Subdural Empyema
A pus collection between the brain's protective layers
Quick Facts
- Type: Serious intracranial infection
- Location: Between layers covering the brain
- Common source: Sinus or ear infections
- Urgency: Medical emergency — treat immediately
Overview
Subdural empyema is a medical emergency. If suspected, urgent hospital care is needed. It is a collection of pus that forms in the subdural space, the area between two of the membranes that cover the brain (the dura and the arachnoid). As pus accumulates and inflammation builds, it presses on the brain and can spread, threatening serious and rapid harm.
Subdural empyema most often develops when an infection spreads from a nearby site, particularly the sinuses or the middle ear, or after head injury or neurosurgery. Because the infection sits right next to the brain and can enlarge quickly, it is treated as an emergency, usually combining surgery to drain the pus with antibiotics. Prompt recognition and treatment are crucial to a good outcome.
Symptoms
Symptoms often progress quickly and reflect both infection and pressure on the brain.
- Fever, often high
- Severe, worsening headache
- Stiff neck
- Nausea and vomiting
- Drowsiness, confusion, or declining alertness
- Seizures, which are common
- Weakness on one side of the body or problems with speech as the brain is affected
There may also be signs of the original infection, such as facial pain and congestion from a sinus infection or ear pain and discharge. A combination of fever, severe headache, and any change in alertness, weakness, or seizure requires emergency care.
Causes
Subdural empyema almost always results from infection spreading to the subdural space from a nearby or distant source.
- Sinus infections: The most common source, particularly infections of the frontal sinuses, which lie close to the brain.
- Ear and mastoid infections: Middle ear infections and infection of the bone behind the ear can extend inward.
- Head injury or surgery: Penetrating injury or neurosurgical procedures can introduce bacteria.
- Spread through the bloodstream: Less commonly, bacteria travel from an infection elsewhere in the body.
- Meningitis: In infants and young children, a fluid collection complicating meningitis can become infected.
Risk Factors
- Untreated or severe sinus infections, especially of the frontal sinuses
- Chronic or complicated middle ear and mastoid infections
- Recent head injury, especially penetrating injury
- Recent neurosurgery
- A weakened immune system
- In young children, a recent episode of meningitis
Prompt treatment of sinus and ear infections reduces the risk of this serious complication.
Diagnosis
Rapid imaging is the key to diagnosis, since the condition can progress quickly.
- Brain imaging: An MRI or CT scan with contrast shows the pus collection, its size, and any pressure on the brain; MRI is particularly sensitive.
- Blood tests and cultures: To detect infection and help identify the bacteria.
- Imaging of the sinuses and ears: To find the source of infection.
- Caution with lumbar puncture: A spinal tap may be avoided when there is significant pressure or a mass effect in the brain.
Treatment
Treatment is urgent and usually combines surgery and antibiotics. Do not delay seeking care.
- Surgical drainage: A neurosurgical procedure to remove the pus and relieve pressure on the brain is often needed quickly.
- Intravenous antibiotics: Prolonged courses of antibiotics given through a vein, refined once the bacteria are identified.
- Treating the source: Addressing the underlying sinus or ear infection, sometimes surgically, to prevent recurrence.
- Seizure control: Anti-seizure medicines, since seizures are common.
- Supportive and intensive care: Monitoring brain pressure and supporting vital functions as needed.
With prompt surgery and antibiotics, recovery is possible, though some people are left with seizures, weakness, or other neurological effects.
Prevention
Preventing and properly treating the infections that can spread to the brain is the main way to lower risk.
- Seek timely treatment for sinus and ear infections rather than letting them linger
- Complete prescribed antibiotic courses for serious infections
- Get prompt care for head injuries, especially penetrating wounds
- Follow medical advice after neurosurgery to reduce infection risk
- Watch for warning signs such as severe headache, fever, and drowsiness after a sinus or ear infection
When to See a Doctor
Subdural empyema is a medical emergency. Seek emergency care or call emergency services immediately if someone has:
- Fever with a severe, worsening headache and a stiff neck
- Drowsiness, confusion, or declining alertness
- A seizure
- Weakness on one side of the body or trouble speaking
- These symptoms developing during or after a sinus or ear infection
Fast diagnosis and treatment are essential to protect the brain.
Frequently Asked Questions
What is a subdural empyema?
It is a collection of pus between two of the membranes covering the brain. The pus and inflammation press on the brain and can spread quickly, making it a medical emergency that usually needs surgical drainage and antibiotics.
What causes a subdural empyema?
It most often spreads from a nearby infection, especially of the sinuses or middle ear, or follows head injury or neurosurgery. Less commonly, bacteria travel through the bloodstream, and in young children it can complicate meningitis.
Why is subdural empyema an emergency?
Because the pus sits right next to the brain and can enlarge rapidly, causing pressure, seizures, weakness, and declining alertness. Without prompt surgery and antibiotics it can cause severe brain damage or be fatal.
How is subdural empyema treated?
Treatment usually combines urgent surgery to drain the pus with a prolonged course of intravenous antibiotics, plus treatment of the underlying sinus or ear infection and anti-seizure medication. Care often takes place in intensive settings.
Can subdural empyema be prevented?
Promptly treating sinus and ear infections, caring for head wounds, and following medical advice after neurosurgery all reduce the risk. Being alert to warning signs like severe headache and drowsiness after such infections helps catch it early.
References
- MedlinePlus, U.S. National Library of Medicine. Subdural empyema.
- National Institute of Neurological Disorders and Stroke (NINDS).
- Mayo Clinic. Brain infections.
- Centers for Disease Control and Prevention (CDC).