Assessment of Head Injury

Introduction

Head injury is one of the most common presentations to emergency departments worldwide, accounting for 1.4 million A&E attendances in the UK alone every year.

The clinical outcomes from head injury can be significant; it is currently the leading cause of death and disability in adolescents and young adults, hence a thorough and accurate clinical assessment of head injury at an early stage is imperative*.

*The following document provides guidance on how to assess head injury in adult patients

Classification

The terms ‘head injury’ and ‘traumatic brain injury’ (TBI) are sometimes used interchangeably but is important to identify the difference between them.

• Head Injury = a patient who has sustained any form of trauma to the head, regardless of whether they have any symptoms of neurological damage
• Traumatic Brain Injury = evidence of damage to the brain as a result from trauma to the head, represented with a reduced Glasgow Coma Scale or presence of a focal neurological deficit

Head injury is classified as minimal, mild, moderate, or severe based on the patient’s Glasgow Coma Scale (GCS); mild head injury/TBI is also known as concussion.

Table 1 – Classification of Head Injury based on Glasgow Coma Scale

Head injuries can also be described by any resulting pathology that is associated with the head injury, such as superficial lacerationsor bruising, fractures (including linear, depressed, facial, basal skull fractures), haemorrhage outside the brain tissue (extradural/subdural/subarachnoid haemorrhage), haemorrhage within brain tissue (contusion/intra-cerebral haemorrhage), or diffuse axonal injury (DAI).

Initial Assessment

Any patients presenting to A&E with evidence of head injury should be examined within 15 minutes of arrival to determine if they have suffered a serious brain or spine injury. The most important aspect in the initial assessment of head injury is to use an A to E algorithm, as discussed here.

Cervical Spine

Frank Gaillard, CC BY-SA 3.0 , via Wikimedia Commons

Figure 1 – CT imaging showing a fracture-dislocation at C6/7

In a patient suffering with head injury, always consider if the cervical spine may have also been injured; certain mechanisms of injury often are accompanied together, particularly high energy trauma.

At the start of the assessment* consider whether the cervical spine requires immobilisation via a semi-rigid collar, blocks, and tape (this may already be in place if the patient was brought in by ambulance)

*The decision whether to immobilise is usually made at the start of the initial assessment as it will affect subsequent airway manoeuvres and moving of the patient

Airway

Any patient with a GCS of 8 or less is at risk of being unable to maintain their own airway. If the GCS is 8 or less, or is rapidly deteriorating, then call the on-call anaesthetic team immediately to assist with airway management.

In those with a suspected cervical spine injury, a jaw thrust is typically the most appropriate, however can also be difficult if a collar is in place.

Be wary in using airway adjuncts if there is extensive facial trauma, especially use of nasopharyngeal airways if there is any suspicion of basal skull fracture.

Breathing

After the initial insult to the brain from the head injury itself the brain may become further damaged through secondary insult, most commonly and significantly is brain ischaemia secondary to tissue hypoxia.

For this reason, ensuring adequate ventilation (with a secure airway) and oxygenation is particularly important following head injury, limiting further brain damage from hypoxia

Circulation

Aside from securing the airway and maintaining oxygenation ensure adequate tissue perfusion to prevent any further secondary ischaemic damage to the brain. Ensure a good circulating volume is maintained from resuscitation with appropriate fluids

Disability & Neurological examination

In all patients presenting with a head injury, an accurate Glasgow Coma Scale must be recorded on admission. This will typically be repeated every 30-60 minutes and repeated immediately if any evidence that the previous score has changed.

Table 2 – The Glasgow Coma Score

The patient’s pupils must also be assessed regularly, both the size of the pupils and response to light*. If the patient is conscious, assess for focal neurological deficit with a full neurological examination (both peripheral neurological and cranial nerve examination)

Measure the blood glucose level and avoid hypoglycaemia. Glucose is the primary energy source used in aerobic metabolism for the brain and this demand can often increase depending on the severity of the head injury.

*A dilated pupil may be a sign of elevated intracranial pressure, secondary to herniation of the brain through the tentorium cerebelli, causing compression of the parasympathetic fibres within the oculomotor nerve (CN III), and is a neurosurgical emergency

Exposure

Examine carefully for lacerations, evidence of facial fractures, or depressed skull fractures. Ensure to check for signs of basal skull fractures, such as bruising around eyes (‘racoon eyes’), bruising behind the ears (Battle’s sign), clear discharge from nose or ear (CSF rhinorrhoea or CSF otorrhoea), blood bulging from middle ear (haemotympanum), or any obvious penetrating injury.

Red Flag Signs

When assessing a patient with a head injury, there are important clinical features that may signify a more serious type of head injury and are important to identify and document.

Key red flag signs in head injury include

• Impaired consciousness level
• Dilated pupils which do not respond to light (“fixed and dilated”)
• Signs of basal skull fracture
• Focal neurological deficit or visual disturbances
• Seizures or amnesia
• Significant headache or nausea and vomiting

Imaging

Following head injury, CT scanning of the head is the primary imaging modality of choice. CT scanning will quickly identify critical pathology such as skull fractures and traumatic intra-cranial bleeding that may require urgent neurosurgical intervention.

However, not all head injuries require imaging and the decision to perform a CT scan is usually made immediately after the initial ABCDE assessment, following set criteria.

Remember that when requesting a CT scan of the head, consider if it would be appropriate to request a CT scan of cervical spine at the same time, if there is a high index of suspicion of injury to this area.

History Following Head Injury

If the patient is conscious, has been adequately resuscitated, and does not require immediate imaging or intervention, it would be appropriate to try and take a brief history. A collateral history from a witness, especially if the patient lost consciousness during the event, is always useful where possible.

Ensure to ask about the nature of the injury (including energy involved and type (blunt vs. penetrating)), any indications warranting imaging or red flags, and drug or alcohol intoxication.

Known bleeding disorders or use of anti-coagulants, previous neurosurgery, and co-morbidities will also aid your decision making and assessment.

Referral to Neurosurgery

Not all patients with a head injury require a referral to neurosurgery, however advice should be sought if any degree of uncertainty.

Current guidelines suggest that patients should be referred to neurosurgery if any of the following are present:

• Significant abnormality on imaging
• GCS 8 or less after resuscitation, or drop in GCS after admission (especially in motor component)
• Unexplained confusion >4 hours
• Focal neurological signs or seizures without full recovery
• Suspected penetrating injury or evidence of cerebrospinal fluid leak