognosis for recovery is excellent with timely hospital care.

Rapid action must take place in the case of an Addison’s crisis. Treatment may take place over a few days and includes intravenous therapy to remedy severe hydration. Cortisol-like drugs, which will regulate the abnormal hormone levels found in your dog, and medications to neutralize the effects of an abnormal heart rhythm (caused by high potassium) are given to stabilize your pet. Improvement in electrolyte and hormone levels with the use of glucocorticoids and mineralocorticoids, and the reparation of fluid volume deficits (with substances such as calcium,saline and dextrose) are critical to your pet’s return to health. Results are most often positive, and dogs in crisis usually show improvement within a few hours of the beginning of the hospital treatment.

There will be veterinarian follow up visits necessary on an every 3 month basis for a period of one year after an Addison’s crisis and diagnosis. With Addison’s disease, your dog will be prescribed mineralocorticoid medication for the duration of his life. This involves a long term daily hormone pill given orally. Sometimes this medication must be given in high doses to be effective. Another option, which is frequently given to large dogs as a cost effective option for treatment, is an injection every 25 days. In some cases, dogs will need the addition of a glucocorticoid, such as prednisone, added to their medication regimen.

Studies have shown that stress may bring about changes in your pet’s health, particularly with Addison’s disease. Discuss this topic with your veterinarian. A slight change in the amount of medication given may be necessary if you are moving, travelling with, or boarding your dog.