head injury

Head Injury

Definition

Injury to the head may damage the scalp, skull or brain. The most important consequence of head trauma is traumatic brain injury. Head injury may occur either as a closed head injury, such as the head hitting a car's windshield, or as a penetrating head injury, as when a bullet pierces the skull. Both may cause damage that ranges from mild to profound. Very severe injury can be fatal because of profound brain damage.

Description

External trauma to the head is capable of damaging the brain, even if there is no external evidence of damage. More serious injuries can cause skull fracture, blood clots between the skull and the brain, or bruising and tearing of the brain tissue itself.Injuries to the head can be caused by traffic accidents, sports injuries, falls, workplace accidents, assaults, or bullets. Most people have had some type of head injury at least once in their lives, but rarely do they require a hospital visit.However, each year about two million people suffer from a more serious head injury, and up to 750,000 of them are severe enough to require hospitalization. Brain injury is most likely to occur in males between ages 15 and 24, usually as a result of car and motorcycle accidents. About 70% of all accidental deaths are due to head injuries, as are most of the disabilities that occur after trauma.A person who has had a head injury and who is experiencing the following symptoms should seek medical care immediately:

serious bleeding from the head or face
loss of consciousness, however brief
confusion and lethargy
lack of pulse or breathing
clear fluid drainage from the nose or ear

Causes and symptoms

A head injury may cause damage both from the direct physical injury to the brain and from secondary factors, such as lack of oxygen, brain swelling, and disturbance of blood flow. Both closed and penetrating head injuries can cause swirling movements throughout the brain, tearing nerve fibers and causing widespread bleeding or a blood clot in or around the brain. Swelling may raise pressure within the skull (intracranial pressure) and may block the flow of oxygen to the brain.Head trauma may cause a concussion, in which there is a brief loss of consciousness without visible structural damage to the brain. In addition to loss of consciousness, initial symptoms of brain injury may include:

memory loss and confusion
vomiting
dizziness
partial paralysis or numbness
shock
anxiety

After a head injury, there may be a period of impaired consciousness followed by a period of confusion and impaired memory with disorientation and a breakdown in the ability to store and retrieve new information. Others experience temporary amnesia following head injury that begins with memory loss over a period of weeks, months, or years before the injury (retrograde amnesia). As the patient recovers, memory slowly returns. Post-traumatic amnesia refers to loss of memory for events during and after the accident.Epilepsy occurs in 2-5% of those who have had a head injury; it is much more common in people who have had severe or penetrating injuries. Most cases of epilepsy appear right after the accident or within the first year, and become less likely with increased time following the accident.

Closed head injury

Closed head injury refers to brain injury without any penetrating injury to the brain. It may be the result of a direct blow to the head; of the moving head being rapidly stopped, such as when a person's head hits a windshield in a car accident; or by the sudden deceleration of the head without its striking another object. The kind of injury the brain receives in a closed head injury is determined by whether or not the head was unrestrained upon impact and the direction, force, and velocity of the blow. If the head is resting on impact, the maximum damage will be found at the impact site. A moving head will cause a "contrecoup injury" where the brain damage occurs on the side opposite the point of impact, as a result of the brain slamming into that side of the skull. A closed head injury also may occur without the head being struck, such as when a person experiences whiplash. This type of injury occurs because the brain is of a different density than the skull, and can be injured when delicate brain tissues hit against the rough, jagged inner surface of the skull.

Penetrating head injury

If the skull is fractured, bone fragments may be driven into the brain. Any object that penetrates the skull may implant foreign material and dirt into the brain, leading to an infection.

Skull fracture

A skull fracture is a medical emergency that must be treated promptly to prevent possible brain damage. Such an injury may be obvious if blood or bone fragments are visible, but it's possible for a fracture to have occurred without any apparent damage. A skull fracture should be suspected if there is:

blood or clear fluid leaking from the nose or ears
unequal pupil size
bruises or discoloration around the eyes or behind the ears
swelling or depression of part of the head

