A 50-year-old woman comes to the office due to lower extremity edema. The edema started about 6 weeks ago and has slowly progressed . Medical history is significant for hypertension, treated with metoprolol for 3 years. Two months ago, amlodipine was added because of inadequate blood pressure control with metoprolol alone. The patient does not use tobacco or alcohol. She has no known drug allergies. Blood pressure is 130/80 mm Hg and pulse is 64/min. Physical examination reveals bilateral symmetric 3+ pitting edema of both lower extremities, without any skin changes or varicosities. Her neck vein pulsation is normal. The rest of the examination is unremarkable. Laboratory results are as follows: Urinalysis is within normal limits. What is the most likely cause of the edema in this patient?

Question

A 50-year-old woman comes to the office due to lower extremity edema.  The edema started about 6 weeks ago and has slowly progressed .  Medical history is significant for hypertension, treated with metoprolol for 3 years.  Two months ago, amlodipine was added because of inadequate blood pressure control with metoprolol alone.  The patient does not use tobacco or alcohol. She has no known drug allergies.  Blood pressure is 130/80 mm Hg and pulse is 64/min.  Physical examination reveals bilateral symmetric 3+ pitting edema of both lower extremities, without any skin changes or varicosities.  Her neck vein pulsation is normal.  The rest of the examination is unremarkable.  Laboratory results are as follows:  Urinalysis is within normal limits.  What is the most likely cause of the edema in this patient?

Quizplus · Accepted Answer

Peripheral edema is a common side effect of treatment with dihydropyridine calcium channel blockers (CCBs). It is due to these medications' vasodilatory effects on peripheral blood vessels, resulting in increased pressure and capillary permeability. It does not represent an allergic reaction. If the edema is significant, the CCB should be discontinued; because the edema is not due to increased plasma volume, diuretics are generally unhelpful. In this patient, clues to the diagnosis of medication-induced peripheral edema include the recent initiation of the dihydropyridine CCB amlodipine in conjunction with unremarkable physical examination findings (apart from the edema) and normal laboratory results. Other more serious causes of edema can often be excluded by clinical and laboratory data. (Choice A) Congestive heart failure is an important cause of lower extremity edema, but the absence of other symptoms (eg, dyspnea, orthopnea) and physical findings (eg, elevated neck vein pulsation, liver enlargement) of heart failure makes this diagnosis unlikely in this patient. (Choice B) Liver diseases can cause lower extremity edema. However, ascites usually dominates over peripheral edema, and abnormal laboratory findings characteristic of liver dysfunction (eg, hypoalbuminemia, hyperbilirubinemia) are present. (Choice C) Renal diseases can cause peripheral edema due to massive proteinuria (eg, nephrotic syndrome) or fluid retention (eg, acute nephritic syndrome). This patient's normal creatinine, lack of proteinuria, and normal albumin result (ie, no hypoalbuminemia) make renal causes of the edema unlikely. (Choice D) Although venous insufficiency can cause edema, symmetric edema without skin changes and varicosities argues against this diagnosis. Educational objective: Dihydropyridine calcium channel blockers can cause peripheral edema and should always be considered in the differential diagnosis of this condition, along with other causes, such as heart failure, renal disease, and venous insufficiency.

A 50-Year-Old Woman Comes to the Office Due to Lower Extremity