An 11-month-old male with a two-day history of irritability and lethargy is brought to the emergency department by his mother. She reports that he has vomited four times today and has had fewer wet diapers than usual. He is up to date with his vaccinations. On examination, he is febrile, and a slight bulging of his anterior fontanel and neck stiffness are noted. Laboratory tests demonstrate a serum glucose of 75 mg/dL, and blood cultures and a lumbar puncture are performed. Analysis of the cerebrospinal fluid (CSF) reveals a predominance of neutrophils.
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Answer: Glucose of 18 mg/dL
This patient’s findings are consistent with a diagnosis of meningitis, an inflammatory disease of the tissues surrounding the brain and spinal cord. The cloudiness of his CSF and the predominance of neutrophils present are suggestive of bacterial meningitis. Although there is some overlap in CSF findings for the different causes of meningitis, the CSF in bacterial meningitis typically has a low glucose concentration and a serum to glucose ratio less than 0.6.
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