Apr 6, 2014
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ADDISON’S DISEASE

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The cause of Addison’s disease (also called chronic adrenal insufficiency and hypocortisolism) is a deficiency of the adrenocortical hormones CORTISOL, ALDOSTERONE and androgens (see ANDROGEN) due to destruction of the adrenal cortex (see ADRENAL GLANDS). It occurs in about 1 in 25,000 of the population. In the past, destruction of the adrenal cortex was due to TUBERCULOSIS (TB), but nowadays fewer than 20 per cent of patients have TB while 70 per cent suffer from autoimmune damage. Rare causes of Addison’s disease include metastases (see METASTASIS) from CARCINOMA, usually of the bronchus; granulomata (see GRANULOMA); and HAEMOCHROMATOSIS. It can also occur as a result of surgery for cancer of the PITUITARY GLAND destroying the cells which produce ACTH (ADRENOCORTICOTROPHIC HORMONE)

– the hormone which provokes the adrenal cortex into action.

Symptoms The clinical symptoms appear slowly and depend upon the severity of the underlying disease process. The patient usually complains of appetite and weight loss, nausea, weakness and fatigue. The skin becomes pigmented due to the increased production of ACTH. Faintness, especially on standing, is due to postural HYPOTENSION secondary to aldosterone deficiency. Women lose their axillary hair and both sexes are liable to develop mental symptoms such as DEPRESSION. Acute episodes – Addisonian crises – may occur, brought on by infection, injury or other stressful events; they are caused by a fall in aldosterone levels, leading to abnormal loss of sodium and water via the kidneys, dehydration, low blood pressure and confusion. Patients may develop increased tanning of the skin from extra pigmentation, with black or blue discoloration of the skin, lips, mouth, rectum and vagina occurring. ANOREXIA, nausea and vomiting are common and the sufferer may feel cold.

Diagnosis This depends on demonstrating impaired serum levels of cortisol and inability of these levels to rise after an injection of ACTH.

Treatment consists in replacement of the deficient hormones. HYDROCORTISONE tablets are commonly used; some patients also require the salt-retaining hormone, fludrocortisone. Treatment enables them to lead a completely normal life and to enjoy a normal life expectancy. Before surgery, or if the patient is pregnant and unable to take tablets, injectable hydrocortisone may be needed. Rarely, treated patients may have a crisis, perhaps because they have not been taking their medication or have been vomiting it. Emergency resuscitation is needed with fluids, salt and sugar. Because of this, all patients should carry a card detailing their condition and necessary management. Treatment of any complicating infections such as tuberculosis is essential. Sometimes DIABETES MELLITUS coexists with Addison’s disease and must be treated.

Secondary adrenal insufficiency may occur in panhypopituitarism (see PITUITARY GLAND), in patients treated with CORTICOSTEROIDS or after such patients have stopped treatment.

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Medical Dictionary

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