Secondary hypertension and complications: Diagnosis and role of imaging

Understanding the imaging appearances of common causes of secondary hypertension is important, as affected patients typically have improved blood pressure and a decreased risk of cardiovascular damage and end-organ dysfunction after diagnosis and treatment. Hypertension is a common problem; if left untreated, it can result in significant complications, including those involving the cardiovascular system and end organs. Approximately 10% of patients with hypertension are classified as having secondary hypertension, defined as hypertension attributable to a specific and potentially remediable cause. The evaluation for secondary hypertension typically begins with acquiring the patient history and performing a physical examination and screening laboratory tests. Directed imaging may be performed, on the basis of laboratory test results, to assess for potential causes of secondary hypertension. The causes can be broadly classified as endocrine (eg, hyperaldosteronism, pheochromocytoma, hyperparathyroidism) and nonendocrine (eg, aortic coarctation, renal vascular hypertension). In addition, patients with hypertension can develop significant complications that also are diagnosed with imaging, including conditions involving the cardiovascular system (eg, aortic aneurysm, acute aortic syndrome) and central nervous system (eg, stroke, subarachnoid hemorrhage, and posterior reversible encephalopathy syndrome). The imaging workup and imaging appearances of some of the causes of secondary hypertension are reviewed, treatment options are discussed, and the imaging appearances of hypertension-related complications are described. It is important for radiologists to accurately diagnose the secondary causes of hypertension, as many of them are treatable, and treatment may result in improved symptoms or resolution of hypertension.