[Clinical presentation and diagnostic procedures in canine hypoadrenocorticism]

Hypoadrenocorticism (HA) is a rare endocrinopathy in dogs that may occur in a primary form, characterized by a combined deficiency of glucocorticoids and mineralocorticoids or isolated glucocorticoid deficiency, or in a secondary form with an isolated glucocorticoid deficiency. In addition, iatrogenic HA may also occur. The primary form represents the most frequent type of the disease. Clinical signs are variable and often nonspecific, ranging from lethargy, inappetence, vomiting, and weight loss to polyuria/polydipsia or acute, life-threatening adrenal crises associated with hypovolemia and electrolyte imbalances.

Typical laboratory findings include the absence of a stress leukogram, hyponatremia, hyperkalemia, azotemia, and hypoglycemia, although not all parameters are necessarily altered.

The ACTH stimulation test (ACTHST) remains the gold standard to confirm the diagnosis, as it reliably demonstrates glucocorticoid deficiency. Classic electrolyte abnormalities such as hyperkalemia and hyponatremia indicate a concurrent mineralocorticoid deficiency indirectly. In the absence of electrolyte disturbances, however, no reliable conclusions can be drawn regarding mineralocorticoid deficiency, and differentiation of the form of HA is therefore not possible. Measurement of endogenous adrenocorticotropic hormone (eACTH) can help to distinguish between primary and secondary HA, whereas aldosterone determination is currently not yet recommended for routine diagnostic use to identify mineralocorticoid deficiency in dogs with normal electrolytes.