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Concussion

• Concussion is defined as alteration of consciousness as a result of closed head injury, but is generally used in describing mild head injury without imaging abnormalities.

• Key Features : Confusion, amnesia

• Patient may be easily distractable, forgetful, slow to interact or emotionally labile.

• Gait disturbance and incoordination may be seen.

• The mechanics of atypical concussion involve sudden deceleration of the head when hitting a blunt object. This creates an anterior-posterior movement of the brain within the skull due to inertia and rotation of the cerebral hemispheres on the relatively fixed upper brainstem.

• LOC in concussion is believed to result from a transient electrophysiological dysfunction of the RAS in the upper midbrain that is at the site of rotation.

• Postconcussive syndrome is a loosely defined constellation of symptoms, persisting for a prolonged period after injury, and exacerbated in some patients by the potential for secondary gain.

• Characterized by headache, dizziness and disorders of hearing and vision.

• They may also suffer a variety of neurocognitive and neuropsychological disturbances, including difficulty with concentration and recall, insominia, emotional lability, fatigue, depression and personality change.

Diffuse Axonal Injury

• It is a form of primary brain injury, seen in high energy accidents and which usually renders the patient comatose.

• It is a deep white matter lesion consists of widespread mechanical disruption or shearing, of axons at the time of impact.

• It is strictly a pathological diagnosis made at post-mortem, but haemorrhagic foci in the corpus callosum and dorsolateral rostral brainstem on CT may be suggestive, although the CT often appears normal.

Updated on 17/7/2015

Reference :

• Bailey & Love. 26 th edition

• Harrison's Principle` of Internal Medicine. 18 th edition

• Update: Evaluation & Management of Concussion in Sports. AAN.2013