Concussion Differential Diagnosis

Concussion and mild traumatic brain injury (mTBI) are not interchangeable. Concussion may be thought as a subcategory of mTBI on the less severe end of the brain injury spectrum, though with similar clinical symptoms 1).

A major difference between the two is that mTBI may demonstrate abnormal structural imaging (such as cerebral hemorrhage/contusion) and concussion, by definition, must have normal imaging studies. mTBI is part of an injury severity spectrum primarily based on GCS score. TBI is evaluated 6 hours after injury and differentiated into mild, moderate and severe

Concussion is evaluated directly after the insult and based on a clinical diagnosis aided by a multitude of standardized assessment tools. To include concussion under the full spectrum of traumatic brain injury then it must fall at the low end of mTBI and overlap with the subset of “minimal” injury. Most mTBIs with negative imaging can be considered concussions, but the majority of sports concussions cannot be classified as mTBI 2) 3).

1)
Harmon KG, Drezner JA, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. 2013; 47:15–26
2)
McCrory P, Meeuwisse WH, Echemendia RJ, et al. What is the lowest threshold to make a diagnosis of concussion? Br J Sports Med. 2013; 47:268–271
3)
Yuh EL, Hawryluk GW, Manley GT. Imaging concussion: a review. Neurosurgery. 2014; 75 Suppl 4: S50–S63