The adrenal glands are located just above the kidneys and produce three major hormones, two of which originate in the outer adrenal cortex (cortisol and aldosterone) and the other from the inner adrenal medulla (epinephrine):
- Cortisol, an important hormone for the regulation of glucose and protein metabolism, as well as blood pressure and the immune system.
- Aldosterone, a hormone involved in blood pressure, sodium and potassium balance.
- Epinephrine (adrenalin), a major hormone of the sympathetic nervous system and the “fight-or-flight” response.
Adrenal disorders can involve either too much or too little production of any of these hormones. The adrenal gland can also develop nodules or masses which require investigation.
Hypercortisolism involves the overproduction of the adrenal hormone cortisol. This can be due to over-stimulation from the pituitary gland from the hormone ACTH (see Cushing's disease in the pituitary section), or from a problem within the adrenal gland itself, either from a single cortisol-secreting adrenal mass or from nodular adrenal disease.
Excess cortisol in the blood can cause a variety of symptoms, including high blood pressure, weight gain, thinning of the skin, easy bruising, poor wound healing and many others (sometimes referred to as Cushing's syndrome). The diagnosis of hypercortisolism is made by blood and/or urine testing. Treatment depends upon cause of the excess cortisol secretion. In the case of a solitary adrenal mass, surgical removal can be curative. However, for other types of hypercortisolism, surgery may not be possible, so medication is used.
Hyperaldosteronism involves the overproduction of the adrenal hormone aldosterone. This can result in low potassium in the blood and high blood pressure that does not respond to usual treatment. The underlying causes of this include a single adrenal mass, or nodular adrenal disease.
The diagnosis is made by blood tests and may require further specialized testing, including adrenal vein sampling which is done by inserting a catheter into the adrenal veins to measure the aldosterone levels. Treatment depends upon the cause. If a single mass is identified as the source of the excess hormone production, then it can usually be surgically removed. However, if the source is nodular disease that involves both adrenal glands (right and left), then surgery may not be possible and medication is used. The investigation and treatment of hyperaldosteronism should be guided by a specialist familiar with this condition.
Adrenal insufficiency involves reduced hormone secretion from the adrenal gland, resulting in a deficiency of all adrenal hormones, including cortisol and aldosterone. Symptoms of adrenal insufficiency include weakness, weight loss, dizziness, and sometimes abdominal pain, nausea and vomiting.
The causes of adrenal insufficiency include autoimmune destruction of the adrenal gland (Addison's disease), bleeding into the adrenal glands, or infections, such as tuberculosis. If the adrenal glands are severely damaged, they do not usually recover and hormone replacement is required.
Hormone replacement for adrenal insufficiency includes cortisol-like medications (e.g. hydrocortisone or prednisone) and aldosterone-like medications (fludrocortisone). The proper doses of each of these medications varies between individuals and should be determined in conjunction with a specialist, who is familiar with the treatment of this condition.
The adrenal gland, like other glands in the body, can develop masses (lumps) within the gland, which are usually benign (non-cancerous) and do not cause any problem. However, some adrenal masses can produce excess adrenal hormones, including cortisol, aldosterone, or epinephrine. Also, rarely adrenal masses can be cancerous.
An adrenal mass may be identified incidentally by a ultrasound, CT scan or MRI. In such cases, testing should be done to make sure that the mass is not producing too much hormone and that it is not cancerous. If the mass is cancerous or produces too much hormone, then surgical removal is usually necessary. If the mass is non-cancerous and does not produce excess hormone, then simple clinical monitoring is often the best course of action.
For more information about adrenal disorders, please see the links to the Canadian Society for Endocrinology & Metabolism or the Endocrine Society in the Endocrine Links section.