Approach

Initial presentation

In most patients with TBI the presentation is obvious, although some patients present with an altered mental status and little or no physical evidence of trauma.

Without a reliable witness, it is not uncommon for a patient initially thought to have an altered mental status due to stroke, seizure, psychosis, or intoxication to ultimately be found to have an occult TBI. Furthermore, in the absence of a witness, loss of consciousness or periods of confusion may not be reported to the clinician, which delays imaging in high-risk populations.

History

After initial resuscitation and management of airway, breathing, circulation, and disability (ABCD), take a focused history from every patient with a TBI or unknown cause of altered mental status. A detailed description of the traumatic event should be solicited from the patient, family members, emergency medical services, first responders, or police. Witnesses or individuals who know the patient may be helpful in ascertaining the details of the traumatic event and environment, as well as the patient’s normal level of functioning. It is important to keep the differential diagnoses broad to avoid making an error of premature closure. The history should include the following:

  • Mechanism of injury and detailed description of the injury

  • Loss of consciousness

  • Antegrade and/or retrograde amnesia

  • Seizures

  • Confusion, deterioration in mental status, any lucid periods

  • Vomiting, number of episodes

  • Headache, including assessment of severity

  • Visual disturbance

  • Rhinorrhoea or otorrhoea

  • Sensory or motor deficits

  • Past medical history, including any central nervous system surgery, past head trauma, haemophilia, or seizures

  • Drug or alcohol use

    • Current intoxication: shown to have an increased association with intracranial injury detected on computed tomography[106]

    • Chronic: associated with cerebral atrophy, thought to increase risk of shearing of bridging veins

  • Current medications, including anticoagulants.

Physical examination

A thorough physical examination must be performed after initial resuscitation. Be vigilant for occult injuries. Physical examination should include the following.

Glasgow Coma Scale (GCS) and pupillary examination

  • Indicated initially in all patients and should be performed serially in:

    • patients with moderate or severe TBI, and

    • patients with minor TBI who are at high risk for intracranial injury.

  • Serial GCS monitoring provides clinical warning of deterioration in neurological function.

Head and neck examination

  • Inspection for cranial nerve deficits, periorbital or postauricular ecchymoses, cerebrospinal fluid rhinorrhoea or otorrhoea, haemotympanum (signs of base of skull fracture)[Figure caption and citation for the preceding image starts]: Haemotympanum: blood in the tympanic cavity of the middle ear (arrow)van Dijk GW. Practical Neurology. 2011 Feb;11(1):50-5 [Citation ends].com.bmj.content.model.assessment.Caption@10d35ef5[Figure caption and citation for the preceding image starts]: Battle's sign: superficial ecchymosis over the mastoid processvan Dijk GW. Practical Neurology. 2011 Feb;11(1):50-5 [Citation ends].com.bmj.content.model.assessment.Caption@4e309d2

  • Fundoscopic examination: can be helpful to document retinal haemorrhage (sign of abuse) and papilloedema (sign of increased intracranial pressure [ICP])[107]

  • Palpation of the scalp: for haematoma, crepitance, laceration, and bony deformity (markers of skull fractures)

  • Auscultation: for carotid bruits (sign of carotid dissection)

  • Evaluation: for cervical spine tenderness, paraesthesias, incontinence, extremity weakness, priapism (signs of spinal cord injury)

  • Obvious foreign bodies or impaled objects should not be removed until the dura is opened in the operating room and the procedure can be performed under direct visualisation.

Cardiovascular status

  • Requires continuous cardiac and serial blood pressure monitoring in patients with moderate or severe TBI. Any episodes of hypotension must be addressed immediately.[55][56]

Respiratory status

  • Requires continuous pulse oximetry in patients with moderate or severe TBI. Patients who are intubated should have continuous end-tidal CO₂ capnography. Any episodes of hypoxia or hypercapnia must be addressed immediately.[55][56]

Motor and sensory examination

  • Of the extremities, for signs of spinal cord injury.

Glasgow Coma Scale (GCS) and pupillary examination

The GCS is widely used to assess the level of consciousness in patients with TBI, and provides prognostic information that allows the physician to plan for expected diagnostic and monitoring requirements.[45] [ Glasgow Coma Scale Opens in new window ] ​​​​

GCS and pupillary assessment are most reliable in haemodynamically stable patients without hypoxia or hypotension, as these may alter the patient's clinical examination.

