Head Injury

This article particularly refers to the NICE clinical guideline for head injury.¹

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 time of impact) or secondary (injury as a result of neurophysiological and anatomical changes minutes to days following primary insult, e.g. from cerebral oedema, haematoma or increased intracranial pressure).

• Hospital Episode Statistics data for the 2000/2001 annual dataset 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 that sustain a head injury are male. ¹
• 10-19% are aged greater than or equal to 65 years. ¹

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.²
• Alcohol may be involved in up to 65% of adult head injuries.

The assessment and classification of patients who have sustained a head injury should be guided primarily by the adult and paediatric versions of the Glasgow Coma Scale (GCS).

Indications for referral to hospital A and E department³

• History of head injury:
  • A high-energy head injury, e.g. diving accident, high-speed motor vehicle collision
  • GCS less than 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 less than or equal to 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 (e.g. 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 greater than or equal to 65 years
  • Any previous cranial neurosurgical interventions
  • History of bleeding or clotting disorder
  • Current anticoagulant therapy such as warfarin
• Other concerns:
  • Suspicion of non-accidental injury
  • Current drug or alcohol intoxication
  • Adverse social factors (e.g. 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

Hospital admission for children following head injury

• 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 non-accidental injury
• Other significant medical problems
• Not accompanied by responsible adult or social circumstances considered unsatisfactory

Give written head injury information regarding warning signs that warrant further immediate medical assessment:⁴

• Increasing drowsiness
• Worsening headache
• Confusion or strange behaviour
• Two or more bouts of vomiting
• Focal neurological problem, e.g. 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

• Resuscitation: Basic and Advanced Trauma Life Support, and Basic and Advanced Paediatric Life Support as necessary.
• Full cervical spine immobilisation attempted (unless other factors prevent this) if:
  • GCS less than 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 and E Department should be made for all patients with a GCS less than 15

• The current primary investigation of choice for the detection of acute clinically important brain injuries is CT imaging of the head.

  CT Scan in Head Injuries1
  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) 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 Coagulopathy + any amnesia or LOC 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 LOC since injury if Aged ≥65 years Coagulopathy or on warfarin Dangerous mechanism of injury RTA as pedestrian RTA - ejected from car Fall > 1m or >5 stairs	Urgent scan if any of the following: Witnessed loss of consciousness >5 minutes Amnesia (antegrate or retrograde) >5 minutes Abnormal drowsiness ≥3 Discrete episodes of vomiting Clinical suspicion of NAI Post-traumatic seizure (no PMH 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 >5cm Dangerous mechanism of injury (high speed RTA, fall from >3m, high speed projectile).
  **Signs of basal skull fracture: haemotympanum, 'panda' eyes (bruising around the eyes), 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.^5,6,7
• 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 non-accidental injury in children. Skull X-rays in conjunction with high quality in-patient observation also have a role where CT scanning resources are unavailable.

• The current investigations of choice for the detection of injuries to the cervical spine are three view plain radiographs of good technical quality. Indications for three-view x-rays of cervical spine:¹
  • Patient cannot actively rotate neck to 45 degrees to left and right (if safe to assess the range of movement in the neck)
  • Not safe to assess range of movement in the neck
  • Neck pain or midline tenderness plus age 65 years or older, or dangerous mechanism of injury
  • Definitive diagnosis of cervical spine injury required urgently (e.g. prior to surgery)
• Where it is not possible to achieve the cervical spine views desired with X-ray, CT imaging is indicated. CT is also indicated if the plain film series is technically inadequate, suspicious or definitely abnormal or if there is continued clinical suspicion of injury despite a normal study.
• In children under 10 years, because of the increased risks associated with irradiation, CT of the cervical spine should only be used in exceptional circumstances (e.g. strong suspicion of injury despite normal plain films, or plain films are inadequate).
• MRI is indicated in the presence of neurological signs and symptoms referable to the cervical spine and if there is suspicion of vascular injury. MRI may also add important information about soft tissue injuries.

• New, surgically significant abnormalities on imaging
• Persisting coma (GCS less than or equal to 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 leak

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

• New, clinically significant abnormalities on imaging
• Not returned to 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 (e.g. persistent vomiting, severe headaches)
• Other sources of concern, e.g. drug or alcohol intoxication, other injuries, shock, suspected non-accidental injury, meningism, cerebrospinal fluid leak)

The following statements relate to the routine management of patients following a head injury. See separate article covering raised intracranial pressure.

• Early nutritional support may be associated with a trend towards better outcomes in terms of survival and disability.⁸
• There is no reduction in mortality with methylprednisolone in the 2 weeks after head injury.⁹ One large study showed an increase in mortality with steroids suggesting that steroids should no longer be routinely used in people with traumatic head injury.¹⁰
• There is no evidence that hypothermia is beneficial in the treatment of head injury.¹¹
• High-dose mannitol is beneficial in the pre-operative management of patients with acute intracranial haematomas. There are insufficient data on the effectiveness of pre-hospital administration of mannitol for acute traumatic brain injury.¹²
• Prophylactic anti-epileptics are effective in reducing early seizures, but there is no evidence that treatment with prophylactic anti-epileptics reduces the occurrence of late seizures.¹³

• Amnesia: common, may be retrograde and/or anterograde
• Raised intracranial pressure, cerebral oedema
• Cerebral herniation
• 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 non-classical. 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 <2 at increased risk. May be acute (<24 hours), subacute (1-14 days) and chronic (>2 weeks). May be few signs with chronic subdurals. High morbidity & mortality if acute. Surgery is usually required.
  • Subarachnoid: 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.¹⁴
  • 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 fibers in the white matter and brainstem. Common in motor vehicle accidents and 'shaken baby syndrome'. Injury occurs immediately and is essentially irreversible. Rapid increase in intracranial pressure and patients often unresponsive. CT scan may be normal. Treatment is limited to minimising secondary damage.
• Penetrating injuries e.g. gunshot wounds. 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.

• 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 scores 13-15) head injury, (47% of patients) and is similar to that after moderate (45%) or severe injury (48%).¹⁵ Moderate is defined as score 9-12 and severe as less than or equal to 8.

• Preventive 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.¹⁶