Differential Diagnosis for Right Side Lower Back Pain
Single Most Likely Diagnosis
- Musculoskeletal Strain: Given the patient's history of being involved in a motor vehicle accident (MVA) 2 weeks ago, where their car was stopped and hit from behind, a musculoskeletal strain is the most likely diagnosis. The constant dull ache in the right side lower back, exacerbated by activity, and the absence of neurological symptoms such as numbness, tingling, bowel, or bladder incontinence, support this diagnosis. The patient's perception that the condition is improving also aligns with the natural history of musculoskeletal strains.
Other Likely Diagnoses
- Lumbar Disc Herniation: Although less likely than musculoskeletal strain due to the absence of neurological symptoms, a lumbar disc herniation could still be considered, especially given the mechanism of injury. The patient's symptoms could represent a small or partial disc herniation that does not significantly impinge on neural structures.
- Ligamentous Sprain: Similar to musculoskeletal strain, a ligamentous sprain could result from the sudden force applied to the patient's body during the MVA. This would also present with pain exacerbated by activity and could improve with time.
Do Not Miss Diagnoses
- Abdominal Aortic Aneurysm (AAA): Although the patient denies symptoms such as abdominal pain or radiation to the groin, an AAA could potentially present with back pain, especially if it is expanding or leaking. Given the potential for catastrophic outcomes if missed, AAA must be considered, particularly in older patients or those with risk factors.
- Kidney Stone or Pyelonephritis: These conditions could present with flank or back pain and are important to rule out, especially if there are associated symptoms like fever, nausea, or changes in urination. However, the patient denies such symptoms.
- Spinal Fracture: Given the mechanism of injury, a spinal fracture is a possibility, especially if the patient has osteoporosis or was subjected to significant force. The absence of neurological deficits does not rule out a fracture.
Rare Diagnoses
- Osteoid Osteoma: A benign bone tumor that could cause nocturnal pain, which is relieved by NSAIDs. It's less likely given the post-traumatic context but could be considered if other diagnoses are ruled out.
- Spinal Infection (Osteomyelitis, Discitis): Infections of the spine are rare but can occur post-trauma, especially if the patient has underlying risk factors such as immunocompromised status. These conditions would likely present with more systemic symptoms like fever and significant pain.