Differential Diagnosis for 38-year-old Female with Neck Pain and Spasms after Motor Vehicle Accident

Single Most Likely Diagnosis

• Muscle Strain or Whiplash Injury: Given the history of a motor vehicle accident and the onset of severe neck pain and spasms, a muscle strain or whiplash injury is the most likely diagnosis. The unremarkable X-ray of the neck supports this, as soft tissue injuries may not be visible on X-ray.

Other Likely Diagnoses

• Fibromyalgia Flare: The patient's history of fibromyalgia could suggest a flare of her condition, exacerbated by the physical stress of the accident. However, the acute onset of severe neck pain and spasms might indicate a more direct injury.
• Cervical Sprain or Ligamentous Injury: Similar to a muscle strain, a sprain or ligamentous injury in the cervical spine could result from the accident, leading to pain and spasms.
• Disc Herniation or Bulge: Although the X-ray was unremarkable, an MRI might be necessary to rule out a disc herniation or bulge, which could cause neck pain and muscle spasms.

Do Not Miss Diagnoses

• Cervical Spine Fracture: Despite an unremarkable X-ray, it's crucial to consider the possibility of a cervical spine fracture, especially if the patient had a significant mechanism of injury. Further imaging (e.g., CT or MRI) might be necessary.
• Spinal Cord Injury: Any injury to the spinal cord could have severe and permanent consequences. The absence of clonus and normal motor strength testing makes this less likely, but it cannot be ruled out without thorough evaluation.
• Vascular Injury (e.g., Vertebral Artery Dissection): A vascular injury, such as a vertebral artery dissection, is a potentially life-threatening condition that requires immediate attention. The presence of nausea could be a red flag for this condition.

Rare Diagnoses

• Inflammatory or Infectious Processes: Conditions like meningitis, abscess, or inflammatory spondyloarthropathies are less common but could present with neck pain and stiffness. The acute onset after a motor vehicle accident makes these less likely but not impossible.
• Neoplastic Processes: Although rare, tumors of the spine could cause neck pain and neurological symptoms. The recent onset after trauma makes this less likely, but it should be considered if other diagnoses are ruled out and symptoms persist or worsen.