Final answer:
When meningitis is suspected and a CT scan shows a mass, a lumbar puncture for CSF analysis is the next diagnostic step. This confirms the diagnosis of bacterial meningitis, which can be treated with antibiotics. Accurate diagnosis is essential for appropriate treatment and informing public health measures.
Step-by-step explanation:
Understanding Suspected Meningitis and Diagnostic Steps
When a CT scan shows a mass in a patient with suspected meningitis, the next step typically involves a lumbar puncture (spinal tap) to collect cerebrospinal fluid (CSF) for analysis. This is essential in confirming a diagnosis of bacterial meningitis. Antibiotics can treat bacterial meningitis but they are ineffective against viral infections or non-infectious causes of meningitis.
Therefore, accurate diagnosis through CSF analysis is critical for appropriate treatment. CSF examination will look for abnormal levels of polymorphonuclear neutrophils (PMNs), glucose, and protein. Presence of pathogens like Neisseria meningitidis, identified by its coffee-bean morphology on Gram stain, would be treated with antibiotics such as broad-spectrum antibiotics initially, and then more specific antibiotics once the organism is identified.
In the case provided, bacterial meningitis was confirmed by the presence of Neisseria meningitidis in the CSF and treated with intravenous antibiotics and rehydration therapy, leading to an improvement in the patient's condition. This is why a spinal tap and immediate lab analysis of the CSF are crucial in suspected cases of meningitis. Furthermore, treatment may start empirically based on the clinical presentation, but laboratory confirmation is necessary to make any needed adjustments to the treatment regimen and to inform prophylactic measures for close contacts.