Differential Diagnosis

The patient's presentation of bilateral lower extremity edema, brownish discoloration of the distal extremities, and a small, shallow, weeping open wound, along with triphasic pulses via Doppler in the dorsalis pedis pulses, suggests a vascular issue. Here's a breakdown of the differential diagnosis:

• Single most likely diagnosis
  • Chronic limb ischemia: The presence of edema, brownish discoloration (possibly indicating chronic changes like hemosiderin deposition), and a weeping wound are more suggestive of chronic rather than acute ischemia. Triphasic pulses, while often associated with normal arterial flow, in the context of these other symptoms, may indicate some degree of arterial disease that is not immediately severe but chronic in nature.
• Other Likely diagnoses
  • Peripheral arterial disease (PAD): This condition is characterized by atherosclerosis of the peripheral arteries, which could explain the patient's symptoms, especially if the disease is advanced. However, PAD typically presents with claudication (pain in the legs or arms during exercise) and may not always have visible signs like edema and skin discoloration as prominent features.
  • Peripheral venous disease: This could explain the edema and possibly the skin changes if there's significant venous insufficiency. However, the presence of triphasic pulses and the specific pattern of skin discoloration might lean more towards an arterial issue.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Acute limb ischemia: Although the presentation seems more chronic, acute limb ischemia is a medical emergency that requires immediate attention. The presence of a weeping wound could potentially be a sign of severe ischemia leading to tissue necrosis. It's crucial to rule out acute limb ischemia due to its high morbidity and mortality.
• Rare diagnoses
  • Chronic venous insufficiency with arterial component: This is a condition where there's both venous and arterial disease contributing to the patient's symptoms. It's less common but could explain the mixed presentation of edema (more typical of venous disease) and the specific pattern of skin changes and pulses.
  • Other rare vascular diseases (e.g., Buerger's disease, vasculitis): These conditions can present with limb ischemia and skin changes but are less common and would typically have other distinguishing features or systemic symptoms.

Each of these diagnoses has a different approach to management, ranging from medical therapy and lifestyle modifications for chronic conditions to immediate surgical or interventional radiology consultation for acute limb ischemia. A thorough diagnostic workup, including imaging studies and potentially angiography, would be necessary to confirm the diagnosis and guide treatment.