Concussion has been derived from Latin word which means Contutere (to shake violently) or concussion (action of striking together).It is the most common type of traumatic brain injury and presently the word is interchangeable with mild traumatic brain injury (MTBI). Concussion includes variety of physical, cognitive and emotional symptoms. In head injury there is temporary loss of brain function. Concussion falls under the classification of mild traumatic brain injury. Injuries such as intracranial hemorrhage (e.g. such as intracranial hematoma, subdural hematoma, epidural hematoma) are not included into MTBI, but neuroimaging may be considered as complication of MTBI.
Mechanism of Concussion
Brain is surrounded by Cerebrospinal fluid (CSF), which mainly functions to protect the brain from light trauma. Impact of striking forces on the brain causes, linear rotation and angular movement of the brain. In rotational movement the head turns around the center of gravity and in angular movement the head turns around the axis. The rotational forces may be thought to be major component in concussion and severity. The midbrain and diencephalon are most affected. The forces disrupt the normal cellular activity in the reticular activity system; the individual becomes unconscious when upper part of the brain system, corpus callosum, temporal lobe and frontal lobe are affected.
Diagnosis of Concussion
In assessing the patient of concussion, it is mandatory to assess the Airways, breathing and Circulation (ABC). Examination of cervical spine, which may found to be injured in unconscious person. Patient may be thoroughly examined for other serious injuries, the signs are at high risk for serious brain injuries are as follows:-
- Persistence headache, and vomiting
- Gradual increase in disorientation or deteriorating level of consciousness
- Unequal pupil size
Brain imaging may be done to detect lesion that are frequently in 24-48 hours. Diagnosis of MTBI is based on the physical and neurological examination, duration and level of unconsciousness (usually less 30 minutes), and in Post Traumatic Amnesia (PTA) less than 24 hours. Glasgow coma scale less (13 to 15) is indicative of MTBI.
- Neurophysiological Test: are used to measure cognitive functions. If Glasgow coma scale is less than 15 in two hour and less than 14 at any time, CT scan is recommended. Most complication with concussion cannot be diagnosed by CT scan and MRI.
- Post Concussional syndrome may be associated with abnormality which is visible on SPECT and PET scan. Mild head injury may or may not produce abnormality on EEG.
Signs and symptoms of Concussion
Concussion is associated with variety of Symptoms the most common are:
- Headache. It is the most common MTBI symptom.
- Other Symptoms include. Dizziness, nausea, vomiting, lack of motor coordination, and difficulty in balancing.
- Visual symptoms: includes, light sensitivity, seeing bright light, blurred vision, double vision,
- Ear Symptoms: tinnitus, or ringing of ear.
- Cognitive and Emotional Symptoms: The patient feels disoriented in time and space and is unable to concentrate.
- Post Traumatic Amnesia: In the event of injury ,the individual is unable to be recall, confusion and other concussion is the hallmark which may developed immediately or takes Several minutes.
Grading of Concussion
In order to simplify the process; three systems of grading are widely followed:-
|Cantu||Post-traumatic amnesia <30 minutes, no loss of consciousness||Loss of consciousness <5 minutes or amnesia lasting 30 minutes–24 hours||Loss of consciousness >5 minutes or amnesia >24 hours|
|Colorado Medical Society||Confusion, no loss of consciousness||Confusion, post-traumatic amnesia, no loss of consciousness||Any loss of consciousness|
|American Academy of Neurology||Confusion, symptoms last <15 minutes, no loss of consciousness||Symptoms last >15 minutes, no loss of consciousness||Loss of consciousness (III a, coma lasts seconds, III b for minutes)|