subdural empyema

Teenager with
nasal congestion for a week who now has a headache, fever, and has become obtunded. Axial (above left and above middle) and coronal (above right) T1 MRI with contrast of the brain shows opacification and rim enhancement of the left ethmoid and frontal sinuses, diffuse enhancement of the left meninges, and subdural fluid collections along the left convexity and falx posteriorly. Axial diffusion weighted (lower left) and ADC (lower right) images show diffuse restriction in the left frontal sinus and parafalcine subdural fluid collections.The diagnosis was pansinusitis with meningitis and subdural empyema.
pediatricimaging.org • CC-by-nc-sa 4.0
Cerebral
venous thrombosis, subdural empyema and cerebral abscess as complications of coalescent otomastoiditis. Subdural area of diffusion restriction in the right upper convexity consistent with subdural empyema.
www.eurorad.org • CC by-nc-sa-4.0
Cerebral
venous thrombosis, subdural empyema and cerebral abscess as complications of coalescent otomastoiditis. Subdural collection in the right upper convexity consistent with subdural empyema.
www.eurorad.org • CC by-nc-sa-4.0
Teenager with
left orbital and forehead swelling. Sagittal CT with contrast of the brain shows frontal and left maxillary sinusitis and extensive soft tissue swelling anterior to the forehead (upper left) and destruction of the anterior left frontal bone in the frontal sinus and extensive soft tissue swelling anterior to the left orbit (upper right). Coronal (lower left) and sagittal (lower right) T1 MRI with contrast of the brain shows diffuse meningeal enhancement, subdural empyemas along the falx and both cerebral convexities, and multiple large non-enhancing subgaleal fluid collections in the left scalp.The diagnosis was meningitis, subdural empyema, and Pott puffy tumor as complications of sinusitis.
pediatricimaging.org • CC-by-nc-sa 4.0
Cerebral
venous thrombosis, subdural empyema and cerebral abscess as complications of coalescent otomastoiditis. Subdural collection in the right upper convexity consistent with subdural empyema.
www.eurorad.org • CC by-nc-sa-4.0
Cerebral
venous thrombosis, subdural empyema and cerebral abscess as complications of coalescent otomastoiditis. Subdural collection in the right upper convexity consistent with subdural empyema.
www.eurorad.org • CC by-nc-sa-4.0
An abscess
that has let to an intracranial subdural empyema as seen on CT
Wikipedia • CC BY-SA 3.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Subdural empyema is a type of intracranial infection characterized by a suppurative collection between the dura mater and arachnoid mater. It is commonly seen as a complication of sinusitis, otitis, mastoiditis, or surgical intervention.

On imaging, it tends to present as a subdural collection, crescentic in shape, with marked meningeal enhancement and, on MRI, typically demonstrates restricted diffusion.

Epidemiology

Subdural empyemas account for approximately 20-33% of all intracranial infections.

Clinical presentation

Clinical presentation depends to some degree on the etiology. When empyemas result from sinusitis or mastoiditis they are often associated with seizures, focal neurological deficits and rapid deterioration of consciousness, progressing from obtundation to coma . Empyemas that occur secondary to prior trauma or surgery are usually more clinically indolent.

Pathology

In the most common scenario, patients develop subdural empyemas as a result of frontal sinusitis. There are two putative mechanisms of spread :

  • direct extension
  • indirect extension secondary to thrombophlebitis

    • Direct spread, resulting from erosion of the posterior wall of the frontal sinus (the corollary of Pott puffy tumor) is relatively uncommon. Thrombophlebitis of communicating veins is thought to be the most common cause of spread .

    Etiology

    Radiographic features

    CT is usually the first investigation performed and often is the only one required, as patients usually expediently proceed to the surgical theater for evacuation.

    CT

    Subdural empyemas typically resemble subdural hematomas in their shape and the relationship to sutures and dural reflections. They are typically crescentic in shape (compared to epidural empyemas which are typically lentiform), although collection pockets may appear biconvex (see case 1). A surrounding membrane that enhances intensely and uniformly following contrast administration is typical.

    MRI

    Appearance on MRI is similar to that on CT, although contrast enhancement is more readily detected. Furthermore, the content of the collection will typically demonstrate restricted diffusion (see case 1).

    MRI is also more sensitive to the complications of subdural empyemas, e.g. cerebritis, cerebral abscess, and venous thrombosis.

    Treatment and prognosis

    Mortality associated with subdural empyemas now approaches 10%, compared with approximately 15-40% in the pre-CT era .

    Successful treatment is predicated on prompt diagnosis, followed by surgical evacuation of the collection and administration of appropriate antibiotics.

    Complications

    Complications are relatively common and may be the cause of presentation. They include:

    Siehe auch:
    und weiter:
    Assoziationen und Differentialdiagnosen zu subdurales Empyem:
    Arachnoidalzyste
     
    Wikipedia • CC BY-SA 3.0
    Empyem
     
    Wikipedia • CC BY-SA 3.0
    Meningitis
     
    Wikipedia • CC BY-SA 3.0
    Mastoiditis
     
    Wikipedia • CC BY-SA 3.0
    chronisches
    Subduralhämatom
    pediatricimaging.org • CC-by-nc-sa 4.0