Signs and Symptoms of Addison's Disease
The symptoms of Addison's disease develop insidiously, and it may take some time to be recognised. The most common symptoms are fatigue, lightheadedness upon standing or while upright, muscle weakness, fever, weight loss, difficulty in standing up, anxiety, nausea, vomiting, diarrhea, headache, sweating, changes in mood and personality, and joint and muscle pains. Some have marked cravings for salt or salty foods due to the urinary losses of sodium. Increased tanning may be noted, particularly in sun-exposed areas, as well as darkening of the palmar creases, sites of friction, recent scars, the vermilion border of the lips, and genital skin. This is not encountered in secondary and tertiary hypoadrenalism.
Causes of Addison's Disease
Causes of adrenal insufficiency can be grouped by the way they cause the adrenals to produce insufficient cortisol. These are adrenal dysgenesis (the gland has not formed adequately during development), impaired steroidogenesis (the gland is present but is biochemically unable to produce cortisol) or adrenal destruction (disease processes leading to the gland being damaged).
Diagnosis of Addison's Disease
Suggestive features
Routine investigations may show:
1) Hypercalcemia
2) Hypoglycemia, low blood sugar (worse in children due to loss of glucocorticoid's glucogenic effects)
3) Hyponatremia (low blood sodium levels), due to the kidney's inability to excrete free water in the absence of sufficient cortisol, and also the effect of Corticotropin-releasing hormone to stimulate secretion of ADH. That hyponatremia occurs even in secondary adrenal insufficiency (i.e. due to pituitary disease), in which aldosterone deficiency is not a feature, underscores the fact that hyponatremia in Addison's disease is not due to lack of aldosterone.
4) Hyperkalemia (raised blood potassium levels), due to loss of production of the hormone aldosterone
5) Eosinophilia and lymphocytosis (increased number of eosinophils or lymphocytes, two types of white blood cells)
6) Metabolic acidosis (increased blood acidity), also due to loss of the hormone aldosterone because sodium reabsorption in the distal tubule is linked with acid/hydrogen ion (H+) secretion. Low levels of aldosterone stimulation of the renal distal tubule leads to sodium wasting in the urine and H+ retention in the serum.
Treatment for Addison's Disease
Treatment for Addison's disease involves replacing the missing cortisol, sometimes in the form of hydrocortisone tablets, or prednisone tablets in a dosing regimen that mimics the physiological concentrations of cortisol. Alternatively one quarter as much prednisolone may be used for equal glucocorticoid effect as hydrocortisone. Treatment must usually be continued for life. In addition, many patients require fludrocortisone as replacement for the missing aldosterone. Caution must be exercised when the person with Addison's disease becomes unwell with infection, has surgery or other trauma, or becomes pregnant. In such instances, their replacement glucocorticoids, whether in the form of hydrocortisone, prednisone, prednisolone, or other equivalent, often need to be increased. Inability to take oral medication may prompt hospital attendance to receive steroids intravenously. People with Addison's are often advised to carry information on them (e.g. in the form of a MedicAlert bracelet) for the attention of emergency medical services personnel who might need to attend to their needs.