Head injuries

Head injury is a trauma to the head, that may or may not include injury to the brain (see also brain injury).

The incidence (number of new cases) of head injury is 300 per 100,000 per year (0.3% of the population), with a mortality of 25 per 100,000 in North America and 9 per 100,000 in Britain.

Head Trauma
Head trauma is a common cause of childhood hospitilization. Serious head trauma is usually secondary to motor vehicle accidents, sports, recreation, and violence. Presentation varies according to the injury. A patient may present with neurologic deficit or without neurologic deficit. Some patients with head trauma may stabilize and other patients may deteriorate. Children with neurologic deficits may have a history of a lucid interval and relapse into coma, or they may have remained abnormal after the injury. The physical examination will vary according to the injury. Some patients may have linear or depressed skull fractures. Basilar skull fractures are associated with battle sign, a subcutaneous bleed over the mastoid, hemotympanum, and cerebrospinal fluid rhinorrhea and otorrhea. Cerebral concussion is the most common head injury seen in children. Patients with concussion may have a history of brief seconds to minutes unconsciousness, then normal arousal. Disturbance of vision and equilibrium may also occur.

Concussion can be divided into three grades and recommendations if asymptomatic for 1 week:


 * In grade I, the patient has confusion only and may return to contact sports in 20 minutes.
 * In grade II, the patient has amnesia and confusion and may return to contact sports in 1 week.
 * In grade III, the patient has loss of consciousness, amnesia, and confusion and may return to contact sports in 1 month.


 * A second time grade 1 concussion may return to play contact sports in 2 weeks after being asymptomatic for a week.
 * A second time grade II may return to play contact sports 1 month after being asymptomatic for a week.
 * A second time grade III the season is over.

However, if the patient has repeated concussions after contact sports, grade I x 3, grade II x 2, and especially grade III x 2, then it should be recommended that the season is over and a thorough medical evaluation should be considered mandatory.

Causes
Common causes of head injury are traffic accidents, home and occupational accidents, falls, and assaults. Contrary to public opinion, riding a bicycle is actually very safe and is a small cause of head injury.

Types of Head Injuries
Head injuries include both injuries to the brain and those to other parts of the head, such as the scalp and skull.

Head injuries may be closed or open. A closed (non-missile) head injury is one in which the skull is not broken. A penetrating head injury occurs when an object pierces the skull and breaches the dura mater. Brain injuries may be diffuse, occurring over a wide area, or focal, located in a small, specific area.

A head injury may cause a skull fracture, which may or may not be associated with injury to the brain.

If intracranial hemorrhage, or bleeding within the brain occurs, a hematoma within the skull can put pressure on the brain. Types of intracranial hematoma include subdural, subarachnoid, extradural, and intraparenchymal hematoma. Craniotomy surgeries are used in these cases to lessen the pressure by draining off blood.

Brain injury can be at the site of impact, but can also be at the opposite side of the skull due to a contrecoup effect (the impact to the head can cause the brain to move within the skull, causing the brain to impact the interior of the skull opposite the head-impact).

If the impact causes the head to move, the injury may be worsened, because the brain may ricochet inside the skull (causing additional impacts), or the brain may stay relatively still (due to inertia) but be hit by the moving skull.

Specific problems after head injury can include:
 * Skull fracture
 * Lacerations to the scalp and resulting hemorrhage of the skin
 * Traumatic subdural hematoma, a bleeding below the dura mater which may develop slowly
 * Traumatic extradural, or epidural hematoma, bleeding between the dura mater and the skull
 * Traumatic subarachnoid hemorrhage
 * Cerebral contusion, a bruise of the brain
 * Concussion, a temporary loss of function due to trauma
 * Dementia pugilistica, or "punch-drunk syndrome", caused by repetitive head injuries, for example in boxing or other contact sports
 * A severe injury may lead to a coma or death

Symptoms
Common symptoms of head injury include those indicitave of traumatic brain injury:
 * loss of consciousness,
 * confusion,
 * drowsiness,
 * personality change,
 * seizures,
 * nausea and vomiting,
 * headache,
 * a lucid interval, during which a patient appears conscious only to deteriorate later

Symptoms of skull fracture can include:
 * leaking cerebrospinal fluid (a clear fluid drainage from nose, mouth or ear) may be and is strongly indicative of basilar skull fracture and the tearing of sheaths surrounding the brain, which can lead to secondary brain infection.
 * visible deformity or depression in the head or face; for example a sunken eye can indicate a maxillar fracture
 * an eye that cannot move or is deviated to one side can indicate that a broken facial bone is pinching a nerve that innervates eye muscles
 * wounds or bruises on the scalp or face.

