The adrenal glands, located on top of each kidney, produce hormones that regulate bodily functions. Adrenal insufficiency occurs when these glands cannot produce sufficient amounts of hormones, particularly cortisol. This deficiency affects the body’s ability to manage stress, regulate blood pressure, and maintain a proper balance of water and electrolytes.
Causes and Types of Adrenal Insufficiency
Adrenal insufficiency is categorized into three types based on the problem’s origin. Primary adrenal insufficiency, also known as Addison’s disease, occurs when the adrenal glands are damaged and cannot produce enough hormones. The most common cause is an autoimmune response where the body’s immune system attacks the adrenal cortex. Less frequently, infections, cancer, or bleeding within the glands can cause this primary type.
Secondary adrenal insufficiency stems from a problem with the pituitary gland. The pituitary produces adrenocorticotropic hormone (ACTH), which signals the adrenal glands to release cortisol. If the pituitary does not produce enough ACTH, the adrenal glands will not receive the proper signal, leading to low cortisol production. This can be caused by pituitary tumors, inflammation, or surgical or radiation treatment to the pituitary area.
Tertiary adrenal insufficiency is related to the hypothalamus, a region of the brain that controls the pituitary gland. The hypothalamus releases corticotropin-releasing hormone (CRH), which tells the pituitary to secrete ACTH. This type often develops when a person taking long-term corticosteroid medications for other conditions abruptly stops them, disrupting the normal hormonal signaling from the hypothalamus.
Recognizing the Symptoms
The onset of symptoms for adrenal insufficiency is often gradual and can be mistaken for other health issues. These symptoms can fluctuate and may become more obvious during periods of physical stress. Common signs that develop over months include:
- Chronic fatigue
- Muscle weakness
- Loss of appetite
- Unexplained weight loss
- Nausea and vomiting
- Diarrhea and abdominal pain
A distinct sign of primary adrenal insufficiency is hyperpigmentation, or a darkening of the skin. This can appear like a tan, especially on skin folds, scars, and pressure points like the elbows and knees. Bluish-black discoloration may also develop on the lips and gums.
Other common indicators include low blood pressure that causes dizziness or fainting upon standing (orthostatic hypotension) and a craving for salty foods due to the loss of sodium. Some individuals may experience low blood sugar (hypoglycemia), irritability, and in women, a loss of body hair or irregular menstrual periods.
The Diagnostic Process
Diagnosis involves specific tests, starting with blood tests to measure sodium, potassium, cortisol, and ACTH levels. Low sodium and cortisol with high potassium and ACTH indicate primary adrenal insufficiency. In secondary adrenal insufficiency, ACTH levels are low along with cortisol.
The definitive diagnostic tool is the ACTH stimulation test. This procedure involves measuring baseline cortisol, injecting synthetic ACTH, and then re-testing blood after 30 to 60 minutes to see how the adrenal glands respond. A limited or absent rise in cortisol levels confirms the diagnosis.
To determine the underlying cause, a doctor may order imaging tests. A computed tomography (CT) scan of the abdomen can reveal damage to the adrenal glands. If secondary adrenal insufficiency is suspected, a magnetic resonance imaging (MRI) scan of the brain may be performed to look for abnormalities in the pituitary gland.
Managing the Condition
Treatment for adrenal insufficiency focuses on replacing deficient hormones and requires lifelong therapy. The primary medication is a corticosteroid, such as hydrocortisone or prednisone, to replace cortisol. These are taken in two or three daily doses to mimic the body’s natural rhythm. For primary adrenal insufficiency, a mineralocorticoid called fludrocortisone is also prescribed to manage salt and water balance.
An important part of management is understanding the need for dose adjustments during physical stress, known as stress dosing. The body’s need for cortisol increases during illness, injury, or surgery. Patients must learn to increase their glucocorticoid dosage during these periods to prevent a medical emergency, with the amount depending on the stressor’s severity.
Proactive safety measures are also required. Individuals should wear a medical alert bracelet or necklace to inform healthcare providers of their condition in an emergency. This is especially important if the person is unable to communicate. Patients are also counseled to carry an emergency injection kit containing hydrocortisone.
Understanding Adrenal Crisis
An adrenal crisis, or Addisonian crisis, is a life-threatening emergency caused by dangerously low cortisol levels. It can be triggered by significant physical stress, such as a severe infection or injury, particularly if medication is not increased appropriately. Suddenly stopping corticosteroid medication can also cause a crisis.
The symptoms of an adrenal crisis are severe, appear suddenly, and can be fatal without immediate medical intervention. They include:
- Sharp, sudden pain in the lower back, abdomen, or legs
- Severe vomiting and diarrhea leading to dehydration
- Profound weakness
- Confusion or loss of consciousness
- A dramatic drop in blood pressure, leading to shock
An adrenal crisis requires immediate emergency medical attention. Treatment includes an intravenous injection of hydrocortisone and IV fluids to treat dehydration and stabilize blood pressure. Educating patients and their families to recognize warning signs and administer an emergency hydrocortisone shot is an important part of long-term management.