Differential Diagnosis for a 67-year-old Female with Sudden Ankle Pain

Single Most Likely Diagnosis

• Ankle Fracture: Given the patient's age, history of hemophilia and von Willebrand's disease, and the mechanism of injury (sudden crack sensation and pain after a fall), an ankle fracture is the most likely diagnosis. The inability to bear weight and radiation of pain up into the upper leg with movement or bending further support this diagnosis.

Other Likely Diagnoses

• Severe Ankle Sprain: Although less likely than a fracture given the severity of symptoms and the "crack" sensation, a severe ankle sprain could still be a consideration, especially if the patient has significant ligamentous injury.
• Osteonecrosis or Insufficiency Fracture: Given the patient's age and underlying coagulopathy, there could be an increased risk for osteonecrosis or an insufficiency fracture, particularly if she has osteoporosis or other underlying bone health issues.

Do Not Miss Diagnoses

• Compartment Syndrome: This is a medical emergency that could occur after a fracture or severe injury. Given the patient's coagulopathy, she might be at higher risk for bleeding into the compartments, leading to increased pressure and potential nerve and muscle damage.
• Deep Vein Thrombosis (DVT): Although the patient denies taking blood thinners, her history of hemophilia and von Willebrand's disease, combined with recent immobility, could potentially increase her risk for DVT, which is a serious condition requiring prompt treatment.
• Rupture of Tendons or Ligaments: While less common, a rupture could present similarly to a fracture, especially in the context of significant trauma and underlying bleeding disorders.

Rare Diagnoses

• Pathological Fracture: If the patient has an underlying bone lesion (e.g., metastatic cancer, osteomyelitis), a pathological fracture could be a consideration, although this would be less likely without other supporting symptoms or history.
• Peripheral Artery Disease (PAD) or Acute Arterial Occlusion: Although rare in this context, severe pain and inability to move could, in some cases, be related to vascular issues, especially if the patient has risk factors for PAD or has experienced recent trauma that could lead to arterial occlusion.