GCS has three components: best eye response (E), best verbal response (V), and best motor response (M). Scoring for each component should be documented separately (e.g., GCS 10 = E3 V4 M3). [ Glasgow Coma Scale Opens in new window ] ​​​ Deficits of the motor component have the strongest correlation with poor outcome in patients with TBI.[108][109]​ If there is asymmetry between the right and left side or the upper and lower limbs, use the best motor response to calculate the GCS: this is the most reliable predictor of outcome.[45]

Patients with oral/ocular trauma or those who are intubated, medicated, or very young can be challenging to assess. Studies have shown that alcohol intoxication has little effect on the GCS, unless the blood alcohol level is greater than 200 mg/dL.[110][111]

[Figure caption and citation for the preceding image starts]: Adult and paediatric GCSUsed with kind permission from Dr Micelle J. Haydel [Citation ends].com.bmj.content.model.assessment.Caption@31a1e49a

The following scoring system is applied:[44]

  • GCS of 13-15 is associated with mild brain injury

  • GCS of 9-12 is associated with moderate brain injury

  • GCS of <9 is associated with severe brain injury.

Although a GCS of 13 is classically considered as mild, many experts believe that it should be considered within the moderate category.[10][11][12]​​​​​ GCS severity is inversely correlated to numerical magnitude. GCS can be serially performed by different members of the healthcare team in order to monitor neurological status; inter-rater reliability is generally considered to be good, although this has been questioned.[67][68][69][70][71]

A score of 13 to 15 is associated with good outcomes, although a GCS of 15 cannot be used to rule out intracranial injury. A score <9 is associated with clinical deterioration and poor outcomes. Serial GCS monitoring provides clinical warning of deterioration.

Additional tools for the assessment of consciousness

The Simplified Motor Score (obeys commands = 2, localises pain = 1, and withdraws to pain or worse = 0) has been shown to have predictive power similar to the GCS.[72]

Similarly, use of a binary assessment of the GCS-motor (GCS-m) score to determine if the patient obeys commands or not (i.e., GCS-m score <6 if patient does not obey commands; GCS-m score = 6 if patient obeys commands) has been proposed as a triage tool for out-of-hospital care. One retrospective analysis found a GCS-m score of <6 is similarly predictive of serious injury as the total GCS score.[73]

The FOUR scale, which adds brainstem reflexes and respiratory patterns to motor and eye findings, has also been shown to have similar predictive power to the GCS.[74][75]

Pupillary examination

Pupillary reflexes function as an indication of both underlying pathology and severity of injury, and should be monitored serially.[76] The pupillary examination can be assessed in an unconscious patient or in a patient receiving neuromuscular blocking agents or sedation.[16][76]

Pupils should be examined for size, symmetry, direct/consensual light reflexes, and duration of dilation/fixation. Abnormal pupillary reflexes can suggest herniation or brainstem injury. Orbital trauma, pharmacological agents, or direct cranial nerve III trauma may result in pupillary changes in the absence of increased ICP, brainstem pathology, or herniation.

  • Pupil size:

    • The normal diameter of the pupil is between 2-5 mm, and although both pupils should be equal in size, a 1-mm difference is considered a normal variant.

    • Abnormal size is noted by >1 mm difference between pupils.

  • Pupil symmetry:

    • Normal pupils are round, but can be irregular due to ophthalmological surgeries.

    • Abnormal symmetry may result from compression of CNIII, which can cause a pupil to initially become oval before becoming dilated and fixed.

  • Direct light reflex:

    • Normal pupils constrict briskly in response to light, but may be poorly responsive due to ophthalmological medications.

    • Abnormal light reflex may be seen in sluggish pupillary responses associated with increased ICP. A non-reactive, fixed pupil has <1 mm response to bright light and is associated with severely increased ICP.

Laboratory investigations

Baseline laboratory investigations in patients with moderate to severe TBI should include:

  • Full blood count including platelets

  • Serum electrolytes and urea

  • Serum glucose

  • Coagulation status: prothrombin time, international normalised ratio, activated partial prothrombin time

  • Blood alcohol level and toxicology screening if indicated.

Venepuncture and phlebotomy animated demonstration
Venepuncture and phlebotomy animated demonstration

How to take a venous blood sample from the antecubital fossa using a vacuum needle.

