AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Background

Although rare in developed countries, brain abscess is a serious, life-threatening emergency. Once having a dire outcome, morbidity and mortality have decreased because of advances in diagnostic modalities, antibiotic regimens, and earlier surgical interventions.^{1, 2} However, changes in epidemiology, including new disease pathogens and predisposing factors, have renewed concern about the diagnosis and treatment of this condition.

Pathophysiology

Brain abscess is a focal infection, which begins when organisms are inoculated into the brain parenchyma, usually from a site distant from the central nervous system (CNS). Abscess formation occurs through several stages. Inflammation during the "early cerebritis" stage evolves into a necrotic collection of pus, eventually surrounded by a well-vascularized capsule after 2 weeks.^{3, 4}

The 3 mechanisms of entry into the brain are as follows:^{2, 5, 6}

• Direct extension: Infections stemming from the sinuses, teeth, middle ear, or mastoid may gain access to the venous drainage of the brain via valveless emissary veins that drain these regions. Because of improved antibiotic therapy for ear infections, this mechanism is decreasing in incidence, accounting for only approximately 25% of cases.²
• Hematogenous: Seeding of the brain occurs from distant infection sites and often results in multiple brain abscesses.⁷ This remains an important cause of brain abscess.
• Following penetrating head injury or neurosurgery: Previously low in incidence, more brain abscesses are developing after head trauma and neurosurgical procedures. A recent case series found that 37% of brain abscesses were associated with head penetration.^{2, 8}

Up to 25% of abscesses are cryptogenic and have no clear source.^{2, 7}

Frequency

United States

Brain abscess is rare in the general population; however, immunocompromised patients have increasing incidence of brain abscess, often with fungal or protozoan organisms.

In the United States, 1500-2500 cases are reported per year.⁷

Mortality/Morbidity

• The mortality rate from brain abscess is currently approximately 10%.^{1, 2, 9}
• However, if the abscess ruptures into the ventricular system, the mortality rate may be 80%.²
• Morbidity in survivors is generally due to residual neurologic defects, increased incidence of seizures due to scar tissue foci, or neuropsychiatric changes.⁷

Race

No compelling evidence exists for racial differences in the incidence of brain abscess.

Sex

Brain abscess occurs twice as often among men than women.^{2, 4, 10, 11}

Age

Traditionally, brain abscesses were disproportionately diagnosed in the young. However, with changes in vaccination practices, treatment of pediatric infections, and the AIDS pandemic, current literature suggests a shift in peak incidence toward the third to fifth decades of life.^{2, 11, 12}

CLINICAL

Section 3 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

History

• Headache is the most common presenting symptom of brain abscess (50-90% of cases).^{2, 11}
• Focal neurologic deficit (50%) may correlate with the local region of infection.⁶
• Classic triad of headache, fever, and focal neurologic deficit is rarely seen (<5% of cases in a recent case series).²
• Seizure (40%) and mental status changes (50%) are common.^{2, 11}
• Nausea, vomiting, or stiff neck may be reported with increased cerebral edema due to the mass lesion.⁶
• Sudden worsening of a preexisting headache accompanied with meningismus may be indicative of a catastrophic event—rupture of the abscess into the ventricular space.⁶

Physical

• Fever is typically low grade, but presence or absence of fever does not aid in diagnosis, as it is present in less than half of all cases.^{6, 11}
• Altered mental status ranges from subtle personality changes through drowsiness to full-blown coma.¹¹
• Nuchal rigidity occurs in about 25% of cases.¹¹
• Focal neurologic findings are commonly present^{6, 11} and can signal increasing cerebral edema around the abscess.⁴
• Seizures are typically generalized.¹¹
• Papilledema indicates the disease process is well advanced and increased intracranial pressure is present.¹¹
• Bulging fontanelles, irritability, and enlarging head circumference may be noted in infants.⁵

Causes

A wide variety of organisms can cause brain abscess, depending on the portal of entry, and up to one third may be polymicrobial.^{3, 6}  

