SEMINARS I N NEURO1,OGY-VOLUME
12, NO. 3 SEPTEMBER 1992
Brain Abscess Brian Wispelwey, M.D., and W. Michael Scheld, M.D.
ILLUSTRATIVE CASE Thc patient is a 34-year-old man who developed multiple brain abscesses. Other than a history of a deep vein thromhoscs (DVI') 2 ycars previously, he had no significant tnedical problems. Three weeks prior to admission, he was struck in the leg by a rock and was rcstartcd on warfarin by his physician. Five days prior to adn~issior~, he began to develop retro-orbital headaches. Over the next 2 days, he developed nausea and vomiting, mild disorientation, and, finally, obtundation and was admitted to the hospital. His examination revealed a drowsy white male arousable only to painful stimuli. Blood pressure 115160 mmHg; temperature 37.2" C. IIead and neck examination revealed no abnormalities and his fundoscopic examination was normal. His chest was clear and his cardiac examination was normal. There was no evidence of DV'r on evaluation of his extremities. Neurologic examination showed that his cranial nerves were intact; he nioved all extremities, but he was inattentive to his left side and the tone of his left limbs was decreased. His reflexes wcrc symmetrical. The initial computed tomographic (CT) scan was interpreted as showing a right frontal hernorrhage with a question of a second lesion in the thalamus (Fig. 111).The patient was rans sf erred to the University of Virginia and a magnetic resonance imaging (MRI) study was perrormed on the same day which, despite motion artifact. revealed multiple lesions consistent with multiple emboli (Fig. I B). Antibiotics were initiated and C'I-guided aspirations of several lesions were perforrned. Gram-positive cocci were seen on gram stains and Streptococcus intcrmcdius grew in culture. T h e patient subsequer~tlyu ~ ~ d e r w e dental nt x-rays, cardiac echocardiography with color contrast, and a pulmonary artcriogram to scarch for a possible source of multiple cerebral abscesses. His blood cultures remained negativc and his studies were negativc for atrial septa1 defect, valvular veg-
etations, or occult pulmonary arteriovenous fistulas. A repeat head C.T 10 days later revealed more precisely the presence of multiple, now ring-enhancing lesions (Fig. 1C). The patient completed an 8-week course of penicillin and metronidazole, with steady improvement in all parameters. Six months later, he had recovered, with no detectable neurologic abnormalities. T h e important issues that a r e addressed by this case include t h e uncertainty engendered by t h e initial C T scan, given t h e presence o f only o n e lesion that was most consistent with a hemorrhage. T h e MRI o n t h e same day, despite motion artifact, revealed multiple lesions a n d supported t h e increased sensitivity of MRI relative LO CT. T h i s case also illustrates the frequent occurrence of cryptogenic brain abscesses despite intensive evaluation for a n underlying cause.
EPIDEMIOLOGY Brain abscess is generally regarded as a r a r e disease, with large autopsy series rcporting a n occurrence rate o f 0.18 to 1.370.' Some series have noted a slightly increased incidence o f brain abscess in recent vears but this may represent a bias of more sensitive diagnostic techn i q u e ~ However, .~~ two series, which span greater than f o u r decades, have noted a decline in t h e incidence o f brain abscess r e ~ e n t 1 v . l .Nonetheless, ~ brain abscess rerrlairis a significant problem i n t h e developing world, with particularly high rates being reported in children from lower socioeconomic regions o f South Africa.".' T h e advent of t h e acquired i m m u n e deficiency synd r o m e (AIDS) has led to increased n u m b e r s o f individuals with focal intracranial infections i n most parts of t h e world. Estimates o f t h e prevalence o f toxoplasmic encephalitis alone, in patients with AIDS, have ranged from 2.6 t o 30.8%.# I n most series, t h e rr1ale:female ratio has bcen > 2 : 1,2-4.~1-I I with t h e median age a t presentation being 30 to 40 years.'y-" Approximately 25% o f brain abscesses occur in children less than a g e 15 years.
Departments of Medicine and Neurosurgery, University of Virginia School of Medicine, Charlottesville, Virginia Reprint requests: Dr. Wispelwcy, Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22904 Copyright O 1992 by Thiente Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
Downloaded by: NYU. Copyrighted material.
Brain abscess is a focal suppurative process within the brain parenchyma oC diverse pathogenesis a n d etiology. Descriptions of' this disease d a t e back to Hippocrates a n d the resultant mortality a n d morbidity o f this process remained extremely high until t h e last two decades. Some degree of uncertainty remains regarding the optimal nlanagement o f a given brain abscess patient d u e to t h e lack of' prospective randomized trials evaluating various treatment approaches.
VOLUME 12, NUMBER 3 SEPTEMBER 1992
Figure 1A. CT on day of admission revealing a high-intensity lesion in the frontal lobe on both unenhanced and enhanced scans. 6.MRI on the same day revealing multiple lesions on T,-weighted imaging despite associated motion artifact. C. CT 10 days later, on therapy, revealing what are multiple, ring-enhancing abscesses.
PATHOGENESIS AND PATHOPHYSIOLOGY
274
Brain abscesses occur most commonly in association with a contiguous focus of infection, as a result of hematogenous spread from a distant focus of infection, or following cranial trauma o r surgery. However, the predisposing factor may remain undefined in approximately 15 to 20%, as in the illustrative case. A review of 19 series of brain abscesses dating from 1927 to the p r e ~ e n t " . ~reveals , ' ~ that approximately 47% of cases were accounted for by associated contiguous infections (predominantly otitis or sinusitis). Recent data
suggest that otogenic brain abscesses are decreasing in frequency, perhaps because of the availability and cornmon use of antibiotics for upper respiratory tract infections. Frequent but inadequate courses of antibiotics for ear or sinus infections have been notec!, however, to alter the natural history of a brain abscess and lead to potentially puzzling or more subtle presentation^.'"'^ Otogenic brain abscesses are most ~ommonlylocated in the temporal lobe or cerebellum. In fact, it has been observed that 85 to 99% of cerebellar abscesses are secondary to otogenic infections. Sinusitis as a cause of brain abscess also appears to be decreasing in incidence. Rhinogenic abscesses have been rare in children less than 10 years of age and in adults greater than age 60.?Brain abscess localization in this setting is most often in the frontal lobe. Sphenoid sinusitis is notable for both the frequency and severity of its potential complications. Pituitary abscesses were observed to complicate 16 of 126 cases of sphenoid sinusitis in a series from the preantibiotic era.I6 Because the diagnosis of sphenoid sinusitis is often difficult to make, treatment may be delayed. Recent reports implicate cocaine inhalation as a risk factor for sphenoid sinusitis and subsequent brain abscess development.17 Dental infections, although previously described as an uncommon cause of brain abscess, have been implicated more frequently (more than 10%) in some recent
Downloaded by: NYU. Copyrighted material.
