A head injury may lead to serious conditions ranging from mild concussion to coma and death; the most serious form is known as traumatic brain injury (TBI). The most common causes of TBI are falls (28%), road traffic accident (20%), struck by objects (19%), and assaults (11%). People at higher risk for TBI are those in the 15-19 year age group where males are more likely to have TBI than female. Adults above 75 years of age or older have a higher risk of TBI related hospitalization and death rates.
Brain injury is defined as the occurrence of an insult to the brain, which causes damages to a different part of the brain. Every injury is unique and often described as either traumatic or acquired simply based on the specific cause. The most important consideration in any head injury is directed to an injury to the brain. Even the minor injury can cause significant brain damage secondary to obstruction of blood flow and a decrease in tissue perfusion. The brain cannot store oxygen or glucose because the cerebral sells need an uninterrupted blood supply to obtain these nutrients, irreversible brain damage and cell death can occur if the blood supply is disturbed for even few minutes.
Closed brain injury occurs when the head accelerates and then rapidly decelerates or collides with another object and brain tissue is damaged but there is no opening through the skull or Dura. Open brain injury occurs when an object penetrates the skull, enters the brain, and damages the soft brain tissue in its path or when blunt trauma to the head is so severe that it opens the scalp, skull and Dura to expose the brain.
Signs and symptoms for assessing brain injury
- Altered level of consciousness
- Pupillary abnormalities ( changes in shape, size and response to light)
- Altered or absent gag reflex and corneal reflex
- Sudden onset of neurologic deficits
- Changes in vital signs (abnormal respiratory pattern, widened pulse pressure, bradycardia, tachycardia, hypothermia or hyperthermia)
- Vision and hearing impairment
- Sensory dysfunction
- A headache
Types of Brain Injury
- Contusion: A contusion is moderate to severe head injury, the brain is bruised and damaged in a specific region due to the severe acceleration-deceleration force or blunt trauma. The impact of the brain against the skull leads to confusion. Usually, the confusion is mostly located in anterior portions of the frontal and temporal lobes, Sylvian fissure, at the orbital areas, less commonly at a parietal region, however, may occur in any area of the brain. Contusions are characterised by loss of consciousness with stupor and confusion, can include neurologic deficit without haematoma formation. Deep Contusions are often associated with haemorrhage and brain herniation.
- Concussion: A concussion is a temporary loss of neurologic function with no apparent structural damage. There are two types of concussion: mild and classic. A mild concussion may lead to a period of observe confusion, disorientation, or impaired consciousness. It can last less than 30 minutes or more as depends on the severity of damage. Other signs and symptoms may include Seizures, headache, dizziness, irritability and fatigue. A class type is an injury that results in a loss of consciousness. This lasts less than 6 hours. The loss of consciousness is always accompanied by some degree of posttraumatic amnesia. The patient may be hospitalized overnight for observation. Recovery may appear complete, but long-term sequelae are possible.
- Diffuse axonal injury: It results from widespread sharing and rotational forces that produce damage throughout the brain which may be diffused with no identifiable focal lesion associated with prolonged traumatic coma.
- Intracranial haemorrhage: Haematomas are collections of blood in the brain that may be epidural (out of the dura), subdural (below the dura) or intracerebral (within the brain). Symptoms are seen only if the Haematoma is large enough to cause distortion of the brain and increased ICP ( Intracranial pressure ). In general, a rapidly developing haematoma, even small one may be fatal whereas a larger but slowly developing one may allow compensation for increases in ICP.
- Epidural Haematoma: After a head injury, there may be a collection of blood in the epidural space between the skull and the dura matter. Symptoms are caused by the expanding hematoma. Epidural haematomas are characterised by a brief loss of consciousness followed by a lucid interval in which the patient is awake and conversant. During a lucid interval, compensation for the expanding haematoma takes place by rapid absorption of CSF and decreased intravascular volume, both of which maintains a normal ICP. When these mechanisms can no longer compensate, even a small increase in the volume of the blood clot produces a marked elevation in ICP. The patient then becomes increasingly restless, agitated, and confused as the condition progresses to coma.