• Direct extension - Sinus, odontogenic, and otogenic sources are common.
• • Streptococcus species (aerobic and anaerobic) are most frequently isolated.
  • Other organisms include Bacteroides, Enterobacteriaceae, Pseudomonas, Fusobacterium, Prevotella, Peptococcus, and Propionibacterium.
• Hematogenous spread - Pathogens depend on predisposing source. Some common examples are listed below.
• • Endocarditis - Streptococcus viridans, Staphylococcus aureus
  • Pulmonary infections - Streptococcus, Fusobacterium, Corynebacterium, and Peptococcus species
  • Cardiac defects with right-to-left shunt - Streptococcus species
  • Intra-abdominal infections - Klebsiella species, E coli, other Enterobacteriaceae, Streptococcus species, anaerobes
  • Urinary tract infections - Enterobacteriaceae, Pseudomonas species
  • Wound infection - S aureus
• Penetrating head trauma, postoperative⁸
• • S aureus is most commonly isolated.
  • Enterobacteriaceae, other gram-negative bacilli, S epidermidis, Clostridium species, anaerobes, and Pseudomonas species may also be found.
  • Opportunistic infection is an increasing cause of brain abscess, as there are more patients with organ transplant, HIV, and immunodeficiencies. Common organisms include Toxoplasma gondii and  Nocardia, Aspergillus, and Candida species.^{4, 5, 6} Cases of Nocardia are increasing even in immunocompetent patients and have high mortality.^{2, 4, 13}
  • Other predisposing risk factors include intravenous drug use, cardiac abnormalities (ie, prosthetic valve, septal defect), cyanotic congential heart disease (most common cause of multiple brain abscesses in children), diabetes, chronic steroid use, alcoholism, and neoplasm.^{2, 7, 11}
  • Case reports of near drowning, foreign body aspiration, application of dental braces, and esophageal dilatation have also been associated with brain abscess.^{14, 15, 16, 17}
  • When there is no obvious source (up to 25% of cases), upper respiratory tract flora and anaerobes are often isolated.² Several sources have identified a patent foramen ovale by echocardiogram in these cases and propose this as a possible mechanism for seeding oral flora to the brain.¹⁸
  • Several cases of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) causing brain abscess have been reported recently, so this must be considered when initiating empiric therapy in patients presenting with neurologic symptoms who also have risk factors for CA-MRSA.^{19, 20}

DIFFERENTIALS

Section 4 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Other Problems to be Considered

Cerebellopontine angle tumor
Extradural abscess
Pediatric AIDS
Subdural empyema
Cranial osteomyelitis 

Recent evidence suggests that a strong statistical association of pulmonary arteriovenous malformation (PAVM) and brain abscess exists. To date, no evidence of a causal relationship between the two exists, but if a patient is known to have PAVM, an increased level of suspicion should exist for brain abscess if symptoms suggest the diagnosis. Conversely, some have called for screening for PAVM in all patients with brain abscess in order to avoid missing this potentially life-threatening disorder.¹⁰

WORKUP

Section 5 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Lab Studies

Laboratory tests are rarely helpful in establishing a diagnosis of brain abscess.^{2, 7}

• Elevated white blood cell (WBC) count or erythrocyte sedimentation rate (ESR) is not reliably found.^{6, 21}
• Blood culture results may only be positive in 30% of patients^{2, 22} but should always be obtained. Hematogenous spread may be the source as noted above, and a positive blood culture result may help guide therapy, especially if empiric antibiotics are started and abscess fluid culture yields no growth.^{6, 2}
• Culture specimen from any other suspected focus of infection should also be collected, as this may also give clues for possible distant sources.¹¹

