Hypertension in Conn’s syndrome
During 1950s Dr Jerome Conn described a young man with hypertension and low potassium levels caused by excess aldosterone secretion from a small adrenal tumour. The eponymous syndrome has witnessed a renewed interest in the last decade.
High blood pressure is a common problem in modern society, with over 16 million allegedly taking anti-hypertension medication in the United Kingdom. Traditionally only 1% of patients were expected to have the high blood pressure caused by excess aldosterone secretion from the adrenal glands. For the last decade there is an increasingly agreed view that at least 5-10% of hypertensive might have an adrenal cause and therefore could potentially be cured (or improved) by adrenal surgery.
If I have hypertension, should I check if I have Conn’s syndrome?
This question remains difficult. No healthcare system can afford to offer a complex set of biochemical and radiological investigations’s to all patients with high blood pressure. On the other hand, if one is found to have Conn’s syndrome their blood pressure could be cured (or at least its control improved significantly) by undergoing adrenal surgery and therefore avoiding many years of complex medical treatment for their high blood pressure.
Current guidelines suggest that the possibility of Conn’s syndrome should be investigated in hypertensive patients with
stage 2 (160–179/100–109 mm Hg) or stage 3 (over 180/110 mmHg) hypertension
drug-resistant hypertension (patients needing to take 3 or more meds)
spontaneous or diuretic-induced hypokalemia
hypertension with adrenal incidentaloma
cerebrovascular accident at a young age (40 yrs)
associated sleep-apnoea
Less than 40% of patients with Conn’s syndrome will have associated low potassium levels (hypokalaemia) therefore the tests should not be limited to patients who already have hypokalaemia.
Why should I consider an operation, can’t I just continue on medication?
Medication can be effective in controlling high blood pressure in the vast majority of patients. Those whose blood pressure is driven by high aldosterone levels are known to have:
higher cardiovascular morbidity and mortality than age- and sex-matched patients.
improved cardiac and cerebrovascular outcomes after reduction in aldosterone levels through an operation
There are sceptics who would emphasise that there have been no clinical trials measuring the impact of screening for Conn’s syndrome on morbidity or quality of life and that patients could potentially be harmed by the work-up and treatment (i.e. by withdrawal of antihypertensive medication, invasive vascular tests and the operation itself). Based on the experience accumulated in the last decade in Oxford, we can provide safe and effective investigations and can guarantee expertise in performing the operation without any serious complications therefore we have no reluctance to encourage patients with Conn’s syndrome to proceed with adrenal surgery.
Should I have my operation in Oxford ?
Absolutely! Adrenal surgery in UK is frequently offered by surgeons with minimal experience - a recent publication showed that out of 220 surgeons who did adrenal surgery in one financial year, 186 of them did an average of only 1 case/year. It is imperative to ensure you are referred to a centre where adrenal venous sampling can be offered as part of the investigations and to a surgeon with significant workload. In Oxford an average of 70-80 patients have adrenal surgery every year and the Radiology Consultant performing adrenal venous sampling has excellent results.