Subdural empyema pathophysiology
Subdural empyema Microchapters
Subdural empyema pathophysiology On the Web
American Roentgen Ray Society Images of Subdural empyema pathophysiology
Subdural empyema is a localized collection of pus between the dura mater and arachnoid mater, which occurs in either the intracranial space or the spinal canal. Subdural empyema generally follows the same progression for both intracranial and spinal subtypes, spreading via blood or from nearby infection.
Intracranial Subdural Empyema
Intracranial subdural empyema is usually unilateral, and affects the base of the brain, its convexity, the inter-hemispheric fissure along the falx cerebri, or the posterior fossa. The anatomy of the meningeal membranes dictate the course and characteristics of the disease. The dura mater and the arachnoid mater, which define the initial limits of the empyema, are joined only at the base of the brain, along the falx cerebri and at the tentorium cerebelli. This virtual space between these two meningeal membranes creates the potential for the infection to spread along the cerebral hemisphere, inter-hemispheric fissure, and posterior cranial fossa.
Intracranial subdural empyema's origin generally depends on the age of the individual. In younger children, the empyema most commonly results from complications of purulent meningitis, while in older children and adults, it most commonly results from complications of sinusitis, otitis media, or mastoiditis. In the case of sinusitis, the frontal sinus is the most commonly affected sinus, followed by the ethmoidal, sphenoidal, and maxillary sinuses. The infection may then spread in two ways:
- Blood, via retrograde infection, from thrombophlebitis of mucosal veins, which drain the sinuses
- Direct contact via:
- Neurosurgical procedures, such as subdural hematoma drainage, craniotomy, and intracranial pressure monitoring
- Head trauma
- Bacteremic seeding of an previous subdural hematoma
The subdural empyema causes an inflammatory reaction in the subdural space, which may be accompanied by cerebrospinal fluid pleocytosis and encephalitis. The venous extension of the infection may lead to hemorrhagic infarction or superficial abscess. Next, cerebral edema and hydrocephalus may develop, which combined with the empyema, creates a mass effect that increases intracranial pressure, and leads to transtentorial herniation, brainstem compression, and death. The most common pathogens in the intracranial type are:
Spinal Subdural Empyema
Spinal subdural empyema is more rare compared to intracranial. This type of infection follows a similar pathophysiology to intracranial subdural empyema. Potential sources of spread of infection include:
- Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- Agrawal, Amit; Timothy, Jake; Pandit, Lekha; Shetty, Lathika; Shetty, J.P. (2007). "A Review of Subdural Empyema and Its Management". Infectious Diseases in Clinical Practice. 15 (3): 149–153. doi:10.1097/01.idc.0000269905.67284.c7. ISSN 1056-9103.
- Greenlee JE (2003). "Subdural Empyema". Curr Treat Options Neurol. 5 (1): 13–22. PMID 12521560.
- Hendaus MA (2013). "Subdural empyema in children". Glob J Health Sci. 5 (6): 54–9. doi:10.5539/gjhs.v5n6p54. PMID 24171874.
- Kapu, Ravindranath; Pande, Anil; Ramamurthi, Ravi; Vasudevan, MC (2013). "Primary interhemispheric subdural empyemas: A report of three cases and review of literature". Indian Journal of Neurosurgery. 2 (1): 66. doi:10.4103/2277-9167.110227. ISSN 2277-9167.
- Courville, C. B. (1944). "SUBDURAL EMPYEMA SECONDARY TO PURULENT FRONTAL SINUSITIS: A CLINICOPATHOLOGIC STUDY OF FORTY-TWO CASES VERIFIED AT AUTOPSY". Archives of Otolaryngology - Head and Neck Surgery. 39 (3): 211–230. doi:10.1001/archotol.1944.00680010224003. ISSN 0886-4470.