- Subdural Haematoma: It is a collection of blood between the dura and the brain, space normally occupied by a thin cushion of fluid. The most common cause is trauma related to any kind of head injury or can occur as a result of the ruptured aneurysm. It is more frequently venous in origin and is caused by the rupture of small vessels that bridge the subdural space. It may be acute or chronic depending on the size of the involved vessels and the amount of the bleeding.
Acute subdural Haematomas are associated with major head injury involving contusion or laceration characterized by changes in the level of consciousness, Pupillary signs and Hemiparesis. The clinical symptoms develop over 24-48 hours.
Chronic subdural Haematoma can develop from seemingly minor head injuries, mostly seen in an elderly patient. The elderly are prone to this type of head injury secondary to brain atrophy, which is a frequent consequence of the ageing process. The time between the injury and onset of symptoms can be long maybe 3weeks to a month or more. Its symptoms include a headache, personality changes, mental deterioration, and focal seizures.
- Intracerebral haemorrhage: It is a bleeding into the substance of the brain, commonly seen in head injuries when force is exerted to the head over a small area (for example bullet wounds, stab wound or a direct hit) or it can also be the result of systemic hypertension, intracranial tumors, bleeding disorder such as leukaemia and aplastic anaemia. The causes can be traumatic or Non-traumatic. The onset may be insidious initially the patient develops a neurologic deficit followed by a headache.
The diagnostic investigation for assessing head injury or brain injury directly focuses on to identify the severity of brain damage. It involves a history of the initial injury with the physical and neurologic examination. CT and MRI scans are the primary neuroimaging diagnostic tools used in evaluating the brain structure. The assessment also includes determining the patient’s level of consciousness using the Glasgow coma scale (GCS) for assessing the patient’s response to stimuli, Pupillary response to light, corneal and gag reflexes, and motor function. A patient with a head injury is presumed to have a cervical spine injury for which cervical spine x-rays should be done if necessary. Several laboratory tests are done for preoperative purposes. After the brain injury is identified the management is done accordingly with its appropriate treatment.
Management of brain injuries
All therapy is directed toward preserving brain homeostasis and preventing secondary brain injury. Common causes of secondary injury are hypotension, cerebral oedema, and respiratory depression that may lead to hypoxemia and electrolyte imbalance. Treatment to prevent secondary injury includes stabilization of Cardiovascular and respiratory function to maintain adequate cerebral perfusion, control of haemorrhage and hypovolemia and maintenance of optimal blood gas values.
The treatment of increased intracranial pressure is very important as the damaged brain swells with oedema or as blood collects within the brain, an increase in ICP occurs. The increased ICP is managed by maintaining adequate oxygenation, elevating the head of the bed, and maintaining normal blood volume. The patient is cared for in intensive care unit where expert nursing care and medical treatment are readily available.
Surgical intervention is required for the evacuation of blood clots, haematoma, debridement and elevation of depressed fractures of the skull and suture of severe scalp lacerations. In epidural haematoma, the treatment consists of making burr hole (openings through the skull), to decrease ICP, remove clot and control bleeding. A drain is inserted after the burr hole is made to prevent reaccumulation of blood and to drain out the residuals.
In subdural Haematoma different surgical procedures are carried out as per the classified acute or chronic subdural Haematoma. The surgical procedures may be carried out through multiple burr holes, or a craniotomy may be performed for a sizable subdural mass that cannot be suctioned or drained through burr holes.
Whereas the intracerebral haemorrhage may need major craniotomy or craniectomy permits removal of the blood clot and control of haemorrhage but may not be possible because of an inaccessible location of bleeding or the lack of clearly circumscribed area of blood that can be removed.
The minor head injury and brain injury involves careful observation and monitoring for deterioration.
Supportive measure: Treatment also includes ventilatory support, prevention of Seizures, fluid and electrolyte maintenance, nutritional support, and management related to relieving pain and anxiety. A comatose patient is intubated and mechanically ventilated to ensure sufficient oxygenation and protect the airway. Anti-seizure medications are prescribed such as benzodiazepines. A nasogastric tube may be inserted because reduced gastric motility and reverse peristalsis are also associated with head injury.
An early management of brain injury can prevent further complication involving a death of patient so immediate treatment should be done.