The paired adrenal glands, located atop the kidneys, secrete hormones that influence blood pressure, including aldosterone and epinephrine. Noncancerous and cancerous adrenal gland tumors that produce excess aldosterone or epinephrine typically cause high blood pressure, or hypertension. High blood pressure caused by a hormone-secreting adrenal gland tumor is called adrenal hypertension.
Types
Conn's syndrome describes high blood pressure caused by an aldosterone-producing tumor of the adrenal gland, also known as an adrenal adenoma. Most of these tumors are noncancerous, although cancerous forms can occur, reports the Merck Manual for Healthcare Professionals. An adrenal pheochromocytoma is an epinephrine-producing tumor that arises from the area of the gland known as the adrenal medulla. More than 90 percent of pheochromocytomas of the adrenal gland prove noncancerous, according to the Merck Manual for Healthcare Professionals.
Mechanisms
Aldosterone helps maintain blood pressure by increasing kidney retention of sodium and water. Excessive aldosterone production associated with Conn's syndrome causes water and sodium overload, leading to adrenal hypertension, explains the medical reference text "Harrison's Principles of Internal Medicine." Epinephrine--the "fight-or-flight" hormone--causes profound constriction of most blood vessels in the body. It also increases the heart rate and the force of heart muscle contractions. The cardiovascular effects of pheochromocytoma-associated epinephrine excess typically lead to profound adrenal hypertension.
Diagnosis
Patients with a pheochromocytoma often present with symptoms that point to the presence of an underlying adrenal tumor. In addition to high blood pressure, people with pheochromocytoma commonly experience headaches, heart palpitations, excessive sweating, weight loss, anxiety, fatigue and abdominal and chest pain, reports the American Urological Association. The blood pressure may cycle between normal and markedly elevated. Blood tests and CT scans are typically used to confirm the diagnosis of pheochromocytoma-induced adrenal hypertension. An aldosterone-producing adenoma often does not cause specific symptoms. A low potassium level in conjunction with treatment-resistant high blood pressure, however, points to the possibility of this condition, notes MayoClinic.com. Blood tests and CT scans help confirm the diagnosis of Conn's syndrome-induced adrenal hypertension.
Treatment
Surgical removal is the treatment of choice for an aldosterone-secreting adrenal tumor, note Drs. Erik Alexander and Robert Dluhy in their chapter "Aldosterone Excess" published by Endotext.com. Surgery is also the definitive treatment for an adrenal pheochromocytoma, according to the Merck Manual for Healthcare Professionals. Doctors may use radiation therapy and chemotherapy to treat a cancerous pheochromocytoma.
Significance
The Endocrine Society estimates that more than 10 percent of people with high blood pressure have underlying Conn's syndrome or a cancerous aldosterone-producing adrenal tumor. Pheochromocytomas account for less than one percent of all cases of high blood pressure, according to the American Urological Association.
Although adrenal hypertension remains a relatively uncommon cause of high blood pressure, identification of people with these disorders proves important because their hypertension is usually curable.
References
- Merck Manual for Healthcare Professionals: Primary Aldosteronism (Conn's Syndrome)
- Merck Manual for Healthcare Professionals: Pheochromocytoma
- "Harrison's Principles of Internal Medicine, 16th Edition"; Dennis L. Kasper, M.D., et al., Editors; 2004
- American Urological Association: Pheochromocytoma
- MayoClinic.com: Primary Aldosteronism, Symptoms
