Headache: There are many types of headaches; some can be serious but most are not and are generally treated with analgesics/painkillers.
Stroke (brain infarction): Blood flow and oxygen are suddenly interrupted to an area of brain tissue, which then dies. A blood clot, or bleeding in the brain, are the cause of most strokes.
Brain aneurysm: An artery in the brain develops a weak area that swells, balloon-like. A brain aneurysm rupture can causes a stroke.
Subdural hematoma: Bleeding within or under the dura, the lining inside of the skull. A subdural hematoma may exert pressure on the brain, causing neurological problems.
Epidural hematoma: Bleeding between the tough tissue (dura) lining the inside of the skull and the skull itself, usually shortly after a head injury. Initial mild symptoms can progress rapidly to unconsciousness and death, if untreated.
Concussion: A brain injury that causes a temporary disturbance in brain function. Traumatic head injuries cause most concussions.
Cerebral edema: Swelling of the brain tissue in response to injury or electrolyte imbalances.
Brain tumor: Any abnormal tissue growth inside the brain. Whether malignant (cancer) or benign, brain tumors usually cause problems by the pressure they exert on the normal brain.
Glioblastoma: An aggressive, malignant brain tumor (cancer). Brain glioblastomas progress rapidly and are very difficult to cure.
Hydrocephalus: An abnormally increased amount of cerebrospinal (brain) fluid inside the skull. Usually this is because the fluid is not circulating properly.
Normal pressure hydrocephalus: A form of hydrocephalus that often causes problems walking, along with dementia and urinary incontinence. Pressures inside the brain remain normal, despite the increased fluid.
Meningitis: Inflammation of the lining around the brain or spinal cord, usually from infection. Stiff neck, neck pain, headache, fever, and sleepiness are common symptoms.
Encephalitis: Inflammation of the brain tissue, usually from infection with a virus. Fever, headache, and confusion are common symptoms.
Traumatic brain injury: Permanent brain damage from a traumatic head injury. Obvious mental impairment, or more subtle personality and mood changes can occur.
Parkinson's disease: Nerves in a central area of the brain degenerate slowly, causing problems with movement and coordination. A tremor of the hands is a common early sign.
Huntington's disease: An inherited nerve disorder that affects the brain. Dementia and difficulty controlling movements (chorea) are its symptoms.
Epilepsy: The tendency to have seizures. Head injuries and strokes may cause epilepsy, but usually no cause is identified.
Dementia: A decline in cognitive function resulting from death or malfunction of nerve cells in the brain. Conditions in which nerves in the brain degenerate, as well as alcohol abuse and strokes, can cause dementia.
Alzheimer’s disease: For unclear reasons, nerves in certain brain areas degenerate, causing progressive dementia. Alzheimer’s disease is the most common form of dementia.
Brain abscess: A pocket of infection in the brain, usually by bacteria. Antibiotics and surgical drainage of the area are often necessary.