From the Guidelines
A meningitis workup involves prompt evaluation with a lumbar puncture to collect cerebrospinal fluid (CSF) for analysis, along with blood cultures and other laboratory tests, and starting empiric antimicrobial therapy immediately after obtaining cultures, without waiting for results, as recommended by the most recent guidelines 1.
Key Components of Meningitis Workup
- Prompt lumbar puncture to collect CSF for analysis
- Blood cultures and other laboratory tests
- Empiric antimicrobial therapy started immediately after obtaining cultures
- Consideration of adjunctive dexamethasone to reduce inflammation and improve outcomes
Empiric Antimicrobial Therapy
- For adults with suspected bacterial meningitis, administer vancomycin (15-20 mg/kg IV every 8-12 hours), plus either ceftriaxone (2g IV every 12 hours) or cefotaxime (2g IV every 4-6 hours) 1
- Add ampicillin (2g IV every 4 hours) for patients over 50 years or immunocompromised to cover Listeria
CSF Analysis
- Cell count with differential
- Protein
- Glucose
- Gram stain
- Culture
- Potentially PCR testing for viral pathogens
Imaging
- CT or MRI may be necessary before lumbar puncture if there are concerns about increased intracranial pressure or mass lesions 1
Antibiotic Therapy
- Adjusted based on culture results
- Continued for 7-21 days depending on the identified pathogen This aggressive approach is necessary because bacterial meningitis progresses rapidly and has high mortality if not treated promptly, as highlighted in the guidelines 1.
From the Research
Meningitis Workup
- The diagnosis of meningitis relies on the examination of cerebrospinal fluid (CSF), which is considered the gold standard for diagnosis 2.
- A lumbar puncture is typically performed to collect CSF for analysis, which can include cell count, glucose concentration, Gram's stain, and bacterial culture 2.
- In some cases, ventricular CSF assessment may not accurately reflect the presence of meningitis, and lumbar puncture sampling may be necessary to obtain a accurate diagnosis 3.
- The treatment of bacterial meningitis often involves the use of antibiotics, such as cefotaxime and ceftriaxone, which can penetrate the CSF and effectively treat the infection 4, 5.
- The penetration of ceftriaxone into the CSF can be influenced by factors such as the degree of inflammation and the presence of bacterial infection 5.
- Laboratory tests, including CSF cell count, glucose concentration, and bacterial culture, can be used to identify the causative organism and differentiate between bacterial and viral meningitis 2.
Key Considerations
- Immediate action is crucial in the treatment of meningitis, as it can be a life-threatening condition 6.
- The clinical presentation of meningitis can vary, and a combination of laboratory tests and clinical evaluation is necessary to determine the appropriate treatment 2.
- The use of antibiotics, such as cefotaxime and ceftriaxone, can be effective in treating bacterial meningitis, but the penetration of these antibiotics into the CSF can be influenced by various factors 4, 5.