E. GAMY; J. MAHLAOU., S. SEMLALI; S.CHAOUIR, T. AMIL; A.HANINE. M.MAHI, S. AKJOUJ Medical Imaging. Military Instruction Hospital Mohamed V Rabat. NR1

 Brain empyema = rare since the use of antibiotic  Often secondary to a sinus infection.  Neurosurgical emergency.  The modern imaging techniques, especially spiral CT and MRI have significantly reduced mortality by allowing earlier diagnosis.  We report 3 cases of extradural empyema complicating sinusitis.

 Case 1:  Patient, 17 years old, suffering from sinusitis and shuffling with a sudden disturbance of the functions above type of confusion.  We performed emergency brain scans  The early establishment of a regimen including anti-coagulants and anti-infective therapy were done  A rapid clinical improvement without neurological squeal were shown

 Case 2:  Patient, 19 years old, with impaired consciousness fever  Case 3:  Child 15 years, well vaccinated,  ATCD: RAS  Medical history: since 2 months, vomiting, impaired general condition and a fever of 40 ° C.  No neurological disorders.  Laboratory tests: Leucocytosis to 15,000 per mm3, CRP 200 mg / l. The CSF analysis was normal. Blood cultures: Sreptocoque sp. IDR and HIV: normal.

 A BRAIN SCAN performed in emergency showed a:  Right frontal extra axial collection, heterogeneous with a spontaneously hyperdensity posterior related bleeding.  There is also another collection in small controlateral frontal (extradural).  In bone window: through the paranasal sinuses show a left frontal sinusitis and ethmidale.

 The additional MRI found both frontal extradural collections, although limited medially by the dura mater in hypo T2 signal.  The subsequent hemorrhagic component is hyperintense T1 and T2 signal hypothesis.  The peripheral contrast enhancement is evident and the mass effect on midline structures.  The MRI also found the heterogeneous aspect of superior sagittal sinus.

 The MR angiography confirmed the cerebral venous thrombosis.  The patient is put on triple antibiotic therapy and underwent emergency surgery. We evacuated 200 ml of pus mixed with blood and found a right frontal osteitis.  Also we realized drainage of the maxillary sinuses. Control is satisfactory postoperative

Figure 1: Axial CT scan after injection of the PC shows the existence of a left frontal sinus with lysis of the posterior wall of the latter (a), two collections of extra-cerebral, frontal hypodense, biconvex, associated with contrast enhancement and a thickening of the dura mater from them. This is suggestive of extra-dural empyema (b and c). Within the superior sagittal sinus, near the empyema, there hypodensity (arrowheads Fig 1b) visible in several sections (Fig. 1d) showing the existence of cerebral thrombophlebitis A B C D

Fig 2 a and b: Axial CT scan of the facial bone and brain window in (c): ethmoid and left frontal sinusitis associated with extradural empyema ABC

Fig 3: MRI axial section T1-weighted (a), T1 gado (b) and 3D AMR venous (c) A B C

Fig 4: CT scan without contrast in axial section of the PC. Fig 5: AMR vein: normalization of the signal of superior sagittal sinus..

 Empyema is a collection tank perished brain, usually secondary to infection neighborhood especially in contact aeric face cavities. It grows on the convexities in 80% of cases, particularly the frontal lobes.  It can be inter hemispheric in 12% of cases.  The subdural empyema (ESD) represents 13-20% of all intracranial suppurations, against 20 to 33% in the extradural empyema (EED).  Empyema secondary to sinus infection symptoms are usually noisy with fast installation.  Febrile headache, usually frontal, are prominent and visible signs of intracranial hypertension and disorders of consciousness. The seizures are not uncommon.

 Conversely, the ESD is soon threatened, because of a faster increase in volume, as well as retrograde propagation through cortical veins thrombophlebitis of explaining the parenchymal lesions.  The most frequent germs are anaerobic streptococci.  These collections are more visible in MRI than CT.  The protein content differentiates their signal from that of the LCR and identifies them.  Compared to the brain collection appears hypointense signal on T1- weighted sequences and hyperintense on T2-weighted images.

 Gadolinium injection produces a contrast enhancement of the Dura and leptomeninges and therefore shows a border of hyper signal between the collection and parenchyma on the one hand, between the collection and vault on the other.  Generally, there are signal changes parenchyma neighborhood and sometimes a seeding of the brain with onset of an abscess  The EED is characterized by the image of the dura mater, T2 hypointense signal, enhanced by gadolinium injection, and the collection between the brain and by the topography and possible detachment of the venous sinuses.

 Ultrasound in infants, according to the topography, can show a collection perished brain and heterogeneous echogenic or transonic sometimes with an echogenic inner boundary.  In CT, the existence of contrast uptake in the periphery of the collection is characteristic

 May arise with:  A chronic subdural hematoma in post traumatic stress disorder (hypo signal in T1 and T2) or a hygroma (hypo T1 signal and hyperintense T2). While on the scanner all the lesions are hypo dense [6].  Septic thrombosis of intracranial venous sinus is also secondary to infection neighborhood. Their mortality is heavy, close 50% [10]. The MRI demonstrates thrombosis, venous infarction and meningeal reactions accompanying [10].  The superior sagittal sinus thrombosis is the classical representation the most telling, as is the case with our patient. When the clinic is raised (convulsion and / or increase of impaired consciousness), replaces the MRI scanner and, mostly, to angiography [1].  It allows using the sequences of angio-MRI in phase contrast to detect direct signs of venous thrombosis.

 The sequence of sinusitis complications, empyema - thrombophlebitis is classic.  At the initial stage of empyema diagnosis can be difficult on CT.  MRI more sensitive and specific, allows early diagnosis, therapeutic monitoring post and helps improve the prognosis