High Blood Pressure (Secondary Hypertension)

Hypertension (high blood pressure) is the sustained elevation of blood pressure above normal levels — generally defined as a systolic pressure persistently at or above 130 mmHg and/or a diastolic pressure at or above 80 mmHg. While the vast majority of hypertension cases are classified as primary (essential) hypertension — meaning no specific underlying cause is identified — a clinically important minority are attributable to an identifiable, potentially treatable cause. This is called secondary hypertension.

Secondary hypertension is particularly relevant in the context of urological and endocrine disorders because specific adrenal gland tumors are among the most important and actionable causes of secondary hypertension. When hypertension is driven by a surgically correctable adrenal tumor, appropriate identification and treatment of the tumor can lead to normalization or significant improvement of blood pressure — and in many cases, a cure of the hypertension itself.

Clinicians should suspect secondary hypertension when hypertension is difficult to control with multiple medications, occurs at a younger age than typical, or is accompanied by specific symptoms or metabolic findings pointing to an adrenal or renal source.

Adrenal tumors causing secondary hypertension

• Pheochromocytoma is a tumor of the adrenal medulla (inner portion of the adrenal gland) that autonomously secretes catecholamines — primarily epinephrine and norepinephrine. These hormones powerfully constrict blood vessels and increase heart rate, producing severe hypertension that can be either sustained or episodic (paroxysmal). Pheochromocytoma-related hypertension is classically accompanied by the triad of severe headache, profuse sweating, and palpitations (rapid heartbeat), often occurring in discrete episodes that may be triggered by physical activity, emotional stress, or surgical manipulation of the tumor. Some patients experience persistent hypertension without paroxysmal episodes. Unrecognized and untreated pheochromocytoma carries a risk of life-threatening hypertensive crisis.
  
  
• Primary aldosteronism (Conn's syndrome / aldosteronoma) occurs when one or both adrenal glands produce excess aldosterone — a hormone that regulates sodium and potassium balance in the kidney. Excess aldosterone causes the kidney to retain sodium and water while excreting potassium, resulting in volume-dependent hypertension. This form of secondary hypertension is often resistant to standard antihypertensive drug therapy. It is also characterized by low serum potassium (hypokalemia), which may produce muscle weakness, cramps, fatigue, and increased urinary frequency. Primary aldosteronism is currently recognized as one of the most common causes of secondary hypertension and is significantly underdiagnosed. When caused by a unilateral aldosterone-secreting adenoma (aldosteronoma), it is surgically curable.
  
  
• Cortisol-secreting adrenal adenoma (Cushing's syndrome) — Excess cortisol from a cortisol-producing adrenal tumor causes hypertension through multiple mechanisms, including mineralocorticoid effects, increased vascular sensitivity to vasopressors, and impaired endothelial function. Hypertension associated with Cushing's syndrome is typically accompanied by the full spectrum of hypercortisolism features, including central obesity, facial rounding, easy bruising, purple striae, and proximal muscle weakness.

Renovascular hypertension

• Narrowing (stenosis) of the renal arteries — most commonly from atherosclerosis or fibromuscular dysplasia — reduces blood flow to the kidney, activating the renin-angiotensin-aldosterone system and causing severe, often refractory hypertension. This is a non-adrenal renal cause of secondary hypertension managed by the urology and nephrology team.

Primary hypertension (essential hypertension)

• The most common form of hypertension, without an identifiable underlying cause. Risk factors include older age, obesity, family history, dietary sodium excess, physical inactivity, tobacco use, and excessive alcohol consumption. Primary hypertension does not have a surgically correctable cause.

See a physician if:

• Blood pressure readings are persistently elevated (systolic ≥ 130 mmHg or diastolic ≥ 80 mmHg) at home or during medical visits
• Hypertension occurs at a younger age (under 40) without obvious lifestyle risk factors
• High blood pressure is accompanied by episodic severe headaches, palpitations, and sweating — this triad is characteristic of pheochromocytoma and warrants urgent evaluation
• Hypertension is accompanied by low potassium levels, muscle weakness, or increased urinary frequency — these features suggest primary aldosteronism
• An adrenal mass has been discovered incidentally on imaging and blood pressure is elevated

Seek emergency evaluation immediately if:

• Blood pressure reaches extremely high levels (systolic > 180 mmHg or diastolic > 120 mmHg), particularly with symptoms such as severe headache, chest pain, shortness of breath, or visual changes — this is a hypertensive emergency
• A known or suspected pheochromocytoma patient develops a sudden severe hypertensive episode