In children, a high percentage of deaths from injury are caused by head injuries and their complications. Severe head injuries may also seriously damage the developing brain, interfering with the child's physical, intellectual, and emotional development and resulting in long-term disabilities. However, most head injuries are minor.
Head injuries are most common in children under age 1 and in adolescents over age 15. Boys are injured more often than girls. Major head injuries are usually caused by motor vehicle and bicycle accidents. Minor head injuries are predominantly caused by falls in and around the home. Because any head injury is potentially serious, every child who has had a head injury should be evaluated carefully.
A minor head injury may cause vomiting, paleness, irritability, or drowsiness without loss of consciousness or any immediate evidence of brain damage. If symptoms continue for more than 6 hours or worsen, a health care practitioner should evaluate the child further to determine whether the injury is severe.
A concussion is a temporary loss of consciousness immediately after a head injury. It should be evaluated promptly, even if it lasts no more than a minute. Often, the child can't remember the injury itself or the events just before it but has no other symptoms of brain damage.
Head injuries may bruise or tear brain tissue or blood vessels in or around the brain, causing bleeding and swelling inside the brain. The most common brain injury is diffuse (widespread) injury to brain cells. A diffuse injury causes brain cells to swell, increasing pressure inside the skull. As a result, a child may lose strength or sensation and become drowsy or unconscious. These symptoms suggest a severe brain injury, likely to result in permanent damage and the need for rehabilitation. As the swelling worsens, the pressure increases, so that even uninjured tissue can be compressed against the skull, causing permanent damage or death. Swelling with its dangerous results usually occurs in the first 48 to 72 hours after the injury.
If the skull is fractured, a brain injury may be more severe. However, a brain injury commonly occurs without a skull fracture, and a skull fracture often occurs without a brain injury. Fractures at the back or base (bottom) of the skull usually indicate a forceful impact, because these parts of the skull are relatively thick. Such fractures often can't be seen on x-rays or computed tomography (CT) scans. However, the following symptoms suggest this type of fracture:
Cerebrospinal fluid (the clear fluid that surrounds the brain) draining from the nose or ears
Blood collecting behind the eardrum or bleeding from the ear if the eardrum is ruptured
Bruising behind the ear (Battle's sign) or around the eyes (raccoon's eyes)
Blood collecting in the sinuses (can only be seen on x-rays)
In an infant, the membranes surrounding the brain may protrude through a skull fracture and become trapped by it, forming a fluid filled sac called a growing fracture. The sac develops over 3 to 6 weeks and may be the first evidence that the skull was fractured.
In depressed skull fractures, one or more fragments of bone press inward on the brain. The resulting bruising of the brain may cause seizures.
Seizures occur in about 5 percent of children over age 5 years and in 10 percent of those under age 5 during the first week after a serious head injury. Seizures that start soon after the injury are less likely to result in a long term seizure problem than those that start i or more days later.
A serious but relatively uncommon complication of head injuries in children is bleeding between the layers of membranes surrounding the brain or in the brain itself. An epidural hematoma-a collection of blood between the skull and the membrane that lines it (dura mater) may exert pressure on the brain. It results from damage to arteries or veins that line the skull. In an adult, symptoms of an epidural hematoma are an initial loss of consciousness; a regaining of consciousness, called a lucid interval; and then a worsening of symptoms of pressure on the brain, such as drowsiness and loss of sensation or strength. However, in a young child, there is no lucid interval but rather a gradual loss of consciousness over a period of minutes to hours because of increasing pressure on the brain.
In a subdural hematoma, blood collects beneath the dura mater, usually in association with a significant injury to brain tissue. Drowsiness to the point of unconsciousness, loss of sensation or strength, and abnormal movements including seizures usually develop rapidly, although symptoms occasionally develop more gradually when the injury is mild.
