Chapter 253. Secondary Hypertension

1. Which patients should be evaluated for secondary causes of hypertension in the inpatient setting?

2. What are the most common secondary causes of hypertension in hospitalized patients?

3. What screening and diagnostic tests are best for each?

4. What specific therapy or therapies are currently recommended?

5. What follow-up should be recommended after discharge?

Hypertension affects 29% of the American public. Its prevalence among hospitalized patients is much higher. Hospitalized patients are older than the general population, and the prevalence of hypertension is 67% in those aged 60 years and older. In addition, hypertension is a major risk factor for the cardiovascular and renal diseases that lead to inpatient admission. Poorly controlled hypertension among general medical inpatients is most often related to other conditions, such as pain, agitation from delirium, and substance withdrawal. Secondary hypertension has a prevalence of less than 5% in the general population, but is more common among inpatients. This is due to three types of selection bias: (1) negative screening for secondary hypertension in outpatients, who are seldom hospitalized for the evaluation and are at low risk of hospitalization for other causes; (2) patients admitted for hypertensive emergencies; and (3) patients with secondary hypertension admitted for diagnostic and therapeutic procedures, often for other diagnoses. For example, 13% of patients undergoing cardiac or peripheral arterial catheterization have a documented stenosis in a renal artery (discovered during “drive-by angiograms”). Secondary causes of hypertension should at least be considered in hypertensive inpatients, especially younger ones. This ensures that these patients are assessed at least once for secondary hypertension during their lifetime. In addition, some causes, such as pheochromocytoma, Conn adenoma, and fibromuscular dysplasia, are amenable to cure, or at least long-term amelioration. This obviates the need to take antihypertensive medications over a long period of time, improving the cost-effectiveness of screening young patients.

The major circumstance in which secondary hypertension leads to hospital admission is a hypertensive emergency (severely elevated blood pressure and acute, ongoing target-organ damage). These patients have a high prevalence of secondary hypertension, and the hypertensive emergency is often the first real clue to the presence of a secondary cause. After stabilization of these patients with short-acting, intravenous antihypertensive drugs, attention should be focused on developing an appropriate antihypertensive drug regimen and excluding secondary hypertension.

Less commonly, patients are admitted electively for diagnostic or therapeutic procedures related to secondary hypertension. Many of these are “23-hour admissions,” and do not require major attention from hospital-based physicians, except those directly involved in the procedure. Examples include patients with ...