Match each of the following cerebrospinal fluid (CSF) laboratory profiles obtained via lumbar puncture to its most likely clinical diagnosis. Assume a normal serum glucose level of 90-100 mg/dL for all patients.
- WBC 4,500/µL (95% neutrophils), Glucose 20 mg/dL, Protein 180 mg/dL, markedly elevated opening pressureBacterial Meningitis
- WBC 85/µL (90% lymphocytes), Glucose 70 mg/dL, Protein 55 mg/dL, normal opening pressureViral Meningitis
- WBC 350/µL (80% lymphocytes), Glucose 25 mg/dL, Protein 300 mg/dL, markedly elevated opening pressureTuberculous Meningitis
- WBC 3/µL, Glucose 65 mg/dL, Protein 145 mg/dL, normal opening pressureGuillain-Barré Syndrome
- RBC 25,000/µL (consistent across tubes 1-4), WBC 15/µL, positive xanthochromia, elevated opening pressureSubarachnoid Hemorrhage
Answer
Profile 1 matches Bacterial Meningitis. Profile 2 matches Viral Meningitis. Profile 3 matches Tuberculous Meningitis. Profile 4 matches Guillain-Barré Syndrome. Profile 5 matches Subarachnoid Hemorrhage.
Each CSF laboratory profile reflects the specific pathophysiology of the matching condition. Bacterial infections consume glucose and recruit neutrophils. Viral infections trigger a lymphocytic response without consuming glucose. TB/Fungal infections trigger a lymphocytic response but consume glucose and raise protein significantly. Immune-mediated root damage in GBS leaks protein into the CSF without white cells. A ruptured aneurysm leaks RBCs directly into the subarachnoid space, which break down into bilirubin, causing xanthochromia.
Step-by-Step Solution
Key Concept
Interpreting Cerebrospinal Fluid (CSF) Laboratory Profiles