Subdural Empyema complicating Sinusitis in Immunocompetent adults

1. Subdural Empyema complicating Sinusitis in Immunocompetent adults Authors Institutions

2. 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

3. 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

4. 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

5. CT on first ER visit

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

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

8. Investigations • WBC 17.7 • CSF: 295 WBC, protein 104, glucose 67 • MRI scan of head

9. MRI

10. 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

11. 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

12. 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

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

14. Investigations • Na 127 • WBC 20.9 • CT brain

15. CT scan

16. 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

17. 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.

18. 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

19. MRI & Subdural Empyema • Study of choice for detecting subdural empyema • Higher sensitivity of detection of small subdural fluid collections • Iso-intense signals on T1-weighted imaging • High signals on T2- weighted imaging • Can help to differentiate between subdural empyema from chronic subdural hematomas ( Low signal on T1WI vs. High signal on T1WI)

20. References Ziai WC, Lewin JJ 3rd. Update in the diagnosis and management of central nervous system infections. Neurol Clin. 2008 May; 2(2): 427-68, viii. Foerster BR, Thurnher MM, Malani PN et al. Intracranial infections: clinical and imaging characteristics. Acta Radiol. 2007 Oct; 48(8): 875-93.

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