Differential Diagnosis for Bilateral Ankle Swelling and Leg Pain

Single Most Likely Diagnosis

• Chronic Venous Insufficiency: This condition is a common cause of bilateral ankle swelling and leg pain, especially in women. Prolonged standing, obesity, and family history can contribute to its development. The symptoms of 2 weeks duration in a 45-year-old woman make this a plausible diagnosis.

Other Likely Diagnoses

• Dependent Edema: Edema that occurs due to gravity when legs are in a dependent position for a long time, common in individuals with sedentary jobs or during long flights.
• Cellulitis: A bacterial skin infection that can cause swelling, redness, and pain in the affected leg. Although it typically presents unilaterally, it could be considered if there's a history of trauma or infection.
• Deep Vein Thrombosis (DVT): Although DVT often presents unilaterally, bilateral DVT can occur, especially in the context of hypercoagulable states or severe immobility.

Do Not Miss Diagnoses

• Pulmonary Embolism (PE) with DVT: While PE itself may not directly cause ankle swelling, the combination of DVT and PE is a life-threatening condition that requires immediate attention. Bilateral leg swelling could be a sign of extensive DVT, increasing the risk of PE.
• Nephrotic Syndrome: A condition characterized by heavy proteinuria, hypoalbuminemia, and edema. It's crucial to consider this diagnosis due to its significant implications on renal function and the need for specific management.
• Heart Failure: Although more commonly associated with bilateral lower extremity edema, heart failure can present with leg pain and swelling due to decreased cardiac output and increased venous pressure.

Rare Diagnoses

• Lymphedema: A condition characterized by chronic swelling due to lymphatic system dysfunction. It's less common and typically has a more gradual onset.
• Eosinophilia-Myalgia Syndrome: A rare condition associated with eosinophilia, myalgia, and sometimes edema, often linked to certain medications or toxins.
• Sarcoidosis: A systemic granulomatous disease that can affect multiple organs, including the skin, lungs, and lymph nodes, and may present with leg swelling among other symptoms.

Each of these diagnoses has different implications for management and prognosis, highlighting the importance of a thorough diagnostic workup to determine the underlying cause of bilateral ankle swelling and leg pain.