The adrenal glands are small, triangle-shaped endocrine organs positioned directly above the kidneys. They produce several hormones, such as cortisol and adrenaline, that regulate fundamental bodily processes, including metabolism, blood pressure, and the body’s response to stress. Calcification is a biological process involving the abnormal deposit of calcium salts within soft tissues. Adrenal calcification refers specifically to this deposition of calcium within the tissue of one or both adrenal glands, signifying a permanent change in the tissue structure, often representing a biological scar.
Defining Adrenal Calcification
Adrenal calcification is most often identified as an incidental finding, discovered on imaging scans like a CT scan or X-ray performed for an unrelated medical concern. The presence of these deposits indicates a previous injury or disease process occurred in the gland, leading the body to lay down mineralized material. This calcified tissue is generally inert and not biologically active.
The calcification is typically dystrophic, meaning calcium accumulates in tissue that has been previously damaged, degenerated, or died, even when calcium levels in the bloodstream are normal. The deposits vary in appearance, ranging from fine specks to large, dense, or curvilinear patterns.
The location is an important distinction: unilateral (affecting one gland) or bilateral (involving both glands). Unilateral calcification is far more common and rarely causes functional problems because the healthy gland can compensate. Bilateral calcification raises greater concern because extensive damage to both glands may impair hormone production.
Primary Causes and Etiology
The events leading to adrenal calcification generally involve inflammation, cell death, or bleeding within the gland.
Infection and Inflammation
Historically, one of the most significant causes is infection, particularly granulomatous diseases like tuberculosis (TB) and histoplasmosis. These infections trigger a severe inflammatory response that results in caseous necrosis, a form of tissue death where the damaged cells are replaced by calcium deposits.
Hemorrhage and Trauma
Adrenal hemorrhage is another frequent cause, often following extreme physiological stress or trauma. In newborns, this bleeding can result from birth trauma or oxygen deprivation. In adults, hemorrhage is often linked to sepsis, major surgery, or the use of blood thinners. The resulting hematoma eventually resolves, leaving behind a residual calcified rim or mass as part of the healing process. Severe systemic infection can cause bilateral adrenal hemorrhage, leading to massive tissue destruction and widespread calcification in both glands. Less common causes include congenital or genetic conditions, such as Wolman disease, which manifests with extensive adrenal calcification in infancy.
Tumors and Masses
Calcification can also occur within adrenal masses or tumors. Neuroblastoma, a tumor that often develops in the adrenal medulla, is frequently associated with calcification, particularly in children. In adults, calcification may be found in both benign tumors (myelolipomas and pheochromocytomas) and malignant tumors (adrenal cortical carcinoma or metastases). While the pattern and extent of calcification can offer clues, imaging alone is often not sufficient for a definitive diagnosis.
Clinical Presentation and Detection
Most adrenal calcification cases are asymptomatic and discovered purely by chance during imaging studies performed for other reasons. Since the calcification represents old, healed damage, the patient is often unaware that the event ever occurred.
In contrast, calcification following an acute event, such as adrenal hemorrhage, may be preceded by severe, nonspecific symptoms. Acute hemorrhage presents with sudden, intense pain in the abdomen or flank, along with generalized symptoms like fever, profound weakness, and nausea or vomiting. If the bleeding is extensive and affects both glands, it can rapidly lead to low blood pressure and shock due to the sudden loss of hormone production.
Computed Tomography (CT) scans are the primary and most effective method for detection and characterization. CT is highly sensitive to calcium, which appears brightly white on the images, clearly outlining the deposits. While plain X-rays and Magnetic Resonance Imaging (MRI) may detect large calcifications, CT provides superior detail and is better able to differentiate calcified tissue from other adrenal masses.
Impact on Adrenal Function and Management
The most significant concern regarding adrenal calcification is the potential for primary adrenal insufficiency (AI), where the glands cannot produce adequate amounts of cortisol and aldosterone. This risk is highest when the calcification is bilateral and extensive, indicating destruction of a large portion of hormone-producing tissue. Unilateral calcification rarely causes AI, as the remaining healthy gland maintains normal function.
To determine if hormone production is impaired, functional testing is necessary. The ACTH stimulation test is the standard method used to evaluate adrenal reserve. This test involves administering a synthetic version of the adrenocorticotropic hormone (ACTH), which normally prompts the adrenal glands to release cortisol.
A blood sample is taken before the injection and again 30 to 60 minutes afterward to measure the cortisol response. If the damaged glands cannot produce a sufficient surge of cortisol, adrenal insufficiency is confirmed. The management strategy depends entirely on the outcome of this testing.
If adrenal function tests are normal, the calcification is considered a benign, non-functional finding, and the primary treatment is simple monitoring. If adrenal insufficiency is confirmed, patients require lifelong hormone replacement therapy. This substitution therapy is essential for survival and typically involves a daily regimen of glucocorticoids (like hydrocortisone) and sometimes mineralocorticoids (like fludrocortisone) to manage stress and maintain normal electrolyte balance.