The approach to the evaluation for secondary and potentially reversible factors that may account for the increase in blood pressure in older individuals is similar to that recommended for younger hypertensive patients. Thus, a standard clinical evaluation consisting of a complete history and physical exam, chemistry profile (to assess electrolytes, renal function, and glucose), ECG, and chest x-ray is recommended to identify these factors.

Further evaluation is normally not needed unless there are abnormal symptoms or signs elicited from this evaluation that would be consistent with renal disease (elevated serum creatinine or abnormal urinalysis), renovascular disease (e.g., presence of abdominal bruit), hyperaldosteronism (hypokalemia), hypercortisolism (hyperglycemia, cushingoid appearance), hyperparathyroidism (hypercalcemia), or pheochromocytoma (symptoms of headache, palpitations, diaphoresis, and paroxysmal elevations of blood pressure). A careful review of medications is warranted to determine if medication-related increases in blood pressure (e.g., due to corticosteroids or nonsteroidal anti-inflammatory drugs) could be contributing to the elevated blood pressure.

Other clinical situations that might lead to an evaluation for secondary hypertension in the older patient include malignant hypertension, the abrupt development of diastolic hypertension (which is unusual in light of the general decrease in diastolic blood pressure with age above the age of 60 years), worsening of blood pressure control, or blood pressure that remains uncontrolled on a regimen of three antihypertensive medications.

As is the case in younger hypertensive populations, the overwhelming majority (greater than 90%) of older hypertensive patients have essential or primary hypertension. Secondary forms of hypertension may be even more rare in the older population. Renal disease and reno-vascular hypertension are the most frequent cause of secondary hypertension in the elderly; endocrinologic causes are generally less common. The only possible exception to this is a suggestion that the incidence rate for pheochromocytoma, although still exceedingly rare (incidence less than 1% among patients with hypertension), may increase progressively with age.