Brain edema on head CT means there is collection of fluid in the brain tissue which is abnormal. Symptoms include headache, nausea, vomiting, and most severely coma and death. Brain edema can cause shift of brain structures. This puts pressure on brain tissue and blood vessels which can lead to loss of blood supply, stroke, and herniation of structures. It is an urgent diagnosis to make.
What does edema look like on head CT?
Edema which involves the white matter in a finger like appearance indicates that there can be a tumor or abscess. Edema which involves white and gray matter usually indicates a stroke. Edema around enlarged ventricles means that is increased pressure and fluid formation. There are multiple other causes of edema and overlap in the patterns. A non contrast head CT tells us there is brain edema but A contrast study or MRI is often needed to identify the cause.
What are some common causes of edema in the brain?
Stroke is a common cause of brain edema. A stroke means that there is a neurological deficit. This is dependent on which area of the brain is involved. Interruption of blood flow results from a blocked artery or from generalized lack of blood flow in the body such as from drowning. This can eventually lead to cell death and swelling of the brain. Non contrast head CT may not show the earliest changes of stroke in the initial hours. Eventually changes appear of swelling in the involved region. Larger infarcts can cause shift of structures and bleed. MRI can better detect acute infarcts.
Vasogenic edema in the white matter can be from increased blood brain barrier breakdown. This can occur with tumors such as glioblastoma. Infections like abscess and encephalitis. Inflammatory diseases like multiple sclerosis. This can also occur from traumatic or radiation injury. Combined types of edema can also occur from many causes.
Brain edema is therefore a serious potentially life threatening condition which can often be diagnosed with a head CT. Sometimes additional imaging with MRI or angiography will be needed to identify the cause. Brain edema has many causes and the clinical history and the imaging is important to arrive at the correct diagnosis.