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PEER REVIEW: ADDISON’S DISEASE
Management and Treatment of Addison’s Disease Written by Theresa Lowry-Lehnen (PhD), CNS, GPN, RNP, South East Technological University
adrenal glands; amyloidosis; and surgical removal of the adrenal glands.2, 3, 5 Secondary Adrenal Insufficiency
Addison’s disease (AD), often referred to as primary adrenal insufficiency or hypoadrenalism, is a rare endocrine disorder which occurs when the adrenal glands do not produce enough of the hormone cortisol and in some cases aldosterone. The disease is characterized by weight loss, muscle weakness, fatigue, hypotension, and sometimes darkening of the skin in both exposed and non-exposed areas of the body. It affects about 1 in 100,000 people, occurs in all age groups, but usually individuals aged 30-50 years and affects men and women equally. In rare cases, Addison’s disease has been noted to occur in families suggesting a genetic predisposition to developing the disorder.1, 3, 5, 11 Cortisol produced by the adrenal glands, located just above the kidneys belongs to a class of hormones called glucocorticoids, which affect almost every organ and tissue in the body. Cortisol’s main function is to help the body respond to stress. It also helps maintain blood pressure and cardiovascular function; slow the immune systems inflammatory response; helps balance the effects of insulin in breaking down sugar for energy; and help regulate the metabolism of proteins, carbohydrates, and fats.1, 3, 7 Aldosterone belongs to a class of hormones called mineralocorticoids also produced
by the adrenal glands. It helps maintain blood pressure and water and salt balance in the body by helping the kidney retain sodium and excrete potassium. When aldosterone production falls too low, the kidneys are unable to regulate salt and water balance, causing blood volume and blood pressure to drop.1, 3, 7 Primary Adrenal Insufficiency The commonest causes of Addison's disease are autoimmune disorders and tuberculosis. While TB is the most common cause of Addison's disease in developing countries most cases of AD are caused by the gradual destruction of the adrenal cortex, the outer layer of the adrenal glands, by the body's own immune system. About 70 percent of reported cases of Addison’s disease are due to autoimmune disorders, in which the immune system makes antibodies which attack the body's own tissues or organs and slowly destroys them. Several autoimmune processes can lead to adrenal insufficiency either affecting the adrenal glands exclusively or as part of a more complex inherited autoimmune polyglandular syndrome. Other causes include certain medications, sepsis, and bleeding into both adrenal glands. Less common causes of primary adrenal insufficiency are chronic infections, mainly fungal infections; cancer cells spreading to the
AUGUST 2022 • HPN | HOSPITALPROFESSIONALNEWS.IE
Secondary adrenal insufficiency is caused by insufficient ACTH produced by the pituitary gland or CRH produced by the hypothalamus. It causes a drop in the production of cortisol but not aldosterone. A temporary form of secondary adrenal insufficiency can occur when a person receiving glucocorticoid hormones such as prednisone for a long time abruptly stops taking the medication. Another cause of secondary adrenal insufficiency is the surgical removal of benign ACTHproducing tumours of the pituitary gland. Although less common, adrenal insufficiency can occur when the pituitary gland decreases in size or stops producing ACTH. This can result from tumours or infections of the area, loss of blood flow to the pituitary, radiation for treatment of pituitary tumours, or surgical removal of parts of the hypothalamus or the pituitary gland during neurosurgery.1, 2, 7 Addison's disease is associated with the development of other autoimmune diseases, such as type I diabetes, Hashimoto's thyroiditis, coeliac disease and vitiligo. Psychiatric symptoms such as mood disturbances, decreased motivation, and behavioural changes are also frequently associated with the condition.2, 3, 5 Hyponatremia and hyperkalemia are commonly associated with Addison's disease, while hypoglycaemia is uncommon. The patient usually complains of gastrointestinal upset with anorexia, nausea, vomiting and diarrhoea and a craving for salty foods can occur due to salt loss. In women, menstrual periods may become irregular or stop. Adrenal calcification and enlargement are commonly seen in Addison's disease associated with tuberculosis.2 The symptoms of Addison disease increase in intensity over time and eventually lead to acute adrenal insufficiency, known
as adrenal crisis. Symptoms of addisonian crisis include sudden penetrating pain in the lower back, abdomen, or legs, severe vomiting and diarrhoea, followed by dehydration, low blood pressure and loss of consciousness. Adrenal crisis is a medical emergency and must be treated immediately. It can cause cardiac arrest, CVA, hypovolaemic shock and hypoxia. If left untreated, adrenal crisis can be fatal leading to coma and death.1, 3 Diagnosis A suspected diagnosis of Addison’s disease is often based upon a detailed patient history, thorough clinical examination and identification of characteristic findings. A confirmed diagnosis is made through a series of specialised biochemical tests including the ACTH stimulation test and insulin-induced hypoglycemia test. X-ray examination of the adrenal and pituitary glands are also useful in helping to establish the diagnosis. Adrenal insufficiency can be difficult to diagnose in the early stages. Because symptoms progress slowly, the condition is often not detected until a stressful event or illness occurs. In about 25 percent of patients, symptoms first appear during an addisonian crisis.3, 5. 10 ACTH Stimulation Test / Synacthen Stimulation Test ACTH stimulation test measures the ability of the adrenal cortex to respond to ACTH. Blood and/ or urine cortisol levels (short/ rapid ACTH test) are measured before and 30-60 minutes after a synthetic form of ACTH (Synacthen) is given by injection. The normal response after an injection of ACTH is a rise in blood and urine cortisol levels. Patients with either form of adrenal insufficiency respond poorly or do not respond at all. If the response to the short ACTH test is abnormal, a "long" ACTH stimulation test is carried out to determine the cause of adrenal insufficiency. ACTH is injected intravenously or intramuscularly over a 48- to 72-hour period,
