The body handles stress by releasing a hormone called cortisol. Cortisol is released from two small glands, one located on top of each kidney, called the adrenal glands. The adrenal glands produce a number of hormones, giving it a variety of roles. Adrenal glands regulate the immune system, blood pressure and energy metabolism. Destruction of the adrenals may be complete or incomplete depending on the cause. Incomplete destruction often leads to vague, gradual symptoms with multiple contributing factors.
Hyperpigmentation
Diagnosis of adrenal gland failure typically includes hyperpigmentation, according to a 2002 Endocrine Reviews article by Betterle and associates. They confirm increased skin darkening as the most specific marker associated with primary adrenal gland failure. Hyperpigmentation is caused by an inappropriate increase in the hormone that regulates release of cortisol. It increases its effort when there is no cortisol to signal it to stop. Skin darkening or pigmentation occurs most prominently in pressure areas, such as elbows, and those that are exposed to the sun. Hyperpigmentation is not typically seen in secondary causes (those outside of adrenal gland) of adrenal insufficiency.
Weakness
Weakness is the body's inability to contract muscles or strength. Deficient adrenal hormones affect both muscle and neurons causing them to function improperly or not at all. Absence or deficiency of cortisol and other adrenal hormones leads to neuromuscular dysfunction, according to the Merck Manual. Hypercalcemia is recognized by both the Cleveland Clinic and a Case Report by Nair & Simmons as a contributing factor to weakness. Cortisol is involved in the uptake of calcium by the kidneys. Electrolyte balance of calcium and other electrolytes must be maintained for normal neuromuscular contraction.
Fatigue
Extreme tiredness is different from weakness. It refers to a patient feeling sluggish or having a general lack of energy. Normal cortisol release breaks down protein, fats and carbohydrates for energy production. Disturbance in adrenal gland hormones means malfunction of energy metabolism. In addition, cortisol helps the body respond to stress. Increased energy demands for any reason--trauma, infection or surgery--normally increases cortisol and other adrenal hormones including epinephrine. If the body's overall state is at a deficit, and without cortisol, it is unable to maintain energy needs and fatigue ensues. Complicating the picture further is the heart muscle. When the heart is not performing optimally, poor circulation causes further decrease in energy production leading to fatigue.
Low Blood Pressure
Deficiency of aldosterone is mainly responsible for low blood pressure according to the Merck Manual. Aldosterone maintains sodium concentration and volume as its primary role. As previously stated, maintaining electrolyte balance is important for all body processes. When aldosterone is deficient, as in adrenal failure, sodium is not reclaimed by the kidney creating a low volume state in the body, therefore low blood pressure on the arterial walls. Experiments performed by Forehead and colleagues postulate multiple mechanisms by which cortisol helps to maintain blood pressure. Resulting symptoms in adrenal failure patients are dizziness and lightheadedness when they stand.
Dehydration
Many of the symptoms of adrenal insufficiency are interrelated. Reclaiming sodium is aldosterone's major role. Sodium balance is significant because it is required for maintenance of the body's water status which is in direct relationship to its volume and blood pressure. Water follows sodium when it is reabsorbed by the kidney. When aldosterone is not available to reabsorb sodium, water is also not available. Advanced adrenal failure may be indicated by the orthostatic hypotension, or low blood volume and pressure upon standing. This is typically seen in primary causes of adrenal deficiency when there is extensive destruction of the gland. Direct destruction of the adrenal gland of more than 90 percent causes severe symptoms such as dehydration and low volume.