Bleeding may occur inside the internal spaces (ventricles) of the brain (intraventricular hemorrhage), within the brain tissue itself (intraparenchymal heLaqxvi4age), or within the membranes covering the brain's surface (subarachnoid hemorrhage). These types of bleeding are evidence of very severe brain injury and are associated with long-term brain damage.
In evaluating a child who has a head injury, a doctor considers the way the injury occurred as well as the resulting symptoms and performs a thorough physical examination. Special attention is paid to the level of consciousness, the ability to feel and move, any abnormal movements. reflexes, the eyes and ears, pulse, blood pressure, and breathing rate. The size of the pupils and their reaction to light are important; the interior of the eyes is examined with an ophthalmoscope to determine whether pressure within the brain is in-creased. Infants who have been shaken (shaken baby syndrome, shaken impact syndrome) often develop areas of bleeding in the back of the eyes (retinal hemorrhages). If a significant brain injury is likely, a CT scan of the head is usually obtained. If a depressed skull fracture without brain injury is possible, the skull may be X-rayed.
Most children who have had mild head injuries are sent home, and their parents are instructed to observe them for persistent vomiting or increasing drowsiness. If the child goes home at night, keeping the child awake during the night is not necessary; parents need only to wake the child periodically (as instructed by the doctor for example, every 2 to 4 hours) to make sure the child can be aroused. Children are observed in the hospital if they are drowsy, were unconscious even briefly, have any abnormality of feeling (numbness) or muscle strength, or are at high risk of worsening. Children who have a skull fracture without evidence of a brain injury need not be routinely hospitalized.
In contrast, infants with a skull fracture, especially if it is depressed, are almost always observed in the hospital; for a depressed skull fracture, surgery may be needed to lift up the bone fragments and prevent further injury to the brain. Children are also kept in the hospital if child abuse is suspected.
In the hospital, children are observed closely for changes in the level of consciousness and in breathing, heart rate, and blood pressure. Doctors also look for evidence of increased pressure within the skull by frequently examining the pupils of the eyes and by watching for changes in sensation or strength and for seizures. A CT scan of the head may be performed or repeated if sei-zures occur, vomiting continues, drowsiness increases, or the condition deteriorates in any other way.
Nothing can reverse damage that has already occurred. However, further damage may be prevented by ensuring that enough blood containing sufficient oxygen is reaching the brain. Pressure within the brain is kept as normal as possible by immediately treating any brain swelling and reducing any pressure on the brain. For an epidural hematoma, emergency surgery must be performed to remove the pooled blood and thus prevent it from pressing on the brain and causing damage. With appropriate treatment, most children who have a simple epidural hematoma recover fully. A subdural hematoma also may need to be removed surgically. Brain swelling is usually evaluated with an intracranial pressure monitor, which measures pressure in the brain. A drain may also be inserted into one of the ventricles to drain cerebrospinal fluid and thus relieve pressure. The head of the bed is raised to reduce pressure within the brain, and various drugs, such as mannitol or furosemide, may be used to reduce this pressure.
Seizures are treated, usually with phenytoin. In children who have seizures after a head injury, an electroencephalogram (EEG) may be performed to assist with diagnosis and treatment.
How much brain function is recovered depends on how severe the injury is, how old the child is, how long he was unconscious, and which part of the brain was most injured. Of the nearly 5 million children who sustain a head injury each year, 4,000 die and 15,000 require prolonged hospitali-zation.
Of those with a severe injury who are unconscious for longer than 24 hours, 50 percent have long-term complications, including significant physical, intellectual, and emotional problems; 2 to 5 percent remain severely handicapped. Young children, especially infants, who have had a severe head injury are more likely to die than older children.
For those who survive, a prolonged period of rehabilitation, particularly in intellectual and emotional development, is often required. Common problems during recovery include loss of memory from the time immediately before the injury (retrograde amnesia), changes in behavior, emotional instability, sleep disturbances, and decreased intellectual ability.
The author is a neuro surgeon in the Kingdom of Saudi Arabia.
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