SEMINARS I N NEUROLOGY
Scheld
s e r i e ~ . ~Brain . l ~ abscess is more likely following infections of nrolar teeth. Brain abscess rarely complicates meningitis in adults, but in neonates with gram-negative (particularly Citrobacter and Proteus spp.) meningitis, an associated brain abscess should be strongly c o n ~ i d e r e d . l ~ - ~ ' Brain abscesses are fortunately infrequent complications of neurosurgical procedures o r cranial trauma. It has been observed that central nervous system (CNS) inrections occur in only 0.6 to 1.7% of clean neurosurgical procedures, and brain abscess accounts for only 10% of these.'2 However, because of the decline in other predisposing factors as causes of brain abscess recently, the relative contribution of intracranial surgery as a cause of brain abscess has increased in some recent series.'"Rrn abscess has been noted to complicate approximately 3% of penetrating cranial injuries, with increased risk noted in the setting of gunshot wound complications. Ketained bone fragments have been consistently noted as an important risk Hematogenous abscesses accounted for 25% of cases in the 19 series mentioned earlier.x.h'2These brain abscesses are most commonly associated with distal, particularly pulmonary, infections; frequently localized in the middle cerebral artery distribution; and more likely than other types to present as multiple abscesses. T h e incidence of rnultiple brain abscesses was only 1 to 15% in older series; however, with the advent of C T scanning, the frequency of multiple lesions has increased to 10 to 50%.?j Prior to more recent therapeutic modalities, the ~nortality from multiple brain abscesses approached 100%. Important preceding processes include chronic lung infections, osteomyelitis, cholecystitis, pelvic infections, and intraabdominal abscesses. Brain abscess has been noted to complicate endoscopic sclerosis of varices or dilation of esophageal stricture^."'"^^ Brain abscess is, however, a surprisingly rare complication of bacterial endocarditis, with Staphylococcus aureus endocarditis carrying the highest risk of associated intracranial involvement in most s e r i e ~ . 'Hereditary ~ hemorrhagic telangicctasia is a particularly irrlportarrt risk factor for brain abscess, especially in those individuals with associated clubbing, cyanosis, or p o l y ~ y t h e m i a Cyanotic .~~ congenital heart disease rnay be the most common cause of brain abscess in children. Tetralogy of Fallot is the rnost commonly cited anonlaly."" T h e development of a brain abscess in any of the settingsjust described appears to require a con~pronlised area of brain as the common denominator. This local-
ized damage is brought about either by retrograde thrombophlebitis (in the setting of contiguous infections o r local areas of infarction associated with emboli) o r by increased blood viscosity (in the setting of hereditary hemorrhagic telangiectasia o r cyanotic congenital heart disease).
MICROBIOLOGY T h e current pattern of microbial isolates from brain abscesses is dependent to a large degree on the immune status of the individual. T h e etiology of focal CNS infections in the setting of various immune defects (AIDS, for example) will be addressed separately. Pyogenic brain abscesses are often (30 to 60%) mixed infections. I n a summary of 12 series of brain abscesses, excluding AIDS patients, 61% of the isolates were aerobic bacteria and 32% were anaerobic bacteria. Aerobic o r microaerophilic streptococci account for half of the aerobic isolates 132% ove;all) and have been noted to be present in approximately 70% of all brain abscesses. T h e most frequently isolated streptococci are those belonging to the Streptococcus milleri group (S. anginosus, S. constellatus, S. intermedius). S. aureus accounts for approximately 13% of the isolates and gramnegative bacilli represent approximately 16%. Those aerobic gram-negative bacilli most frequently encountered include Proteus sp., Escherichia coli, Klebsiella-Enterobacter sp. and Pseudomonas aeruginosa. Anaerobes most frequently encountered include Bacteroides species, (including B. fragilis), Fusobacterium species, and Clostridium species. Anaerobes are particularly implicated in the setting of underlying chronic ear o r pulmonary d~sease~~4.10.~41-38 As noted, the microflora of a brain abscess is dramatically affected by the patient's immune status. Most cases of funaal " brain abscesses are encountered in immunocompromised patients. AIDS is now one of the most important risk factors for the development of a focal intracranial infection. 1t is important to realize that, in this setting, multiple infectious processes may coexist that further complicate the patient's management. In one autopsy series, 11 of 26 individuals with human imrnurrodeficiency virus (HIV) infection exhibited multiple disease processes in the brain. T h e most common causes of mass lesions complicating a given immune defect are listed in Table 1.
Downloaded by: NYU. Copyrighted material.
BRAIN ABSCESS-Wispelwey,
Table 1. Mass Lesions in the Compromised Host T Cell dysfunction
Neutro~enia
HIV Infection -
-
Nocardia asteroides
Enterobacteriaceae
Toxoplasma gondii
Toxoplasma gondii
Pseudomonas aeruginosa
Cryptococcus neoformans
Cryptococcus neoformans
Zygomycetes
Mycobacteria spp
Listeria monocytogenes
Aspergillus spp.
Lymphoma
Mycobacteria spp.
Candida spp.
Progressive multifocal leukoencephalopathy
275
SEMINARS IN NEURO1,OGY
T h e clinical manifestations of a brain abscess are often nonspecific; they clepend on several factors, such as the virulence of the infecting organism, the patient's immune status, and the location of the abscess o r abscesses. T h e triad of fever, headache, and focal deficit is present in less than 50% of patients. Headache is most consistently observed (70%). Fever is present in approximately 5070, arid therefore its absence does not rule out an infectious process. Focal neurologic deficits are also encountered in about half of the cases; the specific features are dependent on the number and locatiorr of brain abscesses. Seizures are observed in 2.5 to 45% of patients and, when present, arc most commonly generalized. T h e presence of nausea and voniiting (20 to 50%) correlates to some degree with the presence of increased intracranial pressure. A change in rriental status (Iethargy to coma) occurs in most patients but frank coma on presentation is now less frequent. This change may reflect the availability of improved diagnostic rr~odalities such as C T scanning.":'Wuchal rigidity, which may be present in up to one fourth of patients, especially in those with more acute presentations, may lead to confusion about the possible presence of m e n i n g i t i ~ .Be~ cause the presentation of brain abscess is nonspecific, the differential diagnosis includes meningitis, subdural ancl epidural abscess, encephalitis, mycotic aneurysm, complicated migraine headache, intracerebral o r subarachnoid hemorrhage, cerebral infarction, and CNS malignancies.
DIAGNOSIS Routine studies, including blood, urine, ancl cerebrospinal fluid (CSF) examination, are rarely helpful in the diagnosis of a brain abscess. I n fact, lurnbar puriclure is contraindicated in a patient with a suspected bacterial brain abscess. T h e diagnostic yield is poor and the risk of subsequent herniation has been reported to be as high as 20%. T h e introduction of C T scanning and, subsequently, MKS has revolutionized both the diagrlosti~and tlierapeutic approach to brain abscess. C T is superior to other radiologic techniques in the evaluation of the paranasal sinuses, mastoids, and middle ear and should be obtained, along with a chest radiograph, in all patients with suspected brain abscess. CT is sensitive (more than 95%) in detecting a brain abscess but can give additional crucial information such as the extent of surrounding edema, the presence of midline shift, the presence of hydrocephalus, and the precise localization of the lesion. T h e typical C T appearance of a brain abscess is that of a lesion with a hvwodense center surrounded by a uniformly contrast-enhancing ring. A variable hypodense area of edema extends beyond this ring. T h e impressive sensitivity of C T is not paralleled by a sirriilar specificity. Other processes, including neoplasms, granulomas, cerebral infarctions, and resolving hematomas can give similar appearances on CT.40.41 T h e use of corticosieroids can aiso alter this typical appearance. Only 40 to 60% of brain abscesses in the setting of corticosteroid therapy will reveal ring enhancement on CT.
,.
SEI'Tb,iZ/IIZk;R 1992
T h e data regarding the utility of MRI in the diagnosis ancl evaluation of the brain abscess continue to accumulate. MRI allows for multiplanar imaging, high contrast between gray and white matter, and a variety of imaging techniques lo elucidate pathologic changes. In addition, bony artifact is not a problem with this technique. MKI is more sensitive than C T in the cerebritis phase as well as in detecting associated cerebral " Therefore, MRI may detect early satellite lesions not demonstrated by C'I' (see case report and Figure 1). Extraparenchymal extension of an abscess (for example, ventricular rupture) is also more easily detected by MRI. hIRI's lack of ionizing radiation, greater tissue characterization, lack of bone artifact, increased sensitivity in follo\v-up evaluations, and less toxic contrast agents make it the procedure of choice in the evaluation of a brain abscess.
