Differential Diagnosis

The patient's presentation of constant, dull, low back pain that began after unloading heavy equipment and is exacerbated by activity and relieved by rest suggests a mechanical origin. Here's a categorized differential diagnosis:

• Single most likely diagnosis
  • D) Muscle strain: The history of recent heavy lifting, the nature of the pain (constant, dull, low back), and the exacerbation with activity and relief with rest are highly suggestive of a muscle strain. The tenderness over the lumbar paraspinal region further supports this diagnosis.
• Other Likely diagnoses
  • A) Herniated disc: Although the pain does not radiate to the extremities, and straight-leg raising does not increase the pain, a herniated disc could still be considered, especially if the patient had a history of heavy lifting that could have caused disc injury. However, the lack of radiculopathy and negative straight-leg raise test makes this less likely.
  • H) Spondylolisthesis: This condition involves the slipping of one vertebra over another and could be exacerbated by heavy lifting. However, it typically presents with more specific findings such as radiculopathy or significant instability on examination, which are not described in this case.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • C) Metastatic cancer: Although rare in a previously healthy 32-year-old, cancer should always be considered in the differential diagnosis of back pain, especially if there's a history of weight loss, night pain, or other systemic symptoms, which are not mentioned here.
  • G) Spinal epidural abscess: This is a medical emergency that presents with severe back pain, fever, and neurological deficits. The patient's presentation does not strongly suggest this diagnosis, but it should always be considered, especially if there's any sign of infection or neurological compromise.
• Rare diagnoses
  • E) Osteoporotic compression fracture: This would be unusual in a healthy 32-year-old male without a history of osteoporosis risk factors.
  • F) Sacroiliitis: Typically presents with buttock pain and is often associated with inflammatory back pain characteristics (e.g., morning stiffness, improvement with activity) and systemic symptoms of spondyloarthritis, which are not described here.
  • B) Lumbar spinal stenosis: Usually presents in older adults with symptoms of neurogenic claudication (pain, weakness, or fatigue in the legs and buttocks when walking or standing), which is not consistent with this patient's age and symptom profile.