Increased Intracranial Pressure

Overview

The skull is a rigid box that holds the brain, blood, and cerebrospinal fluid in a delicate balance. Intracranial pressure (ICP) is the pressure inside this space. When something increases the volume inside the skull, such as swelling, bleeding, a tumor, or excess fluid, the pressure rises because there is nowhere for the contents to expand.

Increased intracranial pressure is dangerous because it can reduce blood flow to the brain and physically push or compress brain tissue. If severe, it can force parts of the brain out of their normal position, a life-threatening situation called herniation. Raised ICP is a medical emergency that requires rapid evaluation and treatment to protect the brain.

Symptoms

Symptoms can develop suddenly after an injury or build up gradually. Warning signs include:

• A severe or worsening headache, often worse when lying down, coughing, or straining
• Nausea and vomiting, sometimes forceful
• Increasing drowsiness, confusion, or difficulty waking
• Blurred or double vision, or changes in pupil size
• Weakness, numbness, or difficulty moving part of the body
• Seizures
• In infants, a bulging soft spot (fontanelle) and unusual irritability

A rapidly declining level of consciousness, an unequal or fixed pupil, slowed breathing, or a slow heart rate with high blood pressure are signs of dangerously high pressure and require emergency care immediately.

Causes

Increased intracranial pressure can result from anything that adds volume or blocks the normal flow of fluid within the skull:

• Bleeding: Bleeding inside or around the brain from injury, a ruptured aneurysm, or a stroke.
• Brain swelling: Swelling (edema) after head injury, stroke, infection, or oxygen deprivation.
• Masses: Brain tumors or abscesses that take up space.
• Fluid buildup: Hydrocephalus, in which cerebrospinal fluid accumulates because it cannot drain normally.
• Infections: Meningitis or encephalitis causing inflammation and swelling.

A condition called idiopathic intracranial hypertension can also raise pressure without an obvious mass or bleed, often in people with significant weight gain.

Risk Factors

• Recent head injury or trauma
• Conditions that cause bleeding in the brain, such as aneurysms or hemorrhagic stroke
• Brain tumors or infections of the brain
• Hydrocephalus or prior shunt problems
• Severe high blood pressure
• Significant, rapid weight gain (a risk for idiopathic intracranial hypertension)

Diagnosis

Because raised ICP can worsen quickly, evaluation is urgent. Doctors use:

• Neurological examination: Checking level of consciousness, pupil responses, strength, and reflexes.
• Brain imaging: CT or MRI scans to find bleeding, swelling, masses, or fluid buildup.
• Pressure monitoring: In serious cases, a monitor may be placed inside the skull in an intensive care setting to measure the pressure directly.
• Lumbar puncture: In selected situations, such as suspected idiopathic intracranial hypertension, but only when imaging shows it is safe.

Treatment

Treatment aims to lower the pressure quickly and address the underlying cause. It is provided in a hospital, often in intensive care:

• Treating the cause: Surgery to remove a clot, tumor, or to drain excess fluid; antibiotics for infection; or other targeted treatment.
• Reducing brain swelling: Medications such as osmotic agents, careful control of fluids, and adjusting the angle of the head and bed.
• Draining fluid: A drain or shunt may be placed to remove cerebrospinal fluid and relieve pressure.
• Supportive care: Controlling breathing, blood pressure, and oxygen levels, and sometimes sedation to protect the brain.

For idiopathic intracranial hypertension, treatment may include weight management, medications that reduce fluid production, and procedures to protect vision.

Prevention

Not all causes can be prevented, but some risks can be reduced:

• Wear helmets and seatbelts to prevent head injuries
• Manage high blood pressure to lower the risk of brain bleeding
• Seek prompt care for severe headaches, head injuries, or signs of brain infection
• Maintain a healthy weight to reduce the risk of idiopathic intracranial hypertension
• Keep follow-up appointments if you have a shunt or a history of hydrocephalus

When to See a Doctor

Call emergency services or go to the nearest emergency department right away if you or someone else has:

• A sudden, severe headache, especially the worst headache of your life
• Repeated vomiting with headache
• Increasing drowsiness, confusion, or difficulty staying awake
• New weakness, vision changes, unequal pupils, or seizures
• A recent serious head injury

Increased intracranial pressure can become life-threatening within minutes to hours, so do not wait to see if symptoms improve.

Related Topics

Frequently Asked Questions

References

1. National Institute of Neurological Disorders and Stroke (NINDS).
2. MedlinePlus, U.S. National Library of Medicine. Increased intracranial pressure.
3. Mayo Clinic. Idiopathic intracranial hypertension.
4. Brain Trauma Foundation. Guidelines for the management of severe traumatic brain injury.