Differential Diagnosis for New Onset Leg Swelling with History of Atrial Fibrillation

• Single Most Likely Diagnosis
  • Deep Vein Thrombosis (DVT): This is the most likely diagnosis given the patient's history of atrial fibrillation, which is a significant risk factor for thromboembolic events. The new onset leg swelling is a classic symptom of DVT.
• Other Likely Diagnoses
  • Pulmonary Embolism (PE) with associated DVT: Although PE typically presents with respiratory symptoms, it can also cause leg swelling if associated with a DVT.
  • Heart Failure: Atrial fibrillation can lead to heart failure, which can cause peripheral edema, including leg swelling.
  • Venous Insufficiency: This condition can cause chronic leg swelling, but it may be exacerbated by the increased risk of thrombosis associated with atrial fibrillation.
• Do Not Miss Diagnoses
  • Phlegmasia Cerulea Dolens: A rare but life-threatening condition caused by a massive DVT that can lead to limb ischemia and potentially fatal outcomes if not promptly treated.
  • Septic Thrombophlebitis: An infection of the veins that can cause sepsis and is associated with a high mortality rate if not recognized and treated promptly.
• Rare Diagnoses
  • Lymphedema: A condition characterized by chronic swelling of the limbs due to lymphatic system dysfunction, which can be primary or secondary to other conditions.
  • Lipodermatosclerosis: A condition that causes inflammation and scarring of the subcutaneous fat, leading to leg swelling and skin changes.
  • Iliac Vein Compression Syndrome (May-Thurner Syndrome): A rare condition where the left iliac vein is compressed by the right iliac artery, leading to DVT and leg swelling.