THERAPY Optirrral rrlanagernent of most patients with a bacterial brain abscess requires both antibiotics arid surgery. Successful and appropriate antibiotic therapy of a brain abscess requires an understanding of the unique features o f t h e blood-brain barrier (EBB). T h e EBB largely resides at the level of the cerebral capillary endothelial cell and results from the presence of perrtalarriinar tight junctior~sbetween these cells and from the activity of a number of enzymes and transport systems. It thereby limits the entry of substances, including many antibiotics, into the CNS. However, studies have suggested that the BBR and blood-CS1' barrier are not identical and therefore evaluations of drug penetration into the C:SF may not directly apply to brain abscess therapy.q5 Antimicrobial regimens recommended for the ernpiric arid specific therapy of a brain abscess reflect consideration of the most likely niicroorgarrisrris in a given setting as well as evidence from both animal and human studies evaluating a giver) agent's ability to penetrate the pus of a brain abscess. Unfortunately, no prospective, randomized trials exist to guide the clinician in the choice of the optimal regimen. Since the early 1960s, penicillin (; (20 to 24 nrillion unitsiday, ir~travenously) and chlorarnphenicol (1 to 1.5 gm every 6 hours) have been advocated in adults. Metronidazole has supplanted chloramphenicol in recent years because of its excellent anaerobic activity, excellent CNS penetration (which is unaffectecl by steroid therapy), arid ur~coritrolleddata that suggest an improved patient outcome in those treated with this agent.+"'" Other antibiotics may be added, deperlding on the suspicion of or culture evidence for organisms not covered by penicillin o r rnetronidazole. T h e isolation of S. aureus necessitates the addition of nafcillin (or vancomycin if methicillin-resistant orgarrisrr~sare present). Third-generation cephalosporins (such as cefotaxirne, ceftriaxone, o r ceftazidirne) are the agents of choice for associated gram-negative infections and, according to recent data, cefotaxime may be adequate for the majority of s~reptococcalisolates as well,"'thereby replacing penicillin in the standard regimen. Cefstazidime with o r without an aminoglycoside is the drug of choice for P. aeruginosa infections. A debate continues as to the relative roles of aspi-
Downloaded by: NYU. Copyrighted material.
CLINICAL MANIFESTATIONS
VO1,IJME 12. NUMBER 3
We present o u r own approach to this problem, realizing that general guidelines d o not ensure a n optimal outcome in each unique situation. Given t h e availability of stereotactic CT-guided aspiration, its low morbidity, a n d its ability to provide a n accurate microbiologic a n d pathologic diagnosis, operative therapy should rernairi t h e definitive approach for most brain abscesses. I f the CT o r MRI scan suggests t h e presence of cerebritis a n d t h e patients is neurologically stable, antibiotic therapy as previously outlined may be initiated a n d t h e patient observed. Numerous reports supporting this medical a p proach to abscess o r cerebritis therapy a r e present in the medical literature." I f t h e vatient remains stable a n d the abscess is accessible, C.1-guided aspiration is then desirable in o r d e r to make a specific pathologic a n d microbiologic diagnosis. Although this delay may r e n d e r cultures negative, aspiration d u r i n g t h e cerebritis stage may be associated with a n unacccptable risk of hemorrhage, especially in children." If the lesion is encapsulated by C T criteria (the more common clinical circumstance), antibiotic trcatment can be started a n d aspiration f o r diagnosis a n d drainage can be performed immediately. Subsequent management d e p e n d s o n both clinical a n d radiologic assessments. Multiple aspirations rnay be required t o drain a given abscess successfully, a n d this is a potential disadvantage relative to total excision. Neurologic deterioration o r failure of the lesion to resolve o n follow-up imaging studies is a n indication fbr f u r t h e r surgery ( i f t e n excision, if feasible). 'l'he duration of antimicrobial therapy is equally uncertain a n d also may relate to t h e initial surgical procedure. Lesions treated by total excision rriay require a shorter duration of therapy than those treated with aspiration only. I n general, most authorities reco m m e n d that p a t i e ~ ~be t s treated with 4 to 8 weeks of parenteral therapy. Metronidazole may be a n exception because of its high oral bioavailahility. T h e management o f t h e HIV-infected ~ a t i e n with t " a focal C N S lesion deserves special comment. Despite t h e numerous potential etiologies in these patients, toxoplasmosis is t h e most common cause of a focal lesion in most series, especially when multiple enhancing lesions a r e obsel-ved by C T o r MRI. Empiric therapy with pyrimethamine a n d sulfjdiazine is therefore frequently reconiniended in this setting a n d brain biopsy can he deferred. For toxoplasmic encephalitis o n e would expect a clinical response within 10 d a y s a n d a radiologic response within 14 days of initiation of therap~.~"n imrrlediate biopsy should be considered in the patient with a negative Toxoplasma serology because this has been encountered in less than 3% o f cases o f proven AIDSrelated toxoplasmic encephalitis. Adjunctive corticosteroid therapy may be required in t h e patient with raised intracranial pressure; however, there a r e concerns regarding t h e usk of these agents: they may reduce antibiotic entry into t h e CNS, alter t h e C T scan appearance o f ring enhancement, rnaking follow-up studies more difficult t o assess,"q-' a n d decrease
collagen formation a n d glial response, thereby allowing abscess extension. Most animal models o f brain abscess d o not describe a n increased mortality in those treated with c o r t i c o s t ~ r o i d s . " ' ~ ~ I h e relative contributions of medical o r surgical approaches to t h e individual patient with a brain abscess continue to be refined. Earlier diagnosis, improved technology, a n d a n aggressive medical-surgical approach remain essential f o r t h e successful management of this otherwise unforgiving C N S infection. 7
.
REFERENCES 1. Nicolosi A, Hauser WA, Musicco M, Kurland KT. Incidence and prognosis of brain ahscess in a defined population: Olmstead County, Minnesota, 1935-1981. Neuroepidemiology 199 1;10: 122-3 1 2. Nielsen H, Glydensted C, Harmsen A . Ccrcbral abscess. Etiology and pathogenesis, syrnptoms, diagrrosis and treatment. Acta Neurol Scand 1982;65:609-22 3. Chun C H , Johnson JD, IIof'stetter M, Rat'f' MJ. Brain abscess. A study of 45 consccutive cases. Medicine 1986; 65:4 15-3 1 4. Samson DS, Clark K. A current review of' brain abscess. Am J Med 1973;54:201-10 5, Arseni C, Civrea AV. Cerebral abscesses secondary to o~orhiriolaryngological infec~ions. A study of 386 cases. Zentrabl Neurochir 1988;49:22-36 6. Samuel J , Fernandes CMC, Steinberg JL. Iritracranial o~ogeniccomplications: a persisting problem. I,aryngoscope 1986;272-8 7. Mathews 'Ilj, Marcus G. Otogenic intradural complications: a review of 37 patients. J Laryngol Otol 1988; 102: 121-4 8. I.evy RM, Janssen RS, Bush TJ, Rosenblum ML. Neuroepidemiology of' the acquired immunodeficiency syndrome. J Acquir Immune Defic Syndr 1988; 1:31-40 9. Morgan H, Wood M, Murphy F. Experience with 88 consecutive cases of' brain abscess. J Neurosurg 1973;38: 698-704 10. Van Alphen HAM, Driessen JJR. Brain abscess and subduralernpyema. J Neurol Neurosurg Psychiatry 1976;39: 481-90 11. de Louvois J. The bacteriology and chemotherapy of brain ahscess. J Antimicrob Chemother 1978;4:395413 12. Yang SH. Brain abscess. A review of 400 cases. J Neurosurg 1981;55:794-9 13. Browning GG. The unsafeness of safe ears. J Laryngol Otol 1984;98:23-6 14. Bradley PJ, Manning KP, Shaw MDM. Brain abscess secondary to otitis media. .J 1.aryngol Otol 1984;98: 1185-9 1 1.5. Samuel J , Fernandes CMC. Otogenic complications with an intact tympanic membrane. Laryngoscope 1985;95: 1387-90 16. Teed RW. Meningitis from the sphenoid sinus. Arch Otolaryngol 1938;28:589-619 17. Kao AN. Brain abscess: a complication of cocaine inhalation. NY State J Med 1988;88:548-50 18. Srnall M, Dale BAB. Intracranial suppuration 19681982-a 15 year review. Clin Otolaryngol 1984;9: 315-21 19. Renier D, Flaudin C, Hirsch E, Hirsch J-F. Brain ahscess in nconates. A study of 30 cases. J Neurosurg 1988;69: 877-82 20. Saez-Llorens XJ, Ulna1111MA, Odio CM, McCracken GH. Nelson JL). Brain abscess in infants and children. Pediatr Infect Dis J 1989;8:449-58 21. IIerras .JA, Ciria I., Henales V, et al. Nonsurgical man-
Downloaded by: NYU. Copyrighted material.
ration a l o r ~ eo r total excision iri the definitive managem e n t of' a civen brain abscess. T h i s debate is similar to t h e discussion regarding antibiotic therapy; it cannot be settled o n t h e basis o f t h e available data, a n d strong opinions supporting both methods a r e f o u n d in t h e literature. 1."."H."""
