ADDISON'S DISEASE

Addison's Disease

Addison's Disease

Addison's disease (also chronic adrenal insufficiency, hypocortisolism, and hypocorticism) is a rare endocrine disorder wherein the adrenal glands produce insufficient steroid hormones (glucocorticoids and often mineralocorticoids). It's generally diagnosed via blood tests and medical imaging. Treatment involves replacing the absent hormones (oral hydrocortisone and fludrocortisone). Regular follow-up treatment and monitoring for other health problems is necessary.

Addison's disease is named after Dr Thomas Addison, the British physician who first described the condition in On the Constitutional and Local Effects of Disease of the Suprarenal Capsules (1849). The adjective "Addisonian" describes features of the condition, and patients suffering Addison's disease. While Addison's six patients in 1855 all had adrenal tuberculosis,[4] the term "Addison's disease" does not imply an underlying disease process.

The symptoms of Addison's disease develop insidiously, and it may take some time to be recognized. The most common symptoms are fatigue, dizziness, muscle weakness, weight loss, difficulty in standing up, anxiety, diarrhea, headache, sweating, changes in mood and personality, sudden drops in blood pressure especially when going from a seated position to standing (orthostatic hypotension), and joint and muscle pains. Some have marked cravings for salt or salty foods due to the urinary losses of sodium. Adrenal insufficiency is manifested in the skin primarily by hyperpigmentation.

In suspected cases of Addison's disease, one needs to demonstrate that adrenal hormone levels are low even after appropriate stimulation (called the ACTH stimulation test) with synthetic pituitary ACTH hormone tetracosactide . Two tests are performed, the short and the long test.

The short test compares blood cortisol levels before and after 250 micrograms of tetracosactide (IM/IV) is given. If, one hour later, plasma cortisol exceeds 170 nmol/L and has risen by at least 330 nmol/L to at least 690 nmol/L, adrenal failure is excluded. If the short test is abnormal, the long test is used to differentiate between primary adrenal failure and secondary adrenocortical failure.

The long test uses 1 mg tetracosactide (IM). Blood is taken 1, 4, 8, and 24 hours later. Normal plasma cortisol level should reach 1000 nmol/L by 4 hours. In primary Addison's disease, the cortisol level is reduced at all stages whereas in secondary corticoadrenal insufficiency, a delayed but normal response is seen.

Other tests that may be performed to distinguish between various causes of hypoadrenalism are renin and adrenocorticotropic hormone levels, as well as medical imaging - usually in the form of ultrasound, computed tomography or magnetic resonance imaging (MRI).

Adrenoleukodystrophy, and the milder form, adrenomyeloneuropathy, cause adrenal insufficiency combined with neurological symtoms. These diseases are estimated to be the cause of adrenal insufficiency in approximately 35% of male patients with idiopathic Addison's disease and should be considered in the differential diagnosis of any male with adrenal insufficiency. Diagnosis is made by a blood test to detect very long chain fatty acids (VLCFA).

An "Addisonian crisis" or "adrenal crisis" is a constellation of symptoms that indicate severe adrenal insufficiency. This may be the result of either previously undiagnosed Addison's disease, a disease process suddenly affecting adrenal function (such as adrenal ...