head injuries

Diffuse Axonal Injuries

Diffuse axonal injury (DAI) results from widespread shearing and rotational forces that produce damage throughout the brain—to axons in the cerebral hemispheres, corpus callosum, and brain stem. The injured area may be diffuse, with no identifiable focal lesion. DAI is associated with prolonged traumatic coma; it is more serious and is associated with a poorer prognosis than a focal lesion or ischemia

Pathophysiology of head injury

Research suggests that not all brain damage occurs at the moment of impact. Damage to the brain from traumatic injury takes two forms: primary injury and secondary injury. Primary injury is the initial damage to the brain that results from the traumatic event. This may include contusions, lacerations, and torn blood vessels due to impact, acceleration/ deceleration, or foreign object penetration. Secondary injury evolves over the ensuing hours and days after the initial injury and results from inadequate delivery of nutrients and oxygen to the cells (Littlejohns & Bader, 2005)

sign and symptom of epidural Hematoma

Symptoms are caused by the expanding hematoma. Epidural hematomas are often characterized by a brief loss of consciousness followed by a lucid interval in which the patient is awake and conversant. During this lucid interval, compensation for the expanding hematoma takes place by rapid absorption of CSF and decreased intravascular volume, both of which help maintain 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 to coma. Then, often suddenly, signs of herniation appear (usually deterioration of consciousness and signs of focal neurologic deficits, such as dilation and fixation of a pupil or paralysis of an extremity), and the patient's condition deteriorates rapidly. The most common type of herniation syndrome associated with an epidural hematoma is uncal herniation (Vacca, 2007b). An epidural hematoma is considered an extreme emergency; marked neurologic deficit or even respiratory arrest can occur within minutes.

Head injury

is a broad classification that includes injury to the scalp, skull, or brain. It is estimated that 1.4 million people sustain a head injury each year in the United States, and approximately 50,000 people die, 235,000 are hospitalized, and 1.1 million are treated and released from an emergency department (Langlois, Rutland-Brown & Thomas, 2006). A head injury may lead to conditions ranging from mild concussion to coma and death; the most serious form is known as a traumatic brain injury (TBI). .

Concussion

A concussion after head injury is a temporary loss of neurologic function with no apparent structural damage. A concussion (also referred to as a mild TBI) may or may not produce a brief loss of consciousness. The mechanism of injury is usually blunt trauma from an acceleration-deceleration force, a direct blow, or a blast injury . If brain tissue in the frontal lobe is affected, the patient may exhibit bizarre irrational behavior, whereas involvement of the temporal lobe can produce temporary amnesia or disorientation. There are two types of concussion: mild and classic. A mild concussion may lead to a period of observed or selfreported transient confusion, disorientation, or impaired consciousness. Commonly, there is a memory lapse at the time of injury and a loss of consciousness lasting less than 30 minutes. Other signs and symptoms of neurologic or neuropsychological dysfunction may include seizures, headache, dizziness, irritability, fatigue, or poor concentration. A classic concussion is an injury that results in a loss of consciousness; characteristically, this usually lasts less than 6 hours. This loss of consciousness is always accompanied by some degree of posttraumatic amnesia. Diagnostic studies may show no apparent structural sign of injury, but the duration of unconsciousness is an indicator of the severity of the concussion. The patient may be hospitalized overnight for observation or discharged from the hospital in a relatively short time after a concussion. Monitoring includes observing the patient for headache, dizziness, lethargy, irritability, emotional lability, fatigue, poor concentration, decreased attention span, memory difficulties, and intellectual dysfunction that may occur from 1 week to 1 year after the initial injury (Hickey, 2009). The occurrence of these symptoms after injury is referred to as postconcussion syndrome. Recovery may appear complete, but long-term sequelae are possible. Problems at work and at home can result in interpersonal relationship problems or the loss of employment (Bay & McLean, 2007). The family is instructed to observe for the following signs and symptoms and to notify the physician or clinic (or bring the patient to the emergency department) if they occur: difficulty in awakening or speaking, confusion, severe headache, vomiting, and weakness of one side of the body.

