Subdural Empyema complicating Sinusitis in Immunocompetent adults Authors Institutions

Introduction  Bacterial sinusitis is a common infection in adults  Posterior invasion through sinus walls causes subdural empyema  Prompt neurosurgery and antibiotics are needed for successful treatment  We report two causes of subdural empyema in patients who had sinusitis as underlying cause

Case One  30 year old male was admitted via ER  Two weeks h/o head ache  Two days h/o intermittent fever, vomiting, facial twitching and tenderness over frontal region of head

Background  Was seen in ER 3 days prior with headache and fever  Febrile, no nuchal rigidity  Had CT head – Pansinusitis  Discharged with amoxicillin-clavulunate  Did not take antibiotics for two days due to lack of insurance

CT on first ER visit

Other History  PMH:Migraine, remote h/o seizure  PSH:None  Social:Non-smoker, no alcohol use  Family:None significant  Medications: None

Physical Exam  Temp 37.9 o C, BP 90/49, PR 52  Drowsy, symmetrical facial twitching and nose wrinkling  Tenderness over frontal sinuses  Mild neck stiffness

Investigations  WBC 17.7  CSF: 295 WBC, protein 104, glucose 67  MRI scan of head

MRI

Management  Commenced on cefotaxime, vancomycin, metronidazole  Debridement of subdural empyema  Cultures grew viridans Streptococcus  Developed seizures and hemiplegia - repeat debridement with craniectomy  Treated with 6 weeks ABX, with resolution of hemiplegia

Case Two  55 year old male  Does not routinely seek medical care  Feeling generally unwell for few weeks  Took few doses of Levofloxacin given by physician friend  Was having intermittent headache, fever and increasingly lethargic  Seen previous day in urgent care, advised to follow with PCP

History continued  Came again with lethargy for 16 hrs, f/b decreased consciousness  PMH : Asthma  PSH: Nasal surgery and knee surgery  Social: Non smoker, no alcohol use  Medications: Advair and Fluticasone

Physical Examination  Temperature 36.8 o C, PR 91, BP 125/71  Did not follow commands, obtunded  Mild menigismus  No grimace on percussion over sinuses  Moderate gingivitis

Investigations  Na 127  WBC 20.9  CT brain

CT scan

Management  Commenced on cefotaxime, vancomycin and metronidazole  Emergent fronto-parietal subdural evacuation  Functional endoscopic sinus surgery  Culture of the subdural empyema grew Streptococcus intermedius  Good recovery and was transferred to rehabilitation

Conclusion  Subdural empyema is uncommon but potentially fatal complication of sinusitis.  Suspect subdural empyema in patients with sinusitis plus any of the following: -altered mental status -nuchal rigidity -seizures -focal neurological changes.  MRI is more sensitive than CT for diagnosis.

CT scan & Subdural Empyema  In early stages small subdural empyema can be subtle in non-contrast CT  Subdural empyema do not cross the midline  Have crescent like configurations  It appears iso-attenuation to low attenuation extra axial collections compared to brain parenchyma with rim enhancement

MRI & Subdural Empyema  Study of choice for detecting subdural empyema  Higher sensitivity of detection of small subdural fluid collections  Iso-intense signals on T 1 -weighted imaging  High signals on T 2- weighted imaging  Can help to differentiate between subdural empyema from chronic subdural hematomas ( Low signal on T1WI vs. High signal on T1WI)

References Ziai WC, Lewin JJ 3rd. Update in the diagnosis and management of central nervous system infections. Neurol Clin May; 2(2): , viii. Foerster BR, Thurnher MM, Malani PN et al. Intracranial infections: clinical and imaging characteristics. Acta Radiol Oct; 48(8):

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