An acute brain injury may involve a blow to the head or a penetrating head injury that impairs the brain's function, according to the Brain Injury Association of America, or the BIAA. The severity of acute brain injuries varies from mild to severe, based on changes in a person's mental status or consciousness. The BIAA states that 1.4 million Americans experience a traumatic brain injury each year, and there are numerous types of acute brain injuries that can occur.
Concussion
Concussions are a common type of acute brain injury. MayoClinic.com states that although concussions vary in significance from mild to severe, they all temporarily impair the way the brain functions. Concussions--which typically involve a blow to the head that may cause a temporary loss of consciousness--do not require surgery, but may affect a person's memory, judgment, reflexes, speech, balance and coordination. Concussions may also cause headaches, nausea and vomiting, dizziness, and impaired memory and concentration. According to MayoClinic.com, the majority of people who sustain a concussion never lose consciousness, and some people who have had a concussion never realize it. Concussions are relatively common in contact sports, such as football and hockey, and repetitive concussions can lead to significant brain damage. Common concussion symptoms include confusion, amnesia and headaches.
Coup Contrecoup
A coup injury typically is caused by an object striking the head, whereas a contrecoup injury involves the head striking an object. If the trauma is severe enough, both injuries may occur, resulting in a coup contrecoup injury. According to the BIAA, coup contrecoup injuries--which are a special type of concussion--involve contusions at the site of skull impact and on the opposite side of the brain. In other words, a person's head is struck with such force that it causes the brain to contact one side of the skull or cranium and rebound off the opposite side, producing damage in two places. Coup contrecoup brain injuries are most often caused by blunt force trauma or whiplash-type accidents. The website BrainandSpinalCord.org states that common causes of coup contrecoup injuries include motor vehicle accidents, assaults, shaken baby syndrome, falls, and sports or athletic injuries.
Subdural Hematoma
According to MedlinePlus, a U.S. National Library of Medicine and National Institutes of Health website, subdural hematomas or hemorrhages, which involve blood accumulation between the brain's outer layers, are usually caused by a serious head injury. Subdural hematomas that occur from blunt force trauma are called acute subdural hematomas and are among the most deadly of all head injuries. With acute subdural hematomas, bleeding inside the skull fills the brain area quickly, compressing brain tissue and often leading to brain injury. Although serious head injuries may cause an acute subdural hematoma, minor head injuries, especially in the elderly, can cause subdural hematomas too. Common subdural hematoma symptoms include confusion, slurred speech, headache, lethargy, loss of consciousness, nausea and vomiting, seizures, weakness and visual disturbances.
