Subdural empyema lumbar puncture

Template:Subdural Empyema Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]

Overview

Subdural empyema, also referred to as subdural abscess, pachymeningitis interna and circumscript meningitis, is a life-threatening infection. It consists of a localised collection of purulent material, usually unilateral, between the dura mater and the arachnoid mater and accounts for about 15-22% of the reported focal intracranial infections. The empyema may develop intracranially (about 95%) or in the spinal canal (about 5%), and in both cases, it constitutes a medical and neurosurgical emergency. The Lumbar Puncture is an invasive procedure which is contraindicated in case of suspicion of subdural empyema and increased intracranial pressure, due to risk of brain herniation and death.

Lumbar Puncture

Ininfants, in which subdural empyema is most commonly a complication of meningitis, spinal fluid culture is the gold-stadard test for the diagnosis, therefore it should be used after ruling-out increased intracranial pressure .

In adults, in which subdural empyema is most commonly a complication of sinusitis, spinal fluid in normal circumstances is sterile, however, changes in white blood cell count, glucose and protein concentrations are usually unspecific. Nevertheless, after increased intracranial pressure has been excluded, the lumbar puncture is a useful diagnostic test to rule out meningeal infection. The CSF findings which may suggest an infection are:

• increased white blood cell count
• increased protein level
• decreased glucose levels
• occasionally CSF results may be normal and sterile