History and exam
Key diagnostic factors
common
history of blunt trauma to the head or acceleration/deceleration forces
Establish how and when the injury occurred and whether the impact was directly to the head or transmitted to the head by the acceleration or deceleration of the body on impact.
A dangerous mechanism of injury in adults is defined by the UK National Institute for Health and Care Excellence (NICE) as:[42]
A pedestrian or cyclist struck by a motor vehicle
An occupant ejected from a motor vehicle
A fall from a height of >1 metre or 5 stairs.
A dangerous mechanism of injury in children is defined by NICE as:[42]
A high-speed road traffic accident either as a pedestrian, cyclist, or vehicle occupant
A fall from a height of >3 metres
A high-speed injury from a projectile or other object.
Corroborate with a witness when possible.
Glasgow Coma Scale score of 13-15 thirty minutes or later post-injury and transient neurological abnormalities
Clinical criteria for identifying a mild traumatic brain injury in a patient with a history of blunt trauma to the head or acceleration/deceleration forces are a Glasgow Coma Scale (GCS) score of 13 to 15 thirty minutes or later post-injury, and ≥1 of the following:[18]
Confusion or disorientation
Loss of consciousness for ≤30 minutes
Post-traumatic amnesia for <24 hours
Other transient neurological abnormalities (e.g., seizure, focal signs, intracranial lesion not requiring surgery).
Practical tip
Be aware that in some patients (e.g.,those with dementia, underlying chronic neurological disorders, or learning disabilities) the pre-injury baseline GCS may be below 15. Establish this where possible, and take it into account during assessment.[42]
Other diagnostic factors
common
headache
Headache is the most commonly reported symptom.[43][44] Although headache is often felt immediately, headache can worsen the day after the injury is sustained. 30% of patients with mild TBI continue to report headache at 3 months post-trauma.[45] Medication overuse, neck injuries, sleep disturbance and psychological comorbidity may all contribute to headache after mild TBI.[46][47]
disturbed gait/balance or dizziness
When occurring after a head injury, dizziness and balance problems are typically related to benign paroxysmal positional vertigo.[46]
Benign paroxysmal positional vertigo is a common, and easily treatable, cause of dizziness.[46] These symptoms may be alarming to patients if they do not settle quickly. Explaining that they are due to debris dislodged into the inner ear by the injury can help to alleviate patients’ concerns about ‘brain damage’.[46] Vestibular migraine and depersonalisation (a sense of disconnection from the body) are other causes of dizziness in this population. Central vestibular disorders can occur but are more typical after moderate or severe brain injury.[46] See Benign paroxysmal positional vertigo.
depersonalisation
Depersonalisation (a sense of disconnection from the body) is a common cause of dizziness, and is highly alarming to patients.[46] Patients describe feeling ‘zoned out’, ‘not quite there’, or that their arms or legs are ‘not their own’.
fatigue
Tiredness is a common symptom.
memory difficulties or amnesia
Can be centered on the injury incident itself or generalised to include difficulty in day-to-day situations, and typically co-occur with other cognitive and/or physical symptoms, such as headaches. Memory lapses are common in the general population and are not specific to mild TBI.[46]
vomiting/nausea
Less typical in adults; occurs much more frequently in adolescents and children.
A vomit is defined as a single discrete episode of vomiting; it is very common in younger children, which alone is not of concern. When vomiting is the only symptom of head injury in a child, traumatic brain injury on CT is uncommon and clinically important traumatic brain injury is very uncommon.[48] Traumatic brain injury is more frequent in children when vomiting is accompanied by other signs or symptoms suggestive of traumatic brain injury.[48] However, request an urgent (i.e., within 1 hour) computed tomographic scan for any children with ≥3 discrete episodes of vomiting and any of the following:[42]
Witnessed loss of consciousness lasting more than 5 minutes
A dangerous mechanism of injury (a high-speed road traffic accident either as a pedestrian, cyclist, or vehicle occupant, fall from a height of more than 3 m, high-speed injury from a projectile or other object)
Amnesia (antegrade or retrograde) lasting more than 5 minutes
Any current bleeding or clotting disorder (liver failure, haemophilia, taking anticoagulants or antiplatelets).
neck pain
More commonly associated with motor vehicle collisions than with other mechanisms of injury.[49] If present, assess the patient for a cervical spine injury. See Acute cervical spine trauma in adults.
normal neurological examination
Patients with mild traumatic brain injury typically have a normal physical examination and no neurological signs other than those typical of mild traumatic brain injury.
Focal neurological deficit, if present, may be a sign of a more severe brain injury. Request an urgent (i.e., within 1 hour) computed tomographic scan in these patients.[42]
Practical tip
Focal neurological deficit may be defined as problems restricted to a particular part of the body or a particular activity, for example:
Difficulties with understanding, speaking, reading, or writing
Decreased sensation
Loss of balance
Weakness of ≥1 limbs
Visual changes
Abnormal reflexes
Problems walking.
abnormalities on cognitive assessment
Attention deficits, planning and problem-solving deficits, and difficulties with visual and verbal memory are common. However, cognitive symptoms usually resolve quickly after mild TBI; a minority of patients have memory and concentration problems within 3 months of injury.[46] Routine referral for cognitive (psychometric) assessment is not recommended after mild TBI.[46][51]
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