Head Injury

Head injury can arise from blunt or penetrating trauma and result in direct injury at the impact site. Indirect injury may also be caused by movement of the brain within the skull, leading to contusions on the opposite side of the head from the impact, or disruptive injuries to axons and blood vessels from shearing or rotational forces as the head is accelerated and decelerated after the impact.

Traumatic brain injury may be categorised as primary (damage occurring at the time of impact) or secondary (injury as a result of neurophysiological and anatomical changes minutes to days following primary insult, eg from cerebral oedema, haematoma or increased intracranial pressure).

Epidemiology

• Hospital Episode Statistics data for the 2000/2001 annual data set indicate that there were 112,978 admissions to hospitals in England with a primary diagnosis of head injury.
• 75% of these were male admissions and 33% were children under 15 years of age.
• 70-88% of all people who sustain a head injury are male. ^[1]
• 10-19% are aged ≥65 years. ^[1]
• Severe traumatic brain injury, defined as Glasgow Coma Score (GCS) <9, occurs in 11,000 people per year and has a mortality rate reaching 50%.^[3]

Aetiology

• Falls (22-43%) and assaults (30-50%) are the most common cause of a minor head injury, followed by road traffic accidents (25%). Road traffic accidents account for a far greater proportion of moderate-to-severe head injuries.^[4]
• Alcohol may be involved in up to 65% of adult head injuries.

Assessment

Immediately assess any needs for urgent resuscitation as outlined by the appropriate guidelines. Following this:

In patients with normal or near normal Glasgow Coma Score (GCS) and who are alert

• Haemodynamic status - pulse rate, blood pressure, fluid status
• Neurological assessment - full history and examination, make notes of pupil size and reaction to light.
• Look for other possible injuries and any other relevant examination

In patients with reduced GCS

• Resuscitate but make a quick assessment of GCS and pupils. The priority is to get the patient to hospital and CT scan within the first hour after injury.^[2]

Prehospital management

• Resuscitation: Basic and Advanced Trauma Life Support, and Basic and Advanced Paediatric Life Support as necessary. In severe traumatic brain injury the time from injury to definitive neurosurgical care plays a crucial role, best outcomes being in those who achieve this within 4 hours.^[3] Other factors pertinent to all cases and especially severe traumatic brain injury:^[3]
  • Airway - endotracheal intubation should only be performed by those experienced and with concomitant anaesthesia (risk of increasing intracranial pressure). Insertion of laryngeal mask airways is easy and provides a good seal around the oropharynx.^[3]
  • Breathing - oxygen should be provided with an aim to beginning ventilation as soon as possible. End tidal CO₂monitoring is advisable as hyperventilation is associated with poorer outcomes, probably relating to cerebral vasoconstriction.
  • Circulation - the systolic blood pressure should be maintained >90 mm Hg ensuring an adequate cerebral perfusion pressure, eg boluses of 0.9% normal saline
• Full cervical spine immobilisation attempted (unless other factors prevent this) if:
  • Glasgow Coma Score (GCS) <15 at any time since the injury
  • Neck pain or tenderness
  • Focal neurological deficit
  • Paraesthesia in the extremities
  • Any other clinical suspicion of cervical spine injury
• An alerting call to the destination A&E department should be made for all patients with a GCS <15

Indications for referral to hospital A&E department^[2]

• History of head injury:
  • A high-energy head injury, eg diving accident, high-speed motor vehicle collision
  • GCS <15 at any time since injury
  • Any loss of consciousness as a result of the injury
  • Any focal neurological deficit since the injury
  • Amnesia for events before or after the injury
  • Persistent headache since the injury
  • Any vomiting episodes since the injury (clinical judgement should be used in those aged ≤12 years)
  • Any seizure since the injury
  • Irritability or altered behaviour, particularly in infants and young children
  • Any suspicion of a skull fracture or penetrating head injury since the injury (eg clear fluid from the ears or nose, black eye with no associated damage around the eyes, bleeding from one or more ears, new deafness in one or more ears, bruising behind one or more ears).
  • Visible trauma to the head not covered above but still of concern to the professional
• Past history:
  • Age ≥65 years
  • Any previous cranial neurosurgical interventions
  • History of bleeding or clotting disorder
  • Current anticoagulant therapy such as warfarin
• Other concerns:
  • Suspicion of nonaccidental injury
  • Current drug or alcohol intoxication
  • Adverse social factors (eg no one able to supervise the injured person at home)
  • Continuing concern by the professional about the diagnosis
  • Continuing concern by the injured person or their carer about the diagnosis

Admission

The following patients meet the criteria for admission to hospital following a head injury:

