Differential Diagnosis

The patient's presentation after a motor vehicle accident (MVA) with multiple rolls down a hill, resulting in a traumatic brain injury (TBI) indicated by the length of amnesia, right upper limb incoordination, and bilateral lower limb dyslexia, with a negative head CT, suggests a range of possible diagnoses. These can be categorized as follows:

• Single Most Likely Diagnosis

  • Diffuse Axonal Injury (DAI): This condition is a common consequence of high-impact trauma, such as an MVA with multiple rolls, leading to shearing injuries in the brain. The symptoms of TBI, limb incoordination, and the absence of focal lesions on the head CT (which might not always show DAI) make DAI a plausible diagnosis.

• Other Likely Diagnoses

  • Concussion: Given the mechanism of injury and the presence of TBI symptoms, a concussion is a likely diagnosis. Concussions can result in a variety of symptoms, including amnesia, incoordination, and cognitive impairments.
  • Post-Traumatic Seizure: Although less common, the patient's symptoms could be indicative of a post-traumatic seizure, especially if the "dyslexia" is interpreted as a possible seizure manifestation or a result of the brain injury affecting language processing areas.
  • Spinal Cord Injury: The bilateral lower limb symptoms could suggest a spinal cord injury, particularly if the mechanism of injury involved significant flexion, extension, or rotation of the spine.

• Do Not Miss Diagnoses

  • Epidural or Subdural Hematoma: Although the head CT is negative, the possibility of a delayed bleed, especially in the context of trauma, cannot be entirely ruled out without close monitoring and possibly repeat imaging.
  • Cervical Spine Injury: Given the mechanism of injury, a cervical spine injury is a critical diagnosis not to miss, as it can lead to significant morbidity or mortality if not promptly addressed.
  • Intracranial Hemorrhage: Similar to epidural or subdural hematoma, any form of intracranial hemorrhage needs to be considered, especially if the patient's condition worsens or if there are focal neurological deficits.

• Rare Diagnoses

  • Hemorrhagic Contusion: While less likely given the negative head CT, a hemorrhagic contusion could present with delayed symptoms, especially if the initial CT was done very early after the injury.
  • Arteriovenous Malformation (AVM) or Aneurysm: Although rare, trauma could potentially precipitate symptoms in a pre-existing AVM or aneurysm, leading to hemorrhage or other neurological deficits.
  • Fat Embolism Syndrome: In patients with long bone fractures (possible in this scenario), fat embolism syndrome is a rare but potentially deadly condition that could present with neurological symptoms among others.