Differential Diagnosis

The patient presents with bilateral thigh muscle pain, left ankle pain and swelling, and a history of breast cancer, high cholesterol, and previous back injuries. The following differential diagnoses are considered:

• Single most likely diagnosis
  • Overuse or repetitive strain injury: The patient's job involves prolonged standing, which may contribute to muscle fatigue and strain, particularly in the thighs and ankles. The symptoms of muscle soreness, worse at night, and swelling in the left ankle support this diagnosis.
• Other Likely diagnoses
  • Musculoskeletal strain or sprain: The patient's history of previous back injuries and current symptoms of muscle soreness and ankle swelling suggest a possible musculoskeletal strain or sprain.
  • Chronic venous insufficiency: The patient's job involves prolonged standing, which may contribute to chronic venous insufficiency, particularly in the left ankle, where swelling is noted.
  • Lipid-induced myopathy: The patient's high cholesterol levels, particularly the elevated LDL, may contribute to muscle pain and soreness.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Metastatic breast cancer: Although the patient is in remission, it is essential to consider the possibility of metastatic disease, particularly given the new symptom of bilateral thigh muscle pain.
  • Deep vein thrombosis (DVT): The patient's swelling and pain in the left ankle, combined with a history of breast cancer, increase the risk of DVT.
  • Osteonecrosis or avascular necrosis: The patient's history of breast cancer and high cholesterol may increase the risk of osteonecrosis or avascular necrosis, particularly in the hips or ankles.
• Rare diagnoses
  • Polymyalgia rheumatica (PMR): Although less likely, PMR is a rare condition that can cause muscle pain and stiffness, particularly in the thighs and hips.
  • Vasculitis: A rare condition that can cause muscle pain, swelling, and skin changes, although the patient's symptoms do not strongly suggest this diagnosis.
  • Neoplastic or paraneoplastic syndromes: Rare conditions that can cause muscle pain and weakness, although the patient's symptoms do not strongly suggest this diagnosis.