Imaging Studies

• CT imaging of the brain (with and without contrast) is the most readily available study for establishing diagnosis of brain abscess in the ED.  
• • Early in the course, abscess appears as a low-density, irregular zone that does not enhance in the presence of intravenous contrast (early cerebritis).
  • Classically, as the disease progresses, a distinctive "ring enhancement" appears on contrast-enhanced CT, as the abscess wall thickens.
  • Rarely, a well-organized abscess wall fails to generate such ring enhancement. Such false-negative results should not have an impact on ED care or disposition; they have more implications for inpatient care, where the timing of surgical intervention may be dictated by response to preliminary intravenous antibiotics and subsequent organization of the abscess wall.²³ 
• CT is generally sufficient to make the preliminary diagnosis, which mandates neurosurgical consultation and admission to the hospital.^{2, 3, 6}
• However, MRI is increasingly being used for further evaluation.
• • MRI is more sensitive in detecting early cerebritis.²
  • Posterior fossa lesions may not be identified on CT scan and may require MRI to make the critical diagnosis.^{2, 4}
  • A ring-enhancing lesion on CT scan may give rise to a differential diagnosis including abscess versus primary tumor or metastasis. Gadolinium-enhanced MRI is helpful in characterizing these lesions. On diffusion-weighted imaging, pyogenic abscesses have a hyperintense signal, whereas nonpyogenic lesions will have a hypointense or mixed signal. Although not readily available in the emergency department, proton magnetic resonance spectroscopy may also be used to differentiate abscesses.^{24, 25}

See Brain, Abscess for images.

Other Tests

• Ultrasonography: As ultrasonography is becoming widely used in the emergency department, bedside ocular ultrasonography may be performed to assess for increased intracranial pressure.²⁶

Procedures

• Lumbar puncture (LP)
• • LP results are generally not helpful in the diagnosis of brain abscess. Performing this procedure in the emergency department is generally indicated only in cases highly suspicious for bacterial meningitis, with a careful balance between any potential change in management and the risk of CNS herniation.^{4, 11}
  • The suspicion of brain abscess, presence of any focal neurologic finding, or of papilledema is an absolute indication for CT imaging prior to LP.²⁷
• In cases where LP had been performed, the findings were nonspecific and cultures were rarely positive.²
• Abscess aspiration: Culture of the abscess fluid is the most important microbiological study to ensure appropriate targeted therapy. As a result, urgent or emergent neurosurgical consultation is necessary.^{2, 3}

TREATMENT

Section 6 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Prehospital Care

Rapid transport is the key component of prehospital care for suspected intracranial abscess.

Emergency Department Care

• The initial evaluation is dictated by the severity of the patient's condition.
• Emergent intubation using a cerebroprotective rapid sequence induction regimen is often necessary in patients with obtundation, inability to protect the airway, and suspected herniation.
• Stable patients whose presentation suggests the diagnosis should undergo rapid neuroimaging after initial evaluation.²,³,⁷ Close monitoring of neurologic status is essential and having at least one nurse or advanced provider in attendance while the patient is undergoing imaging is probably advisable.
• Antibiotics should be administered as early as possible in the patient's course in the ED. These may be given prior to imaging in cases where the diagnosis is very strongly suspected.¹¹
• Seizures should be treated aggressively to decrease the risk of sustained increases in intracranial pressure. Prophylactic anticonvulsants are often used given the relatively high frequency of seizures in this population.³

Consultations

• Once the diagnosis is clear, immediate neurosurgical consultation is mandatory.^{2, 3}
• Infectious disease consultation may be necessary to optimize antibiotic therapy, especially in immunocompromised hosts.^{2, 4}
• Neurology consultation is helpful in guiding both immediate and long-term management.

MEDICATION

Section 7 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Selection of appropriate antimicrobials with adequate CNS penetration and coverage of typical anaerobic and aerobic organisms is critical in controlling infection and preventing complications.

In the early phase of abscess formation, cerebritis, patients may respond to antibiotic therapy alone.^{7, 5}

However, in almost all cases, definitive treatment of brain abscess requires surgical drainage.^{2, 3}

Since seizures are a frequent complication of brain abscess, anticonvulsants for seizure prophylaxis are often recommended at the initial time of diagnosis and for a prolonged period of time, often greater than 1 year.^{3, 7}

Drug Category: Antibiotics

In the ED, empirical regimens of antibiotic therapy are the first-line pharmacologic treatment of brain abscess based on presumed source:³ 

