What Is Cerebral Edema?

Cerebral edema is the swelling of the brain as a result of an injury. The thick skull surrounding the brain prevents tissue from expanding when injured. This pressure restricts blood circulation and deprives the brain of the oxygen it needs to function properly. Elevated pressure in the brain as a result of cerebral edema can be damaging and possibly life threatening without medical treatment.

This article covers the types, symptoms, and treatment of cerebral edema.

Types

The types of cerebral edema vary based on the cause and severity of the brain injury. They are also dependent on how the injury affects the blood-brain barrier (BBB), a barrier in the brain that protects immunity by keeping nutrients flowing in and harmful pathogens out.

Cerebral edema of any type results in increased pressure on the brain. The most common types of cerebral edema include:

• Vasogenic edema: An accumulation of fluid on the outside of brain cells due to a BBB disturbance. This can be caused by a brain tumor.
• Cellular edema: An accumulation of fluid on the inside of brain cells. This may be caused by brain ischemia (stroke) or hypoxia (oxygen restriction).
• Osmotic edema: Water intoxication of brain cells due to electrolyte imbalance. This may be caused by hyponatremia (lower-than-normal sodium in the bloodstream), diabetic ketoacidosis (DKA), or another metabolic cause.
• Interstitial edema: When cerebrospinal fluid (a clear fluid that bathes the brain and spinal cord) infiltrates other parts of the brain. This may result from hydrocephalus or meningitis.
• Hydrostatic edema: This is a result of hypertension (high blood pressure) in the brain arteries.

Although the types of cerebral edema depend on the cause, each results in swelling that prevents oxygen and nutrients from circulating through the brain.

Symptoms

The symptoms of cerebral edema depend on the type and cause of the edema. Cerebral edema can be localized to a small part of the brain or affect the entire brain, which can dictate some of the symptoms.

Symptoms may include:

• Headache
• Nausea or vomiting
• Vision problems
• Seizures
• Behavioral changes
• Memory loss
• Weakness or numbness
• Loss of consciousness

Blood pressure may increase to compensate for the decreased blood flow in the brain. This results in irregular breathing and a reduced heart rate.

Causes 

A number of neurological injuries and conditions can cause cerebral edema. These include:

• Traumatic brain injury (TBI)
• Stroke
• Brain bleeding (hemorrhage)
• Brain aneurysm
• Tumors
• Infections such as meningitis or encephalitis
• Seizures

Non-neurological conditions and certain environmental factors can also cause cerebral edema. These include:

• Hypertension
• Hepatitis
• Reye’s syndrome
• Carbon monoxide poisoning
• Lead poisoning

Certain environmental factors, like being at a high altitude, have also been known to cause cerebral edema.

Diagnosis

A patient’s symptoms will determine what diagnostic tools a physician uses to examine a patient. The initial exam may include a neurological exam to assess motor and sensory skills, hearing, speech, vision, balance, and coordination.

Diagnostic tests for cerebral edema include:

• Computerized tomography (CT scan): Generally the first test used to diagnose cerebral edema in the hospital, because it is the fastest diagnostic imaging available
• CT angiography (CTA): A CT scan with injectable dye to see blood vessels and tissue
• Magnetic resonance imaging (MRI): Provides more in-depth diagnostic information than a CT alone
• Lumbar puncture (or spinal tap): A puncture in the lower spine to remove cerebrospinal fluid

Results of diagnostic testing will indicate what type of treatment a patient will receive for cerebral edema.

Treatment

The goal of treatment is to re-regulate blood flow and oxygen to the brain.

Treatments for cerebral edema will vary depending on the cause of the condition.

Treatment for cerebral edema may include:

• Surgery: A craniotomy may be performed to release pressure on the brain and prevent permanent brain damage.
• Medications: These include steroids such as dexamethasone or other corticosteroids, fever-reducing medications, anticonvulsants used for seizure prevention, and intravenous salines.
• Optimal head positioning: This involves elevating the head to decrease pressure on the skull.
• Ventilation: Patients with a decreased level of consciousness may be intubated to ensure that oxygen and carbon dioxide levels are maintained.
• Ventricle drainage via a catheter
• Management of hyperglycemia (high blood sugar)
• Moderate hypothermia: This the the lowering of body temperature to facilitate brain healing.

Patients experiencing more extensive cerebral edema will require close bedside monitoring and level of consciousness (LOC) examinations. Frequent neurological checks are performed to measure any new or declining neurological changes. 

Worsening changes in the level of consciousness or neurological function often require admission to an intensive care unit (ICU).

Prognosis

The prognosis of cerebral edema depends on the cause and severity of the injury and how quickly medical intervention occurs.

If left untreated, severe cerebral edema can cause brain and brainstem compression or could lead to death.

A Word From Verywell 

Cerebral edema is a serious condition that requires medical treatment. However, effective treatments and knowledgable medical professionals who are experienced in neurological care can help. If you or someone around you experiences a head injury or a decline in neurological function, you should go to the emergency room or contact your physician as soon as possible.