Key Clinical Questions
Which patients should be evaluated for secondary causes of hypertension in the inpatient setting?
What are the most common secondary causes of hypertension in hospitalized patients?
What screening and diagnostic tests are best for each?
What specific therapy or therapies are currently recommended?
What follow-up should be recommended after discharge?
Hypertension affects 29% of the American public, and a greater proportion of hospital inpatients. Hospitalized patients are older than the general population; the prevalence of hypertension is 65% in those aged 60 years and older, and 77% in those aged 80 years and older. In addition, hypertension is a major risk factor for 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 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, ensuring that these patients are assessed at least once for secondary hypertension during their lifetime. In addition, some causes are curable or at least amenable to intervention, such as pheochromocytoma, Conn adenoma, and fibromuscular dysplasia. This may obviate the need to take long-term antihypertensive medications, improving the cost-effectiveness of screening young patients.
CRITERIA FOR HOSPITAL ADMISSION
Secondary hypertension leads to hospital admission when there is a hypertensive emergency (severely elevated blood pressure and acute, ongoing target-organ damage). See Chapter 91. 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.
There are many reasons why a hospitalized patient may have severe hypertension, including pain, fluid overload, fragmentary knowledge of the patient’s home medications, and drug and alcohol withdrawal. Clinicians should seek out precipitating factors that commonly raise blood pressure in the acutely ill and may require a different approach from simply prescribing antihypertensive medications.
Occasionally, secondary hypertension becomes an issue ...