Hypertension

Hypertension: secondary causes

It is thought that between 5-10% of patients diagnosed with hypertension have primary hyperaldosteronism, including Conn's syndrome. This makes it the single most common cause of secondary hypertension.

However, the most common cause of secondary hypertension in children is fibromuscular dysplasia (~20% of all cases of renal hypertension)

Fibromuscular dysplasia is also generally seen in premenopausal women (women age <50)

Bruit or venous hum may be heard at the costovertebral angle (due to well-developed collaterals)

Right renal artery is more affected than the left

Angiogram reveals the "string of beads" sign

Renal disease accounts for a large percentage of the other cases of secondary hypertension. Conditions which may increase the blood pressure include:

• glomerulonephritis
• pyelonephritis
• adult polycystic kidney disease
• renal artery stenosis

Renovascular hypertension should be suspected and evaluated in the follow ing situations:

• Elevation in serum creatinine >30% from baseline after starting angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker
• Severe hypertension in patients with recurrent flash pulmonary edema
• Severe hypertension in patients with diffuse atherosclerosis
• Onset of severe hypertension after age 55