Phaeochromocytoma

A rare tumour of the adrenal gland, which releases excessive quantities of chemicals known as catecholamines, typically adrenaline and noradrenaline. Though these are normally part of our body's response to alarm and emergency, when present in excessive amounts they cause over-activity of the sympathetic nervous system.

What causes this?
There may be a single adrenal tumour or multiple tumours, usually in the core of the gland, but occasionally elsewhere in the body. Around 10 percent are malignant. They may arise at any time, but are most common in young adults.

Symptoms
Often there are paroxysms of symptoms at irregular intervals, becoming more frequent and severe as the tumour grows. These attacks typically include severe headache, accompanied by a rapid heart rate and palpitations, flushing and sweating, chest or abdominal pain, trembling, nausea, nervousness and irritability, even severe anxiety, panic and a sense of doom. These may occur once a month or several times a day, and can last anything from seconds to hours.

There may be increased appetite but loss of weight. There is high blood pressure, but this is often episodic, so may not be picked up at any particular assessment. Orthostatic hypotension, in which the blood pressure drops significantly when you stand up, may also be observed.

In diagnosis, history and physical examination are important. Blood and urine tests can confirm the diagnosis. The collection of a 24-hour sample of urine output is usually needed. Scanning, typically a MRI or CT, often shows the tumour(s).

Treatment
Antihypertensive medicines may be used to lower and control high blood pressure, and the tumour should be removed in surgery.

Prognosis
If recognised and treated early, many of the potential complications and risks can be prevented, and recovery is good.

If not, hypertension can be dangerous, especially when undergoing anaesthesia for other surgery. There is also a risk of dangerous arrhythmias (abnormalities of heart rhythm) in untreated cases. A crisis or attack can be caused by an interaction between the chemicals produced by the tumour and other drugs, including decongestants, tricyclic antidepressants, or cocaine.

In around one-quarter of cases, blood pressure does not return to normal after the surgery, and must be controlled by medications.

The tumour recurs in around one in ten cases.

When to call your doctor
If you experience an attack of the sort outlined above.

(M. A. Simpson, Health24, February 2008)