Adrenal gland diseases and disorders

Hyposecretion of cortisol from the adrenal gland causes Addison disease. Hypersecretion of cortisol causes Cushing syndrome, an umbrella term for cortisol excess from any cause; when the excess is caused specifically by an ACTH-secreting pituitary tumor, the condition is called Cushing disease. The following sections discuss these conditions.

Addison disease

Addison disease is a malfunction of the adrenal cortex, leading to adrenal insufficiency (hyposecretion) of cortisol. Addison disease affects adults ages 30 to 50, though it can occur at any age. Addison disease can be acute or chronic. Acute Addison disease may be called Addisonian crisis, a condition marked by life-threatening symptoms. A crisis can be brought on by stressful situations, infections, minor illnesses, or surgery.

The causes of Addison disease include an autoimmune reaction, tuberculosis, and damage to or disease of the adrenal glands or pituitary gland. Acute Addison disease can cause the following responses:

• Pain in the lower back, abdomen, and legs
• Severe vomiting and diarrhea, dehydration, and low blood pressure
• Loss of consciousness
• Hyperkalemia (an abnormally high blood potassium level) and hyponatremia

Aldosterone, the adrenal cortex hormone that regulates sodium and water balance and promotes potassium excretion, drops along with cortisol in Addison disease - this is why sodium falls (hyponatremia) and potassium rises (hyperkalemia).

Chronic Addison disease may occur over weeks to months. It can cause the following:

• Irritability, extreme fatigue, weight loss, lack of appetite, and a craving for salt
• Darkening of the skin and buccal membranes (hyperpigmentation)
• Hypotension, fainting, nausea, diarrhea, and vomiting
• Hypoglycemia
• Muscle pain, depression, and loss of body hair

After a physical exam, the provider may order blood tests (e.g., cortisol, sodium, potassium, and ACTH), imaging tests, and an ACTH stimulation test.

Example: Interpreting an ACTH stimulation test

A provider draws a baseline cortisol level, then injects synthetic ACTH and draws a second level 30-60 minutes later. In a healthy adrenal gland, cortisol rises sharply after the injection - for example, from 7 mcg/dL at baseline to 22 mcg/dL after stimulation. In Addison disease, the damaged adrenal gland cannot respond, so cortisol stays low even after the injection - for example, 3 mcg/dL at baseline and still only 4 mcg/dL after stimulation.

Answer: A blunted or absent cortisol rise after ACTH stimulation confirms primary adrenal insufficiency (Addison disease).

Addisonian crisis treatment requires the immediate administration of an intravenous saline and dextrose solution with corticosteroids. Other treatments involve corticosteroids to replace cortisol and aldosterone and dietary changes (e.g., a diet high in carbohydrates and protein; adequate sodium and fluids).

Cushing syndrome

Cushing syndrome refers to the effects of excess cortisol in the body, regardless of cause. When the excess cortisol results specifically from a pituitary tumor that secretes too much ACTH, the condition is called Cushing disease. Causes of Cushing syndrome include:

• A benign pituitary tumor that secretes excess ACTH (Cushing disease)
• An adrenal adenoma (benign adrenal cortex tumor) that autonomously secretes cortisol independent of ACTH
• Taking long-term corticosteroids for another medical condition (e.g., organ transplantation, severe asthma, or rheumatoid arthritis)

Cushing syndrome can cause the following:

• High blood pressure
• Weight gain, especially in the abdomen, upper back, face (moon face), and between the shoulder blades (buffalo hump)
• Pink or purple stretch marks on the abdomen, thighs, breasts, and arms
• Fragile, thin skin that bruises easily
• Infections, slow-healing wounds, and acne
• Severe fatigue, muscle weakness, and headaches
• Depression, anxiety, irritability, loss of emotional control, and difficulty thinking clearly
• Slowed or impaired growth in children
• Decreased libido and infertility in men
• Thicker or more noticeable facial and body hair (hirsutism or hypertrichosis) in women

After obtaining a medical history and performing a physical exam, the provider may order a number of tests:

• Blood, saliva, and urine tests to measure cortisol levels
• An ACTH stimulation test
• Imaging tests

Treatment is focused on the cause of the disorder and may include medications to control cortisol levels, radiation therapy to shrink the tumor, or surgery to remove the tumor.

Addison vs. Cushing: Addison disease reflects cortisol deficiency - expect hyperpigmentation, hypotension, hyponatremia, and hyperkalemia. Cushing syndrome reflects cortisol excess - expect moon face, buffalo hump, hypertension, and sodium retention with potassium loss, the opposite electrolyte pattern from Addison disease.

Additional adrenal gland diseases and disorders

Additional adrenal gland diseases include these:

• Adrenocortical carcinoma: A malignant adrenal tumor that starts in the adrenal cortex.
• Congenital adrenal hyperplasia (CAH): A genetic disorder that causes the body to make a decreased amount of cortisol. Usually, people with CAH also have other hormone imbalances.
• Pheochromocytoma: A type of paraganglioma tumor that develops in the adrenal medulla and produces adrenaline, causing high blood levels of epinephrine.