Cerebral abscess (summary)
Updates to Article Attributes
- this is a basic article for medical students and non-radiologists
-
for more information, see the mainbrain abscessarticle
Cerebral abscesses are foci of infection in the brain parenchyma. They typically have enhancing walls but can mimic a number of other significant pathologies.
Epidemiology
All age groups are susceptible to development of cerebral abscesses, however some are at high risk, including those with systemic infection or remote abscesses and IVDAs1.
Clinical presentation
Neurological symptoms are more common than overt infective signs. Signs of raised intracranial pressure, focal neurological changes or seizures are signs to lead to imaging and investigation.
Pathology
Abscesses develop following spread of bacteria to brain tissues. Initially there will be inflammation and irritation of parenchyma before a typical walled "abscess" forms.
Haematogenous spread is the commonest route for bacteria to enter the brain1. Lesions can make their way to the peripheries (where vessels get smaller and bacteria get lodged). Direct spread from upper respiratory or scalp infections contribute to some cases but fewer than historically.
Microbiology
Most cases haveThere can be mixed bacteriology, with common pathogens in the Streptococcal groups 1. Sterile cultures can be found in 25-34% of cases 1,2. Gram Gram negative bacteria are commoner in paediatric cases and immunocompromised patients are at risk to other opportunistic pathogens.
Radiological features
MRI is the best method of investigating cerebral abscesses 3 but there are some signs on CT which is usually more readily available.
CT
Post-contrast views are usually required to be of use in abscess diagnosis. Better in advanced cases, where the wall of the abscess ("ring enhancing lesion") can be visualised with central and surrounding hypodensities (consisting of pus and oedema, respectively).
MRI
There are a number of features that MRI shows in abscess formation. These are described in the main article which again illustrate the enhancing rim, fluid/pus filled cavity (with restricted diffusion) and surrounding oedema.
MRI can be used to guide drainage and monitor response to treatment in follow-up imaging.
Treatment and prognosis
These deep-seated infections usually require neurosurgical involvement for drainage or craniotomy as well as intensive intravenous broad spectrum antibiotics1.
Differential diagnosis
A number of conditions can mimic the appearance of cerebral abscesses. This is the reason why expert care and treatment is required.
Differentials include:
-
tumours
- primary CNS tumour
- metastasis
- demyelination
- infarction or haemorrhage
- post-treatment changes e.g. radiation necrosis
More information
-<ul>-<li>this is a basic article for medical students and non-radiologists</li>-<li>for more information, see the main <a href="/articles/brain-abscess-1">brain abscess</a> article</li>-</ul><p><strong>Cerebral abscesses</strong> are foci of infection in the brain parenchyma. They typically have enhancing walls but can mimic a number of other significant pathologies.</p><h4>Epidemiology</h4><p>All age groups are susceptible to development of cerebral abscesses, however some are at high risk, including those with systemic infection or remote abscesses and IVDAs.</p><h4>Clinical presentation</h4><p>Neurological symptoms are more common than overt infective signs. Signs of raised intracranial pressure, focal neurological changes or seizures are signs to lead to imaging and investigation.</p><h4>Pathology</h4><p>Abscesses develop following spread of bacteria to brain tissues. Initially there will be inflammation and irritation of parenchyma before a typical walled "abscess" forms.</p><p>Haematogenous spread is the commonest route for bacteria to enter the brain. Lesions can make their way to the peripheries (where vessels get smaller and bacteria get lodged). Direct spread from upper respiratory or scalp infections contribute to some cases but fewer than historically.</p><h5>Microbiology</h5><p>Most cases have mixed bacteriology, with the commonest pathogen being <em>Streptococcus pneumoniae.</em> Gram negative bacteria are commoner in paediatric cases and immunocompromised patients are at risk to other opportunistic pathogens.</p><h4>Radiological features</h4><p>MRI is the best method of investigating cerebral abscesses but there are some signs on CT which is usually more readily available.</p><h5>CT</h5><p>Post-contrast views are usually required to be of use in abscess diagnosis. Better in advanced cases, where the wall of the abscess ("ring enhancing lesion") can be visualised with central and surrounding hypodensities (consisting of pus and oedema, respectively).</p><h5>MRI</h5><p>There are a number of features that MRI shows in abscess formation. These are described in the <a href="/articles/brain-abscess-1">main article</a> which again illustrate the enhancing rim, fluid/pus filled cavity (with restricted diffusion) and surrounding oedema.