Subdural empyema

Case contributed by Dr Dylan Kurda

Presentation

Headache followed by reduced conscious state.

Patient Data

Age: 17 years
Gender: Male
Modality: CT

There is a large extra-axial (subdural) left parafalcine collection with extension along the tentorium cerebelli on both sides. There is significant mass effect with rightward subfalcine herniation, partial effacement of left lateral ventricle (more on the occipital horn). There is also left cerebral hemisphere sulcal effacement. Importantly, the left ambient cistern is obliterated with evidence of compression of the left cerebral crus associated with left sided uncal herniation. 

There is subtle hypodensity in the left hemispheric white matter, more conspicuous in the left frontal lobe. 

Evidence of left frontal and bilateral ethmoid sinus opacification. 

Interpretation: 

Given the lack of trauma, a subdural empyema is highly suspected, likely from paranasal sinusitis. 

Modality: MRI

As seen in the previous CT, there is a large subdural collection, which is high on T2, low on T1, demonstrating peripheral enhancement, and restricted pattern on DWI. The collection extends along the tentorium on both sides, associated with extensive adjacent dural and leptomeningeal enhancement. Demonstrated again are: the mass effect, rightward subfalcine and left sided uncal herniation as well as sinusitis. No evidence of tonsillar herniation.  

A small oval shaped peripherally enhancing collection is seen in the left gyrus rectus, with adjacent dural enhancement and restricted diffusion, could represent a small intraparenchymal abscess or part of the subdural empyema. 

Interpretation: 

Imaging appearances are those of extensive subdural empyema with mass effect and left sided uncal herniation. 

Case Discussion

Typical imaging features of sinusitis-related subdural empyema which is a neurosurgical emergency. The CT finding can be similar to subdural haematoma (subacute to chronic); however, the lack of traumatic history along with presence of sinusitis should suggest the possibility of empyema. The MRI appearance is an "aunt minnie". 

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Case Information

rID: 44789
Case created: 4th May 2016
Last edited: 3rd Jun 2016
Inclusion in quiz mode: Included

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