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What is Adrenal insufficiency (Addison disease)


gafacom image result for the Primary adrenal insufficiency (Addison disease)

Primary adrenal insufficiency (Addison disease) most often involves the destruction of all regions of the adrenal cortex. There are deficiencies of cortisol, aldosterone, and the various androgens, and levels of CRH and ACTH increase in a compensatory manner.

Autoimmune dysfunction is responsible for 80% to 90% of cases in developed countries, whereas tuberculosis is the predominant cause in developing countries. Medications that inhibit cortisol synthesis (eg, ketoconazole) or accelerate cortisol metabolism (eg, phenytoin, rifampin, phenobarbital) can also cause primary adrenal insufficiency.

Secondary adrenal insufficiency most commonly results from exogenous corticosteroid use, leading to suppression of the hypothalamic-pituitary-adrenal axis and decreased ACTH release, resulting in impaired androgen and cortisol production. Mirtazapine and progestins (eg, medroxyprogesterone acetate, megestrol acetate) have also been reported to induce secondary adrenal insufficiency. Secondary disease typically presents with normal mineralocorticoid concentrations.

CLINICAL PRESENTATION

Weight loss, dehydration, hyponatremia, hyperkalemia, and elevated blood urea nitrogen are common in Addison disease. Hyperpigmentation is common in Addison disease and may involve exposed and nonexposed parts of the body. Hyperpigmentation is usually not seen in secondary adrenal insufficiency because of low amounts of melanocyte-stimulating hormone.

DIAGNOSIS




The short cosyntropin stimulation test can be used to assess patients with suspected hypocortisolism. An increase to a cortisol level of 18 mcg/dL or more (500 nmol/L) rules out adrenal insufficiency.

Patients with Addison disease have an abnormal response to the short cosyntropin stimulation test. Plasma ACTH levels are usually 400 to 2000 pg/mL (88 to 440 pmol/L) in primary insufficiency versus normal to low (5–50 pg/mL [1.1–11 pmol/L]) in secondary insufficiency. A normal cosyntropin-stimulation test does not rule out secondary adrenal insufficiency.

Other tests include the insulin hypoglycemia test, the metyrapone test, and the CRH stimulation test.

What is Adrenal insufficiency (Addison disease) What is Adrenal insufficiency (Addison disease) Reviewed by gafacom on June 23, 2019 Rating: 5

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