Symptoms of Hypoadrenocorticism in a Dog

by Catherine Troiano
Some breeds are genetically predisposed to develop hypoadrenocorticism.

Some breeds are genetically predisposed to develop hypoadrenocorticism.

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Hypoadrenocorticism, also known as Addison’s disease, is defined as a deficiency of cortisol and aldosterone, the corticosteroid hormones the adrenal gland’s cortex produces. Hypoadrenocorticism symptoms mimic those of numerous other health conditions, making diagnosis a challenge. Look for patterns that occur following stressful events; your observation can point your veterinarian in the direction of a specific diagnostic test, enabling a definitive diagnosis and initiation of a lifelong treatment protocol to manage the disease.

Risk Factors and Symptom Presentation

Hypoadrenocorticism patients are often young or middle-age dogs. The disease usually presents around 4 or 5 years of age, but older pets can also be stricken. The condition is more common in females than it is in males, and there is a genetic predisposition in breeds include bearded collies, standard poodles, Portuguese water dogs and Nova Scotia duck trolling retrievers, West Highland white terriers, wheaten terriers and Rottweilers. Any dog who develops hypoadrenocortisicm will not show signs of the disease until roughly 90 percent of the adrenal cortex has ceased to function.

Symptoms of Hypoadrenocorticism

The early symptoms of hypoadrenocorticism are generally vague. These symptoms include occasional diarrhea, vomiting, lethargy and a decrease in appetite. Initial bouts of these symptoms are often shrugged off as indigestion, a virus or over-excitement. The occurrence of these symptoms may be subtle or gradual as they wax and wane, flaring up when the dog has been stressed. As their frequency increases, joined by possible dehydration, hair loss, muscle weakness, and increases in water intake and urinary output, other illnesses may be suspected, including kidney disease, pancreatitis, hypoglycemia, or heart disease. As the symptoms continue undiagnosed or wrongly diagnosed, a frightening event that is known as an Addisonian crisis will result. One-third of dogs with hypoadrenocorticism are diagnosed only when they are presented to their veterinarians in the throes of an Addisonian crisis.

Signs of an Addisonian Crisis

An Addisonian crisis is the result of a severe electrolyte imbalance. When this occurs, blood sugar levels plummet dangerously low. Potassium levels climb abnormally high and the sodium level drops. The combination disturbs normal heart rhythm, slows the heart rate and causes arrhythmia and a weak pulse. Blood pressure and temperature both drop. These are all signs that occur with shock, even though the dog has sustained no trauma or exposure to toxins. The only outward sign that owners will witness is sudden collapse. An Addisonian crisis can be fatal -- when it occurs, immediate emergency medical intervention is required to save the dog’s life.

Laboratory Indications

Dogs with hypoadrenocorticism will likely have abnormal findings on blood chemistry panels and urinalyses, but these abnormalities are not conclusive in making a definitive diagnosis of the disease. A patient may show elevated blood potassium and low blood sodium during an Addisonian crisis, but their levels can normalize between attacks. Low urine specific gravity and elevated blood urea nitrogen and creatinine levels are common findings in dogs with hypoadrenocorticism, but they are also the defining parameters of a dog with kidney disease. The only definitive laboratory test for diagnosing hypoadrenocorticism is a blood test called the ACTH stimulation test. Once the disease is diagnosed, managed and monitored, your dog can life a full and happy life.

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