</p><p>MRI can be used to guide drainage and monitor response to treatment in follow-up imaging.</p><h4>Treatment and prognosis</h4><p>These deep-seated infections usually require neurosurgical involvement for drainage or craniotomy as well as intensive intravenous broad spectrum antibiotics.</p><h4>Differential diagnosis</h4><p>A number of conditions can mimic the appearance of cerebral abscesses. This is the reason why expert care and treatment is required.</p><p>Differentials include:</p><ul>-<li>tumours<ul>- +<ul><li>this is a basic article for medical students and non-radiologists</li></ul><p><strong>Cerebral abscesses</strong> are foci of infection in the brain parenchyma. They typically have enhancing walls but can mimic a number of other significant pathologies.</p><h4>Epidemiology</h4><p>All age groups are susceptible to development of cerebral abscesses, however some are at high risk, including those with systemic infection or remote abscesses and IVDAs <sup>1</sup>.</p><h4>Clinical presentation</h4><p>Neurological symptoms are more common than overt infective signs. Signs of raised intracranial pressure, focal neurological changes or seizures are signs to lead to imaging and investigation.</p><h4>Pathology</h4><p>Abscesses develop following spread of bacteria to brain tissues. Initially there will be inflammation and irritation of parenchyma before a typical walled "abscess" forms.</p><p>Haematogenous spread is the commonest route for bacteria to enter the brain <sup>1</sup>. Lesions can make their way to the peripheries (where vessels get smaller and bacteria get lodged). Direct spread from upper respiratory or scalp infections contribute to some cases but fewer than historically.</p><h5>Microbiology</h5><p>There can be mixed bacteriology, with common pathogens in the <em>Streptococcal</em> groups <sup>1</sup>. Sterile cultures can be found in 25-34% of cases <sup>1,2</sup>. Gram negative bacteria are commoner in paediatric cases and immunocompromised patients are at risk to other opportunistic pathogens.</p><h4>Radiological features</h4><p>MRI is the best method of investigating cerebral abscesses <sup>3 </sup>but there are some signs on CT which is usually more readily available.</p><h5>CT</h5><p>Post-contrast views are usually required to be of use in abscess diagnosis. Better in advanced cases, where the wall of the abscess ("ring enhancing lesion") can be visualised with central and surrounding hypodensities (consisting of pus and oedema, respectively).</p><h5>MRI</h5><p>There are a number of features that MRI shows in abscess formation. These are described in the <a href="/articles/brain-abscess-1">main article</a> which again illustrate the enhancing rim, fluid/pus filled cavity (with restricted diffusion) and surrounding oedema.</p><p>MRI can be used to guide drainage and monitor response to treatment in follow-up imaging.</p><h4>Treatment and prognosis</h4><p>These deep-seated infections usually require neurosurgical involvement for drainage or craniotomy as well as intensive intravenous broad spectrum antibiotics <sup>1</sup>.</p><h4>Differential diagnosis</h4><p>A number of conditions can mimic the appearance of cerebral abscesses. This is the reason why expert care and treatment is required.</p><p>Differentials include:</p><ul>
- +<li>
- +<a title="tumours" href="/articles/brain-tumours-basic">tumours</a><ul>
-<li>demyelination</li>-<li>infarction or haemorrhage</li>- +<li><a title="demyelination" href="/articles/multiple-sclerosis-basic">demyelination</a></li>
- +<li><a title="infarction or haemorrhage" href="/articles/stroke-basic">infarction or haemorrhage</a></li>
-</ul>- +</ul><h4>More information</h4><ul><li><a href="/articles/brain-abscess-1">brain abscess</a></li></ul>
References changed:
- 1. Xiao F, Tseng MY, Teng LJ et-al. Brain abscess: clinical experience and analysis of prognostic factors. Surg Neurol. 2005;63 (5): 442-9. <a href="http://dx.doi.org/10.1016/j.surneu.2004.08.093">doi:10.1016/j.surneu.2004.08.093</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/15883068">Pubmed citation</a><span class="auto"></span>
- 2. Greenberg MS. Handbook of neurosurgery. George Thieme Verlag. (2006) ISBN:313110886X. <a href="http://books.google.com/books?vid=ISBN313110886X">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/313110886X?ie=UTF8&tag=radiopaediaor-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=313110886X">Find it at Amazon</a><div class="ref_v2"></div>
- 3. Haimes AB, Zimmerman RD, Morgello S et-al. MR imaging of brain abscesses. AJR Am J Roentgenol. 1989;152 (5): 1073-85. <a href="http://www.ajronline.org/cgi/content/abstract/152/5/1073">AJR Am J Roentgenol (abstract)</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/2705342">Pubmed citation</a><div class="ref_v2"></div>
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