Arterial blood gas is not typically indicated in TBI, as the decision to secure a definitive airway is based on clinical findings and expected course of hospitalisation. Any patient with TBI who is not spontaneously breathing, not able to maintain an open airway, or not able to maintain >90% oxygen saturation with supplementary oxygen, requires a definitive airway. The dogmatic intubation of all trauma patients with a GCS of <9 has been challenged.[113]​ Patients who are not intubated must have close continuous monitoring of pulse oximetry and end-tidal CO₂.

Imaging in patients with TBI and suspected intracranial injury

Consensus recommendations from the American College of Radiology support non-contrast CT use as a first-line imaging modality in patients with TBI.[114]​​

Computed tomography (CT)

Non-contrast CT is the imaging modality of choice for patients with TBI and suspected intracranial injury; it is able to detect the vast majority of clinically important injuries and can guide in the medical and surgical management of TBI.[18]​​[45]

An immediate CT is indicated in all patients with TBI with penetrating injuries; suspected basilar, depressed, or open fracture; GCS <13; or focal neurological deficits.

Several guidelines recommend, or suggest consideration of, CT head imaging for anticoagulated patients after minor head injury, regardless of symptoms.[18]​​​​[99]​​[100]​​ UK guidelines recommend that a CT head scan within 8 hours of the injury should be considered for all patients taking anticoagulants.[18]​ However, the supporting evidence base is limited.​​[99]​​[100][101]

The following CT findings are associated with a poor outcome in TBI: midline shift, subarachnoid haemorrhage into, or compression/obliteration of, the basal cisterns.[115]

Magnetic resonance imaging (MRI)

Indicated when the clinical picture remains unclear after a CT, in order to identify more subtle lesions, such as those found in diffuse axonal injury. MRI is, however, frequently impractical in the acute setting.[116] MRI is contraindicated if there is any suspicion that a metal object has penetrated the skull.

In high-volume paediatric trauma centres, MRI may be performed as an initial investigation to decrease radiation exposure. One prospective cohort study found that fast MRI was feasible and accurate relative to CT in clinically stable children with suspected TBI.[117]

Transcranial doppler (TCD)

Has been used in the intensive care unit setting to monitor cerebral haemodynamics in both adults and children with severe TBI. TCD monitors blood flow velocity in large intracerebral arteries, which is altered in the setting of elevated intracranial pressure.

Some studies have suggested a role for TCD in patients with TBI in the accident and emergency department but, to date, the majority of use is in the intensive care unit setting.[118][119][120]

Mild TBI (concussion)

The diagnosis of mild TBI (mTBI) is dependent on careful history taking and examination. The patient’s history and collateral interviews are important in generating a diagnosis.[121] As per the definitions of TBI, careful assessment of loss of consciousness, retrograde amnesia, post-traumatic amnesia, confusion and disorientation, and focal neurological deficit should be performed.[121] In addition, signs and symptoms may be influenced by alcohol, drugs, or medications.[121]

CT is typically normal following mild TBI, although a significant number of patients are left with neurocognitive deficits and may benefit from follow-up with a neurologist and consideration of diffusion tensor imaging.[122][123]

Imaging in patients with mild TBI

The use of CT in patients with isolated mild TBI is controversial.

The New Orleans Criteria and the Canadian CT Head Rule are highly sensitive (99% to 100%) in patients with a GCS of 13-15, and in patients with and without loss of consciousness.[124][125][126][127][128][129]​ Both instruments include the following variables: some form of vomiting, advanced age, altered mental status, and signs of head trauma on physical examination. 

In the UK, the National Institute for Health and Care Excellence guidelines for the approach to patients with mild TBI include the variables from the Canadian CT Head Rule.[18]​​ In the US, the Centers for Disease Control and Prevention has adapted the variables from the New Orleans Criteria in the approach to adult patients with mild TBI. CDC: mild TBI pocket guide Opens in new window

New Orleans criteria

CT is indicated in patients with minor head trauma (minor head injury defined as loss of consciousness in patients with normal findings on a brief neurological examination and a GCS score of 15, as determined by a physician upon arrival at the accident and emergency department) with any one of the following:[129]

High risk (for neurosurgical intervention)

  • Headache

  • Vomiting

  • Aged over 60 years

  • Drug or alcohol intoxication

  • Persistent anterograde amnesia (deficits in short-term memory)

  • Evidence of traumatic soft-tissue or bone injury above clavicles

  • Seizure (suspected or witnessed).

