Addisons's disease is associated with all except :
low rennin levels 1 Ref Harrison 17th/e p 2264, 2263 & 16th/e p 2142] The normal serum coisol ranges between 5-23 lug/dl In addison's disease the coisol level is usually below (< 3 pg/dL). Patients tend to be hypotensive and ohostatic, about 90% have systolic blood pressure under 110 mm Hg. Diastolic blood pressure is also decreased, the B.P. is usually in the range of 80/50 or less. In addison's diseases the hea is usually smallQ. In addison's disease the plasma renin activity is usually elevated, - It indicates the presence of depleted intravascular volume. Addison's disease The predominant manifestations in Addison's disease occur due to mineralocoicoid deficiency but the symptoms are also contributed by glucocoicoid deficiency and increased ACTH FEATURES OF:- Mineralocoicoid deficiency lack of aldosterone secretion greatly decreases renal tubular sodium reabsorption and consequently allows sodium ions, chloride ions and water to be lost into urine in great profusion. The net result is greatly decreased extracellular fluid volume. Fuhermore, hyponatremia2, hyperkalemia0 and mild acidosis0 develop because of failure of potassium and hydrogen ions to be secreted in exchange for sodium reabsorption. Glucocoicoid deficiency Loss of coisol secretion leads to hypoglycaemia because of decreased gluconeogenesis and increased peripheral utilization of glucose. Fuhermore, lack of coisol reduces0 the mobilization of both proteins and fats from the tissues thereby depressing many other metabolic functions of the body. This sluggishness of energy mobilization when coisol is not available is one of the major detrimental effects of glucocoicoid lack. Increased ACTH When coisol secretion is depressed the normal negative feedback to the hypothalamus and anterior pituitary gland is also depressed, therefore allowing tremendous rates of ACTH secretion as well as simultaneous secretion of increased amount of MSH. Probably the tremendous amount of ACTH cause most of the pigmenting effect because they can stimulate formation of melanin by the melanocytes in the same way that MSH does. REMEMBER The clinical features and laboratory features described above are characteristically seen only in primary addison's disease because in primary addison's disease both aldosterone and glucocoicoid are deficient, whereas In secondary addison's disease only glucocoicoid deficiency is seen." ALSO KNOW The basis for acute adrenal deficiency or addisonian crisis During conditions of physical or mental stress, large amount of glucocoicoids are secreted to cope up with the situation. But in persons with addison's disease, the output of glucocoicoids does not increase during stress. Thus the deficiency of glucocoicoids, when a person actually has acute need for the excessive amount of glucocoicoids produces addisonian crisis. The manifestations are produced due to extracellular fluid dehydration and low blood volume leading to circulatory shock.
Cardiac atrophy
Decreased diastolic B.P.
Serum coisol < 8
Low renin levels