22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.
33. 34. 35. 36. 37. 38. 39. 40. 41. 42.
agement of neonatal multiple brain abscesses d u e to Proteus mirabilis. Helv Paediatr Acta 1987;42:451-5 Tenney J H . Bacterial infections of the central nervous system in neurosurgery. Neurol Clin 1986;4:91-114 Schlaimser SE, Backman K, Norrby SR. lntracranial abscess in adults: a n analysis of 54 consecutive cases. Scand J Infect Dis 1988;20: 1-9 Rish BL, Caveness WF, Dillon JD, e t al. Analysis of brain abscess after penetrating craniocerebral injuries in Vietnam. Neurosurgery 198 1;9:535-4 1 Rousseaux M, Lesoin F, Destee A, et al. Developments in the treatment and prognosis of multiple brain abscesses. Neurosurgery 1985; 16:304-8 Schlitt M, Mitchem L, Zorn G, e t al. Brain abscess after esophageal dilation for caustic stricture: report of three cases. Neurosurgery 1985; 17:947-5 1 Cohen FL, Koerne RS, Taub SJ. Solitary brain abscess following endoscopic injection sclerosis of esophageal varices. Gastrointest Endosc 1985;3 1:33 1-3 Pruitt AA, Rubib RHJ, Karchmer AW, Duncan GW. Neurologic complications of bacterial endocarditis. Medicine 1978;57:329-43 Press OW, Ramsey PC. Central nervous system infections associated with hereditary hemorrhagic telangiectasia. Am L Med 1984;77:86-92 Yang SY. Brain abscess associated with congenital heart disease. Surg Neurol 1989;31: 129-32 Brewer NS, MacCarty CS, Wellmarl WE. Brain abscess: a review of recent experience. Ann Intern Med 1975; 82:571-6 Ariza J , Casanova A, Valadrich PF, et al. Etiologic agent and primary source of infection in 42 cases of focal intracranial suppuration. J Clin Microbial 1986;24:899902 Giller GR, Garner JE, Brenner DA. Antimicrobial management of intracranial abscess. Aust NZ J Surg 1984;54:253-5 Schliamser SE, Backrnan K, Norrby SR. I~ltracrarlialabscesses in adults: a n analysis of 5 4 consecutive cases. Scand J Infect Dis 1988;20: 1-9 Jadavji T, Humphreys RP, Prober CG. Brain abscesses in infants and children. Pediatr Infect Dis J 1985;4: 394-8 Harris LF, Maccubbin DA, Triplett JN, Haws FP. Brain abscess:' recent experience at a comrrlunity hospital. South Med J 1985;78:704-7 Mathisen GE, Meyer RD, George WL, Ditron DM, Finegold SM. Brain abscess and cerebritis. Rev Infect Dis 1984;6:(Suppl):S101-6 Stroobandt G, Sech F, Thauvoy C, Mathurin P, d e Nijs C, Gilliard C. Treatment and aspiration of brain abscesses. Acta Neurochir 1987;85: 138-47 Mampalam TJ, Rosenblum ML. Trends in the management of bacterial brain abscess: a review of 102 cases over 17 years. Neurosurgery 1988;23:451-8 Weisberg L. Clinical-CT correlation in intracranial suppurative (bacterial) disease. Neurology 1984;34: 509- 10 Dobkin JF, Healton EB, Dichinson T, Brust JCM. Nonspecificity of ring enhancement in medically cured brain abscess. Neurology 1984;34: 139-44 Brant-Zawadzki M, Enzmann DR, Placor~e RC, et al. NMR imaging of experimental brain abscess: comparison with CT. AJNR 1983;4:245-53
VOLUME 12, NUMBER 3 SEPTEMBER 1992
43. Runge V M , Clanton JA, Price AC, et al. Evaluation of contrast-enhanced MR imaging in a brain-abscess model. AJNR 1985;6: 139-47 44. Grossman R1, Joseph PM, Wolf G, et al. Experimental intracranial septic infarction: magnetic resonancc enhancement. Radiology 1985; 155:649-53 45. Gortvai P, DeLouvois J , Hurley R. T h e bacteriology and chemotherapy of acute pyogenic brain abscess. B r J Neurosurg 1987; 1: 189-203 46. Miller ES, Psrilal SD, Uttley D. C T scanning in the management of intracranial abscess: a review of 100 cases. Br J Neurosurg 1988;2:439-46 47. delouvois J , Hurley R. Inactivation of penicillin by purulent exudates. Br Med J 1977;1:998-1000 48. Alderson D, Strong AJ, Ingham HR, Selkon JB. FifLeer~ year review of the mortality of brain abscess. Neurosurgery 198 1 ;8: 1-6 49. Warner J , Perkiris RL, Cordero L. Metronidazole therapy of anaerobic bacteremia, meningitis, and brain abscess. Arch Intern Med 1979; 139: 167-9 50. Sjolin J , Eriksson N, Arneborn P, Cars 0. Penetration of cefotaxime and desacetylcefotaxime into brain abscesses in humans. Antimicrob Agents Chemother 1991;35:2606-10 5 1. Garfield J. Management of supratentorial intracranial abscess: a review of 200 cases. Br Med J 1969;2:7-1 1 52. Beller AJ, Sahar A, Praiss I. Brain abscess. Review of' 89 cases over 30 years. J Neurol Neurosurg Psychiatry 1973;36:757-68 53. Stepanov S. Surgical treatment of brain abscess. Neurosurgery 1988;22:724-30 54. Urestcombe DS, Dorsch NWC, Teo C. Managernent of cerebral abscess in adolescents and adults. Acta Neurochir 1988;95:85-9 55. Taylor JC. T h e case for excision in the treatment of brain abscess. Br J Neurosurg 1987; 1: 173-8 56. Rousseaux M, Lesoin F, Destee A, Jomin M, Petit H. Long term sequelae of hemispheric abscesses as a function of the treatment. Acta Neurochir 1985;74:61-7 57. Kosenblum ML, Manpalam TJ, Pons VG. Controversies in the management of brain abscesses. Clin Neurosurg 1986;33:603 58. Epstein F, Whelan M. Cerebritis masquerading as brain abscess: case report. Neurosurgery 1982; 10:757-9 59. Luft BJ, Remington JS. Toxoplasmic encephalitis. .J Infect Dis 1988; 157: 106 60. Neuwelt EA, Lawrence MS, Blank NK. Effect of gcntarr~icir~ and dexamettiasorle or] the natural history ot'the rat Escherichia coli brain abscess model with histopathologic correlation. Neurosurgery 1984;15:475-83 61. Scheld WM, Brodeur JP. Effect of rnethylpredr~isolone o n entry of ampicillin and gentamicin into the cercbrospinal fluid in experimental pneumococcal and E. coli meningitis. Antimicrob Agents Chemother 1983;23: 108-12 62. Black KI., Farhat SM. Cerebral abscess: loss of computed tomographic enhancement with steroids. Neurosurgery 1984;14:215-7 63. Schroeder KA, McKeever PE, Schaberg DR, Hot'fJT. Effect of dexamethasone or1 experimental brain abscess. J Neurosurg 1987;66:264-9
Downloaded by: NYU. Copyrighted material.
