A new test could help identify thousands of people with a curable cause of high blood pressure.
Researchers have discovered that a hi-tech scan can detect 1c-sized tumours that cause blood pressure to rise.
Conn’s syndrome is the most common curable cause of high blood pressure, which is thought to affect five per cent of all people with the condition.
This means around 600,000 Britons could have Conn’s syndrome.
While Conn’s is difficult to diagnose, it can be successfully treated once identified.
It is caused by a benign, 1c-sized tumour called an adenoma growing in one of the adrenal glands close to the kidneys.
The tumour causes the over-production of a key blood pressure-regulating hormone called aldosterone.
Treatment for Conn’s includes removing the affected gland through surgery or through a drug which blocks the effects of aldosterone.
The study by Cambridge University found that a hi-tech PET-CT scan, commonly used to detect cancer, could identify Conn’s syndrome.
The current test for Conn’s involves taking blood from a vein supplying the adrenal gland to measure levels of aldosterone.
This can be difficult to perform, and often fails to confirm the diagnosis.
However, the new study showed the 45-minute scan accurately identified adenomas causing high blood pressure in 76 per cent of patients.
Overall, 80 per cent of patients having the test were either accurately identified with adenomas or had them accurately ruled out.
Researchers analysed scans from a total of 44 patients attending Addenbrooke’s Hospital in Cambridge.
Morris Brown, professor of clinical pharmacology at the University of Cambridge, who led the study, said: “We were excited to see our technique work so well, and shortcut the delays and discomforts associated with the alternative test.
“We’re using PET-CT on our patients already, but we also plan a larger study to work out who will benefit the most.
“The test could be especially important for older patients – we often see growths in the adrenal glands during a routine CT scan.
“Often these growths are not Conn’s adenomas, but it’s difficult to be sure and they create a lot of anxiety in patients and doctors.
“In the future, PET-CT could be a quick way to reassure a lot of patients without the need for detailed investigations.”
The research was funded by the British Heart Foundation and National Institute of Health Research.
Dr Shannon Amoils, research adviser at the BHF, said: “Conn’s syndrome is the most common curable cause of high blood pressure.
“And although it affects only a small fraction of people with hypertension, it’s almost certainly more widespread than we previously thought,” he said.