Differential Diagnosis for CSF Analysis
Given values: CSF glucose 32, protein >500
The following differential diagnosis is organized into categories to facilitate consideration of potential causes.
Single most likely diagnosis
- Bacterial meningitis: This condition is characterized by low CSF glucose (<50% of serum glucose) and elevated protein levels (>500 mg/dL), which matches the provided CSF analysis results. The presence of a high protein level and low glucose in the CSF is highly suggestive of bacterial meningitis.
Other Likely diagnoses
- Tuberculous meningitis: Although less common than bacterial meningitis, tuberculous meningitis can also present with low CSF glucose and elevated protein levels. The clinical presentation and additional diagnostic tests (e.g., CSF culture for TB, PCR) would help differentiate it from bacterial meningitis.
- Fungal meningitis: Certain fungal infections, such as cryptococcal meningitis, can cause similar changes in CSF glucose and protein levels, especially in immunocompromised patients.
- Subarachnoid hemorrhage: While the primary issue in subarachnoid hemorrhage is blood in the subarachnoid space, it can lead to increased protein in the CSF and potentially decrease glucose levels due to the metabolic demands of the blood cells.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Viral meningitis with significant inflammation: Although viral meningitis typically has normal or slightly decreased glucose and mildly elevated protein, some cases with significant inflammation or specific viral etiologies (e.g., herpes simplex encephalitis) might present with more pronounced CSF abnormalities.
- Carcinomatous meningitis: Metastatic cancer to the meninges can cause elevated protein and decreased glucose in the CSF, mimicking infectious causes. Missing this diagnosis could lead to delayed treatment of the underlying cancer.
- Sarcoidosis: Neurosarcoidosis can involve the meninges, leading to increased protein and potentially decreased glucose in the CSF. It's a diagnosis that requires consideration to avoid missing a treatable condition.
Rare diagnoses
- Neurosyphilis: This condition can cause a variety of CSF abnormalities, including elevated protein and decreased glucose, especially in the tertiary stage.
- Cysticercosis: Infection with the pork tapeworm (Taenia solium) can lead to neurocysticercosis, which may cause changes in CSF glucose and protein levels, particularly if there is significant inflammation or cyst rupture.
- Leptomeningeal metastases from lymphoma: Similar to carcinomatous meningitis, lymphomatous meningitis can cause elevated protein and decreased glucose in the CSF, requiring prompt diagnosis and treatment to improve outcomes.