Adult

• New, clinically significant abnormalities on imaging
• Not returned to Glasgow Coma Scale (GCS) equal to 15 after imaging, regardless of the imaging results
• When a patient fulfils the criteria for CT scanning but this cannot be done
• Continuing worrying signs (eg persistent vomiting, severe headaches)
• Other sources of concern, eg drug or alcohol intoxication, other injuries, shock, suspected nonaccidental injury, meningism, cerebrospinal fluid (CFS) leak)

Children

• History of loss of consciousness
• Neurological abnormality, persisting headache or vomiting
• Clinical or radiological evidence of skull fracture or penetrating injury
• Difficulty in making a full assessment
• Suspicion of nonaccidental injury
• Other significant medical problems
• Not accompanied by a responsible adult or social circumstances considered unsatisfactory

Patients not requiring admission

Give written head injury information regarding warning signs that warrant further immediate medical assessment:^[5]

• Increasing drowsiness
• Worsening headache
• Confusion or strange behaviour
• Two or more bouts of vomiting
• Focal neurological problem, eg limb weakness
• Dizziness, loss of balance, or convulsions
• Any visual problems such as blurring of vision, or double vision
• Blood, or clear fluid, leaking from the nose or ear
• Unusual breathing patterns

Investigations

• The current primary investigation of choice for the detection of acute clinically important brain injuries is CT imaging of the head. See separate article CT Head Scanning Indications.

  CT Scan in Head Injuries[1][2]
  Selection of adults for CT Scan	Selection of children (under 16 years) for CT Scan
  Urgent scan if any of the following (results within 1 hour): Glasgow Coma Scale (GCS) <13 when first assessed or GCS <15 two hours after injury Suspected open or depressed skull fracture  Signs of base of skull fracture* Post-traumatic seizure Focal neurological deficit >1 episode of vomiting (SIGN guidance suggests 2 distinct episodes of vomiting) Coagulopathy + any amnesia or loss of consciousness since injury A CT scan is also recommended (within 8 hours of injury) if there is either: More than 30 minutes of amnesia of events before impact Or any amnesia or loss of consciousness since injury if: Aged ≥65 years Coagulopathy or on warfarin Dangerous mechanism of injury Road traffic accident (RTA) as a pedestrian RTA - ejected from car Fall >1 m or >5 stairs	Urgent scan if any of the following: Witnessed loss of consciousness >5 minutes Amnesia (antegrade or retrograde) >5 minutes Abnormal drowsiness ≥3 Discrete episodes of vomiting Clinical suspicion of nonaccidental injury Post-traumatic seizure (no PMH of epilepsy) GCS <14 in emergency room (Paediatric GCS <15 if aged <1) Suspected open or depressed skull fracture or tense fontanelle Signs of base of skull fracture* Focal neurological deficit Aged <1 - bruise, swelling or laceration on head >5 cm Dangerous mechanism of injury (high-speed RTA, fall from >3 m, high-speed projectile)
  *Signs of basal skull fracture: haemotympanum, 'panda' eyes (bruising around the eyes), cerebrospinal fluid (CSF) leakage (ears or nose) or Battle's sign (bruising which sometimes occurs behind the ear in cases of basal skull fracture).

• Guidelines on the indications for CT scans following a head injury have also been developed in Canada, New Orleans and following the US Nexus II study.^[6][7][8][2]
• MRI: for safety, logistic and resource reasons, MRI scanning is not currently indicated as the primary investigation.
• Skull X-rays have a role in the detection of nonaccidental injury in children. Skull X-rays in conjunction with high-quality in-patient observation also have a role where CT scanning resources are unavailable. See separate article Plain Skull X-ray.

Investigations for the cervical spine

Always consider the possibility of cervical spine injury in cases of head injury.
For assessment see separate article Whiplash and Cervical Spine Injury.

Indications for neurosurgical opinion^[2]

• New, surgically significant abnormalities on imaging
• Persisting coma (Glasgow Coma Score (GCS) ≤8) after initial resuscitation
• Unexplained confusion which persists for more than 4 hours
• Deterioration in GCS score after admission (greater attention should be paid to motor response deterioration)
• Progressive focal neurological signs
• A seizure without full recovery
• Depressed skull fracture
• Definite or suspected penetrating injury
• A cerebrospinal fluid (CSF) leak

Management

The following statements relate to the routine management of patients following a head injury. See separate article Rising Intracranial Pressure.

