Subdural effusion

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Subdural effusion

Definition

A subdural effusion is a collection of cerebrospinal fluid (CSF) trapped between the surface of the brain and the outer lining of the brain (the dura matter). If this fluid becomes infected, the condition is called a subdural empyema.

Causes

A subdural effusion is a rare complication of meningitis caused by bacteria. Subdural effusion is more common in infants.

It may also occur after head trauma.

Symptoms

Symptoms may include:

Outward curving of a baby's skull's soft spot (bulging fontanelle)
Abnormally wide spaces in the bony joints of a baby's skull (separated sutures)
Increased head circumference
Low energy (lethargy)
Persistent fever
Seizures
Vomiting
Weakness or loss of movement on both sides of the body

Exams and Tests

Your health care provider will perform a physical exam and ask about the symptoms.

To detect the subdural effusion, tests that may be done include:

CT scan of the head
Head size (circumference) measurements
MRI scan of the head
Ultrasound of the head

Treatment

Surgery to drain the effusion is often necessary. The fluid is usually tested. In rare cases, a permanent drainage device (shunt) is needed to drain fluid. Antibiotics may need to be given through a vein.

Treatment may include:

Surgery to drain the effusion
Drainage device, called a shunt, left in place for a short time or longer time
Antibiotics given through a vein to treat an infection

Outlook (Prognosis)

Full recovery from a subdural effusion is expected. If nervous system problems continue, they are generally due to the meningitis, not the effusion. Long-term antibiotics are usually not needed.

Possible Complications

Complications of surgery may include:

Bleeding
Brain damage
Infection

When to Contact a Medical Professional

Contact your provider if:

Your child has recently been treated for meningitis and symptoms continue
New symptoms develop

References

De Vries LS, Volpe JJ. Bacterial and fungal intracranial infections. In: Volpe JJ, ed. Volpe's Neurology of the Newborn. 7th ed. Philadelphia, PA: Elsevier; 2025:chap 39.

Kim KS. Bacterial meningitis beyond the neonatal period. In: Cherry JD, Harrison GJ, Kaplan SL, Steinbach WJ, Hotez PJ, eds. Feigin and Cherry's Textbook of Pediatric Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 31.

Nath A. Meningitis: bacterial, viral, and other. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 381.

Review Date: 8/19/2024
Reviewed By: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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