SEMINARS IN NEUROLOGY
12, NO. 3 SEPTEMBER 1992
Brain Abscess Brian Wispelwey, M.D., and W. Michael Scheld, M.D.
ILLUSTRATIVE CASE Thc patient is a 34-year-old man who developed multiple brain abscesses. Other than a history of a deep vein thromhoscs (DVI') 2 ycars previously, he had no significant tnedical problems. Three weeks prior to admission, he was struck in the leg by a rock and was rcstartcd on warfarin by his physician. Five days prior to adn~issior~, he began to develop retro-orbital headaches. Over the next 2 days, he developed nausea and vomiting, mild disorientation, and, finally, obtundation and was admitted to the hospital. His examination revealed a drowsy white male arousable only to painful stimuli. Blood pressure 115160 mmHg; temperature 37.2" C. IIead and neck examination revealed no abnormalities and his fundoscopic examination was normal. His chest was clear and his cardiac examination was normal. There was no evidence of DV'r on evaluation of his extremities. Neurologic examination showed that his cranial nerves were intact; he nioved all extremities, but he was inattentive to his left side and the tone of his left limbs was decreased. His reflexes wcrc symmetrical. The initial computed tomographic (CT) scan was interpreted as showing a right frontal hernorrhage with a question of a second lesion in the thalamus (Fig. 111).The patient was rans sf erred to the University of Virginia and a magnetic resonance imaging (MRI) study was perrormed on the same day which, despite motion artifact. revealed multiple lesions consistent with multiple emboli (Fig. I B). Antibiotics were initiated and C'I-guided aspirations of several lesions were perforrned. Gram-positive cocci were seen on gram stains and Streptococcus intcrmcdius grew in culture. T h e patient subsequer~tlyu ~ ~ d e r w e dental nt x-rays, cardiac echocardiography with color contrast, and a pulmonary artcriogram to scarch for a possible source of multiple cerebral abscesses. His blood cultures remained negativc and his studies were negativc for atrial septa1 defect, valvular veg-
etations, or occult pulmonary arteriovenous fistulas. A repeat head C.T 10 days later revealed more precisely the presence of multiple, now ring-enhancing lesions (Fig. 1C). The patient completed an 8-week course of penicillin and metronidazole, with steady improvement in all parameters. Six months later, he had recovered, with no detectable neurologic abnormalities. T h e important issues that a r e addressed by this case include t h e uncertainty engendered by t h e initial C T scan, given t h e presence o f only o n e lesion that was most consistent with a hemorrhage. T h e MRI o n t h e same day, despite motion artifact, revealed multiple lesions a n d supported t h e increased sensitivity of MRI relative LO CT. T h i s case also illustrates the frequent occurrence of cryptogenic brain abscesses despite intensive evaluation for a n underlying cause.
EPIDEMIOLOGY Brain abscess is generally regarded as a r a r e disease, with large autopsy series rcporting a n occurrence rate o f 0.18 to 1.370.' Some series have noted a slightly increased incidence o f brain abscess in recent vears but this may represent a bias of more sensitive diagnostic techn i q u e ~ However, .~~ two series, which span greater than f o u r decades, have noted a decline in t h e incidence o f brain abscess r e ~ e n t 1 v . l .Nonetheless, ~ brain abscess rerrlairis a significant problem i n t h e developing world, with particularly high rates being reported in children from lower socioeconomic regions o f South Africa.".' T h e advent of t h e acquired i m m u n e deficiency synd r o m e (AIDS) has led to increased n u m b e r s o f individuals with focal intracranial infections i n most parts of t h e world. Estimates o f t h e prevalence o f toxoplasmic encephalitis alone, in patients with AIDS, have ranged from 2.6 t o 30.8%.# I n most series, t h e rr1ale:female ratio has bcen > 2 : 1,2-4.~1-I I with t h e median age a t presentation being 30 to 40 years.'y-" Approximately 25% o f brain abscesses occur in children less than a g e 15 years.
Departments of Medicine and Neurosurgery, University of Virginia School of Medicine, Charlottesville, Virginia Reprint requests: Dr. Wispelwcy, Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22904 Copyright O 1992 by Thiente Medical Publishers, Inc., 381 Park Avenue South, New York, NY 10016. All rights reserved.
Downloaded by: NYU. Copyrighted material.
Brain abscess is a focal suppurative process within the brain parenchyma oC diverse pathogenesis a n d etiology. Descriptions of' this disease d a t e back to Hippocrates a n d the resultant mortality a n d morbidity o f this process remained extremely high until t h e last two decades. Some degree of uncertainty remains regarding the optimal nlanagement o f a given brain abscess patient d u e to t h e lack of' prospective randomized trials evaluating various treatment approaches.
VOLUME 12, NUMBER 3 SEPTEMBER 1992
Figure 1A. CT on day of admission revealing a high-intensity lesion in the frontal lobe on both unenhanced and enhanced scans. 6.MRI on the same day revealing multiple lesions on T,-weighted imaging despite associated motion artifact. C. CT 10 days later, on therapy, revealing what are multiple, ring-enhancing abscesses.
PATHOGENESIS AND PATHOPHYSIOLOGY
274
Brain abscesses occur most commonly in association with a contiguous focus of infection, as a result of hematogenous spread from a distant focus of infection, or following cranial trauma o r surgery. However, the predisposing factor may remain undefined in approximately 15 to 20%, as in the illustrative case. A review of 19 series of brain abscesses dating from 1927 to the p r e ~ e n t " . ~reveals , ' ~ that approximately 47% of cases were accounted for by associated contiguous infections (predominantly otitis or sinusitis). Recent data
suggest that otogenic brain abscesses are decreasing in frequency, perhaps because of the availability and cornmon use of antibiotics for upper respiratory tract infections. Frequent but inadequate courses of antibiotics for ear or sinus infections have been notec!, however, to alter the natural history of a brain abscess and lead to potentially puzzling or more subtle presentation^.'"'^ Otogenic brain abscesses are most ~ommonlylocated in the temporal lobe or cerebellum. In fact, it has been observed that 85 to 99% of cerebellar abscesses are secondary to otogenic infections. Sinusitis as a cause of brain abscess also appears to be decreasing in incidence. Rhinogenic abscesses have been rare in children less than 10 years of age and in adults greater than age 60.?Brain abscess localization in this setting is most often in the frontal lobe. Sphenoid sinusitis is notable for both the frequency and severity of its potential complications. Pituitary abscesses were observed to complicate 16 of 126 cases of sphenoid sinusitis in a series from the preantibiotic era.I6 Because the diagnosis of sphenoid sinusitis is often difficult to make, treatment may be delayed. Recent reports implicate cocaine inhalation as a risk factor for sphenoid sinusitis and subsequent brain abscess development.17 Dental infections, although previously described as an uncommon cause of brain abscess, have been implicated more frequently (more than 10%) in some recent
Downloaded by: NYU. Copyrighted material.
