Out of the Blue

A CLINICAL PROBLEM-SOLVING article by Christopher Gibson from Brigham and Women's Hospital, Boston.
A 55-year-old man with a history of heart failure presented to the emergency department with pain and swelling of his right foot and leg, which began 3 days earlier, without any prior trauma. The swelling worsened progressively, extending to the upper leg, and was accompanied by pain in the foot and calf. On the day of presentation, he noted new dusky discoloration of the right toes. The patient's medical history was notable for obesity, paroxysmal atrial fibrillation, hypertension, and heart failure with a preserved ejection fraction. He reported an intentional weight loss of 22.7 kg (50 lb) over the preceding 6 months, which he attributed to a combination of diet and exercise. On physical examination, the legs were markedly asymmetric, and the right leg and foot were dusky and cold. Although the differential diagnosis for lower-extremity edema is broad, two features of this presentation help to narrow it: the acute onset and the asymmetric distribution. Deep venous thrombosis appears to be most likely. If a deep venous thrombosis is present, its development in a patient taking warfarin suggests either a subtherapeutic international normalized ratio or a hypercoagulable state. The patient's dramatic weight loss, which would be difficult to achieve even with vigorous dieting and exercise, raises concern about an underlying cancer, which could result in a hypercoagulable state.