injuries and poisoning
Overview of Head Injuries
Symptoms of Head Injuries
A bump may appear on the head. If the scalp is cut, bleeding may be profuse because the scalp has many blood vessels close to the skin surface. Consequently, a scalp injury may appear to be more serious than it is. Because the scalp has many blood vessels, a scalp injury may bleed profusely even if the injury itself is not serious. Common symptoms of minor head injuries may include headache and the sensation of spinning or light-headedness. Some people also have mild confusion, nausea, and, more commonly in children, vomiting. Young children may simply become irritable. A Concussion is a temporary, brief change in mental function without damage to the structure of the brain. Often, people lose consciousness briefly (usually a few minutes or less), but they may simply become confused or be unable to recall events and experiences (amnesia) that occurred shortly before or soon after the injury. For some time after a concussion, people may experience headache, dizziness, fatigue, poor memory, inability to concentrate, trouble sleeping, difficulty thinking, irritability, depression, and anxiety. These symptoms are called the postconcussion syndrome. People may have some of the same symptoms as occur with minor head injury. Some symptoms, such as headache, may be more severe. Also, symptoms often start with a period of unconsciousness that begins at the time of impact. How long people remain unconscious varies. Some people awaken in seconds, while others do not awaken for hours or even days. On awakening, people often are drowsy, confused, restless, or agitated. They may also vomit, have seizures, or both. Balance and coordination may be impaired. Depending on which area of the brain is damaged, the ability to think, control emotions, move, feel, speak, see, hear, and remember may be impaired—sometimes permanently. Clear fluid or blood may drain from the nose, ears, or both if a person has a Skull Fracture . Bleeding or swelling in the brain can cause pressure that forces the brain downward in the skull. The result may be a herniation, in which brain tissue is forced through a small natural opening in the relatively rigid sheets of tissue that separate the brain into right and left compartments and into upper and lower compartments. (These dividers are extensions of the outer layer of tissue covering the brain, the dura mater.) Herniation compresses brain tissue and thus damages it. The most common type of herniation is a transtentorial herniation. Part of the temporal lobe is forced through the tentorial notch—the opening in the sheet of tissue between the temporal lobe and cerebellum. The pupil of the eye may become dilated and may not constrict in response to light. A transtentorial herniation can have catastrophic consequences, including paralysis, stupor, coma, abnormal heart rhythms, disturbances or cessation of breathing, cardiac arrest, and death. An injured brain may bleed or swell because fluid accumulates (called cerebral edema). This bleeding and swelling gradually increase the pressure inside the skull, called intracranial pressure. Even mild bleeding and swelling can increase intracranial pressure a lot because the skull cannot expand to accommodate any increase in its contents. As the intracranial pressure increases, it limits the amount of blood that can flow through the brain. The limited blood flow prevents the brain from working normally and causes symptoms. The first symptoms of increased intracranial pressure include worsening headache, impaired thinking, a decreased level of consciousness, and vomiting. Later, the person may become unresponsive. The pupils may widen (dilate). Eventually (usually within a day or two of injury), the increased pressure may force the brain downward, causing a herniation of the brain—an abnormal protrusion of brain tissue through a natural opening between the compartments of the brain. Herniation of the brain can cause coma or even death if too much pressure is put on the brain stem, the lower part of the brain, which controls such vital functions as heart rate and breathing. Even without herniation, if intracranial pressure gets high enough, it can shut off blood flow through the brain, leading rapidly to Brain Death . 