hypocortisolism

Hypocortisolism, commonly referred to as adrenal insufficiency, is a condition characterized by inadequate production of cortisol by the adrenal cortex or insufficient signaling from the pituitary or hypothalamus. Cortisol helps regulate metabolism, blood pressure, stress response, and immune function. When cortisol is deficient, the body cannot respond adequately to stress, and a range of symptoms can develop. Hypocortisolism can be classified as primary, due to adrenal gland failure, or secondary/tertiary, due to pituitary or hypothalamic dysfunction or suppression of the hypothalamic-pituitary-adrenal axis.

Primary adrenal insufficiency results from destruction or dysfunction of the adrenal cortex, with autoimmune disease being the most common cause in many regions. Other causes include infections, hemorrhage, genetic disorders, and infiltration of the adrenal glands. In primary disease, there is deficient cortisol and often deficient aldosterone, leading to fatigue, abdominal pain, weight loss, hyponatremia, hyperkalemia, low blood pressure, and sometimes hyperpigmentation from excess ACTH.

Secondary and tertiary adrenal insufficiency arise from insufficient ACTH production by the pituitary or insufficient corticotropin-releasing hormone from the hypothalamus, or from prolonged exogenous glucocorticoid therapy that suppresses the axis. Aldosterone is usually preserved in these forms, so hyperkalemia is less common.

Common symptoms across forms include fatigue, weakness, nausea, vomiting, weight loss, abdominal pain, dizziness or fainting, and hyponatremia. In primary disease, hyperpigmentation and signs of mineralocorticoid deficiency may be present.

Diagnosis involves morning cortisol measurements, ACTH levels, and a dynamic ACTH stimulation test. Distinguishing primary from secondary disease relies on ACTH level and response to stimulation. Imaging may be used to evaluate structural causes.

Treatment requires glucocorticoid replacement, typically hydrocortisone, with dose adjustments for stress or illness. In primary adrenal insufficiency, mineralocorticoid replacement (fludrocortisone) is often needed. Patients are educated about stress dosing and emergency injections for crisis situations. Acute adrenal crisis is a medical emergency requiring immediate hydrocortisone, intravenous fluids, and relentless monitoring. With appropriate therapy, most individuals can lead normal lives.