SEMINARS I N NEUROLOGY
Scheld
s e r i e ~ . ~Brain . l ~ abscess is more likely following infections of nrolar teeth. Brain abscess rarely complicates meningitis in adults, but in neonates with gram-negative (particularly Citrobacter and Proteus spp.) meningitis, an associated brain abscess should be strongly c o n ~ i d e r e d . l ~ - ~ ' Brain abscesses are fortunately infrequent complications of neurosurgical procedures o r cranial trauma. It has been observed that central nervous system (CNS) inrections occur in only 0.6 to 1.7% of clean neurosurgical procedures, and brain abscess accounts for only 10% of these.'2 However, because of the decline in other predisposing factors as causes of brain abscess recently, the relative contribution of intracranial surgery as a cause of brain abscess has increased in some recent series.'"Rrn abscess has been noted to complicate approximately 3% of penetrating cranial injuries, with increased risk noted in the setting of gunshot wound complications. Ketained bone fragments have been consistently noted as an important risk Hematogenous abscesses accounted for 25% of cases in the 19 series mentioned earlier.x.h'2These brain abscesses are most commonly associated with distal, particularly pulmonary, infections; frequently localized in the middle cerebral artery distribution; and more likely than other types to present as multiple abscesses. T h e incidence of rnultiple brain abscesses was only 1 to 15% in older series; however, with the advent of C T scanning, the frequency of multiple lesions has increased to 10 to 50%.?j Prior to more recent therapeutic modalities, the ~nortality from multiple brain abscesses approached 100%. Important preceding processes include chronic lung infections, osteomyelitis, cholecystitis, pelvic infections, and intraabdominal abscesses. Brain abscess has been noted to complicate endoscopic sclerosis of varices or dilation of esophageal stricture^."'"^^ Brain abscess is, however, a surprisingly rare complication of bacterial endocarditis, with Staphylococcus aureus endocarditis carrying the highest risk of associated intracranial involvement in most s e r i e ~ . 'Hereditary ~ hemorrhagic telangicctasia is a particularly irrlportarrt risk factor for brain abscess, especially in those individuals with associated clubbing, cyanosis, or p o l y ~ y t h e m i a Cyanotic .~~ congenital heart disease rnay be the most common cause of brain abscess in children. Tetralogy of Fallot is the rnost commonly cited anonlaly."" T h e development of a brain abscess in any of the settingsjust described appears to require a con~pronlised area of brain as the common denominator. This local-
ized damage is brought about either by retrograde thrombophlebitis (in the setting of contiguous infections o r local areas of infarction associated with emboli) o r by increased blood viscosity (in the setting of hereditary hemorrhagic telangiectasia o r cyanotic congenital heart disease).
MICROBIOLOGY T h e current pattern of microbial isolates from brain abscesses is dependent to a large degree on the immune status of the individual. T h e etiology of focal CNS infections in the setting of various immune defects (AIDS, for example) will be addressed separately. Pyogenic brain abscesses are often (30 to 60%) mixed infections. I n a summary of 12 series of brain abscesses, excluding AIDS patients, 61% of the isolates were aerobic bacteria and 32% were anaerobic bacteria. Aerobic o r microaerophilic streptococci account for half of the aerobic isolates 132% ove;all) and have been noted to be present in approximately 70% of all brain abscesses. T h e most frequently isolated streptococci are those belonging to the Streptococcus milleri group (S. anginosus, S. constellatus, S. intermedius). S. aureus accounts for approximately 13% of the isolates and gramnegative bacilli represent approximately 16%. Those aerobic gram-negative bacilli most frequently encountered include Proteus sp., Escherichia coli, Klebsiella-Enterobacter sp. and Pseudomonas aeruginosa. Anaerobes most frequently encountered include Bacteroides species, (including B. fragilis), Fusobacterium species, and Clostridium species. Anaerobes are particularly implicated in the setting of underlying chronic ear o r pulmonary d~sease~~4.10.~41-38 As noted, the microflora of a brain abscess is dramatically affected by the patient's immune status. Most cases of funaal " brain abscesses are encountered in immunocompromised patients. AIDS is now one of the most important risk factors for the development of a focal intracranial infection. 1t is important to realize that, in this setting, multiple infectious processes may coexist that further complicate the patient's management. In one autopsy series, 11 of 26 individuals with human imrnurrodeficiency virus (HIV) infection exhibited multiple disease processes in the brain. T h e most common causes of mass lesions complicating a given immune defect are listed in Table 1.
Downloaded by: NYU. Copyrighted material.
BRAIN ABSCESS-Wispelwey,
Table 1. Mass Lesions in the Compromised Host T Cell dysfunction
Neutro~enia
HIV Infection -
-
Nocardia asteroides
Enterobacteriaceae
Toxoplasma gondii
Toxoplasma gondii
Pseudomonas aeruginosa
Cryptococcus neoformans
Cryptococcus neoformans
Zygomycetes
Mycobacteria spp
Listeria monocytogenes
Aspergillus spp.
Lymphoma
Mycobacteria spp.
Candida spp.
Progressive multifocal leukoencephalopathy
275
SEMINARS IN NEURO1,OGY
T h e clinical manifestations of a brain abscess are often nonspecific; they clepend on several factors, such as the virulence of the infecting organism, the patient's immune status, and the location of the abscess o r abscesses. T h e triad of fever, headache, and focal deficit is present in less than 50% of patients. Headache is most consistently observed (70%). Fever is present in approximately 5070, arid therefore its absence does not rule out an infectious process. Focal neurologic deficits are also encountered in about half of the cases; the specific features are dependent on the number and locatiorr of brain abscesses. Seizures are observed in 2.5 to 45% of patients and, when present, arc most commonly generalized. T h e presence of nausea and voniiting (20 to 50%) correlates to some degree with the presence of increased intracranial pressure. A change in rriental status (Iethargy to coma) occurs in most patients but frank coma on presentation is now less frequent. This change may reflect the availability of improved diagnostic rr~odalities such as C T scanning.":'Wuchal rigidity, which may be present in up to one fourth of patients, especially in those with more acute presentations, may lead to confusion about the possible presence of m e n i n g i t i ~ .Be~ cause the presentation of brain abscess is nonspecific, the differential diagnosis includes meningitis, subdural ancl epidural abscess, encephalitis, mycotic aneurysm, complicated migraine headache, intracerebral o r subarachnoid hemorrhage, cerebral infarction, and CNS malignancies.
DIAGNOSIS Routine studies, including blood, urine, ancl cerebrospinal fluid (CSF) examination, are rarely helpful in the diagnosis of a brain abscess. I n fact, lurnbar puriclure is contraindicated in a patient with a suspected bacterial brain abscess. T h e diagnostic yield is poor and the risk of subsequent herniation has been reported to be as high as 20%. T h e introduction of C T scanning and, subsequently, MKS has revolutionized both the diagrlosti~and tlierapeutic approach to brain abscess. C T is superior to other radiologic techniques in the evaluation of the paranasal sinuses, mastoids, and middle ear and should be obtained, along with a chest radiograph, in all patients with suspected brain abscess. CT is sensitive (more than 95%) in detecting a brain abscess but can give additional crucial information such as the extent of surrounding edema, the presence of midline shift, the presence of hydrocephalus, and the precise localization of the lesion. T h e typical C T appearance of a brain abscess is that of a lesion with a hvwodense center surrounded by a uniformly contrast-enhancing ring. A variable hypodense area of edema extends beyond this ring. T h e impressive sensitivity of C T is not paralleled by a sirriilar specificity. Other processes, including neoplasms, granulomas, cerebral infarctions, and resolving hematomas can give similar appearances on CT.40.41 T h e use of corticosieroids can aiso alter this typical appearance. Only 40 to 60% of brain abscesses in the setting of corticosteroid therapy will reveal ring enhancement on CT.
,.
SEI'Tb,iZ/IIZk;R 1992
T h e data regarding the utility of MRI in the diagnosis ancl evaluation of the brain abscess continue to accumulate. MRI allows for multiplanar imaging, high contrast between gray and white matter, and a variety of imaging techniques lo elucidate pathologic changes. In addition, bony artifact is not a problem with this technique. MKI is more sensitive than C T in the cerebritis phase as well as in detecting associated cerebral " Therefore, MRI may detect early satellite lesions not demonstrated by C'I' (see case report and Figure 1). Extraparenchymal extension of an abscess (for example, ventricular rupture) is also more easily detected by MRI. hIRI's lack of ionizing radiation, greater tissue characterization, lack of bone artifact, increased sensitivity in follo\v-up evaluations, and less toxic contrast agents make it the procedure of choice in the evaluation of a brain abscess.