Intracranial hemorrhage

Bleeding (hemorrhage) inside the skull may accompany a head injury and cause additional damage to the brain. A blood clot (hematoma) may occur if a blood vessel between the skull and the brain ruptures; when the blood leaks out and forms a clot, it can press against brain tissue, causing symptoms from a few hours to a few weeks after the injury. If the clot is located between the bones of the skull and the covering of the brain (dura), it is called an epidural hematoma. If the clot is between the dura and the brain tissue itself, the condition is called a subdural hematoma. In other cases, bleeding may occur deeper inside the brain. This condition is called intracerebral hemorrhage or intracerebral contusion (from the word for bruising).In any case, if the blood flow is not stopped, it can lead to unconsciousness and death. The symptoms of bleeding within the skull include:

nausea and vomiting
headache
loss of consciousness
unequal pupil size
lethargy

Postconcussion syndrome

If the head injury is mild, there may be no symptoms other than a slight headache. There also may be confusion, dizziness, and blurred vision. While the head injury may seem to have been quite mild, in many cases symptoms persist for days or weeks. Up to 60% of patients who sustain a mild brain injury continue to experience a range of symptoms called "postconcussion syndrome," as long as six months or a year after the injury.The symptoms of postconcussion syndrome can result in a puzzling interplay of behavioral, cognitive, and emotional complaints that can be difficult to diagnose, including:

headache
dizziness
mental confusion
behavior changes
memory loss
cognitive deficits
depression
emotional outbursts

Diagnosis

The extent of damage in a severe head injury can be assessed with computed tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scans, electroencephalograms (EEG), and routine neurological and neuropsychological evaluations.Doctors use the Glasgow Coma Scale to evaluate the extent of brain damage based on observing a patient's ability to open his or her eyes, respond verbally, and respond to stimulation by moving (motor response). Patients can score from three to 15 points on this scale. People who score below eight when they are admitted usually have suffered a severe brain injury and will need rehabilitative therapy as they recover. In general, higher scores on the Glasgow Coma Scale indicate less severe brain injury and a better prognosis for recovery.Patients with a mild head injury who experience symptoms are advised to seek out the care of a specialist; unless a family physician is thoroughly familiar with medical literature in this newly emerging area, experts warn that there is a good chance that patient complaints after a mild head injury will be downplayed or dismissed. In the case of mild head injury or postconcussion syndrome, CT and MRI scans, electroencephalograms (EEG), and routine neurological evaluations all may be normal because the damage is so subtle. In many cases, these tests can't detect the microscopic damage that occurs when fibers are stretched in a mild, diffuse injury. In this type of injury, the axons lose some of their covering and become less efficient. This mild injury to the white matter reduces the quality of communication between different parts or the brain. A PET scan, which evaluates cerebral blood flow and brain metabolism, may be of help in diagnosing mild head injury.Patients with continuing symptoms after a mild head injury should call a local chapter of a head-injury foundation that can refer patients to the best nearby expert.

Treatment

If a concussion, bleeding inside the skull, or skull fracture is suspected, the patient should be kept quiet in a darkened room, with head and shoulders raised slightly on pillow or blanket.After initial emergency treatment, a team of specialists may be needed to evaluate and treat the problems that result. A penetrating wound may require surgery. Those with severe injuries or with a deteriorating level of consciousness may be kept hospitalized for observation. If there is bleeding inside the skull, the blood may need to be surgically drained; if a clot has formed, it may need to be removed. Severe skull fractures also require surgery. Supportive care and specific treatments may be required if the patient experiences further complications. People who experience seizures, for example, may be given anticonvulsant drugs, and people who develop fluid on the brain (hydrocephalus) may have a shunt inserted to drain the fluid.In the event of long-term disability as a result of head injury, there are a variety of treatment programs available, including long-term rehabilitation, coma treatment centers, transitional living programs, behavior management programs, life-long residential or day treatment programs and independent living programs.

Prognosis

Prompt, proper diagnosis and treatment can help alleviate some of the problems after a head injury. However, it usually is difficult to predict the outcome of a brain injury in the first few hours or days; a patient's prognosis may not be known for many months or even years.The outlook for someone with a minor head injury generally is good, although recovery may be delayed and symptoms such as headache, dizziness, and cognitive problems can persist for up to a year or longer after an accident. This can limit a person's ability to work and cause strain in personal relationships.Serious head injuries can be devastating, producing permanent mental and physical disability. Epileptic seizures may occur after a severe head injury, especially a penetrating brain injury, a severe skull fracture, or a serious brain hemorrhage. Recovery from a severe head injury can be very slow, and it may take five years or longer to heal completely. Risk factors associated with an increased likelihood of memory problems or seizures after head injury include age, length and depth of coma, duration of post-traumatic and retrograde amnesia, presence of focal brain injuries, and initial Glasgow Coma Scale score.As researchers learn more about the long-term effects of head injuries, they have begun to uncover links to later conditions. A 2003 report found that mild brain injury during childhood could speed up expression of schizophrenia in those who were already likely to get the disorder because of genetics. Those with a history of a childhood brain injury, even a minor one, were more likely to get familial schizophrenia than a sibling and to have earlier onset. Another study in 2003 found that people who had a history of a severe head injury were four times more likely to develop Parkinson's disease than the average population. Those requiring hospitalization for their head injuries were 11 times as likely. The risk did not increase for people receiving mild head injuries.

