Subdural empyema medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
Subdural empyema, also referred to as subdural abscess, pachymeningitis interna and circumscript meningitis, is a life-threatening infection, first reported in literature approximately 100 years ago.[1] It consists of a localised collection of purulent material, usually unilateral, between the dura mater and thearachnoid mater. It accounts for about 15-22% of the reported focal intracranial infections. The empyema may develop intracranially (about 95%) or in the spinal canal (about 5%), and in both cases, it constitutes a medical and neurosurgical emergency.[2] The intracranial type tends to behave like an expanding mass, causing clinical symptoms, such as fever, lethargy, headache and neurological deficits. These, result from the extrinsic compression of the brain, caused not only from the inflammatory mass, but also from the inflammation of the brain and meninges. Because the subdural space has no septations, except in areas where arachnoid granulations attach to the dura mater, the subdural empyema tends to spread quickly, until it finds those boundaries. In children, subdural empyema most often happens as a complication of meningitis, while in adults it usually occurs as a complication of sinusitis, otitis media, mastoiditis, trauma or as a complication of neurological procedures.[1] The most common pathogens in the intracranial type are anaerobic and microaerophilic streptococci, however others like Escherichia coli and Bacteroides may be present simultaneously. Spinal subdural empyemas, on the other hand, are almost always caused bystreptococci or by staphylococcus aureus.[2] The classic clinical syndrome includes acute fever, that rapidly progresses into neurological deterioration, which if left untreated will eventually lead to a comaand death.[1] The diagnostic procedure of choice is the MRI with gadolinium enhancement. Since the clinical symptoms might be mild and unspecific initially, the rapid diagnosis and treatment are crucial. The sooner the proper treatment is initiated, the better the recovery will be. The treatment, for almost all causes, requires prompt surgical drainage and antibiotic therapy.[2] With treatment, resolution of the empyema occurs from the dural side, and, if it is complete, a thickened dura may be the only residual finding.
Medical Therapy
In the treatment of subdural empyema, an early accurate diagnosis, timely surgical intervention and appropriate antibiotic therapy, are essential to a favorable outcome, with no, or the least sequelae possible. As a general rule, the treatment of intracranial or spinal subdural empyema requires both prompt surgical drainage and appropriate antibiotic therapy, an exception being, when there are contraindications to surgery or significant mortality risks.[1] The evacuation of the empyema can be done either by craniotomy or burr hole drainage.[3] Although the pus collection might be localised by imaging studies, and a evacuated by placement of a burr hole, the procedure of choice for evacuation of subdural purulent material is a wide range craniotomy with irrigation of the area. This improves the outcome by allowing wide exposure and adequate exploration, since the goal of the procedure is not only the evacuation of the pus, but also the eradication of the source of the infection. [1] After surgical drainage, the antibiotic therapy should be given parenterically for a period of 3-4 weeks however, complications, such as cranial osteomyelitis, may require longer therapy.
Intracranial subdural empyema
This subtype may have multiple pathogens involved, therefore initial antibiotic therapy should cover Staphylococcus aureus, microaerophilic and anaerobic streptococci and gram negative organisms. [1]
- Antibiotics for community-acquired subdural empyema should include a combination of:
- Nafcillin, Oxacillin or Vancomycin
- Third generation Cephalosporin
- Metronidazole
- Patients with hospital-acquired subdural empyema may be infected with different pathogens, such as Pseudomonas spp. or MRSA. Therefore, should receive coverage with the following:
- (Metronidazole is not necessary for the therapy of anaerobic agents in the presence of Meropenem)
Spinal subdural empyema
Initial antibiotic therapy should be directed to Staphylococcus aureus and Streptococci and should include:
The definitive pathogen diagnosis is made by Gram's stain and culture of the fluid obtained from the surgical drainage. After this diagnosis has been made, a more pathogen-oriented antibiotic therapy can be given.
Antibiotic Therapy
- Empirical antibiotic therapy of focal CNS Infections: [4]
▸ Click on the following categories to expand treatment regimens.
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INDICATION ▸ Infants < 1 month ▸ Infants 1-3 months ▸ > 3 months Immunocompetent Children; Adults < 55 years ▸ Adults > 55 years; Alcoholics; Debilitating Illness ▸ Specific Situations |
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Subdural Empyema Drug Summary
Nafcillin and Oxacillin
- Group of narrow spectrum antibiotics, of the penicillin class, both penicillinase-resistant. Their mechanism of action is based on binding transpeptidases, thereby blocking the cross-linkage of peptidoglycan. They are also involved in the activation of autolytic enzymes.
- They are used to treat gram-positive bacteria, particularly staphylococci, however are not indicated in the treatment of MRSA/ORSA.
- They are known to cause hypersensitivity reactions and to interfere with cytochrome P-450. Their use in congestive heart failure and kidney disease patients should also be cautious because of risk of edema.
Vancomycin
- A glycopeptide antibiotic that exerts its activity by inhibiting peptidoglycan synthesis and hence bacterial cell walls. It has bactericidal activity agains most pathogens and bacteriostatic activity agains enterococci.
- A narrow spectrum antibiotic used only for gram-positive bacteria.
- Due to its toxicity (Ototoxicity, Nephrotoxicity and Thrombophlebitis), its use is restricted to multidrug-resistant organisms (MRSA/ORSA, Clostridium difficile).
- In recent years, the emergence of vancomycin-resistant pathogens, has increased the use of antibiotics, such as carbapenem and linezolid.
Cephalosporin
- A bactericidal antibiotic, with a similar mechanism of action as other penicillins, cephalosporins interfere with the synthesis of peptidoglycan of the cell wall, being however less susceptible to penicillinases.
- Used for prophylaxis and treatment of certain bacteria.
- There are 4 generations of cephalosporins: 1st generation are indicated for gram-positive bacteria, while 2nd, 3rd and 4th generations have increased activity against gram-negatives.
- 1st generation cephalosporins include: cafalexin and cefazolin; 2nd generation: cefuroxime and cefoxitin; 3rd generation: ceftriaxone and cefotaxime; and 4th generation: cefepime and cefquinome.
- Organisms not usually covered by cephalosporins include: Listeria, MRSA and Enterococci.
Metronidazole
Carbapenem
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Agrawal, Amit; Timothy, Jake; Pandit, Lekha; Shetty, Lathika; Shetty, J.P. (2007). "A Review of Subdural Empyema and Its Management". Infectious Diseases in Clinical Practice. 15 (3): 149–153. doi:10.1097/01.idc.0000269905.67284.c7. ISSN 1056-9103.
- ↑ 2.0 2.1 2.2 Greenlee JE (2003). "Subdural Empyema". Curr Treat Options Neurol. 5 (1): 13–22. PMID 12521560.
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.
- ↑ Longo, Dan L. (Dan Louis) (2012). Harrison's principles of internal medici. New York: McGraw-Hill. ISBN 978-0-07-174889-6.