Secondary Hypertension

Most patients with hypertension have no clear etiology and are classified as having primary hypertension. However, 5%–10% of these patients may be harboring an underlying cause of their hypertension, known as secondary hypertension. A patient’s age alone may guide the differential diagnosis and consideration for causes of secondary hypertension.

In children, the leading causes of secondary hypertension include coarctation of the aorta and renal parenchymal disease. In adults aged 65 or older, often the kidneys are a culprit, with renal artery stenosis and chronic kidney disease being leading diagnoses. In addition, endocrine abnormalities may be implicated.

Although not every patient with hypertension should undergo extensive workup for a secondary cause, any clinician should be aware of the possibility of secondary hypertension and evaluate the need for laboratory or imaging workup based on suggestive history. Some red flags that should prompt consideration of secondary hypertension include hypertension that is very severe or resistant to therapy, hypertension presenting in patients less than 30 years of age, malignant or accelerated hypertension, or acutely worsening hypertension in a previously stable patient.