Prevention

Many severe head injuries could be prevented by wearing protective helmets during certain sports, or when riding a bike or motorcycle. Seat belts and airbags can prevent many head injuries that result from car accidents. Appropriate protective headgear always should be worn on the job where head injuries are a possibility.

Key terms

Computed tomography scan (CT) — A diagnostic technique in which the combined use of a computer and x rays produce clear cross-sectional images of tissue. It provides clearer, more detailed information than x rays alone.Electroencephalogram (EEG) — A record of the tiny electrical impulses produced by the brain's activity. By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain.Magnetic resonance imaging (MRI) — A diagnostic technique that provides high quality cross-sectional images of organs within the body without x rays or other radiation.Positron emission tomography (PET) scan — A computerized diagnostic technique that uses radioactive substances to examine structures of the body. When used to assess the brain, it produces a three-dimensional image that reflects the metabolic and chemical activity of the brain.

Resources

Periodicals

"Childhood Head Injury Tied to Later Schizophreia." The Brown University Child and Adolescent Behavior Letter June 2003: 5."Link to Head Injury Found." Pain & Central Nervous System Week June 9, 2003: 3.

Organizations

American Epilepsy Society. 342 North Main Street, West Hartford, CT 06117-2507. (860) 586-7505. http://www.aesnet.org.Brain Injury Association. 1776 Massachusetts Ave. NW, Ste. 100, Washington, DC 20036. (800) 444-6443.Family Caregiver Alliance. 425 Bush St., Ste. 500, San Francisco, CA 94108. (800) 445-8106. http://www.caregiver.org.Head Injury Hotline. PO Box 84151, Seattle WA 98124. (206) 621-8558. http://www.headinjury.com.Head Trauma Support Project, Inc. 2500 Marconi Ave., Ste. 203, Sacramento, CA 95821. (916) 482-5770.National Head Injury Foundation. 333 Turnpike Rd., Southboro, MA 01722. (617) 485-9950.

head

[hed] 1. the anterior or superior part of a structure or organism.2. in vertebrates, the part of the body containing the brain and the organs of special sense. Called also caput.articular head an eminence on a bone by which it articulates with another bone.head injury traumatic injury to the head resulting from a fall or violent blow. Such an injury may be open or closed and may involve a brain concussion, skull fracture, or contusions of the brain. All head injuries are potentially dangerous because there can be a slow leakage of blood from damaged blood vessels into or around the brain. Such a process will gradually increase pressure within the skull and compress the surrounding brain (see hematoma).
One of the most common complications of head injury is subdural hematoma, resulting from the oozing of blood from the cortical veins and the small blood vessels that lie between the arachnoid and the dura mater. A less common but more serious complication that constitutes an extreme surgical emergency is epidural hematoma, a collection of blood in the space between the skull and the dura mater. The leaking of blood into the epidural space is the result of the rupture of a large meningeal artery. It progresses rapidly and therefore requires immediate treatment. A third complication that may occur following head injury is herniation of either the brainstem or a part of the cerebellum through the tentorial hiatus (transtentorial herniation). This is an extreme emergency demanding immediate relief of pressure against the blood vessels serving the brain stem and cerebellum.
Long-term effects of head injury include chronic headache, disturbances in mental and motor function, diabetes insipidus, and a host of other symptoms that may or may not be psychogenic. Organic brain damage and posttraumatic epilepsy resulting from scar formation are possible sequels to head injury.Treatment. The method of treatment will depend on the kind and amount of damage inflicted on the brain and surrounding membranes. Surgical procedures to relieve intracranial pressure include the drilling of burr holes in the skull to aspirate accumulated blood, and intracranial surgery to remove hematomas. Edema of brain tissue may be reduced by the intravenous administration of mannitol. dexamethasone(Decadron" >Decadron), a steroid antiinflammatory agent that has little salt-retaining action, is often used. If no immediate surgery is indicated, the physician may choose to treat the head injury conservatively, with rest and quiet and the careful monitoring of the patient for signs of change in the neurologic status.Patient Care. Continuous monitoring of the vital signs and assessment of the patient's neurologic status are essential to the care of the patient with a head injury. Fluid intake and output are measured and recorded and are limited according to the degree of edema present. Intravenous fluids must be given with caution and oral liquids allowed as soon as the patient is able to swallow. An excessively large urinary output is reported immediately, as this may indicate damage to the hypothalamus and suppression of antidiuretic hormone.
Any one of the following symptoms should be reported to the physician: (1) changes in the patient's blood pressure, pulse, or respiratory rate, especially slowing of the pulse with a rising blood pressure; (2) extreme restlessness or excitability following a period of comparative calm; (3) changes in the level of consciousness; (4) headache that increases in intensity; (5) vomiting, especially persistent, projectile vomiting; (6) unequal size of pupils; (7) inability to move one of the extremities; (8) leakage of spinal fluid (clear yellow or pink-tinged) from the nose or ear.
When leakage of spinal fluid is suspected, this can be verified by using a Clinistix test for sugar. If it is positive, the leaking fluid is spinal fluid rather than mucus. When there is leakage of spinal fluid through the nose, the patient must be warned not to blow the nose. Leakage of spinal fluid from the nose or the ear demands absolute bed rest with the head elevated 30 degrees to maintain neutral intracranial pressure and promote healing.
Patients who are unconscious must be watched closely for respiratory difficulty or inability to swallow. If the patient cannot swallow, the head must be turned to the side and the mouth and trachea suctioned as necessary to prevent aspiration of mucus into the lungs. A tracheostomy set and ventilator should be readily at hand in case severe respiratory embarrassment occurs.
Side rails are applied and the headboard of the bed is padded with pillows or a blanket if the patient is delirious or if convulsions are anticipated. An accurate record of the patient's intake and output is kept and the patient is observed for signs of retention of urine, incontinence, or abdominal distention.

