Review Question - QID 221244

This patient with bilateral lower extremity pitting edema and thin, yellow-brown or red-brown pigmented skin most likely has stasis dermatitis. This is most likely due to underlying chronic venous insufficiency.

Chronic venous insufficiency is a result of increased venous pressure due to malfunctioning valves in lower extremity veins. Chronically elevated venous pressure overcomes the capacity of the valves that typically prevent backflow. The reflux of blood into the superficial veins further elevates venous pressure, resulting in extravasation of fluid into the interstitial space. This causes pitting edema. Risk factors include increasing age, female sex, prolonged standing, obesity, pregnancy, and a sedentary lifestyle. Patients present with pitting edema, pruritus, yellow-brown or red-brown pigmentation, and ulcers in late-stage disease. Treatment includes compression stockings and endovenous thermal ablation for severe cases.

Youn et al. review the pathophysiology of chronic venous insufficiency in the lower extremities. They discuss how lower extremity venous insufficiency can be treated with compression socks, but low adherence limits efficacy. They recommend that earlier use of ablation therapies should be considered in symptomatic patients to prevent progression of the disease.

Figure/Illustration A is a clinical photograph demonstrating bilateral lower extremity edema and color changes (red circles). These findings are consistent with chronic venous insufficiency.

Incorrect Answers:
Answer 1: Damage to hepatocytes can lead to decreased synthesis of proteins (albumin) in the liver, resulting in bilateral lower extremity pitting edema. Although this patient has a risk factor for hepatitis (intravenous drug use), she does not have signs of end-stage liver disease (jaundice, ascites, and hepatomegaly).

Answer 2: Dermal fibroblast stimulation and deposition of glycosaminoglycans in pretibial connective tissue causes pretibial myxedema in patients with Grave disease. This patient's Grave disease was treated with a thyroidectomy and she is being managed properly as she is taking levothyroxine and has no other sequelae of hyperthyroidism or hypothyroidism.

Answer 3: A glomerular filtration barrier defect can lead to nephrotic syndrome, which is a common cause of bilateral lower extremity pitting edema. This is an uncommon cause of edema in adults, but could occur in conditions such as focal segmental glomerulosclerosis which is common in intravenous drug users and presents with kidney dysfunction that progresses to kidney failure.

Answer 5: Left ventricular failure, such as seen in patients with chronic heart failure, is a common cause of bilateral lower extremity edema; however, this patient does not have dyspnea, orthopnea, or signs of pulmonary congestion.

Bullet Summary:
Chronic venous insufficiency is the most common cause of bilateral lower extremity pitting edema and is the result of incompetent valves in the lower extremity veins.