Head Injury

The most common type of injury we see in emergency department.   We treat patients with various degree of head injury. Most commonly we see simple falls in paediatric patients who requires only observation for a period of time.

The most common cause of head injury is road traffic accident, falls and assaults followed by sports related injuries and penetrating injuries.

Our brain is an amazingly sensitive structure.  It is anatomically placed in a cushion of tissue to prevent damage from certain velocity of impact.  When the force disrupts these layers, the impact reaches the brain tissue.  Normal cerebral blood flow necessary for a 100g of brain tissue is 55ml for a minute.  Any decrease in this blood flow could cause significant injury to brain tissue.

When there is an injury to head, our brain has some mechanism to adopt itself to sudden changes.  During an injury, any increase in the normal mass of the brain could cause increase in pressure in the brain. The brain compensates it by displacing the cerebrospinal fluid and venous blood out of the cavity. When there is an additional increase to the mass, the brain loses its capability to adopt and results in increase intracranial pressure, brain herniation and quick fall in patient’s consciousness.                                                 

Classification of Head injury:

Classification of Head Injury is based on different factors.

Primary:   Injury to brain occurring at the time of impact. This damage includes any injury to brain tissue.

Secondary:  Injury to brain tissue following a trauma after certain period time could be a result of decreased oxygen to brain, decreased blood pressure, increased intracranial pressure, low cerebral perfusion pressure, pyrexia, seizures and metabolic  disturbances.

It can also be classified according the severity of injury and it is determined by the 

Glasgow coma scale.

Minor head injury: GCS 15 with no loss of consciousness.

Mild head injury: GCS 14 or 15 with Loss of consciousness

Moderate head injury: GCS 9-13

Severe Head Injury: GCS 3-8

According to the force of injury

Blunt

Penetrating

The   effect of an injury is usually based on the mechanism of injury.  As a doctor we could identify the nature of the impact the patient has had with just considering the following questions:

1.   Mechanism of Injury

2.   Loss of consciousness

3.   Level of consciousness at scene and on transfer

4.   Seizure

5.   Probable hypoxia or hypotension

6.   Pre existing medical condition

7.   Medications

8.   Illicit drugs and alcohol.

For example, a person is brought in to the hospital after a fall from a height or after a high impact accident where the other person involved in the accidents GCS is still low. Here you would expect a multiple injuries.

How do we begin to examine a person with head injury?

It is always easy to resuscitate a patient if we follow the principles of

ABCDE

A-AIRWAY

B-BREATHING

C-CIRCULATION

D-DISABILITY

E-EXPOSURE

We perform a primary survey which itself is assessing ABCDE and then a secondary survey which includes head to toe survey looking for any signs of injury.  We should assess GCS which includes eye response, verbal response and motor response.

The pupilary size is an excellent mirror of the occulomotor nerve. Any change in size or any variation of light response suggests a dysfunction of the third nerve.

Management of Head Injury:

1.   Mild Head injury:

When there is no significant impairment in patient’s health and the GCS has always been 15/15, then the patient can be discharged home after a period of observation.

In certain condition, patient’s age and other medical condition may play important factors. In that case we might need a CT scan. It is unnecessary to scan everyone that not to miss any intracranial hematomas.

NICE GUIDELINES FOR CT SCAN IN HEAD INJURY:

GCS <13 AT ANY POINT

GCS 12 OR 14 AT 2HOURS

FOCAL NEUROLOGICAL DEFICIT

SUSPECTED OPEN, DEPRESSSED OR BASAL SKULL FRACTURE

SEIZURE

VOMITING >ONE EPISODE

URGENT CT SCAN IF NONE OF THE ABOVE

AGE >65

COAGULOPATHY

DANGEROUS MECHANISM OF INJURY (CT WITHIN 8HOURS)

ANTEGRADE AMNESIA >30MIN

2.   Moderate to severe Head injury:

The main aim of resuscitation of severe head injury is to prevent any secondary brain injury, so it is important to maintain normal oxygen supply to brain and the blood pressure.  CT scan should be done and intracranial hematomas should be reduced which will decrease the pressure in the brain.  If any hematomas found, then we always discuss it with the neurosurgery specialists.

WHAT TYPE OF HEAD INJURY REQUIRES SURGICAL MANAGEMENT?

1.   EXTRADURAL HEMATOMA:

                   It occurs between the skull and the duramater. It is commonly seen in young male patients.  The hematomas usually occur after the tear of meningeal artery and a mass forms in between the skull and duramater.

It usually causes secondary brain injury.  Immediately after the injury, patients complain of headache, but there will be no focal neurological deficit, but after minutes or hours patient starts to deteriorate. Early recognition and treatment is vital in case of extradural hematoma.  Immediate evacuation of the mass is significant for a better prognosis of patient’s condition.

2.   ACUTE SUBDURAL HEMATOMA:

It occurs between duramater and arachnoid.  As it involves the layer nearer to the brain tissue, we would expect some degree of damage to the brain and blood supply. It causes significant primary brain injury.  Patients with acute subdural hematoma have impaired level of consciousness from time of injury.  Treatment is usually evacuation via a craniotomy.

       

3.   SUBARACHNOID HAEMORRHAGE:

Aneurysms are the most common cause of subarachnoid haemorrhage. Traumatic subarachnoid haemorrhage is managed conservatively.

  

4.   CHRONIC SUBDURAL HEMATOMA:

It is usually seen in elderly, particularly in patients on blood thinners.  There is usually a history of trauma but sometimes it occur without one.  It can present with headaches, cognitive impairment, focal neurological deficit and seizures.  Treatment is usually evacuation of the mass via a burr hole.

5. CEREBRAL CONTUSION:

It occurs when the brain tissue has an impact against skull either at the point of impact or on the other side of the head.  It is usually bruising to the brain tissue which involves micro haemorrhages.  A patient with cerebral contusion requires observation for a period of time and in rare cases might need surgical evacuation.

If you have anyone you know has had a head injury and you think they are acting strangely or complaints of severe headache, discomfort to light, vomiting or drowsy,  then it is time for them to be taken to the hospital immediately.

In elderly and children with a head injury, it would be sensible to get it checked by your general practitioner or at the nearest hospital.