Differential Diagnosis for a Suspicious Spot on the Back of the Right Thigh

The patient presents with a history of a fall and a subsequent hematoma, which has since healed, but now exhibits an area of tenderness and warmth on the back of her right leg. Given these symptoms, the differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis
  • Deep Vein Thrombosis (DVT): This is a likely diagnosis given the patient's history of a recent hematoma and immobilization, which are risk factors for DVT. The symptoms of tenderness and warmth, although not classic (which often includes erythema and swelling), could still be indicative of a DVT, especially in the context of her history.
• Other Likely Diagnoses
  • Muscle Strain or Contusion: Given the history of a fall, it's possible that the patient has a muscle strain or a contusion that has become irritated or inflamed, leading to the current symptoms.
  • Cellulitis: Although the patient denies erythema, cellulitis could still be a consideration, especially if the area of tenderness and warmth is significant. The absence of erythema does not entirely rule out cellulitis, as it can sometimes present atypicallyally.
• Do Not Miss Diagnoses
  • Osteomyelitis: This is an infection of the bone that could occur after a traumatic injury, especially if the skin was broken. It's a serious condition that requires prompt diagnosis and treatment.
  • Compartment Syndrome: Although the patient denies difficulty walking, compartment syndrome is a medical emergency that can present with pain out of proportion to the injury, and it's crucial not to miss it.
  • Malignancy (e.g., Soft Tissue Sarcoma): While rare, any unexplained mass or area of persistent symptoms after trauma should prompt consideration of malignancy.
• Rare Diagnoses
  • Pyomyositis: A rare infection of the skeletal muscle that could present with localized pain, swelling, and warmth.
  • Necrotizing Fasciitis: A severe infection of the fascia, which is a layer of tissue that covers muscles, nerves, fat, and blood vessels in the affected area. It's rare but life-threatening and requires immediate medical attention.

Labs/Orders

Given the differential diagnoses, the following labs and orders should be considered:

• D-Dimer: To help rule out DVT, although it's sensitive but not specific.
• Complete Blood Count (CBC): To look for signs of infection or inflammation.
• Blood Cultures: If there's a suspicion of bacteremia or sepsis.
• Imaging Studies:
  • Ultrasound of the leg: To evaluate for DVT.
  • MRI of the leg: If there's a concern for osteomyelitis, soft tissue sarcoma, or other soft tissue injuries.
• Consults:
  • Orthopedic or Vascular Surgery: Depending on the suspected diagnosis and the need for potential intervention.