Subdural Empyema Workup

  • Author: Segun T Dawodu, MD, JD, MBA, FAAPMR, FAANEM, CIME, DipMI(RCSed); Chief Editor: Karen L Roos, MD   more...
 
Updated: Jul 14, 2011
 

Laboratory Studies

  • CBC count may show a toxic leukocytosis.
  • Erythrocyte sedimentation rate (ESR) may be elevated.
  • Blood should be cultured for aerobic and anaerobic organisms.
  • Preoperative tests should include electrolytes, BUN, liver function tests, and CBC count if surgical intervention is being considered.
Next

Imaging Studies

Cranial MRI is now the imaging study of choice, being superior to cranial CT scan in outlining the extent of subdural empyema and demonstrating the convexity and interhemispheric collections.

MRI also shows greater morphological detail than CT scan.

The sensitivity of MRI is improved by using gadolinium contrast medium. See the image below.

MRI scan of a subdural empyema in the left parietaMRI scan of a subdural empyema in the left parietal area.

Cranial CT[1] scan was the standard technique for quick diagnosis before the advent of MRI. The use of high-resolution, contrast-enhanced CT scan increases diagnostic yield, although it sometimes gives equivocal or normal results.

On CT scan, subdural empyema shows as a hypodense area over the hemisphere or along the falx; the margins are better delineated with the infusion of contrast material. Cerebral involvement also is visible.

Cranial osteomyelitis may be seen.

CT scan is the modality of choice if the patient is comatose or critically ill and MRI is not possible or is contraindicated. See the image below.

CT scan of a subdural empyema in the left temporalCT scan of a subdural empyema in the left temporal/parietal area.

Cranial ultrasound[2] has been helpful in differentiating subdural empyema from anechoic reactive subdural effusion in infants with meningitis accompanied by complex features (eg, increased echogenicity in the convexity collections, presence of hyperechoic fibrinous strands or thick hyperechoic inner membrane, and increases in echogenicity of the pia-arachnoid).

Previous
Next

Other Tests

  • Preoperative - ECG, chest radiograph
  • Studies to define causes - Chest radiograph for pulmonary source, CT scan of paranasal sinuses and mastoid cells, sputum culture, nasal drip culture
Previous
Next

Procedures

Lumbar puncture is currently contraindicated because of possible cerebral herniation from increased intracranial pressure.

Lumbar puncture may be performed in the course of a workup to rule out meningeal infection when increased intracranial pressure has been excluded.

CSF examination[3] is an adjunctive test in the diagnosis of subdural empyema and may be obtained in addition to the other diagnostic tests previously outlined. CSF findings include the following:

  • WBC count (predominantly polymorphonuclear neutrophils) is increased. A significant increase (>50/µL) may be seen, although a slightly elevated cell count of 5-20/µL (reference range, 0-5/µL) does not rule out the possibility of subdural empyema.
  • Increased protein level greater than 100 mg/dL may be seen (reference range, 20-40 mg/dL), although less substantial elevations (50-90 mg/dL) do not rule out the possibility of subdural empyema.
  • Decreased glucose levels of 40 mg/dL or less usually are seen (reference range, 50-80 mg/dL). CSF glucose levels should be normalized with a blood glucose level obtained concurrently.
  • Occasionally, the CSF is normal and sterile in these cases.
  • The specific CSF findings should be compared with the accepted normal values of the treating physician's laboratory.
Previous
Proceed to Treatment & Management
 
 
Contributor Information and Disclosures
Author

Segun T Dawodu, MD, JD, MBA, FAAPMR, FAANEM, CIME, DipMI(RCSed)  Associate Professor of Rehabilitation Medicine and Interventional Pain Medicine, Albany Medical College

Segun T Dawodu, MD, JD, MBA, FAAPMR, FAANEM, CIME, DipMI(RCSed) is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American College of Sports Medicine, American Medical Association, American Medical Informatics Association, Association of Academic Physiatrists, International Society of Physical and Rehabilitation Medicine, and Royal College of Surgeons of England

Disclosure: Nothing to disclose.

Coauthor(s)

Nicholas Lorenzo, MD  Chief Editor, eMedicine Neurology; Consulting Staff, Neurology Specialists and Consultants

Nicholas Lorenzo, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Neurology, and American College of Physician Executives

Disclosure: Nothing to disclose.

