-IBIS-1.5.0-
tx
endocrine system
Addison's disease
diagnoses

definition and etiology

definition:
Adrenocortical hypofunction causing an insidious, gradual and typically progressive disease. May be primary (Addison's Disease) or secondary (from ACTH deficiency).

etiology:
Addison's disease is rare, affecting about 1-4:100,000. It affects men and women equally. The glands must be at least 90% destroyed before symptoms are evident. In approximately 70% of cases it is due to an autoimmune adrenalitis. Other causes include sarcoidosis, fulminating infection (meningococcal septicemia), tuberculosis, neoplasm, or iatrogenic influences. Usually the disease becomes clinically evident when the patient undergoes metabolic stress or trauma.

signs and symptoms

• Fatigue and depression.
• Weight loss, and gastrointestinal discomfort, anorexia, nausea, vomiting.
• Hypotension with dizziness and faintness.
• Decreased sexual desire.
• Loss of body hair.
• Amenorrhea.
• Vitiligo and/or excess of pigmentation (like a tan) along areas that are submitted to pressure (bony prominences), hand creases, buccal mucosa, and areas exposed to light. The increased pigmentation is due to the increased levels of ACTH circulation in the body in response to the adrenal insufficiency. Other skin changes include black freckles over the face, neck, and shoulders as well as bluish-black skin changes on the lips, mouth, vagina and rectum.
• Dehydration.
• Hypoglycemia.
• Increased susceptibility to infections.
• Decreased cardiac output potentially leading to circulatory collapse.
• Cold intolerance.

An adrenal crisis may occur with acute infection, trauma, postoperatively, or excess perspiration (especially in hot weather). Symptoms and signs include:
• Severe asthenia.
• Peripheral vascular collapse.
• Marked pains in legs, lower back or abdomen.
• Renal failure with azotemia.

lab findings:
• Low plasma sodium and chloride, high plasma potassium and high urea.
• Low plasma cortisol (< 5 micrograms/dl; 8 a.m. specimen)
• Lack of response of plasma cortisol to an injection of ACTH or cosyntropin (an ACTH analog with less side-effects).
• increased hematocrit due to decreased blood volume, but normocytic anemia present
• fasting hypoglycemia with insulin hypersensitivity
• eosinophilia
• decreased urine 17-hydroxy-ketosteroids, 17-KS, and 17-KGS

course and prognosis

Conventional treatment comprises hydrocortisone injections of 20 mg. in the morning and 10 mg at night. Mineralocorticoid supplementation is normally also required, except in secondary Addison's, when aldosterone is still produced. Prognosis is good with replacement therapy.

differential diagnosis

• Malignant disease.
• Adrenal insufficiency may occur in conjunction with thyroid disease and pernicious anemia.
• Other causes of hyperpigmentation: pregnancy, Cushing's Disease, liver disease, carcinomatosis.
• Psychiatric conditions.
• Malabsorption.


footnotes