Concussion and its consequences are becoming an ever more topical subject, largely due to some high profile sports-related concussions and a few cases of recurrent injuries leading to tragic outcomes. There is also increasing attention being paid to the longer-term sequelae of repetitive concussions, and whether these accelerate neurodegenerative processes. Concussion is often used synonymously with the term minor traumatic brain injury, which is the reason for an estimated 1 million A&E attendances per year in the UK. Most people will have no significant repercussions from such an injury, but in certain groups, the effects can be substantial and prolonged.
Concussion is variably defined, but there are certain key elements to it:
- It is a complex pathophysiological process affecting the brain
- It is induced by mechanical forces
- It has characteristic clinical and cognitive symptoms
- There is a typical onset and resolution of symptoms
Loss of consciousness is not a prerequisite for concussion.
The issue with making a diagnosis is that there are no pathognomonic symptoms or signs, and no diagnostic imaging test. Diagnosis needs to be based on assessment of symptoms, cognitive function and focused neurological assessment of balance. Such assessment needs to factor in pre-existing symptoms, and is often most useful when done serially to detect changes, particularly given that symptoms may present in a delayed fashion. The symptoms that point to a diagnosis of concussion are:
- Headache or “pressure in head”
- Neck pain
- Nausea or vomiting
- Blurred vision
- Balance problems
- Sensitivity to light
- Sensitivity to noise
- Feeling slowed down
- “Don’t feel right”
- Difficulty concentrating
- Difficulty with memory
- Low energy
- Fatigue easily
- Trouble falling asleep
- More emotional
- Nervous or anxious
There are a number of tools now available to act as a guide to diagnosing concussion. These do not provide absolute thresholds for diagnosis, nor have they all been validated. However, they provide a checklist of symptoms and signs to look for, and a valuable framework for documenting recovery following a concussion.
The Sports Concussion Assessment Tool (in its third version – SCAT3) is one such tool endorsed by FIFA, the IRB and the IOC.
Investigation of a concussed patient
Brain imaging is not routinely useful in the diagnosis or management of acute concussion. This is largely because the most available imaging modality, CT scanning, is almost always normal. However, any impairment of the Glasgow Coma Scale (GCS) remains an indication for an urgent CT scan.
Magnetic resonance (MR) imaging has a much greater sensitivity for detecting minor structural changes in concussion. Nonetheless, its role is currently in those cases where symptoms persist, as it is a useful prognostic tool.
New MR imaging techniques are advancing our understanding of concussion through advanced structural and functional analysis of the injured brain, and this in turn, may have therapeutic implications. This is particularly the case with higher magnetic field strengths, such as offered by the 3 Tesla MR scanner at 52 Alderley Road, the only such static private facility in the region.
The treatment of concussion is dealt with in the concussion and post-concussion syndrome treatment page.