Causes of Secondary Hypertension
| Cause | Clues/investigation |
|---|---|
| Intrinsic renal disease | Family history of heritable renal disease (e.g. polycystic kidney disease) Abnormal urine stick test and microscopy Raised creatinine Abnormal kidneys on ultrasound Discuss further investigation with nephrologist if intrinsic renal disease suspected |
| Primary hyperaldosteronism | Low plasma potassium High plasma aldosterone with suppressed plasma renin |
| Cushing syndrome | Truncal obesity, thin skin with purple abdominal striae, proximal myopathy (unable to rise from chair without using arms) Increased urinary free cortisol excretion |
| Pheochromocytoma (see Chapter94) | Paroxysmal headache, sweating or palpitation Hypertensive crisis following anaesthesia or administration of contrast Family history of pheochromocytoma Increased urinary catecholamine excretion |
| Coarctation of aorta | Radiofemoral delay Coarctation demonstrated by echocardiography/MRI |
| Renal artery stenosis | May be due to fibromuscular dysplasia (age <50 with no family history of hypertension) or, more commonly, to atherosclerosis (age >50 with other atherosclerotic arterial disease) Refractory hypertension Deteriorating blood pressure control in compliant, long-standing hypertensive patients Rise in creatinine on treatment with ACE inhibitor Renal impairment with minimal proteinuria Low plasma sodium and potassium (due to secondary hyperaldosteronism) Difference in kidney size >1.5cm on ultrasound |
| Other causes | Many causes including drugs, obstructive sleep apnoea, acromegaly |
ACE, angiotensin-converting enzyme.