Some mechanisms of head injury. Head injury results from penetration or impact. A, A direct injury (blow to skull) may fracture the skull. Contusion and laceration of the brain may result from fractures. Depressed portions of the skull may compress or penetrate brain tissue. B, In the absence of skull fracture, a blow to the skull may cause the brain to move enough to tear some of the veins going from the cortical surface to the dura. Subsequently, subdural hematoma may develop. Note the areas of cerebral contusion (shaded in red). C, Rebound of the cranial contents may result in an area of injury opposite the point of impact. Such an injury is called a contrecoup injury. In addition to the three injuries depicted, secondary phenomena may result from the injury and cause additional brain dysfunction or damage. For example, ischemia, especially cerebral edema, may occur, elevating intracranial pressure. From Polaski and Tatro, 1996.sperm head (head of spermatozoon) the oval anterior end of a spermatozoon, which contains the male pronucleus and is surrounded by the acrosome. See illustration at spermatozoon.

injury

[in´jŭ-re] harm or hurt; usually applied to damage inflicted on the body by an external force. Called also trauma and wound.brain injury impairment of structure or function of the brain, usually as a result of a trauma.deceleration injury a mechanism of motion injury in which the body is forcibly stopped but the contents of the body cavities remain in motion due to inertia; the brain is particularly vulnerable to such trauma.head injury see head injury.risk for injury a nursing diagnosis approved by the North American Nursing Diagnosis Association, defined as the state in which a person is at risk for injury as a result of environmental conditions interacting with the individual's adaptive and defensive resources. Any pathophysiological condition such as altered level of consciousness, impaired sensory perception, tissue hypoxia, and pain or fatigue can contribute to or be the cause of personal injury. Age-related factors include infancy and early childhood, advanced age, and the 20- to 29-year age group in which accidents and harmful lifestyles are major causes of illness and death.risk for perioperative-positioning injury a nursing diagnosis approved by the North American Nursing Diagnosis Association, defined as being at risk for injury as a result of the environmental conditions found in the perioperative setting.ventilator-induced injury injury to the lung secondary to ventilator treatment, the result of excessive airway pressures, maldistribution of tidal volume, or high oxygen concentrations. See also barotrauma.

head injury

See BRAIN DAMAGE, EXTRADURAL HAEMORRHAGE, SKULL FRACTURE, SUBDURAL HAEMORRHAGE.

Patient discussion about head injury

Q. What is a concussion? How do you treat it? My child fell and hit his head and passed out. We went to the hospital and they say it’s a concussion and he’ll be fine. Can some one explain what it is exactly? A. When your brain gets hit hard- this is concussion. But there’s a nice short video about it with a nice pediatrician that explains it:
http://www.5min.com/Video/Dealing-with-Baby-Head-Injuries-7104

More discussions about head injury

head mounted display

head mounted display

head injury

Head Injury

Definition

Description

Causes and symptoms

Closed head injury

Penetrating head injury

Skull fracture

Intracranial hemorrhage

Postconcussion syndrome

Diagnosis

Treatment

Prognosis

Prevention

Key terms

Resources

Periodicals

Organizations

head

injury

head injury

Patient discussion about head injury