The patient

A 27 year old man with a six month history of mild but progressive headache visited his general practitioner and was found to have a blood pressure of 178/108 mm Hg. He had an unremarkable medical history, but his father had had high blood pressure and had died from a stroke at age 45 years. Clinical examination with a particular emphasis on the cardiovascular system including funduscopy was unremarkable, and no renal artery bruit was heard. Basic laboratory tests at his general practice were all normal (sodium 144 (normal range 135-145) mmol/l; potassium 3.8 (3.5-5.1) mmol/l; creatinine 105 (60-110) μmo/l; urea 5.4 (2.9-9.4) mmol/l), with no proteinuria.

What is the next investigation?

Arterial hypertension warrants further investigations to exclude secondary causes of hypertension in young people (aged <40 years), those with blood pressure resistant to antihypertensive treatment, and those with a family history of hypertension or stroke at age <50 years. Furthermore, a detailed social history, including alcohol intake and substance misuse (such as cocaine) might show reversible contributors of increased blood pressure.

Before further investigations the diagnosis of arterial hypertension needs to be established by blood pressure measurements on at least three …