What Is Cerebral Edema? Symptoms, Causes, Diagnosis, Treatment, and Prevention

If you bump your elbow, you can simply apply ice and the swelling will disappear. But what happens when you hit your head and your brain starts to swell?

Cerebral edema is a life-threatening condition that can cause permanent brain damage or death if not treated quickly.

The symptoms of cerebral edema vary widely, depending on the cause, and can be extremely painful. Patient age, brain size, and edema location can also affect symptom severity. “Generally, suspected edema is not the symptom that will bring someone into the hospital,” says Ramani Balu, MD, PhD, an adjunct assistant professor of neurology at the University of Pennsylvania in Philadelphia. “People will either have a traumatic brain injury, a stroke, or experience a range of neurological symptoms before brain swelling is determined. Cerebral edema is a consequence of an underlying condition.”

Typical signs of brain swelling include:

• Headache, which is the most common symptom anytime the brain starts to swell, Dr. Balu says
• Dizziness
• Nausea
• Mood changes, such as depression, anxiety, or aggression as a result of a brain injury
• Cognitive changes

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• Altered consciousness
• Seizure

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• Lack of coordination
• Intestinal obstruction (volvulus, intussusception)
• Numbness or weakness that can be generalized or localized

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• Double vision due to inability to fully move one of your eyes in a particular direction
• Bulging in the soft spots of an infant’s skull

Head trauma, infections, and a number of other neurological conditions can cause the brain to swell as pressure increases and compresses brain tissue. The typical causes of brain swelling include:

Types of Brain Swelling

There are four main types of cerebral edema. The type a person may be suffering from is dependent on the cause.

Osmotic “Cells have water inside and outside, and water can pass through their semipermeable membranes,” says Balu. “This process is called osmosis. Sometimes, there can be a buildup of electrolytes inside the cell, and this causes a high concentration of water to move into the cells.”

“If a patient comes in with a TBI, stroke, or acute brain injury, there’s almost always brain swelling,” says Balu. “They’ll be immediately admitted to the ICU, and then we perform a neurological and physical exam.” According to Balu, the clinical neurological exam tests brain function and level of consciousness to see if there’s brain damage. Any slight change in level of consciousness may indicate brain damage.

“Signs we look out for include increases in intracranial pressure in the head, sleepiness, responsiveness, and problems with vision,” Balu says.

When a person is admitted to the hospital with a brain injury, sometimes neurologists will place a device directly into the brain itself to monitor intracranial pressure, Balu says.

“Next, we’ll do a scan to see what’s causing the swelling and neurological symptoms and where it’s located,” he says. “We’ll either perform a CT [computerized tomography] scan or an MRI [magnetic resonance imaging], but often we do MRIs, because they tell us more about the brain swelling and give us a picture of the type of neurological problem, whether it’s a stroke, bleeding, or tumor.”

The duration of cerebral edema will vary depending on the individual, the cause of the brain swelling, and treatment plan.

Those who are experiencing brain swelling should be closely monitored during the first 48 to 72 hours after the injury or infection. The speed at which a patient receives treatment can affect recovery time and improve outcome.

“Once we determine what’s going on, patients will be monitored in the hospital for complications from the swelling itself, and we’ll treat the neurological condition that’s causing the edema,” Balu says. “Treatment is dictated by the type of neurologic injury.”

If the cause is cytotoxic, doctors will look to reverse the underlying medical condition first with acute treatments, Balu says — for example, by starting an intravenous (IV) delivery of hypertonic saline that increases electrolytes in the blood and pulls water out of the brain. “Same for bleeding in the brain or TBI,” he says. "In extreme cases, we’ll have our colleagues do a craniectomy, where they take a portion of the skull off to let the brain swell out.” And if a patient comes in with acute symptoms of a stroke, Balu says they first work to get blood flow to the brain.

Once cerebral edema has been diagnosed through a scan, a doctor may help relieve pressure by:

• Keeping the hospital bed elevated 30 or 45 degrees. According to Balu, when the head is flat, it can increase pressure in the brain, so it’s best to keep the head up.
• Maintaining normal body temperature with antipyretics
• Maintaining a calm environment with low lighting to avoid agitation
• Monitoring fluid and electrolyte levels
• Prescribing pain relievers to increase comfort
• Draining CSF fluid by inserting a catheter into the ventricle
• Administering neuromuscular blockades
• Offering hyperosmolar therapy

In extreme cases, your doctor may consider a craniectomy to relieve pressure. Controlled hyperventilation, high-dose barbiturate therapy, and moderate hypothermia are other treatments to reduce swelling.

Balu says an initial treatment of brain swelling is often a drug, such as:

• dexamethasone (Decadron)
• mannitol (Aridol, Osmitrol)
• acetazolamide (Diamox)
• furosemide (Lasix)
• diuretics
• corticosteroids

Prevention of Cerebral Edema

Preventing cerebral edema involves taking measures to protect your head. Some measures you can take to reduce the risk of edema include:

• Using a helmet during sports or physical activities to prevent brain injury.

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• Controlling your blood pressure and cholesterol to prevent heart disease and stroke.

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• Wearing a seat belt when traveling in a vehicle.
• Slowly ascending to high elevations to avoid HACE.

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• Avoiding smoking to reduce the oxidative and inflammatory risk of stroke

If left untreated, cerebral edema can lead to permanent brain damage or result in a wide range of complications. These include:

• Vision loss
• Headaches
• Cerebral atrophy
• Cognitive decline
• Altered mental status
• Depression
• Sleep problems
• Epilepsy
• Irreversible brain damage

No official statistics exist on the number of people affected by cerebral edema, but there is data on some of the primary causes of brain swelling.

Certain racial and ethnic minorities are at a greater risk for some of the main causes of cerebral edema.

According to a study published in the Journal of Head Trauma Rehabilitation, the annual rate of emergency department visits for traumatic brain injuries is higher for Black Americans than for white Americans — 569 per 100,000 compared with 457 per 100,000, respectively. Black Americans also have higher rates of hospitalization due to brain injury.

Evidence suggests that traumatic brain injury, one of the main causes of cerebral edema, puts people at a greater risk of Alzheimer’s disease or another form of dementia. TBI can affect a person’s cognitive functioning, including thinking and learning.

According to the Alzheimer’s Association, older adults with a history of moderate traumatic brain injury have a 2.3 times greater risk of developing Alzheimer’s than those with no history of brain injury. Those with a severe TBI have a 4.5 times greater risk.