American Board of Internal Medicine (ABIM) Certification Practice Exam

In which situation should lumbar puncture be performed before administering antimicrobials?

1. All patients with fever

2. Patients with symptoms of meningitis

3. Patients with a known history of headaches

4. Patients with a cough

The correct answer is: Patients with symptoms of meningitis

Lumbar puncture should be performed before administering antimicrobials in patients with symptoms of meningitis. This is primarily because performing the lumbar puncture allows for the collection of cerebrospinal fluid (CSF), which can be analyzed for the presence of pathogens, inflammatory cells, glucose, and protein levels. Early and accurate diagnosis through CSF analysis is critical in guiding the treatment of meningitis, as different etiologies (bacterial, viral, fungal) require distinct management strategies. Administering antimicrobials before obtaining CSF can lead to reduced sensitivity of cultures and may obscure the findings in the CSF analysis. This is particularly crucial in cases of suspected bacterial meningitis, where timely identification and treatment of the causative organism are essential for improving patient outcomes. The information gained from the lumbar puncture can also influence the need for specific types of therapy, such as antivirals or adjunct therapies like corticosteroids. In contrast, performing a lumbar puncture is not routinely indicated for all patients with fever, as fever can arise from a variety of non-infectious or less critical processes that might not require immediate CSF analysis. Similarly, a known history of headaches or having a cough does not inherently necessitate a lumbar puncture,