therefore , action must be taken immediately to diagnose and treat such intracranial complications before irreversible tissue damage has occurred , and both physicians and patients at putative risk should be aware . here , a case of sinusitis originating from an odontogenic focus leading to severe subdural empyema with subsequent neurological sequelae
a 45yearold man was admitted to the ophthalmological department with a periorbital swelling so severe it disabled him to open his left eye .
he was overweight ( bmi = 28 ) , without any known diabetes , was a smoker , and was undergoing treatment for rheumatoid arthritis ( ra ) ; methotrexate tablets ( 25 mg / week ) . at the time of admission the patient was febrile ( 38.7c ) and his state of consciousness was moderately affected . on inspection
the left periorbital region showed massive swelling ; the skin was warm , red , and sore ; and the left pupil was vaguely responsive equaling a small relative afferent pupillary defect .
the vital signs were as follows : pulse , 103 beats / min ; respiration , 16 breaths / min ; blood pressure , 118/71 mmhg ; hemoglobin , 7.3 gm / dl ; white blood cell count , 18.5  10/l ; neutrophils , 15.6  10/l ; creactive protein ( crp ) , 298 meq / l ; procalcitonin , 12.1 meq / l ; potassium , 3.3 meq / l ; and sodium , 133 meq / l . after ophthalmic examination a computed tomography ( ct ) scan of the orbit was performed and showed left orbital inflammation interpreted as postseptal cellulitis , exophthalmos , and
these findings led to the performance of an acute canthotomy in an effort to save the patient 's vision on the left eye . computed tomography scan in the axial plane showing exophthalmos and dirty fat ( arrow ) on the left eye . on the same day
large amounts of pus were evacuated from the left ethmoidal , frontal , and maxillary sinuses , and only a limited volume was present in and removed from the periorbita . simultaneously
two teeth ( 10 , 14 ) were extracted due to apical periodontitis with pus under pressure .
the patient was given a dose of antibiotics , cefuroxime ( 1500 mg ) and metronidazole ( 500 mg ) , following surgery and 6 h postoperatively .
an acute ct scan of the cerebrum was performed and a subdural accumulation visualized on the left side along with midline shift ( fig .
2 ) . computed tomography scan with contrast in the axial plane showing midline shift and a subdural accumulation ( arrow ) on the left side . under general anesthesia a burr hole surgery ( bhs ) was performed , and large amounts of pus were emptied under high pressure , and an external ventricular drain ( evd ) was placed in the anterior horn of the right lateral ventricle by neurosurgeons .
postoperatively the patient was aphasic and could only answer questions with onesyllable words . on hospital day 3 , a control ct still showed subdural empyema along with swelling of the left hemisphere , bleeding in the left frontal lobe , and perifocal edema ( fig .
3 ) . computed tomography scan in the axial plane showing swelling of the left hemisphere , empyema , bleeding in the left frontal lobe ( arrow ) , and perifocal edema .
day 4 , the patient 's gcs was 9 , and a new ct showed extensive swelling of the left hemisphere and still some empyema .
the ventricles had collapsed and therefore the evd did not produce any pus or cerebrospinal fluid . the crp had not changed much despite the antibiotics and antifungal medication ; voriconazole ( 400  2 mg the first day , then 200  2 mg the following ) now was initiated .
in addition to the bhs , 510 ml pus was drained from the extracranial abscess in relation to the left eye .
subsequently a sinuscopy was performed revealing an edematous mucosa and large amounts of coagulated blood , which were removed . upon ophthalmic examination on hospital day 5 the patient 's left pupil was found nonresponsive and the vision of this eye was declared lost .
there were still clear signs of inflammation and staphylococcus aureus , fusobacterium nucleatum , propionibacterium species , and group c streptococcus were found in the pus ; only group c streptococcus was found in the blood .
the antifungal medication was discontinued , while metronidazole ( 500  3 mg ) , meropenem ( 2  3 g ) , and linezolid ( 600  2 mg ) treatment was initiated . by hospital
4 ) of the brain showed improvement ; decreasing midline shift , increasing depth of sulci , and visible basal cisterns .
computed tomography scan in the axial plane showing decreased midline shift . during the next 2 days
over the course of 3 weeks he regained the ability to walk and his ability to construct more advanced sentences improved .
fortyfour days after admission the patient was discharged from the hospital . he still had neurological sequelae from the infection , such as loss of vision on the left eye and speech impairment as well as loss of shortterm memory .
generally , most cases of sinusitis , including suppurative infections , are uncomplicated . however , in some instances like this case the suppurative infection can spread and affect the orbita as well as intracranial structures , causing subdural empyema .
the sinusitis is believed to infect the subdural space either through osteomyelitis of the skull or by retrograde movement of septic thrombi via the small veins of the involved sinus 2 , 3 , 4 .
since subdural empyema is such a rare complication to sinusitis and in this case odontogenic , it can be difficult to diagnose because of a low index of suspicion .
when the patient was initially admitted to the hospital no dental complaints were mentioned and the symptoms from the eye were the predominant focus of the examination .
in addition , the initial examination did not reveal any dental abnormalities nor raise any suspicion to the fact that the patient was immunosuppressed .
this may explain why the dental infectious focus was not detected until during the first surgery .
the rapid progression of the infection in this case is probably due to immunosuppression as a result of methotrexate treatment .
it is important that action is taken early on to provide effective treatment and avoid a fatal outcome 5 .
therefore , it is important that patients experiencing orbital symptoms undergo cranial imaging at the slightest suspicion of suppurative complications . in this case
the patient underwent acute canthotomy as a result of the ct scan performed on the date of admission . despite this early intervention ,
the patient 's vision was lost , which may be contributed to the fact that he waited for several days before consulting a physician , while the swelling was building up . a contributing factor to the rapid progression of the infection in this particular patient
may be the suppression of the patient 's immune system due to ra and methotrexate intake , allowing the infection to persist despite the first bhs .
acute severe infection is a known risk of methotrexate treatment 8 ; however , the dose in this case was within the lowdose interval ( 25 mg / week ) . despite the low dose ,
the patient might have benefitted from being instructed by the prescribing doctor to see a physician at the representation of infectious symptoms .
generally the management of a subdural empyema has three components : early localization and treatment of the primary infectious focus , drainage of the empyema itself , and administration of antibiotics 1 . in this case
the infection originated from an odontological focus and the two affected teeth were extracted early on .
no consensus exists on the surgical intervention of choice as either bhs or craniotomy can be used . because of limited exposure when using bhs there is a higher incidence of recurring pus formation 3 .
this might explain why the first bhs in this case was not sufficient to eliminate the subdural empyema . as shown in this case of an aggressive purulent odontogenic and sinogenic infection with severe orbital and neurologic sequelae , early awareness , diagnosis , and treatment are essential , especially in immunosuppressed patients .
it is important to recognize that purulent spread to the orbit and intracranial requires immediate medical and surgical intervention .
 key clinical messagesubdural empyema is a rare but potentially lifethreatening complication to sinusitis . 
 awareness of infection and early diagnosis is of the essence when dealing with a putatively immunosuppressed patient . 
 furthermore , patients at increased risk of infections due to immunosuppression need to be fully informed of risks associated with their treatment . 
Introduction
Case Report
Discussion
Conflict of Interest