Hypoadrenocorticism (Addison’s Disease)

Jack, a (nearly) 10 year old male shih-tzu presented to the clinic in January with vague symptoms of being unwell. He had a little bit of diarrhoea and vomiting and was sometimes off his food. He was shaking a bit at home (his owner thought this might be for attention) and looking back at his records he had gradually lost weight. His owner described him as being “depressed”. Jack was very unwell when he arrived at the clinic and was hospitalised for fluid therapy and blood testing.

Preliminary blood tests showed that Jack’s electrolytes were out of balance (a hallmark finding in Addisons disease) and a specific test confirmed this diagnosis. Jack had Hypoadrenocorticism or Addisons Disease and likely had been Addisonion for some time.

Although a relatively uncommon disease Addisons Disease is when the adrenal glands fail to produce enough mineralocorticoids and glucocorticoids hormones. These hormones are critical to the healthy functioning of the body. Deficient production of both these hormones can cause a number of symptoms such lethargy, vomiting, weight loss, diarrhoea, shaking, increased thirst and urination, depression, dehydration, weak pulse, collapse, blood in faeces, hair loss, low body temperature and painful abdomen. These symptoms overlap with those seen in other disease processes and Addisons is not usually at the top of the list of differentials.

More severe (sometimes life threatening) symptoms occur in acute episodes called an Addisonian Crisis and Jack was teetering on the edge of a crisis. A sudden and severe (acute) episode of hypoadrenocorticism is a medical emergency requiring immediate hospitalization and intensive therapy.  Blood glucose levels can fall rapidly and be incompatible with life. Patients with low body fluids are given intravenous fluids to replace the deficient fluid levels, but the cornerstone of therapy is to supplementally replace the deficient hormones.

Dogs that have been diagnosed with this condition need to be treated with hormone therapy for the rest of their lives. The dose of  hormones may need to be increased occasionally, especially during periods of stress like travel, hospitalization, and surgery. Treatment can be the form of tablets or injections every 3-4 weeks for the rest of your pet’s life. Electrolyte levels will also be checked regularly due to the significant alternations in electrolytes that are typically seen with this disease.

Good owner compliance is required for the life of the patient in order to benefit from treatment. However, with regular treatment, most patients do well and have a good prognosis.

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