• Direct extension from sinuses, teeth, middle ear - Penicillin G + metronidazole + third-generation cephalosporin
• Hematogenous spread or penetrating trauma - Nafcillin + metronidazole + third-generation cephalosporin
• Postoperative - Vancomycin (concern for MRSA) + ceftazidime or cefepime (concern for Pseudomonas)
• No predisposing factor - Metronidazole + vancomycin + third-generation cephalosporin

Imipenem or meropenem can also be used for broad-spectrum coverage when other drug toxicities are unacceptable, but imipenem has been associated with seizures in patients with brain abscess.⁴

Additional targeted therapy may also be initiated in suspected fungal or protozoan infections, especially in immunocompromised patients.²

Drug Category: Corticosteroids

Use of steroids is controversial. The anti-inflammatory effects of steroid therapy can decrease cerebral edema, reducing intracranial pressure (ICP). These benefits are offset somewhat by the fact that steroid use decreases antibiotic penetration into the abscess and may slow encapsulation of the abscess site. Therefore, many authors recommend steroids only in cases of massive cerebral edema with impending herniation.^{3, 11}

FOLLOW-UP

Section 8 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Further Inpatient Care

• A combined medical and surgical approach is used for most brain abscesses to eradicate the invasive organism.
• Duration of antibiotic treatment is unclear and is dictated by clinical response. Traditionally 6-8 weeks of intravenous antibiotics has been used followed by oral antibiotics for another 4-8 weeks to prevent relapse.^{2, 4, 7, 28} A recent series reported clinical resolution in some patients with only 2 weeks of intravenous therapy,² indicating that some patients may not need extended parenteral treatment.
• Surgery is the only way to precisely isolate the causative organism and tailor antibiotic therapy. One study concluded that antibiotic pretreatment for up to 10 days does not alter culture positivity of intracerebral specimen.¹¹ At present, most neurosurgeons use nonoperative management (ie, prolonged courses of parenteral antibiotics) only in rare cases, such as an abscess at an inoperable site or multiple abscesses.^{2, 3}
• Surgical options include aspiration, incision and drainage, or excision depending on the location, size, number of sites, and other characteristics of the abscess as well as the patient's clinical status.^{2, 3} The specific choice of surgical technique is less important than the basic principle of removing the pathogen.³
• Many abscesses that were once inoperable can now be reached by stereotactic aspiration guided by precision mapping of the lesion's location by CT or MRI.^{3, 28} Stereotactic aspiration is widely preferred to open craniotomy because it is minimally invasive, has low morbidity/mortality, and allows rapid drainage.^{2, 6} Reports of magnetic resonance fluoroscopy to guide aspiration also exist.²⁹
• Some interest exists in the possible role of hyperbaric oxygen as an adjunct therapy to the initial phase of treatment with intravenous antibiotics. Reports in children³⁰ and in adults³¹ suggest that such adjunct therapy may reduce the length of inpatient stay by decreasing the duration of antibiotics needed for clinical improvement; however, the number of cases studied to date is small.

Further Outpatient Care

Interval CT scans are recommended for inpatients and outpatients to followup for complications and resolution of abscess,³,⁴ as there is a risk of abscess reaccumulation or failure to resolve in some cases requiring reaspiration.²

Transfer

Lack of neurosurgical availability is an indication for transfer to a medical center that has such support.

Complications

• Uncal or tonsillar herniation due to increased intracranial pressure (ICP)²¹
• Rupture of abscess into ventricles or subarachnoid space is a complication. This is often lethal. High-risk features for this complication include an abscess that is deep seated, multiloculated, and/or close to the ventricular wall.³²
• Recurrence of abscess²
• Long-term neurologic sequelae in up to 50% of patients (ie, hemiparesis, seizures)^{4, 6, 11, 22}