Because brain injuries can be life threatening, even people with apparently slight injuries, with no noticeable signs or complaints, require close observation. The caretakers of those patients with mild trauma who are released from the hospital are frequently advised to rouse the patient several times during the next 12 to 24 hours to assess for worsening symptoms.

The Glasgow Coma Scale is a tool for measuring degree of unconsciousness and is thus a useful tool for determining severity of injury.

Mild concussion
Mild concussion are not associated with any sequelae. However, a slightly greater injury can be associated with both anterograde and retrograde amnesia not be able to remember events before or after the injury. The amount of time that the amnesia is present correlates with the severity of the injury. In some cases the patients may develop postconcussion syndrome, which includes memory difficulties, dizziness, and depression.

Epidural hematoma
Epidural hematoma is a rapidly accumulating hematoma between the dura and the cranium. These patients have a history of head trauma with loss of consciousness, then a lucid period, followed by loss of consciousness. Clinical onset occurs over minutes to hours. Many of these injuries are associated with lacerations of the middle meningeal artery. A lenticular extracerebral hemorrhage will be noted on CT of the head. The need for an operation should be determined by a neurosurgeon. Although death is a potential complication, the prognosis is good when this injury is recognized and treated.

Subdural hematoma
This occurs when there is tearing of the bridging vein between the cerebral cortex and a draining venous sinus. At times they may be cause by arterial lacerations on the brain surface. Patients may have a history of loss of consciouness but they recover and do not relapse. Clinical onset occurs over hours. A crescent shaped hemorrhage compressing the brain will be noted on CT of the head. Surgical evacuation is the treatment. Complications include uncal herniation, focal neurologic deficits, and death. The prognosis is guarded.

Cerebral contussion
This is bruising of the brain parenchyma. The majority of them occur in the frontal and temporal lobes. Multiple low density areas and punctate hemorrhages will be noted on the CT of the head. Complications may include cerebral edema and transtentorial herniation. The goal of treatment should be to treat the increased intracranial pressure. The prognosis is guarded.

Diagnosis
A CT of the head should be performed on children who have a history of loss of consciousness for > 1 minute. A CT of the head should be performed on children for whom the time of LOC is unknown. A CT of the head should be performed on children with abnormal neurologic findings. A CT of the head should be performed on those who have a neurologic status that is deteriorating. Cevical spine films should be obtained on children with head trauma suspected of having an associated neck injury. Attention should be paid to airway, breathing, and circulation. Bleeding should be controlled if present. Head injury may be associated with a neck injury. Bruises on the back or neck, back pain,painradiating to the arms is a sign of cervical spine injury and should be immobilizied and a cervical collar applied. It is common for head trauma patients to have drowsiness but easily aroused, headaches, and vomiting after injury. If exam and consciousness are preserved, this is of no concern. But if these symptoms persist > 1 or 2 days, a CT of the head should be performed. In some cases transient neurologic disturbance may occur, lasting minutues to hours and causing occiptal blindness and a state of confusion. Malignant posttraumatic cerebral swelling can develop unexpectedly in stable patients after an injury, as can postraumatic seizures. The child with worsening neurologic signs change in level of consciousness, respirations, blood pressure, pulse, seizures) must be suspected of having subarachnoid or subdural bleeding. Recovery in children with neurologic deficits will vary. Children with neurologic deficits who improve daily are more likely to recover. Children who are vegetative for months are less likely to improve. Most patients without deficits have full recovery.

Pediatric Glasgow Coma Scale
Eye Opening, Verbal response, and Motor response are the three criteria. Highest possible total is 15, if the score is 8 intubate and resuscitate.

Eye Opening
Spontaneous 4 points To voice 3 points To pain 2 points None 1 point

Verbal Response
Older child: Oriented 5 points Confused 4 points Inappropriate 3 points Incomprehensible 2 points None 1 point

Infant: Smiles, Fixes, follows 5 points Consolable cry 4 points Persistently irritable 3 points Restless and agitated 2 points None 1 point

Motor Response
Obeys 6 points Localizes pain 5 points Withdraws 4 points Flexion 3 points Extension 2 points None 1 point