Head injuries occur most often in sports that involve body contact, the risk of falling or being struck by a ball. A blow to the head may affect the brain causing a headache, nausea, dizziness, unsteadiness, pressure, blurred vision, loss of memory and impaired concentration. However, these symptoms can also occur because of reasons not associated with trauma.
Brain Tumor
Because the skull is made of bone, a growing tumor cannot expand, causing pressure to build. The dangerous increase in pressure produces symptoms such as severe, persistent headaches, sudden and unexpected vomiting, dizziness, visual disturbances, personality changes or sudden onset of abnormal and uncharacteristic behavior. According to the American Brain Tumor Association, primary brain tumors arise from tissues inside the skull. They include gliomas from supporting cells of the brain, meningiomas from the membranes that cover the brain, pituitary tumors and an acoustic neuroma. Secondary tumors arise from tumors in other parts of the body.
Skull Fracture
A skull fracture may be a closed fracture---confined to the skull, or an open fracture where the bone may break through the skin. Most fractures do not affect the brain, but in rare cases, fragments of the skull may be driven into the brain, leading to infection or brain hemorrhage, which can be fatal. Symptoms include head pain, nausea, dizziness and pressure.
Abscess and Infection
A headache may result from increased pressure inside the skull due to a brain abscess---a collection of pus in a limited area of brain tissue caused by an infection. According to the U.S. National Library of Medicine, the increased pressure inside the skull due to the swelling produced by a brain infection or from infection and inflammation of the membranes surrounding the brain and spinal cord can block the blood vessels of the brain.
Cerebral Aneurysm
A weak spot on a blood vessel within the brain that gets bigger as it fills with blood is an intracranial or intracerebral aneurysm. As the blood vessel expands, it puts pressure on surrounding brain tissue and nerves. The bulge may leak or rupture, hemorrhaging into the surrounding tissue. According to the National Institute of Neurological Disorders and Stroke, symptoms of an aneurysm may include pain around the eyes, numbness, weakness, dilated pupils and changes in vision, gradually getting worse as it grows. When the aneurysm bursts, it can cause a sudden and severe headache, nausea, vomiting and loss of consciousness.