Prognosis

• Survival rates for brain abscess are excellent.
• Characteristics associated with an excellent prognosis include the following:
• • Young age¹¹
  • Absence of severe neurologic defect on initial presentation^{11, 33}
  • Absence of neurologic deterioration during initial workup^{11, 33}
  • Absence of comorbid disease^{11, 33}
• Worse prognosis of brain abscess is associated with the following:
• • Signs of herniation on initial presentation (Mortality rate exceeds 50%.¹¹)
  • Extent of brain lesion on radiology (ie, increased size, critical location, more lesions, increasing edema/midline shift)³⁴
  • Short duration of symptom-onset before diagnosis⁴
  • Gram-negative infection³⁵
  • Nocardial abscess (Mortality rate is 3 times that of bacterial abscess and can reach fatality rates as high as 50% in immunocompromised patients.¹³)

Patient Education

• For excellent patient education resources, visit eMedicine's Infections Center, Brain and Nervous System Center, and Brain and Nervous System Center. Also, see eMedicine's patient education articles Brain Infection, Antibiotics, and Brain Infection.

MISCELLANEOUS

Section 9 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Medical/Legal Pitfalls

• Failure to obtain emergency neuroimaging in patients with headache and new neurologic defect
• Discharging a patient without explaining a new neurologic finding
• Failure to heed family concerns about unusual patient behavior when other symptoms suggestive of brain abscess are present.

ACKNOWLEDGMENTS

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, William Ernoehazy, Jr, MD, to the development and writing of this article.

