Epidemiology and demography
Epidural empyemas are relatively rare, but acount for ca. 30% of all intracranial infections. They can appear at every age with no sex preference.
The most common pathogens are streptococci, Haemophilus influenzae, Staphylococcus aureus and Staphylococcus epidermidis.
In more than 2/3 of cases epidural empyemas are a complication of sinusitis. Spreading can be per continuitatem through the sinus walls or retrograde through valve-less bridging veins.
Approximately 20% of cases are complications of mastoiditis. Epidural empyemas can occur as a complication of traumatic brain injury, neurosurgical operations or meningitis.
Fever, headache, meningism, sinusitis.
Focal-neurologic deficits or seizures can occur in cases of large, space-consuming empyemas.
Biconvex, bounded by sutures, can cross thr midline.
Extra-axial, liquorisodense or hyperdense space-consuming lesion, lensoid / biconvex.
Strong peripheral contrast enhancement.
- T1: Hyperintense
- T2/PD: Iso- or hyperintense
- FLAIR: Hyperintense
- DWI: Pus is hyperintense with decreased ADC
- T1 + Gd: strong peripheral contrast enhancement
- Kastrup O, Wanke I, Maschke M. Neuroimaging of infections of the central nervous system. Semin Neurol. 2008;28:511-22.
- Tsuchiya K, Osawa A, Katase S, Fujikawa A, Hachiya J, Aoki S. Diffusion-weighted MRI of subdural and epidural empyemas. Neuroradiology. 2003;45:220-3.
- Wong AM, Zimmerman RA, Simon EM, Pollock AN, Bilaniuk LT. Diffusionweighted MR imaging of subdural empyemas in children. AJNR Am J Neuroradiol. 2004;25:1016-21.