A 62-year-old woman comes to the physician due to lower extremity edema. She has never had such edema before. She has no dyspnea, cough, or palpitations. Her concurrent medical problems include hypertension, type 2 diabetes mellitus, and chronic bronchitis. She smokes 1.5 packs of cigarettes a day but does not use alcohol or illicit drugs. She brings in a shopping bag of medications, including a variety of antihypertensive and antidiabetic medications, but is uncertain which ones she takes and which she does not. Her blood pressure is 140/90 mm Hg and pulse is 65/min. Physical examination shows symmetric lower extremity edema but is otherwise unremarkable. Which of the following is the most likely potential cause of this patient's condition?

Question

A 62-year-old woman comes to the physician due to lower extremity edema.  She has never had such edema before.  She has no dyspnea, cough, or palpitations.  Her concurrent medical problems include hypertension, type 2 diabetes mellitus, and chronic bronchitis.  She smokes 1.5 packs of cigarettes a day but does not use alcohol or illicit drugs.  She brings in a shopping bag of medications, including a variety of antihypertensive and antidiabetic medications, but is uncertain which ones she takes and which she does not.  Her blood pressure is 140/90 mm Hg and pulse is 65/min.  Physical examination shows symmetric lower extremity edema but is otherwise unremarkable.  Which of the following is the most likely potential cause of this patient's condition?

Quizplus · Accepted Answer

Explanation: Peripheral edema is a common side effect of calcium channel blocker (CCB) therapy, with a reported incidence of approximately 25% after 6 months of therapy. The edema is likely related to preferential dilation of precapillary vessels (arteriolar dilation), which leads to increased capillary hydrostatic pressure and fluid extravasation into the interstitium. Dihydropyridine (DHP) CCBs (eg, amlodipine and nifedipine) are potent arteriolar dilators and cause more peripheral edema than non-DHP CCBs (eg, diltiazem, verapamil). Other major side effects associated with DHP CCBs include headache, flushing, and dizziness. Renin-angiotensin system blockers (angiotensin converting enzyme [ACE] inhibitors or angiotensin receptor blockers) cause post-capillary venodilation and can normalize the increased capillary hydrostatic pressure. In clinical studies, the combination of CCBs with ACE inhibitors was associated with a significantly lower risk of peripheral edema compared to CCB monotherapy. (Choice B) ACE inhibitors (eg, enalapril) can lead to the development of angioedema in approximately 0.1%-0.7% of patients. They typically cause nonpitting swelling of the subcutaneous or submucosal tissue and most commonly affects the lips, tongue, face, and upper airway. ACE inhibitors do not cause peripheral or dependent edema. (Choice C) Glyburide can cause dermatologic side effects including photosensitivity reactions, maculopapular eruptions, purpura, or urticaria. It is not associated with peripheral edema. (Choice D) The most common side effects of hydrochlorothiazide are electrolyte imbalances (hyponatremia, hypokalemia), renal failure, hyperuricemia (may precipitate acute gout), and elevated glucose and lipid levels. However, hydrochlorothiazide does not cause peripheral edema. (Choice E) On rare occasions, ipratropium can lead to angioedema, but it does not cause peripheral edema. Educational objective: Peripheral edema is a common side effect of calcium channel blockers (CCBs). It is most common with dihydropyridine CCBs (eg, amlodipine, nifedipine). The combination of CCBs with ACE inhibitors is associated with a significant reduction in CCB-associated peripheral edema. References: Peripheral edema associated with calcium channel blockers: incidence and withdrawal rate - a meta-analysis of randomized trials. (http://www.ncbi.nlm.nih.gov/pubmed/21558959) Mitigation of calcium channel blocker-related edema in hypertension by antagonists of the renin-angiotensin system. (http://www.ncbi.nlm.nih.gov/pubmed/19148104) Effect of renin-angiotensin system blockade on calcium channel blocker-associated peripheral edema. (http://www.ncbi.nlm.nih.gov/pubmed/21295192)

A 62-Year-Old Woman Comes to the Physician Due to Lower