New test for Conn’s disease

By combining positron emission tomography (PET) with x-ray computer tomography (CT), researchers hope to detect small benign tumours which cause hypertension.

Research funded by the British Heart Foundation (BHF) and the National Institute of Health Research showed that high-tech PET-CT could detect Conn’s syndrome, which causes up to 5% of hypertension cases.

Conn’s syndrome is caused by a benign tumour or adenoma about the size of a five pence piece in one of the adrenal glands, close to the kidney. It causes the over-production of aldosterone, a key blood pressure-regulating hormone. Researchers from the University of Cambridge developed a special radioactive tracer called 11C-metomidate, which lights up the adenoma during the PET-CT scan.

They tested the technique – which takes about 45 minutes – on 44 patients at Addenbrooke’s Hospital in Cambridge, picking up the adenoma in the majority of patients.

“We were excited to see our technique work so well, and shortcut the delays and discomforts associated with the alternative test,” said study leader Morris Brown, a professor of Clinical Pharmacology.

The researchers plan a larger study to work out who might benefit from the technique the most. This test could be especially important for older patients, said brown, who believes the PET-CT could be a quick way to reassure patients without the need for detailed investigations.

“Conn’s syndrome is the most common curable cause of high blood pressure,” said Dr Shannon Amoils, research advisor at the BHF. “Although it affects only a small fraction of people with hypertension, it’s almost certainly more widespread than we previously thought.”

Conn’s disease is currently treated with drugs to block the effects of aldosterone, or with surgery to remove the affected gland.

“There are drugs that can control the high blood pressure caused by Conn’s syndrome, but the only cure is surgery, so making the diagnosis is very important,” Amoils said. “This new approach offers real hope that more people with Conn’s disease will be accurately diagnosed in the future.”

• See Professor Brown talking about his research, plus an interview with a Conn’s syndrome sufferer