Coordinated Health



A subdural effusion is a collection of fluid 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, incidence, and risk factors

A subdural effusion is a rare complication of bacterial meningitis. Subdural effusion is more common in infants and in persons who have meningitis caused by Haemophilus influenzae.


  • Bulging fontanelles in babies
  • Increased head circumference
  • Lethargy
  • Persistent fever
  • Seizures
  • Separated sutures in babies
  • Vomiting
  • Weakness or loss of movement on both sides of the body

Signs and tests

The doctor or nurse will examine you. Tests include:

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


Surgery to drain the effusion is often necessary. Rarely, a permanent drainage device (shunt) is needed to drain fluid. Antibiotics may need to be given through a vein.

Expectations (prognosis)

Full recovery from a subdural effusion is expected. If neurological problems continue, they are generally due to the meningitis, not the effusion. Long-term use of antibiotics is usually not necessary.


Complications from surgery include:

  • Bleeding
  • Brain damage
  • Infection

Calling your health care provider

Call your health care provider if:

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