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Sunday, July 11, 2010

White Coat Hypertension

An 85-year-old woman is evaluated in the office for resistant hypertension. She has a long-standing history of hypertension that had been well controlled with β-blocker therapy. Her physician recently died, and results of blood pressure measurement performed in a new office have been high. Records from her previous physician show that office blood pressure measurements were always normal. She also has fatigue, weakness, and dizziness, particularly after standing up. She has been unable to tolerate angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, and dihydropyridine calcium antagonist therapy. Current medications are metoprolol, 50 mg/d, and hydrochlorothiazide, 25 mg/d.

On physical examination, heart rate is 60/min and blood pressure in the supine and standing positions is 170/70 mm Hg. The remainder of the examination is normal.

Serum creatinine is 0.8 mg/dL, blood urea nitrogen is 18 mg/dL, and serum potassium is 3.6 meq/L.

Which of the following is the most appropriate next step in this patient's management?
A Ambulatory blood pressure monitoring
B Discontinuation of metoprolol
C Increase in the hydrochlorothiazide dose to 50 mg/d
D Magnetic resonance angiography of the renal arteries

Answer and Critique (Correct Answer = A)

Key Point
In selected patients, ambulatory blood pressure monitoring can exclude white coat hypertension.
The most appropriate next step in this patient's management is ambulatory blood pressure monitoring. White coat hypertension due to this patient's anxiety regarding a new physician and medication change is highly possible, and ambulatory blood pressure monitoring would confirm this diagnosis. In addition, overtreatment of hypertension in elderly patients is associated with increased adverse effects of medication, particularly symptoms associated with hypotension. Moreover, this patient's fatigue, weakness, and dizziness suggest that she is already overmedicated. Although current blood pressure targets for the elderly have not been clearly defined, a systolic blood pressure ≤160 mm Hg in this population has been associated with better outcomes. Ambulatory blood pressure monitoring is useful in this setting to document the level of blood pressure control.

Performing magnetic resonance angiography would be premature in this patient. Renovascular hypertension is a possible cause of resistant hypertension in the elderly, but her symptoms are consistent with overmedication. In addition, her long-standing history of stable hypertension is consistent with primary or essential hypertension. Increasing her hydrochlorothiazide dose before excluding a white coat effect could lead to increased symptoms. Lower doses of medication are indicated for many elderly patients, and 50 mg/d of hydrochlorothiazide most likely will be poorly tolerated in this patient.

Discontinuation of metoprolol may be reasonable. However, because of her elevated office blood pressure measurements, this agent should be discontinued only after documenting that her blood pressure is adequately controlled.

1. Fisher M, Blackwell J, Saseen J. Clinical inquiries. What is the best way to identify patients with white-coat hypertension? J Fam Pract. 2005;54:549-50, 552. [PMID: 15939009] [PubMed]

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