II. Definitions

  1. Subdural Abscess (Subdural Empyema)
    1. Purulent collection between the Dura Mater and the acrachnoid membrane
    2. Most commonly a complication of Sinusitis or Mastoiditis

III. Epidemiology

  1. Subdural Empyema is most common in young males

IV. Pathophysiology

  1. Spread of infection from the sinuses directly into the subdural space (via bone haversian canals)
  2. Children are more prone to Subdural Empyema due to highly vascular sinuses
  3. Infections spread more rapidly through the subdural space than through the epidural or intracranial space

V. Risk Factors

  1. Prior Head Trauma
  2. Neurosurgery history

VI. Causes: Source

  1. See Brain Abscess
  2. Subdural Abscess (Subdural Empyema) is a spread of Sinusitis or Mastoiditis in 60-90% of cases
    1. Mastoiditis (due to Chronic Otitis Media)
    2. Sinusitis (most commonly frontal, but also ethmoid, sphenoid and Maxillary)
    3. Dental Infection

VII. Causes: Organisms

VIII. Symptoms

  1. Recent Upper Respiratory Infection
  2. Severe Headache
    1. Typically unilateral in the region of abscess
  3. Photophobia
  4. Vomiting
  5. Seizures
  6. Fever
  7. Confusion

IX. Signs

  1. Fever
  2. Focal neurologic deficit
  3. Seizure
  4. Altered Level of Consciousness
    1. Associated with significant brain edema and with worse prognosis
  5. Comorbid Orbital Cellulitis may also be present

X. Imaging

  1. CT Head with contrast OR
  2. MRI Brain with gadolinium (preferred)

XII. Labs

  1. Complete Blood Count
  2. C-Reactive Protein
  3. Lumbar Puncture
    1. Indicated if Meningitis is suspected, but may be non-diagnostic in Subdural Empyema
    2. Contraindicated in focal symptoms/signs, CNS mass, Increased Intracranial Pressure (risk of Herniation)
    3. Obtain CNS imaging prior to Lumbar Puncture

XIII. Management

  1. See Brain Abscess
  2. Urgent Consultations (neurosurgery, infectious disease, otolaryngology)
  3. Initial Empiric Antibiotics
    1. Overall Antibiotic course of 4-6 weeks is typical
    2. Cefotaxime 2 g IV q4 hours OR Ceftriaxone 2 g IV every 12 hours (or Pen G 3-4 MU q4h) AND
    3. Metronidazole 7.5 mg/kg every 6 hours AND
    4. Vancomycin for suspected Staphylococcus Aureus
  4. Neurosurgical drainage
    1. Early intervention within first 72 hours may have greatest effect on outcome
    2. Craniectomy or burr hole drainage are most common
    3. Nonsurgical approach considered if clinically stable, <1 cm abscess and no midline shift
  5. Other adjuntive measures to consider (consult local expert opinion)
    1. Corticosteroids for brain edema
    2. Endoscopic Sinus Surgery may be considered
      1. Direct extension from sinus into subdural space through bony defect

XIV. Prognosis

  1. Mortality as high as 35% in Subdural Empyema

XV. Complications

  1. Associated with high morbidity and mortality
  2. Cognitive difficulties
  3. Hemiparesis
  4. Expressive Aphasia

XVI. References

  1. (2016) Sanford Guide, accessed 4/9/2016
  2. Marcom (2023) Crit Dec Emerg Med 37(7): 12-4
  3. Southwick in Calderwood (2016) UpToDate, accessed 4/9/2016
  4. Brouwer (2014) N Engl J Med 371:447 [PubMed]

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Related Studies

Ontology: Empyema, Subdural (C0038539)

Definition (MSH) An intracranial or rarely intraspinal suppurative process invading the space between the inner surface of the DURA MATER and the outer surface of the ARACHNOID. Bacteria and other pathogenic organisms may gain entrance to the subdural space from the FRONTAL SINUS; ETHMOID SINUS; middle ear (EAR, MIDDLE); MASTOID; or as the result of CRANIOCEREBRAL TRAUMA or NEUROSURGICAL PROCEDURES. This condition may be associated with intracranial sinus thrombosis (SINUS THROMBOSIS, INTRACRANIAL). Circumscribed collections of purulent material in the subdural space are referred to as subdural abscesses. (From Adams et al., Principles of Neurology, 6th ed, p709)
Concepts Disease or Syndrome (T047)
MSH D013354
SnomedCT 37660004
English Empyema, Subdural, Subdural Empyema, Subdural Empyemas, subdural empyema (diagnosis), subdural empyema, Empyema, Subdural [Disease/Finding], subdural abscess, Empyema (collection of pus), subdural space, Subdural abscess, Subdural empyema, Subdural abscess (disorder), empyema; subdural, abscess; subdural, subdural; abscess, subdural; empyema
French Empyème sub-dural, Empyème subdural, Empyème sous-dural, Empyèmes sous-duraux, Empyèmes subduraux
Swedish Subduralempyem
Czech subdurální empyém, Subdurální empyém
Finnish Subduraaliempyeema
Russian EMPIEMA SUBDURAL'NAIA, ABSTSESS SUBDURAL'NYI, SUBDURAL'NAIA EMPIEMA, АБСЦЕСС СУБДУРАЛЬНЫЙ, СУБДУРАЛЬНАЯ ЭМПИЕМА, ЭМПИЕМА СУБДУРАЛЬНАЯ
Japanese 膿瘍-硬膜下, 硬膜下蓄膿症, 蓄膿症-硬膜下, 硬膜下膿瘍, 硬膜下蓄膿, コウマクカチクノウショウ
Croatian EMPIJEM, SUBDURALNI, SUBDURALNI EMPIJEM
Polish Ropniak podtwardówkowy
Norwegian Subduralt empyem, Subduralempyem
Spanish empiema subdural, Empiema subdural, absceso subdural (trastorno), absceso subdural, Empiema Subdural
Dutch subduraal empyeem, abces; subduraal, empyeem; subduraal, subduraal; abces, subduraal; empyeem, Empyeem, subduraal, Subduraal empyeem
German subdurales Empyem, Empyem, subdurales, Subdurales Empyem, Abszeß, subduraler
Hungarian Subduralis empyema
Italian Empiema subdurale, Empiema sottodurale
Portuguese Empiema subdural, Empiema Subdural