THERAPY Optirrral rrlanagernent of most patients with a bacterial brain abscess requires both antibiotics arid surgery. Successful and appropriate antibiotic therapy of a brain abscess requires an understanding of the unique features o f t h e blood-brain barrier (EBB). T h e EBB largely resides at the level of the cerebral capillary endothelial cell and results from the presence of perrtalarriinar tight junctior~sbetween these cells and from the activity of a number of enzymes and transport systems. It thereby limits the entry of substances, including many antibiotics, into the CNS. However, studies have suggested that the BBR and blood-CS1' barrier are not identical and therefore evaluations of drug penetration into the C:SF may not directly apply to brain abscess therapy.q5 Antimicrobial regimens recommended for the ernpiric arid specific therapy of a brain abscess reflect consideration of the most likely niicroorgarrisrris in a given setting as well as evidence from both animal and human studies evaluating a giver) agent's ability to penetrate the pus of a brain abscess. Unfortunately, no prospective, randomized trials exist to guide the clinician in the choice of the optimal regimen. Since the early 1960s, penicillin (; (20 to 24 nrillion unitsiday, ir~travenously) and chlorarnphenicol (1 to 1.5 gm every 6 hours) have been advocated in adults. Metronidazole has supplanted chloramphenicol in recent years because of its excellent anaerobic activity, excellent CNS penetration (which is unaffectecl by steroid therapy), arid ur~coritrolleddata that suggest an improved patient outcome in those treated with this agent.+"'" Other antibiotics may be added, deperlding on the suspicion of or culture evidence for organisms not covered by penicillin o r rnetronidazole. T h e isolation of S. aureus necessitates the addition of nafcillin (or vancomycin if methicillin-resistant orgarrisrr~sare present). Third-generation cephalosporins (such as cefotaxirne, ceftriaxone, o r ceftazidirne) are the agents of choice for associated gram-negative infections and, according to recent data, cefotaxime may be adequate for the majority of s~reptococcalisolates as well,"'thereby replacing penicillin in the standard regimen. Cefstazidime with o r without an aminoglycoside is the drug of choice for P. aeruginosa infections. A debate continues as to the relative roles of aspi-
Downloaded by: NYU. Copyrighted material.
CLINICAL MANIFESTATIONS
VO1,IJME 12. NUMBER 3
We present o u r own approach to this problem, realizing that general guidelines d o not ensure a n optimal outcome in each unique situation. Given t h e availability of stereotactic CT-guided aspiration, its low morbidity, a n d its ability to provide a n accurate microbiologic a n d pathologic diagnosis, operative therapy should rernairi t h e definitive approach for most brain abscesses. I f the CT o r MRI scan suggests t h e presence of cerebritis a n d t h e patients is neurologically stable, antibiotic therapy as previously outlined may be initiated a n d t h e patient observed. Numerous reports supporting this medical a p proach to abscess o r cerebritis therapy a r e present in the medical literature." I f t h e vatient remains stable a n d the abscess is accessible, C.1-guided aspiration is then desirable in o r d e r to make a specific pathologic a n d microbiologic diagnosis. Although this delay may r e n d e r cultures negative, aspiration d u r i n g t h e cerebritis stage may be associated with a n unacccptable risk of hemorrhage, especially in children." If the lesion is encapsulated by C T criteria (the more common clinical circumstance), antibiotic trcatment can be started a n d aspiration f o r diagnosis a n d drainage can be performed immediately. Subsequent management d e p e n d s o n both clinical a n d radiologic assessments. Multiple aspirations rnay be required t o drain a given abscess successfully, a n d this is a potential disadvantage relative to total excision. Neurologic deterioration o r failure of the lesion to resolve o n follow-up imaging studies is a n indication fbr f u r t h e r surgery ( i f t e n excision, if feasible). 'l'he duration of antimicrobial therapy is equally uncertain a n d also may relate to t h e initial surgical procedure. Lesions treated by total excision rriay require a shorter duration of therapy than those treated with aspiration only. I n general, most authorities reco m m e n d that p a t i e ~ ~be t s treated with 4 to 8 weeks of parenteral therapy. Metronidazole may be a n exception because of its high oral bioavailahility. T h e management o f t h e HIV-infected ~ a t i e n with t " a focal C N S lesion deserves special comment. Despite t h e numerous potential etiologies in these patients, toxoplasmosis is t h e most common cause of a focal lesion in most series, especially when multiple enhancing lesions a r e obsel-ved by C T o r MRI. Empiric therapy with pyrimethamine a n d sulfjdiazine is therefore frequently reconiniended in this setting a n d brain biopsy can he deferred. For toxoplasmic encephalitis o n e would expect a clinical response within 10 d a y s a n d a radiologic response within 14 days of initiation of therap~.~"n imrrlediate biopsy should be considered in the patient with a negative Toxoplasma serology because this has been encountered in less than 3% o f cases o f proven AIDSrelated toxoplasmic encephalitis. Adjunctive corticosteroid therapy may be required in t h e patient with raised intracranial pressure; however, there a r e concerns regarding t h e usk of these agents: they may reduce antibiotic entry into t h e CNS, alter t h e C T scan appearance o f ring enhancement, rnaking follow-up studies more difficult t o assess,"q-' a n d decrease
collagen formation a n d glial response, thereby allowing abscess extension. Most animal models o f brain abscess d o not describe a n increased mortality in those treated with c o r t i c o s t ~ r o i d s . " ' ~ ~ I h e relative contributions of medical o r surgical approaches to t h e individual patient with a brain abscess continue to be refined. Earlier diagnosis, improved technology, a n d a n aggressive medical-surgical approach remain essential f o r t h e successful management of this otherwise unforgiving C N S infection. 7
.
REFERENCES 1. Nicolosi A, Hauser WA, Musicco M, Kurland KT. Incidence and prognosis of brain ahscess in a defined population: Olmstead County, Minnesota, 1935-1981. Neuroepidemiology 199 1;10: 122-3 1 2. Nielsen H, Glydensted C, Harmsen A . Ccrcbral abscess. Etiology and pathogenesis, syrnptoms, diagrrosis and treatment. Acta Neurol Scand 1982;65:609-22 3. Chun C H , Johnson JD, IIof'stetter M, Rat'f' MJ. Brain abscess. A study of 45 consccutive cases. Medicine 1986; 65:4 15-3 1 4. Samson DS, Clark K. A current review of' brain abscess. Am J Med 1973;54:201-10 5, Arseni C, Civrea AV. Cerebral abscesses secondary to o~orhiriolaryngological infec~ions. A study of 386 cases. Zentrabl Neurochir 1988;49:22-36 6. Samuel J , Fernandes CMC, Steinberg JL. Iritracranial o~ogeniccomplications: a persisting problem. I,aryngoscope 1986;272-8 7. Mathews 'Ilj, Marcus G. Otogenic intradural complications: a review of 37 patients. J Laryngol Otol 1988; 102: 121-4 8. I.evy RM, Janssen RS, Bush TJ, Rosenblum ML. Neuroepidemiology of' the acquired immunodeficiency syndrome. J Acquir Immune Defic Syndr 1988; 1:31-40 9. Morgan H, Wood M, Murphy F. Experience with 88 consecutive cases of' brain abscess. J Neurosurg 1973;38: 698-704 10. Van Alphen HAM, Driessen JJR. Brain abscess and subduralernpyema. J Neurol Neurosurg Psychiatry 1976;39: 481-90 11. de Louvois J. The bacteriology and chemotherapy of brain ahscess. J Antimicrob Chemother 1978;4:395413 12. Yang SH. Brain abscess. A review of 400 cases. J Neurosurg 1981;55:794-9 13. Browning GG. The unsafeness of safe ears. J Laryngol Otol 1984;98:23-6 14. Bradley PJ, Manning KP, Shaw MDM. Brain abscess secondary to otitis media. .J 1.aryngol Otol 1984;98: 1185-9 1 1.5. Samuel J , Fernandes CMC. Otogenic complications with an intact tympanic membrane. Laryngoscope 1985;95: 1387-90 16. Teed RW. Meningitis from the sphenoid sinus. Arch Otolaryngol 1938;28:589-619 17. Kao AN. Brain abscess: a complication of cocaine inhalation. NY State J Med 1988;88:548-50 18. Srnall M, Dale BAB. Intracranial suppuration 19681982-a 15 year review. Clin Otolaryngol 1984;9: 315-21 19. Renier D, Flaudin C, Hirsch E, Hirsch J-F. Brain ahscess in nconates. A study of 30 cases. J Neurosurg 1988;69: 877-82 20. Saez-Llorens XJ, Ulna1111MA, Odio CM, McCracken GH. Nelson JL). Brain abscess in infants and children. Pediatr Infect Dis J 1989;8:449-58 21. IIerras .JA, Ciria I., Henales V, et al. Nonsurgical man-
Downloaded by: NYU. Copyrighted material.
ration a l o r ~ eo r total excision iri the definitive managem e n t of' a civen brain abscess. T h i s debate is similar to t h e discussion regarding antibiotic therapy; it cannot be settled o n t h e basis o f t h e available data, a n d strong opinions supporting both methods a r e f o u n d in t h e literature. 1."."H."""
