HEALTHNET

Secondary Hypertension Caused by Adrenal Tumor

Adrenal tumor is the cause for 1% to 2% of all hypertension cases. This kind of hypertension is one of the few that can be cured permanently by surgical treatment.

(Posted on 8 March 2007)

Adrenal tumor is the cause for 1% to 2% of all hypertension cases. This kind of hypertension is one of the few that can be cured permanently by surgical treatment. Hypertension can be classified into 2 types: primary and secondary. Primary hypertension can only be controlled by medication while secondary hypertension is caused by other illnesses, such as adrenal and growth enzyme-secreting tumors.

Laparoscopic surgery to remove the adrenal gland can effectively cure secondary hypertension caused by adrenal tumor. Compared with traditional open surgery, blood loss is reduced and the wound is smaller, thus facilitating patient's recovery.

Hypertension Caused by Adrenal Tumor

The adrenal gland is a part of the endocrine system located above the kidney. Its size is small, measuring 5cm x 3cm x 1cm on average, and weighs only 4 to 5 grams. The adrenal gland produces and releases adrenal hormone for the control of metabolism. These include aldosterone and catecholamines, which are important hormones to control water and electrolytes balance and to assist us for stress handling in the body respectively. Imbalance of these adrenal hormones will cause body malfunctions.

Adrenal tumor may cause secondary hypertension. Patients are relatively young, usually under 50 years of age. Adrenal tumors that cause hypertension include Conn's adenoma and pheochromocytoma. Conn's adenoma is caused by tumors arising in the adrenal cortex. The overproduction of aldosterone causes hypertension. Pheochromocytoma is caused by tumors in the adrenal medulla, which also causes hypertension.

Too much aldosterone causes hypertension. Abnormally high level of the hormone increases sodium absorption while excretes too much potassium. Too much sodium and salt in the body causes hypertension. Patients with hypertension experience dizziness, and the chances of contracting stroke and heart diseases are increased. Severe hypokalemia can cause heart failure, fatigue, paralysis, and irregular heart rhythm.

Lethal Pheochromocytoma Difficult to Diagnose

Pheochromocytoma is potentially lethal if not properly treated, but is also difficult to be diagnosed at the same time. In addition, it is challenging to clinicians because of its protean manifestations. Sustained poorly controlled hypertension is present in about 50% of patients. On the other hand, paroxysmal hypertension may occur. A typical paroxysm or panic attack is characterized by a sudden and major increase in blood pressure. It is associated with severe throbbing headache, nausea, profuse sweating, palpitations, anxiety and abdominal pain. In addition, it may present as convulsive seizure, hyperglycaemia, or a catastrophic cardiovascular illness including myocardial infarction, stroke, cardiac arrthythmias, postural hypotension and sudden death.

In undiagnosed or unprepared patients, severe or lethal paroxysms have occurred during invasive procedures such as needle biopsy, administration of contrast for computed tomography, or surgical procedures. However, diagnosis can only be expeditiously made if clinicians can maintain a high level of awareness. Cause of pheochromocytoma can be hereditary. Patients and their family members may have multiple endocrine tumors in the adrenal, thyroid and parathyroid glands.

Laparoscopic Surgery for Adrenalectomy

Laparoscopic surgery for the removal of the adrenal gland was conducted for the first time in 1992. Today, the operation was proved effective and safe. Since the discovery of Conn's adenoma in 1954, open surgery has been the only way to remove the adrenal gland. However, the death rate of open adrenalectomy is up to 2% and patients need at least 4 to 6 weeks to recover. On the other hand, there is an almost nil death rate for laparoscopic surgery, and patients usually recover within 1 to 2 weeks.

The cost of laparoscopic surgery is higher than that of open surgery. However, taking into account patient's satisfaction and their shortened recovery period, laparoscopic surgery is a more cost-effective option.

The Department of Medicine of The University of Hong Kong introduced laparoscopic adrenalectomy for the first time to Hong Kong since 1995, and has adopted the technique widely. In the past 10 years, over 100 patients received this operation. Up to 70% of the patients have completely recovered from secondary hypertension while the rest can have a better blood pressure control with reduced level of medication. All patients' problem of low potassium is solved.

An increasing number of adrenalectomy is also being performed in other local hospitals. It increases from 68 in 1999 to 111 cases in 2004, according to statistics of the Hospital Authority. More and more hospitals are beginning to introduce laparoscopic surgery for adrenalectomy.

There is no known prevention for adrenal tumor. Body check is recommended for people who have a family history of adrenal tumor. Besides, as the frequency of germline mutations in pheochromocytoma approaches 30%, patients with pheochromocytoma should undergo genetic evaluation so that early diagnosis for their relatives can be achieved. People who are relatively young, and having poorly-controlled hypertension and/or hypokalemia should have hormone blood tests performed, followed up by a computed tomography (CT) or magnetic resonance imaging (MRI) scan to confirm the diagnosis of adrenal tumor.

Source: The University of Hong Kong Li Ka Shing Faculty of Medicine