• Early nutritional support may be associated with a trend towards better outcomes in terms of survival and disability.^[9]
• There is no reduction in mortality with methylprednisolone in the 2 weeks after head injury.^[10] One large study showed an increase in mortality with steroids suggesting that steroids should no longer be used routinely in people with traumatic head injury.^[11]
• There is no evidence that hypothermia is beneficial in the treatment of head injury.^[12]
• High-dose mannitol is beneficial in the preoperative management of patients with acute intracranial haematomas. There are insufficient data on the effectiveness of prehospital administration of mannitol for acute traumatic brain injury.^[13]
• Prophylactic anti-epileptics are effective in reducing earlyseizures, but there is no evidence that treatment with prophylactic anti-epileptics reduces the occurrence of late seizures.^[14]

Complications

• Amnesia: common, and may be retrograde and/or antegrade
• Raised intracranial pressure, cerebral oedema
• Cerebral herniation
• Cerebrospinal fluid (CSF) leak (test fluid for glucose or drop on filter paper to see double halo):
  • From ear - possible fracture of petrous temporal bone, may involve VII/VIIIth nerves, leak closes spontaneously, lower risk of meningitis
  • From nose - possible fracture of cribriform plate, may originate from ear, anosmia, leak may require surgery, don't blow nose or insert nasogastric tube
• Meningitis: following skull fracture, may occur weeks to years later. The role of prophylactic antibiotics for CSF leak are controversial.
• Intracranial haemorrhage:
  • Extradural: not common. Classically, middle meningeal artery torn under a temporal bone fracture and follows an injury-lucid interval coma pattern. However, many are nonclassical. 80% progress to uncal herniation. Immediate evacuation of the haematoma is required.
  • Subdural: caused by sudden acceleration-deceleration of brain parenchyma with tearing of the bridging veins. Common in severe traumatic brain injury, atrophic brains (elderly, alcoholics) and children aged <2. May be acute (<24 hours), subacute (1-14 days) or chronic (>2 weeks). There may be few signs with chronic subdurals. High morbidity and mortality if acute. Surgery is usually required.
  • Subarachnoid: the most common haemorrhage in moderate-to-severe injury. May present with meningeal signs and has a significant mortality. Nimodipine shows a beneficial effect in brain injury patients with subarachnoid haemorrhage, but the increase in adverse reactions indicates that the drug is harmful for some patients.^[15]
  • Intracerebral: cerebral contusions are common and often associated with a subarachnoid haemorrhage.Intracerebral haemorrhage can occur days after significant blunt trauma, often at the site of resolving contusions (especially in patients with a coagulopathy). CT scans in the immediate post-injury phase may be normal.
• Extracranial haemorrhage: scalp lacerations, nasal injuries and injuries to the face and neck can lead to significant blood loss
• Skull fractures: up to 50% will not have significant loss of consciousness or any neurological findings. Prophylactic antibiotics are controversial.
• Diffuse axonal injury: shearing/rotational forces disrupt axonal fibres in the white matter and brainstem. Common in motor vehicle accidents and 'shaken baby syndrome'. Injury occurs immediately and is essentially irreversible. There is a rapid increase in intracranial pressure and patients are often unresponsive. CT scan may be normal. Treatment is limited to minimising secondary damage.
• Penetrating injuries, eg gunshot wounds. There is a high incidence of infection and mortality.
• Seizures: more common following penetrating injury. Can lead to secondary brain injury.
• Concussion: symptoms of amnesia and confusion. Duration of amnesia is predictive of injury severity. Other symptoms include dizziness, headaches, poor concentration, nausea, and vomiting. Resolution is often rapid, but symptoms may persist as a post-concussive syndrome for weeks, months or occasionally years.
• Late complications of head injury include chronic daily headache, post-traumatic stress disorder, vertigo and cognitive impairment.

Prognosis

• The annual incidence of disability in adults with head injuries admitted to hospital is 100-150 per 100,000 population.
• Survival with moderate or severe disability is common after mild (Glasgow Coma Score (GCS) 13-15) head injury, (47% of patients) and is similar to that after moderate (45%) or severe injury (48%).^[16] Moderate is defined as score 9-12 and severe as ≤ 8.

Prevention

• Preventative measures include safer roads, barriers to prevent falls, and gun control legislation.
• In addition, bicycle and motorcycle helmets, seatbelts, airbags, and soft surfaces on playgrounds are effective.^[17]

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Further reading & references

1. Triage - assessment - investigation and early management of head injury in infants, children and adults; NICE Clinical Guideline (September 2007)
2. Early Management of Patients with a Head Injury, Scottish Intercollegiate Guidelines Network - SIGN (May 2009)
3. Hammell CL, Henning JD; Prehospital management of severe traumatic brain injury. BMJ. 2009 May 19;338:b1683. doi: 10.1136/bmj.b1683.