22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.
33. 34. 35. 36. 37. 38. 39. 40. 41. 42.
agement of neonatal multiple brain abscesses d u e to Proteus mirabilis. Helv Paediatr Acta 1987;42:451-5 Tenney J H . Bacterial infections of the central nervous system in neurosurgery. Neurol Clin 1986;4:91-114 Schlaimser SE, Backman K, Norrby SR. lntracranial abscess in adults: a n analysis of 54 consecutive cases. Scand J Infect Dis 1988;20: 1-9 Rish BL, Caveness WF, Dillon JD, e t al. Analysis of brain abscess after penetrating craniocerebral injuries in Vietnam. Neurosurgery 198 1;9:535-4 1 Rousseaux M, Lesoin F, Destee A, et al. Developments in the treatment and prognosis of multiple brain abscesses. Neurosurgery 1985; 16:304-8 Schlitt M, Mitchem L, Zorn G, e t al. Brain abscess after esophageal dilation for caustic stricture: report of three cases. Neurosurgery 1985; 17:947-5 1 Cohen FL, Koerne RS, Taub SJ. Solitary brain abscess following endoscopic injection sclerosis of esophageal varices. Gastrointest Endosc 1985;3 1:33 1-3 Pruitt AA, Rubib RHJ, Karchmer AW, Duncan GW. Neurologic complications of bacterial endocarditis. Medicine 1978;57:329-43 Press OW, Ramsey PC. Central nervous system infections associated with hereditary hemorrhagic telangiectasia. Am L Med 1984;77:86-92 Yang SY. Brain abscess associated with congenital heart disease. Surg Neurol 1989;31: 129-32 Brewer NS, MacCarty CS, Wellmarl WE. Brain abscess: a review of recent experience. Ann Intern Med 1975; 82:571-6 Ariza J , Casanova A, Valadrich PF, et al. Etiologic agent and primary source of infection in 42 cases of focal intracranial suppuration. J Clin Microbial 1986;24:899902 Giller GR, Garner JE, Brenner DA. Antimicrobial management of intracranial abscess. Aust NZ J Surg 1984;54:253-5 Schliamser SE, Backrnan K, Norrby SR. I~ltracrarlialabscesses in adults: a n analysis of 5 4 consecutive cases. Scand J Infect Dis 1988;20: 1-9 Jadavji T, Humphreys RP, Prober CG. Brain abscesses in infants and children. Pediatr Infect Dis J 1985;4: 394-8 Harris LF, Maccubbin DA, Triplett JN, Haws FP. Brain abscess:' recent experience at a comrrlunity hospital. South Med J 1985;78:704-7 Mathisen GE, Meyer RD, George WL, Ditron DM, Finegold SM. Brain abscess and cerebritis. Rev Infect Dis 1984;6:(Suppl):S101-6 Stroobandt G, Sech F, Thauvoy C, Mathurin P, d e Nijs C, Gilliard C. Treatment and aspiration of brain abscesses. Acta Neurochir 1987;85: 138-47 Mampalam TJ, Rosenblum ML. Trends in the management of bacterial brain abscess: a review of 102 cases over 17 years. Neurosurgery 1988;23:451-8 Weisberg L. Clinical-CT correlation in intracranial suppurative (bacterial) disease. Neurology 1984;34: 509- 10 Dobkin JF, Healton EB, Dichinson T, Brust JCM. Nonspecificity of ring enhancement in medically cured brain abscess. Neurology 1984;34: 139-44 Brant-Zawadzki M, Enzmann DR, Placor~e RC, et al. NMR imaging of experimental brain abscess: comparison with CT. AJNR 1983;4:245-53
VOLUME 12, NUMBER 3 SEPTEMBER 1992
43. Runge V M , Clanton JA, Price AC, et al. Evaluation of contrast-enhanced MR imaging in a brain-abscess model. AJNR 1985;6: 139-47 44. Grossman R1, Joseph PM, Wolf G, et al. Experimental intracranial septic infarction: magnetic resonancc enhancement. Radiology 1985; 155:649-53 45. Gortvai P, DeLouvois J , Hurley R. T h e bacteriology and chemotherapy of acute pyogenic brain abscess. B r J Neurosurg 1987; 1: 189-203 46. Miller ES, Psrilal SD, Uttley D. C T scanning in the management of intracranial abscess: a review of 100 cases. Br J Neurosurg 1988;2:439-46 47. delouvois J , Hurley R. Inactivation of penicillin by purulent exudates. Br Med J 1977;1:998-1000 48. Alderson D, Strong AJ, Ingham HR, Selkon JB. FifLeer~ year review of the mortality of brain abscess. Neurosurgery 198 1 ;8: 1-6 49. Warner J , Perkiris RL, Cordero L. Metronidazole therapy of anaerobic bacteremia, meningitis, and brain abscess. Arch Intern Med 1979; 139: 167-9 50. Sjolin J , Eriksson N, Arneborn P, Cars 0. Penetration of cefotaxime and desacetylcefotaxime into brain abscesses in humans. Antimicrob Agents Chemother 1991;35:2606-10 5 1. Garfield J. Management of supratentorial intracranial abscess: a review of 200 cases. Br Med J 1969;2:7-1 1 52. Beller AJ, Sahar A, Praiss I. Brain abscess. Review of' 89 cases over 30 years. J Neurol Neurosurg Psychiatry 1973;36:757-68 53. Stepanov S. Surgical treatment of brain abscess. Neurosurgery 1988;22:724-30 54. Urestcombe DS, Dorsch NWC, Teo C. Managernent of cerebral abscess in adolescents and adults. Acta Neurochir 1988;95:85-9 55. Taylor JC. T h e case for excision in the treatment of brain abscess. Br J Neurosurg 1987; 1: 173-8 56. Rousseaux M, Lesoin F, Destee A, Jomin M, Petit H. Long term sequelae of hemispheric abscesses as a function of the treatment. Acta Neurochir 1985;74:61-7 57. Kosenblum ML, Manpalam TJ, Pons VG. Controversies in the management of brain abscesses. Clin Neurosurg 1986;33:603 58. Epstein F, Whelan M. Cerebritis masquerading as brain abscess: case report. Neurosurgery 1982; 10:757-9 59. Luft BJ, Remington JS. Toxoplasmic encephalitis. .J Infect Dis 1988; 157: 106 60. Neuwelt EA, Lawrence MS, Blank NK. Effect of gcntarr~icir~ and dexamettiasorle or] the natural history ot'the rat Escherichia coli brain abscess model with histopathologic correlation. Neurosurgery 1984;15:475-83 61. Scheld WM, Brodeur JP. Effect of rnethylpredr~isolone o n entry of ampicillin and gentamicin into the cercbrospinal fluid in experimental pneumococcal and E. coli meningitis. Antimicrob Agents Chemother 1983;23: 108-12 62. Black KI., Farhat SM. Cerebral abscess: loss of computed tomographic enhancement with steroids. Neurosurgery 1984;14:215-7 63. Schroeder KA, McKeever PE, Schaberg DR, Hot'fJT. Effect of dexamethasone or1 experimental brain abscess. J Neurosurg 1987;66:264-9
Downloaded by: NYU. Copyrighted material.
SEMINARS IN NEUROLOGY
