Head injury associated with traumatic brain injury and is the most common cause of mortality in most of the road traffic accidents (RTAs). The brain injuries those occur at the time of impact are called primary brain injury whereas the secondary brain injuries are those that occur sometimes after the moment of impact during accidents. The causes of secondary brain injury are hypoxia, hypotension, raised intracranial pressure, seizures, and reduced cerebral perfusion pressure. Those kinds of brain injuries is preventable.
Types of Head Injuries:
It is further classified into:
a. Low-velocity injuries- eg stabbing
b. High-velocity injuries-eg gunshot injuries
Morphological classification of head injuries:
1) Skull fractures: It may be further classified as:
- vault fractures
- the base of skull fractures
2) Intracranial hematomas: These are of different types:
- extradural(epidural) hematoma
- subdural hematoma
- subarachnoid hematoma
- intracerebral hematoma
3) Diffuse axonal injuries
4) Contusions of brain
Glasgow coma scale: severity of the head injury can be classified per the Glasgow coma scale (GCS). GCS has three components i.e eye-opening(E), verbal response(V) and motor response(M) and the total score is 15.
Mild head injury: if GCS is 14 or 15 with loss of consciousness
Moderate head injury: if GCS 9-13
Severe head injury: if GCS is less than 8
It is important to identify the severity of the head injury because the treatment plan is different for different types of head injury.
Emergency Management of head injury:
It begins with resuscitation and a primary survey. ATLS (advanced trauma life support) principle should be followed.
A:- stands for airway and cervical spine stabilization by three points fixations. Oxygen should be given to the patient to prevent hypoxia which is a major cause of secondary brain injury.
B:- stands for breathing and ventilation should be maintained
C:- stands for circulation and hemorrhage control. Intravenous line should be opened and normal saline should be given to prevent hypotension and shock.
D:- stands for disability: neurological status of the patient should be evaluated. It includes assessment of pupillary size and reactivity. GCS should be monitor repeatedly and frequently.
E:- stands for exposing of the whole body to look for any other injuries in the body.
In the second survey of head injury patient, a detailed examination of head, neck, and face should be performed. We should look for any clinical evidence of skull fractures with or without cerebrospinal fluid (CSF) leak.
In the eyes look for bilateral periorbital bruising which is called as raccoon eyes, hyphaema and so on.
Look for bruising over the mastoid process which is called as battle’s sign
Look for CSF rhinorrhoea (CSF leak through the nose), CSF otorrhea (CSF leak through the external auditory canal) and hemotympanum (blood in the tympanic cavity). Peripheral nerve examination should be done and limb tone, power, evidence of motor weakness, loss of reflexes if present should be recorded.
Non-contrast CT scan of head Via CT scan we can see hematoma, skull fracture, midline shift, swelling of the brain, cervical spine. Other investigation includes: MRI of head MRI is rather expensive and normally not done as in most cases CT scan is sufficient to find the underlying head injury.
Conservative Management of Head Injury:
Patients should be admitted to the neurosurgical ICU and neuro charting should be done that is continuous monitoring of blood pressure, pulse, pupil, level of consciousness. Any changes should be recorded. continuous administration of oxygen and normal saline to prevent hypoxia and hypotension respectively. A patient should be nursed in the 30-degree head elevation in order to decrease the intracranial pressure. seizure prophylaxis(phenytoin) is given. A nasogastric tube is inserted for nutrition and bladder catheterization should be done to monitor the urine output. Frequent change of posture to prevent the bed sores.
Surgical management of head injury:
1) Extradural hematoma: CT appearance-lens shaped hyperdense lesion usually limited to their extent by cranial sutures. Treatment is an immediate surgical evacuation of hematoma via a craniotomy (surgical removal of vault of the skull) as it is a surgical emergency.
2) Acute subdural hematoma: CT scan appearance- crescent-shaped hyperdense lesion crossing the cranial sutures. Treatment is an evacuation of hematoma via a craniotomy.
3) Chronic subdural hematoma: CT scan appearance-hypodense lesion. Treatment is an evacuation of the hematoma via burr holes rather than craniotomy under Local anesthesia.