Hypoadrenocorticism is a disease resulting in decreased production of adrenal hormones.  It is also called Addison’s disease after Thomas Addison who first described the disease in human patients in 1855.  In the normal individual, the two adrenal glands (which sit just adjacent to the kidneys) produce glucocorticoids (cortisol) and mineralocorticoids.  These hormones are essential for life.

Mineralocorticoids control salt and water balance.  Proper salt and water balance is needed to maintain blood pressure.  When blood pressure is reduced, many adverse consequences can ensue including weakness, kidney failure, shock and other organ failure.  Potassium levels can elevate resulting in muscle weakness, decreased pumping ability of the heart and slowing of the heart rate to the point of cardiac arrest.

Glucocorticoids have effects on nearly every tissue in the body.  They promote a sense of well-being, stimulate appetite, maintain blood glucose levels, help maintain serum calcium levels, protect against shock and help maintain blood pressure.

Most affected dogs are female and present before the age of 7 years old.  Some familial tendencies exist in standard poodles, labrador retrievers and portuguese water spaniels.  These are generalities and the disease can be seen in any age, breed, or gender.  It is a rare disease in cats.

Symptoms may be vague.  Depression, lethargy, weakness, loss of appetite and weight loss are common problems.  Gastrointestinal symptoms may predominate with vomiting and diarrhea.  Signs (increased thirst and urination) and laboratory evidence of kidney disease may  also be evident.  Signs frequently wax and wane and may be exacerbated by stressful situations.  Some animals develop an acute, life threatening “adrenal” crisis with cardiovascular collapse and shock.

Diagnosis is made by specific adrenal axis testing.  This involves cortisol level measurement and sometimes aldosterone measurement.  Routine chemistry panels can show many abnormalities including:  low blood glucose, low calcium, elevated urea nitrogen, elevated creatinine, elevated potassium, and low sodium.

Long term treatment is directed at replacement of the decreased hormones and stabilizing the patient as indicated.  Daily  treatments of oral cortisone and florinef are often used for this purpose.  DOCP injections can be used in lieu of daily oral medications.  These injections are generally required every 25 – 30 days, but dosage scheduled must be tailored to each patient’s needs.  It is critical that an addisonian patient receive their medication regularly and without lapses.  We generally recommend checking electrolyte levels every 6 months and routine blood tests at least yearly in the stable patient.

In the initial stages, patients may need much more intensive treatment to try and stabilize them.  Shock, kidney failure, cardiac irregularities, low blood sugar, low salt levels, vomiting, and dehydration can all be life threatening if not specifically addressed in the initial treatment.  Dogs will usually respond to treatment in an average of 1-3 days.  Cats can take 5-7 days to respond.

Once the patient is stabilized and hormone supplementation is instituted, the prognosis is excellent.  However, it is crucial that the pet receive their hormone supplement either orally or by injection for the balance of their lifetime.