Skull Fractures

A skull fracture is a break in the continuity of the skull caused by forceful trauma. It may occur with or without damage to the brain. Skull fractures can be classified as simple, comminuted, depressed, or basilar. A simple (linear) fracture is a break in the continuity of the bone. A comminuted skull fracture refers to a splintered or multiple fracture line. Depressed skull fractures occur when the bones of the skull are forcefully displaced downward and can vary from a slight depression to bones of the skull being splintered and embedded within brain tissue. A fracture of the base of the skull is called a basilar skull fracture (Fig. 63-2)(Porth & Matfin, 2009). A fracture may be open, indicating a scalp laceration or tear in the dura (eg, from a bullet or an ice pick), or closed, in which case the dura is intact.

what is a Subdural Hematoma?

A subdural hematoma is a collection of blood between the dura and the brain, a space normally occupied by a thin cushion of fluid. The most common cause of subdural hematoma is trauma, but it can also occur as a result of coagulopathies or rupture of an aneurysm. A subdural hemorrhage is more frequently venous in origin and is caused by the rupture of small vessels that bridge the subdural space. The subdural hematoma that results may be acute, subacute, or chronic, depending on the size of the involved vessel and the amount of bleeding.

Epidural Hematoma

After a head injury, blood may collect in the epidural (extradural) space between the skull and the dura mater. This can result from a skull fracture that causes a rupture or laceration of the middle meningeal artery, the artery that runs between the dura and the skull inferior to a thin portion of temporal bone. Hemorrhage from this artery causes rapid pressure on the brain .

Contusion

In cerebral contusion, a moderate to severe head injury, the brain is bruised and damaged in a specific area because of severe acceleration-deceleration force or blunt trauma. The impact of the brain against the skull leads to a contusion. Although a contusion may occur in any area of the brain, most are usually located in the anterior portions of the frontal and temporal lobes, around the sylvian fissure, at the orbital areas, and, less commonly, at the parietal and occipital areas. Contusions are characterized by loss of consciousness associated with stupor and confusion. Other characteristics can include tissue alteration and neurologic deficit without hematoma formation, alteration in consciousness without localizing signs, and hemorrhage into the tissue that varies in size and is surrounded by edema. The effects of injury (hemorrhage and edema) peak after about 18 to 36 hours. Patient outcome depends on the area and severity of the injury. Temporal lobe contusions carry a greater risk of swelling, rapid deterioration, and brain herniation. Deep contusions are more often associated with hemorrhage and destruction of the reticular activating fibers altering arousal.

etiology of head injury

The most common causes of TBIs are falls (28%), motor vehicle crashes (20%), being struck by objects (19%), and assaults (11%)

Signs and Symptoms of DAI

The patient with DAI in severe head trauma experiences no lucid interval, immediate coma, decorticate and decerebrate posturing (see Fig. 61-1 in Chapter 61), and global cerebral edema. Diagnosis is made by clinical signs in conjunction with a CT or MRI scan. Recovery depends on the severity of the axonal injury.

what is the treatment of Epidural Heamtoma?

Treatment consists of making openings through the skull (burr holes) to decrease ICP emergently, remove the clot, and control the bleeding. A craniotomy may be required to remove the clot and control the bleeding. A drain is usually inserted after creation of burr holes or a craniotomy to prevent reaccumulation of blood.

Incidence of head injury

people at highest risk for TBI are those in the 15- to 19-year age group. Males are twice as likely as females to sustain a TBI. Adults 75 years of age or older have the highest TBIrelated hospitalization and death rates, and African Americans also have high mortality rates (Langlois, et al., 2006). An estimated 5.3 million Americans are currently living with a TBI-related disability (National Center for Injury Prevention and Control, 2007). The best approach to head injury is prevention