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

1. Alderson D, Strong AJ, Ingham HR, et al. Fifteen-year review of the mortality of brain abscess. Neurosurgery. Jan 1981;8(1):1-6. [Medline].
2. Carpenter J, Stapleton S, Holliman R. Retrospective analysis of 49 cases of brain abscess and review of the literature. Eur J Clin Microbiol Infect Dis. Jan 2007;26(1):1-11. [Medline].
3. Lu CH, Chang WN, Lui CC. Strategies for the management of bacterial brain abscess. J Clin Neurosci. Dec 2006;13(10):979-85. [Medline].
4. Mathisen GE, Johnson JP. Brain abscess. Clin Infect Dis. Oct 1997;25(4):763-79; quiz 780-1. [Medline].
5. Sáez-Llorens X. Brain abscess in children. Semin Pediatr Infect Dis. Apr 2003;14(2):108-14. [Medline].
6. Bernardini GL. Diagnosis and management of brain abscess and subdural empyema. Curr Neurol Neurosci Rep. Nov 2004;4(6):448-56. [Medline].
7. Mamelak AN, Mampalam TJ, Obana WG, et al. Improved management of multiple brain abscesses: a combined surgical and medical approach. Neurosurgery. 1995;36(1):76-85. [Medline].
8. Yang KY, Chang WN, Ho JT, et al. Postneurosurgical nosocomial bacterial brain abscess in adults. Infection. Oct 2006;34(5):247-51. [Medline].
9. Sennaroglu L, Sozeri B. Otogenic brain abscess: review of 41 cases. Otolaryngol Head Neck Surg. Dec 2000;123(6):751-5. [Medline].
10. Gallitelli M, Lepore V, Pasculli G, et al. Brain abscess: a need to screen for pulmonary arteriovenous malformations. Neuroepidemiology. 2005;24(1-2):76-8. [Medline].
11. Seydoux C, Francioli P. Bacterial brain abscesses: factors influencing mortality and sequelae. Clin Infect Dis. Sep 1992;15(3):394-401. [Medline].
12. Vidal JE, Oliveira AC, Filho FB, et al. Tuberculous brain abscess in AIDS patients: report of three cases and literature review. Int J Infect Dis 9(4):201-7. 2005;9(4):201-7. [Medline].
13. Kennedy KJ, Chung KH, Bowden FJ, et al. A cluster of nocardial brain abscesses. Surg Neurol. Jul 2007;68(1):43-9; discussion 49. [Medline].
14. Wolf J, Curtis N. Brain abscess secondary to dental braces. Pediatr Infect Dis J. Jan 2008;27(1):84-5. [Medline].
15. Gaïni S, Grand M, Michelsen J. Brain abscess after esophageal dilatation: case report. Infection. Feb 2008;36(1):71-3. [Medline].
16. Roberts J, Bartlett AH, Giannoni CM, et al. Airway foreign bodies and brain abscesses: report of two cases and review of the literature. Int J Pediatr Otorhinolaryngol. Feb 2008;72(2):265-9. [Medline].
17. Katragkou A, Dotis J, Kotsiou M, et al. Scedosporium apiospermum infection after near-drowning. Mycoses. Sep 2007;50(5):412-21. [Medline].
18. Khouzam RN, El-Dokla AM, Menkes DL. Undiagnosed patent foramen ovale presenting as a cryptogenic brain abscess: case report and review of the literature. Heart Lung. Mar-Apr 2006;35(2):108-11. [Medline].
19. Enany S, Higuchi W, Okubo T, et al. Brain abscess caused by Panton-Valentine leukocidin-positive community-acquired methicillin-resistant Staphylococcus aureus in Egypt, April 2007. Euro Surveill. Sep 27 2007;12(9):E070927.2. [Medline].
20. Sifri CD, Park J, Helm GA, et al. Fatal brain abscess due to community-associated methicillin-resistant Staphylococcus aureus strain USA300. Clin Infect Dis. Nov 1 2007;45(9):e113-7. [Medline].
21. Hakan T, Ceran N, Erdem I, et al. Bacterial brain abscesses: an evaluation of 96 cases. J Infect. May 2006;52(5):359-66. [Medline].
22. Kao PT, Tseng HK, Liu CP, et al. Brain abscess: clinical analysis of 53 cases. J Microbiol Immunol Infect. Jun 2003;36(2):129-36. [Medline].
23. Marshman LA, Connor S, Chandler CL. Persistent absence of ring-enhancement on CT with an encapsulated brain abscess. Br J Neurosurg. Aug 2004;18(4):377-82. [Medline].
24. Kastrup O, Wanke I, Maschke M. Neuroimaging of infections. NeuroRx. Apr 2005;2(2):324-32. [Medline].
25. Lai PH, Hsu SS, Ding SW, et al. Proton magnetic resonance spectroscopy and diffusion-weighted imaging in intracranial cystic mass lesions. Surg Neurol. 2007;68 Suppl 1:S25-36. [Medline].
26. Kimberly HH, Shah S, Marill K, et al. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med. Feb 2008;15(2):201-4. [Medline].
27. Hasbun R, Abrahams J, Jekel J, et al. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med. Dec 13 2001;345(24):1727-33. [Medline].
28. Boviatsis EJ, Kouyialis AT, Stranjalis G, et al. CT-guided stereotactic aspiration of brain abscesses. Neurosurg Rev. Jul 2003;26(3):206-9. [Medline].
29. Unal O, Sakarya ME, Kiymaz N, et al. Brain abscess drainage by use of MR fluoroscopic guidance. Am J Neuroradiol. 2005;26(4):839-42. [Medline].
30. Kurschel S, Mohia A, Weigl V, et al. Hyperbaric oxygen therapy for the treatment of brain abscess in children. Childs Nerv Syst. 2005;May 5:[Medline].
31. Kutlay M, Colak A, Yildiz S, et al. Stereotactic aspiration and antibiotic treatment combined with hyperbaric oxygen therapy in the management of bacterial brain abscesses. Neurosurgery. Dec 2005;57(6):1140-6; discussion 1140-6. [Medline].
32. Lee TH, Chang WN, Su TM, et al. Clinical features and predictive factors of intraventricular rupture in patients who have bacterial brain abscesses. J Neurol Neurosurg Psychiatry. Mar 2007;78(3):303-9. [Medline].
33. Xiao F, Tseng MY, Teng LJ, et al. Brain abscess: clinical experience and analysis of prognostic factors. Surg Neurol. May 2005;63(5):442-9; discussion 449-50. [Medline].
34. Demir MK, Hakan T, Kilicoglu G, et al. Bacterial brain abscesses: prognostic value of an imaging severity index. Clin Radiol. Jun 2007;62(6):564-72. [Medline].
35. Prasad KN, Mishra AM, Gupta D, et al. Analysis of microbial etiology and mortality in patients with brain abscess. J Infect. Oct 2006;53(4):221-7. [Medline].

Article Last Updated: Sep 25, 2008