Differential Diagnosis for Right Ankle Pain

The patient presents with right ankle pain after rolling her ankle two weeks ago, with increased pain this morning, and an x-ray showing no acute fracture but mild soft tissue swelling. Here's a differential diagnosis based on the provided information:

• Single Most Likely Diagnosis
  • Ankle Sprain: This is the most likely diagnosis given the history of rolling her ankle and the presence of mild soft tissue swelling along the lateral aspect of the ankle. The mechanism of injury and the symptoms are consistent with a sprain, which is a common injury after such incidents.
• Other Likely Diagnoses
  • Ligamentous Injury: Beyond a simple sprain, there could be a more significant ligamentous injury that wasn't evident on the x-ray. This would explain the continued pain and difficulty bearing weight.
  • Tendinopathy: Tendons around the ankle could be inflamed or damaged, leading to pain, especially if the patient continued to use the ankle after the initial injury.
  • Osteochondral Lesion of the Talus: Although the x-ray did not show an acute fracture, an osteochondral lesion (a piece of cartilage and bone that can become damaged) could be present and might not be visible on all x-rays, requiring further imaging like an MRI for diagnosis.
• Do Not Miss Diagnoses
  • Fracture Not Visible on X-ray: Some fractures, especially stress fractures or those involving the cartilage and not the bone directly, might not be visible on initial x-rays. It's crucial to consider this possibility, especially with significant pain.
  • Infection: Although less likely without other symptoms like fever or redness, an infection could be present, especially if the skin was broken during the injury.
  • Deep Vein Thrombosis (DVT): This is a less common but serious condition that could cause leg pain and swelling, especially after an injury that leads to immobilization.
• Rare Diagnoses
  • Gout or Pseudogout: These conditions involve the deposition of crystals within the joints and can cause sudden, severe pain. They are less common in young individuals but should be considered in the differential diagnosis.
  • Osteonecrosis: A condition where the bone tissue dies due to lack of blood supply. It's rare and might not be immediately suspected but could be a complication of significant trauma.

Treatment Plan

Given the significant pain and the inability to bear weight, the application of a boot and the use of crutches are appropriate to reduce stress on the ankle. A referral to an orthopedic specialist is also prudent, considering the severity of the pain and the need for further evaluation, possibly including an MRI to rule out other diagnoses like osteochondral lesions or ligamentous injuries that were not visible on the x-ray.