Specialty Editor Board

Edward L Hogan, MD  Professor, Department of Neurology, Medical College of Georgia; Emeritus Professor and Chair, Department of Neurology, Medical University of South Carolina

Edward L Hogan, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Neurology, American Neurological Association, American Society for Biochemistry and Molecular Biology, Phi Beta Kappa, Sigma Xi, Society for Neuroscience, and Southern Clinical Neurological Society

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Florian P Thomas, MD, MA, PhD, Drmed  Director, Spinal Cord Injury Unit, St Louis Veterans Affairs Medical Center; Director, National MS Society Multiple Sclerosis Center; Director, Neuropathy Association Center of Excellence, Professor, Department of Neurology and Psychiatry, Associate Professor, Institute for Molecular Virology, and Department of Molecular Microbiology and Immunology, St Louis University School of Medicine

Florian P Thomas, MD, MA, PhD, Drmed is a member of the following medical societies: American Academy of Neurology, American Neurological Association, American Paraplegia Society, Consortium of Multiple Sclerosis Centers, and National Multiple Sclerosis Society

Disclosure: Nothing to disclose.

Selim R Benbadis, MD  Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, Tampa General Hospital, University of South Florida College of Medicine

Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, and American Medical Association

Disclosure: UCB Pharma Honoraria Speaking, consulting; Lundbeck Honoraria Speaking, consulting; Cyberonics Honoraria Speaking, consulting; Glaxo Smith Kline Honoraria Speaking, consulting; Pfizer Honoraria Speaking, consulting; Sleepmed/DigiTrace Honoraria Speaking, consulting

Chief Editor

Karen L Roos, MD  John and Nancy Nelson Professor of Neurology, Professor of Neurological Surgery, Department of Neurology, Indiana University School of Medicine

Karen L Roos, MD is a member of the following medical societies: American Academy of Neurology and American Neurological Association

Disclosure: Nothing to disclose.

References

  1. Zimmerman RD, Leeds NE, Danziger A. Subdural empyema: CT findings. Radiology. Feb 1984;150(2):417-22. [Medline].

  2. Chen CY, Huang CC, Chang YC. Subdural empyema in 10 infants: US characteristics and clinical correlates. Radiology. Jun 1998;207(3):609-17. [Medline].

  3. Brennan MR. Subdural empyema. Am Fam Physician. Jan 1995;51(1):157-62. [Medline].

  4. Greenlee JE. Subdural empyema. In: Mandell GL, ed. Principles and Practice of Infectious Diseases. Vol 1. 4th ed. New York: Churchill;1994:900-903.

  5. Feuerman T, Wackym PA, Gade GF. Craniotomy improves outcome in subdural empyema. Surg Neurol. Aug 1989;32(2):105-10. [Medline].

  6. Sanford JP. Guide to antimicrobial therapy. Bethseda MD: Uniformed Services University Health Sciences. 1993;3.

  7. Delgado Tapia JA, Galera Lopez J, Santiago Martin J, et al. Subdural empyema due to Mycoplasma hominis after a cesarean section under spinal anesthesia. Rev Esp Anestesiol Reanim. 2005;52(4):239-242. [Medline].

  8. Dwarakanath S, Suri A, Mahapatra AK. Spontaneous subdural empyema in falciparum malaria: a case study. J Vector Borne Dis. Sep-Dec 2004;41(3-4):80-2. [Medline].

  9. Foerster BR, Thurnher MM, Malani PN, Petrou M, Carets-Zumelzu F, Sundgren PC. Intracranial infections: clinical and imaging characteristics. Acta Radiologica. October 2007;48(8):875-93. [Medline].

  10. Hall WA, Truwit CL. The surgical management of infections involving the cerebrum. Neurosurgery. February 2008;62 Supplement 2:519-30. [Medline].

  11. Krauss WE, McCormick PC. Infections of the dural spaces. Neurosurg Clin N Am. Apr 1992;3(2):421-33. [Medline].

  12. Mauser HW, Van Houwelingen HC, Tulleken CA. Factors affecting the outcome in subdural empyema. J Neurol Neurosurg Psychiatry. Sep 1987;50(9):1136-41. [Medline].

  13. Migirov L, Eyal A, Kronenberg J. Intracranial complications following mastoidectomy. Pediatr Neurosurg. Sep-Oct 2004;40(5):226-9. [Medline].

  14. .

  15. [Best Evidence] Moorthy RK, Rajshekhar V. Intracranial Abscess. Neurosurg Focus. 2008;24 (6):E3.

 
Previous
Next
 
MRI scan of a subdural empyema in the left parietal area.
CT scan of a subdural empyema in the left temporal/parietal area.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2012 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

DISCLAIMER: The content of this Website is not influenced by sponsors. The site is designed primarily for use by qualified physicians and other medical professionals. The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Please check with a physician if you suspect you are ill.