Canine Hypoadrenocorticism Study Guide

Overview and Clinical Importance

Hypoadrenocorticism (Addison's disease) is an uncommon but potentially life-threatening endocrine disorder resulting from inadequate production of adrenocortical hormones, primarily glucocorticoids (cortisol) and mineralocorticoids (aldosterone). Often called "The Great Pretender," this disease mimics many common conditions, making it a diagnostic challenge and a favorite NAVLE topic.

The disease has an estimated prevalence of 0.06% to 0.28% in the canine population. Early recognition and treatment are critical, as untreated Addisonian crisis can result in death from hypovolemic shock, cardiac arrhythmias, and severe electrolyte disturbances. With appropriate therapy, the long-term prognosis is excellent, with median survival times exceeding 4.7 years.

Anatomy and Physiology of the Adrenal Glands

The adrenal glands are paired endocrine organs located craniomedial to the kidneys in the retroperitoneal space. Each gland consists of two distinct regions: the outer cortex (80-90% of the gland) and the inner medulla (10-20%). In dogs, the left adrenal gland is typically larger and positioned more caudal than the right.