Hypoadrenocorticism (Addison's Disease)

Hypoadrenocorticism (Addison's Disease) is a serious condition in which the adrenal glands produce insufficient amounts of two essential hormones—glucocorticoids (cortisol) and mineralocorticoids (aldosterone).

 

Disease occurs when adrenal tissues are damaged (primary hypoadrenocorticism) or the pituitary gland malfunctions (secondary hypoadrenocorticism). Some cases are iatrogenic; disease develops because steroid medications are withdrawn too quickly or an animal with Cushing's Syndrome is receiving a high dose of medication.

 

Common signs and symptoms may be transient—often described as "waxing and waning" over weeks to months—and include:

  • Anorexia
  • Vomiting
  • Diarrhea
  • Weak femoral pulse
  • Lethargy
  • Weakness
  • Dehydration
  • Depression
  • Weight loss
  • Bradycardia

 

Clinical signs may be initially vague and may become life threatening if the diagnosis and treatment are delayed. It's crucial that these signs are identified quickly to prevent or correct a potential Addisonian crisis.

Hypoadrenocorticism (Addison’s Disease)

 

Diagnosis of Addison's Disease should include an evaluation of the animal's history and clinical signs, as well as the results of blood chemistry and screening tests.

 

There may be mild or even no notable changes in the CBC, biochemical profile and urinalysis. The absence of a stress leukogram in a very ill patient may cause suspicion. A normocytic, normochromic nonregenerative anemia may also be noted. Hypoglycemia, hyponatremia, hypochloremia and hyperkalemia, metabolic acidosis and prerenal azotemia may also be noted.

 
ACTH Stimulation Test

Diagnostic Protocol for Cases of Suspected Cushing's Syndrome or Addison's Disease

 

 

View/print the diagnostic protocol.

 

Addison's disease requires two types of treatment: crisis management and maintenance.

 

Animals in crisis should be hospitalized, and require intravenous fluids and replacement glucocorticoid and mineralocorticoid therapy. Treatment is aimed at correcting dehydration and electrolyte imbalances.

 

Patients should not be released from the hospital until they are stable, eating and drinking, and their electrolytes are normal for at least 24 to 48 hours after discontinuation of intravenous fluid therapy.

 

All animals with Addison's disease will require lifelong supplementation with a glucocorticoid (e.g., prednisone) and mineralocorticoid (e.g., oral fludrocortisone or injectable desoxycorticosterone [DOCP]).

 

Monitoring

Long term monitoring of the patient's overall well-being and electrolytes is necessary. Frequency and timing of rechecking electrolytes depends on the type of mineralocorticoid supplement used. There is no reason to repeat an ACTH stimulation test in a patient that has been diagnosed with Addison's disease.