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Difficulty: MediumInfectious Diseases

Match the following clinical vignettes of central nervous system infections with their most appropriate targeted or empiric antimicrobial therapy.

  • A 72-year-old man presents with acute fever, nuchal rigidity, and confusion. Cerebrospinal fluid analysis reveals neutrophilic pleocytosis, elevated protein, and decreased glucose.Intravenous ceftriaxone, vancomycin, and ampicillin
  • A 35-year-old man with a CD4 count of 45 cells/mm³ presents with a progressive headache. Cerebrospinal fluid cryptococcal antigen testing is positive.Intravenous liposomal amphotericin B and oral flucytosine
  • A 45-year-old woman presents with fever, aphasia, and focal seizures. Magnetic resonance imaging of the brain demonstrates hyperintensity in the left temporal lobe.Intravenous acyclovir
  • A 28-year-old man with untreated HIV (CD4 count 30 cells/mm³) presents with left-sided hemiparesis. Brain imaging reveals multiple ring-enhancing lesions in the basal ganglia.Oral sulfadiazine, pyrimethamine, and leucovorin

Answer

Elderly meningitis matches with Ceftriaxone, Vancomycin, and Ampicillin; Cryptococcal meningitis matches with Amphotericin B and Flucytosine; HSV encephalitis matches with Intravenous acyclovir; Toxoplasma encephalitis matches with Sulfadiazine, pyrimethamine, and leucovorin.
Each clinical presentation directly corresponds to a specific infectious etiology that dictates its treatment. 1) Empiric therapy for bacterial meningitis in adults older than 50 years includes ceftriaxone (for pneumococcus and meningococcus), vancomycin (for resistant pneumococcus), and ampicillin (for Listeria). 2) Cryptococcal meningitis (positive CSF antigen) requires induction with amphotericin B and flucytosine. 3) HSV encephalitis (temporal lobe edema, focal neurologic signs) is treated with intravenous acyclovir. 4) Toxoplasma encephalitis (ring-enhancing lesions in advanced HIV) is treated with sulfadiazine, pyrimethamine, and leucovorin.

Step-by-Step Solution

1
Diagnose the underlying central nervous system infection based on the clinical vignette.
The vignettes describe bacterial meningitis in an elderly patient, cryptococcal meningitis in advanced HIV, HSV encephalitis, and Toxoplasma encephalitis in advanced HIV, respectively.
Accurate etiological diagnosis is necessary to select the appropriate empiric or targeted antimicrobial therapy.
2
Determine the guideline-concordant antimicrobial therapy for each identified condition.
Empiric meningitis therapy in patients over 50 years of age must include Listeria coverage (ampicillin). Cryptococcus requires amphotericin B and flucytosine. HSV requires acyclovir. Toxoplasmosis requires sulfadiazine and pyrimethamine.
Applying standard infectious disease guidelines optimizes patient outcomes and aligns with antimicrobial stewardship principles.

Key Concept

First-line antimicrobial therapy for common and opportunistic central nervous system infections
Estimated Time:1m 30s
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Topics

Infectious Diseases

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