Adrenal insufficiency (AI) occurs when the adrenal glands do not produce adequate amounts of certain hormones, primarily cortisol. Cortisol is a glucocorticoid that helps the body respond to stress, regulate metabolism, and maintain blood pressure. In the most common form, the glands also fail to produce enough aldosterone, a mineralocorticoid that balances salt and water levels. This hormonal deficit can lead to symptoms ranging from chronic discomfort to a sudden, life-threatening emergency.
Chronic Symptoms of Adrenal Insufficiency
The initial signs of adrenal insufficiency often develop slowly over many months, making the condition difficult to recognize early. Persistent fatigue and generalized muscle weakness are frequently reported complaints, often leading to a reduction in daily activity. These long-term symptoms are often non-specific and can be mistakenly attributed to other common illnesses.
Unexplained weight loss and a noticeable decrease in appetite are characteristic chronic symptoms. Gastrointestinal issues are also common, including recurring nausea, intermittent vomiting, and abdominal pain. These symptoms reflect the body’s inability to properly regulate metabolic functions without sufficient cortisol.
Many individuals experience low blood pressure (hypotension), which can cause dizziness or fainting, particularly when standing up quickly (orthostatic hypotension). This drop is often exacerbated by an aldosterone deficiency, which normally helps maintain blood volume. Due to this salt imbalance, some patients develop an intense craving for salty foods.
A unique physical sign, specifically associated with primary adrenal insufficiency (Addison’s disease), is hyperpigmentation, or darkening of the skin. This discoloration is most visible on sun-exposed areas, pressure points like the knuckles and elbows, and on the gums or inside the cheeks. The change in skin tone occurs because the body’s attempt to stimulate cortisol production inadvertently increases the level of a hormone that also promotes melanin synthesis.
Adrenal Crisis – Recognizing the Emergency
Adrenal insufficiency carries the risk of a life-threatening acute exacerbation known as an adrenal crisis. This emergency typically occurs when the body is subjected to severe physical stress, such as trauma, major infection, or surgery, and the adrenal glands cannot produce the necessary surge of cortisol. The onset of symptoms is rapid and requires immediate medical intervention.
Profound weakness progresses quickly to hypovolemic shock, caused by severely low blood volume and extremely low blood pressure. Patients may experience sudden, agonizing pain in the lower back, abdomen, or legs. Severe vomiting and diarrhea are common, rapidly accelerating dehydration and electrolyte imbalance.
If left untreated, an adrenal crisis can cause confusion, loss of consciousness, or coma. Treatment involves the immediate administration of an injectable glucocorticoid, such as hydrocortisone, followed by intravenous fluids to restore blood volume and stabilize blood pressure. This condition is a medical emergency, and anyone experiencing these severe symptoms should seek immediate emergency services.
Underlying Causes of Adrenal Insufficiency
Adrenal insufficiency is categorized into types based on the location of the hormonal problem. Primary adrenal insufficiency (Addison’s disease) results from damage directly to the adrenal glands. The most common cause in developed countries is an autoimmune response where the body mistakenly attacks and destroys the adrenal cortex, resulting in a deficiency of both cortisol and aldosterone.
Secondary adrenal insufficiency is more common and arises from a lack of adrenocorticotropic hormone (ACTH), which is produced by the pituitary gland. Since ACTH signals the adrenal glands to make cortisol, a problem in the pituitary or hypothalamus leads to insufficient cortisol production. Secondary AI preserves aldosterone function because its release is primarily regulated by the kidney’s renin-angiotensin system.
Tertiary adrenal insufficiency is most frequently caused by the abrupt withdrawal of long-term, high-dose corticosteroid medication, which suppresses the hypothalamic-pituitary-adrenal axis.
Seeking Diagnosis and Long-Term Management
Diagnosis of adrenal insufficiency is often delayed due to the vague nature of the chronic symptoms. If the condition is suspected, a physician will typically order blood tests to measure morning cortisol and ACTH levels. The definitive diagnostic tool is the ACTH stimulation test, where synthetic ACTH is injected to see if the adrenal glands respond by producing cortisol.
Long-term management centers on hormone replacement therapy to substitute the missing hormones. Glucocorticoids, such as hydrocortisone or cortisone acetate, are prescribed to replace cortisol and are taken daily, often in divided doses. Patients with primary adrenal insufficiency also require a mineralocorticoid, typically fludrocortisone, to replace aldosterone and manage salt and water balance.
A fundamental aspect of living with this condition is stress dosing, which involves temporarily increasing the glucocorticoid dose during periods of illness, injury, or high fever to prevent a crisis. Patients must also be equipped with an emergency injection kit containing an injectable form of hydrocortisone for use in severe situations. They should wear medical identification to alert first responders, as this lifelong regimen requires careful monitoring and adjustment by a specialist.