Where possible, a history of coagulopathy should be obtained and considered with respect to CT scanning.

Canadian CT head rule

CT is indicated in patients with minor head injuries (minor head injury defined as witnessed loss of consciousness, definite amnesia, or witnessed disorientation in patients with a GCS score of 13-15) with any one of the following:[7] [ Canadian Head CT Rule for Minor Head Injury Opens in new window ]

  • High risk (for neurological intervention):

    • GCS <15 at 2 hours after injury

    • Suspected open or depressed skull fracture

    • Any sign of basal skull fracture (haemotympanum, raccoon eyes [periorbital ecchymosis], cerebrospinal fluid otorrhoea/rhinorrhoea, Battle's sign [ecchymosis of the mastoids])

    • Two or more episodes of vomiting

    • Age ≥65 years

  • Medium risk (for brain injury on CT):

    • Amnesia more than 30 minutes before impact (retrograde amnesia)

    • Dangerous mechanism (pedestrian struck by motor vehicle, occupant ejected from motor vehicle, fall from height >1 metre [3 feet] or >5 stairs).

Assessing infants and children with suspected TBI

Validated clinical decision rules, such as the Pediatric Emergency Care Applied Research Network (PECARN) decision rule, effectively identify children at low risk for intracranial injury (and those at increased risk, for whom head CT may be indicated).[130]

Clinical decision rules to identify children who benefit from CT after head injury have been derived from three large prospective studies (PECARN, CATCH, and CHALICE).[131][132][133] The PECARN clinical decision rule has the highest sensitivity for identifying children with clinically important TBI.[134]

Based on the PECARN clinical decision rule, CT is indicated for all children with a GCS score <15, altered mental status (agitation, somnolence, repetitive questioning, slow to verbal response), palpable skull fracture, or suspected basilar skull fracture.[131] Further indications for CT differ based on patient age.

Additional PECARN indications for CT in children under the age of 2 years:[131]

  • Loss of consciousness >3 seconds

  • Non-frontal scalp haematoma

  • Not acting normal (per parent)

  • Severe mechanism of injury: motor vehicle accident with ejection, death of passenger, rollover, struck by vehicle, fall >3 feet (0.9m), head struck by high impact object.

Observation for 6 hours is an option for patients >3 months (and <2 years) if no more than one of the four criteria is present. CT is indicated for new, worsening, or unresolved symptoms by 6 hours.

Additional PECARN indications for CT in children aged 2 years or older:[131]

  • Loss of consciousness

  • Severe headache

  • Vomiting

  • Severe mechanism of injury: motor vehicle accident with ejection, death of passenger, rollover, struck by vehicle, fall >3 feet (0.9m), head struck by high impact object.

Observation for 6 hours is an option for patients >2 years if no more than one of the four criteria is present. CT is indicated for new, worsening, or unresolved symptoms by 6 hours.

Routine use of imaging to diagnose mild TBI in children in the acute setting is not recommended.[116][130] BMJ: clinical decision making tools image Opens in new window

Post-injury monitoring

Post-trauma monitoring will vary depending on the clinical findings and the results of the diagnostic work-up. Patients with moderate or severe TBI should be admitted to a hospital with neurosurgical consultants, and an intensive care unit able to provide monitoring to identify and limit secondary brain injury. Most patients with polytrauma and/or those who do not attain a normal neurological examination while in the accident and emergency department will benefit from a similar hospitalisation, and may require re-imaging as the clinical picture changes.

One systematic review found that patients with mild TBI and an initially abnormal CT did not benefit from routine repeat CT, but should be re-imaged based on neurological deterioration.[135]

Post-concussive syndrome (the persistence of physical, cognitive, emotional, and sleep symptoms beyond the acute post-injury period) is monitored using the same symptom scales employed in the acute phase of the injury.[136]

Patients with a normal neurological examination and negative CT scan (or where scanning was not indicated), may be discharged home after 2 hours of observation under the care of a responsible individual.[125][137][138][139]

Patients should be provided with written information regarding signs and symptoms that should prompt a return to the accident and emergency department, including focal weakness, persistent or worsening headache or vomiting, decrease in consciousness, rhinorrhoea, otorrhoea, or agitation.

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