The adrenal glands are small, triangle-shaped structures positioned just above each kidney. Their primary role involves producing hormones that regulate various bodily functions, including metabolism, blood pressure, and responses to stress. Adrenal nodules are abnormal growths or lumps that form within these glands. While most growths are harmless, they cause symptoms when they interfere with the normal production and release of hormones. The resulting health effects are directly linked to which specific hormone is being produced in excess quantities.
The Difference Between Functional and Non-Functional Nodules
The distinction between a functional and non-functional nodule determines whether a person experiences symptoms. Non-functional nodules, often discovered accidentally during imaging for an unrelated condition, are frequently termed incidentalomas. These growths do not actively secrete hormones in amounts large enough to disrupt the body’s chemistry, meaning they are usually asymptomatic.
A functional nodule, by contrast, is active endocrine tissue that overproduces one or more specific hormones. This excessive and unregulated hormone release causes noticeable and often systemic symptoms that lead to a diagnosis. Since the vast majority of adrenal nodules are non-functional, symptoms are relatively rare. The specific symptoms experienced depend entirely on the type of hormone being secreted in excess.
Symptoms Related to Cortisol Overproduction
When an adrenal nodule produces an unregulated amount of cortisol, the resulting symptoms are medically recognized as Cushing’s syndrome. A common physical change is a noticeable shift in body fat distribution, leading to rapid weight gain concentrated in the trunk and abdomen. This central obesity is often accompanied by the development of a rounded, flushed facial appearance, sometimes referred to as a “moon face.”
The skin shows characteristic signs due to the effects of excess cortisol on connective tissue. Patients frequently report easy bruising and the appearance of wide, purplish-red stretch marks (striae), typically found on the abdomen, thighs, and chest. These stretch marks are distinct because of their deep color and size, reflecting the breakdown of collagen.
Chronic exposure to high cortisol levels also leads to significant muscle weakness, particularly affecting the upper legs and arms. Cortisol directly opposes the action of insulin, which can lead to the onset of high blood sugar levels, pre-diabetes, or overt type 2 diabetes. These systemic changes develop slowly, making them easy to initially overlook or attribute to general aging.
Symptoms Related to Aldosterone Overproduction
Excessive production of aldosterone leads to a condition that primarily disrupts the body’s fluid and electrolyte balance. The main observable symptom is often severe and sustained high blood pressure (hypertension), which frequently proves resistant to standard medications. Aldosterone acts on the kidneys to retain sodium and water while simultaneously excreting potassium, driving the rise in blood pressure.
The loss of potassium leads to a state called hypokalemia, which causes a second set of symptoms. Low potassium levels interfere with normal muscle and nerve function, resulting in muscle cramps and generalized fatigue. Patients may also experience increased thirst and frequent urination, particularly at night.
Potassium imbalance can also impact the electrical stability of the heart muscle, sometimes causing irregular heart rhythms felt as palpitations. This hormonal overproduction is often investigated when hypertension is diagnosed at a young age or proves unusually difficult to control.
Symptoms Related to Catecholamine Overproduction
When an adrenal nodule, known as a pheochromocytoma, secretes excessive catecholamines (primarily adrenaline and noradrenaline), the symptoms are typically acute and episodic. These hormones are responsible for the body’s “fight or flight” response, and their unregulated release creates sudden, intense physical episodes. The classic presentation involves a triad of symptoms: severe, pounding headaches, excessive sweating, and intense, rapid heart rates (tachycardia).
These attacks are often paroxysmal, starting abruptly and subsiding after a few minutes to an hour. During an episode, the release of adrenaline causes a sudden and severe spike in blood pressure that can be dangerous. The surges in these hormones can also manifest as pronounced anxiety, a feeling of impending doom, and noticeable fine tremors.
The episodic nature means patients may feel completely normal between attacks, making diagnosis challenging. Because the physical sensations are prominent, these episodes are sometimes mistakenly attributed to panic attacks or generalized anxiety disorder. However, the presence of extremely high blood pressure and drenching sweats, often without an emotional trigger, points toward an underlying physiological cause.
Finding the Cause
Once symptoms suggest a hormonally active adrenal nodule, the diagnostic process proceeds in a structured two-step manner. The first step involves biochemical testing to definitively confirm that a specific hormone is being overproduced. This typically requires specialized blood tests and often a 24-hour urine collection to measure the levels of hormones or their metabolic byproducts. Confirming the biochemical abnormality provides objective evidence that the symptoms are related to adrenal overproduction.
The second step involves imaging studies to locate and characterize the nodule itself. Computed tomography (CT) or magnetic resonance imaging (MRI) scans are used to visualize the adrenal glands and determine the size and specific features of the growth. The combination of laboratory confirmation and precise imaging allows healthcare providers to accurately diagnose the type of functional adrenal nodule.