A 44-year-old man who presented with an episode of collapse described a 2-week history of fatigue, agitation, confusion and left arm weakness, but no headaches, visual problems, vomiting, seizures or dental pain. On examination he is found to be febrile. He has a reduced level of consciousness.
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1. What is the differential diagnosis?
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Reduced consciousness and fever should make one consider bacterial meningitis, cerebral malaria, brain abscess or cerebral haemorrhage
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2. What does the absence of papilloedema suggest?
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The history of this presentation is short so the absence of papilloedema does not exclude raised intracranial pressure.
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3. What investigation is required now?
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A CT scan is necessary to determine whether there is any raised intracranial pressure.
- More info: A CT scan showed left frontal and right parietal lobe abscesses.
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4. What is the most appropriate treatment?
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The patient should be commenced on a regimen that includes a third-generation cephalosporin and metronidazole.
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5. What additional treatment should be considered?
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For diagnosis and therapy the abscess could be drained.
- More info: A sample of pus from a brain abscess was sent to the laboratory for microscopy and culture, where a few white blood cells and numerous Gram-positive cocci were seen. α-haemolytic streptococci grew on routine culture media. The isolate was identified by biochemical testing to be Streptococcus parasanguis. A 16S rRNA gene PCR, followed by sequencing was performed and the isolate was identified as Streptococcus intermedius.
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6. How would you interpret these results?
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The molecular identification is more likely to be correct. Streptococcus parasanguis is usually found as a commensal in the mouth, whereas Streptococcus intermedius is capable of causing abscesses throughout the body.
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7. How would these results affect the treatment?
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The streptococcus will be sensitive to the cephalosporin and treatment should continue as before.