An epidural abscess is a collection of pus (infected material) and germs between the outer covering of the brain and spinal cord and the bones of the skull or spine. The abscess causes swelling in the area.
Causes
Epidural abscess is a rare disorder caused by an infection in the area between the bones of the skull, or spine, and the membranes covering the brain and spinal cord (meninges). This infection is called an intracranial epidural abscess if it is inside the skull area. It is called a spinal epidural abscess if it is found in the spine area. Most are located in the spine.
The spinal infection is usually caused by bacteria but may be caused by a fungus. It can be due to other infections in the body (especially a urinary tract infection), or germs that spread through the blood. In some people, though, no other source of infection is found.
An abscess inside the skull is called an intracranial epidural abscess. The cause may be any of the following:
- Chronic ear infections
- Chronic sinusitis
- Head injury
- Mastoiditis
- Recent neurosurgery
An abscess of the spine is called a spinal epidural abscess. It may be seen in people with any of the following:
- Had back surgery or another invasive procedure involving the spine
- Bloodstream infections
- Boils, especially on the back or scalp
- Bone infections of the spine (vertebral osteomyelitis)
People who inject drugs are also at increased risk.
Symptoms
Spinal epidural abscess may cause these symptoms:
- Bowel or bladder incontinence
- Difficulty urinating (urinary retention)
- Fever and back pain
Intracranial epidural abscess may cause these symptoms:
- Fever
- Headache
- Lethargy
- Nausea and vomiting
- Pain at the site of recent surgery that gets worse (especially if fever is present)
Nervous system symptoms depend on the location of the abscess and may include:
- Decreased ability to move any part of the body
- Loss of sensation in any area of the body, or abnormal changes in sensation
- Weakness
Exams and Tests
The health care provider will perform a physical exam to look for a loss of functions, such as movement or sensation.
Tests that may be done include:
- Blood cultures to check for bacteria in the blood
- Complete blood count (CBC)
- CT scan of head or spine
- Draining of abscess and examination of the material
- MRI of head or spine
- Urine analysis and culture
Treatment
The goal of treatment is to cure the infection and reduce the risk for permanent damage. Treatment usually includes antibiotics and surgery. In some cases, antibiotics alone are used.
Antibiotics are usually given through a vein (IV) for at least 4 to 6 weeks. Some people need to take them for a longer time, depending on the type of bacteria and how severe the disease is.
Surgery may be needed to drain or remove the abscess. Surgery is also often needed to reduce pressure on the spinal cord or brain, if there is weakness or damage to the nerves.
Prognosis
Early diagnosis and treatment greatly improve the chance of a good outcome. Once a weakness, paralysis, or sensation changes occur, the chance of recovering lost function is greatly reduced. Permanent nervous system damage or death may occur.
Possible Complications
Complications may include:
- Brain abscess
- Brain damage
- Bone infection (osteomyelitis)
- Chronic back pain
- Meningitis (infection of the membranes covering the brain and spinal cord)
- Nerve damage
- Return of infection
- Spinal cord abscess
When to Contact a Medical Professional
An epidural abscess is a medical emergency. Go to the emergency room or call the local emergency number (such as 911) if you have symptoms of spinal cord abscess.
Prevention
Treatment of certain infections, such as ear infections, sinusitis, and bloodstream infections, may decrease the risk for an epidural abscess. Early diagnosis and treatment are important to prevent complications.
Alternative Names
Abscess – epidural; Spinal abscess
References
Kusuma S, Klineberg EO. Spinal infections: diagnosis and treatment of discitis, osteomyelitis, and epidural abscess. In: Steinmetz MP, Benzel EC, eds. Benzel’s Spine Surgery. 4th ed. Philadelphia, PA: Elsevier; 2017:chap 122.
Tunkel AR. Subdural empyema, epidural abscess, and suppurative intracranial thrombophlebitis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, Updated Edition. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 93.
