Differential Diagnosis for 62 yo man with Meningitis
Single Most Likely Diagnosis
- B. Gram -ve cocci: This is the most likely diagnosis given the presentation of meningitis with low glucose, high protein, and the presence of neutrophils in the cerebrospinal fluid (CSF). Gram-negative cocci, such as Neisseria meningitidis, are a common cause of bacterial meningitis, especially in adults, and can present with these CSF findings.
Other Likely Diagnoses
- D. Gram -ve rod: Gram-negative rods, such as Haemophilus influenzae or Escherichia coli, can also cause bacterial meningitis, particularly in older adults or those with certain risk factors (e.g., head trauma, neurosurgery). The CSF profile can be similar to that seen with Gram-negative cocci.
- A. Gram + cocci: While less common than Gram-negative cocci in adults, Gram-positive cocci like Streptococcus pneumoniae can cause meningitis, especially in the context of pneumonia or other infections. The CSF findings can overlap with those of Gram-negative infections.
Do Not Miss Diagnoses
- C. Gram + rod: Although less common, Gram-positive rods like Listeria monocytogenes can cause meningitis, particularly in immunocompromised individuals, the elderly, or those with certain underlying conditions. Missing this diagnosis could be deadly due to its severity and the need for specific antibiotic coverage.
- Fungal or Tubercular Meningitis: While not listed among the choices, it's crucial to consider fungal (e.g., Cryptococcal) or tubercular meningitis in the differential, especially in immunocompromised patients or those with exposure history. These conditions can present with similar CSF abnormalities and require distinct treatments.
Rare Diagnoses
- Other Bacterial Causes: Rare bacterial causes of meningitis, such as Borrelia burgdorferi (Lyme disease) or Treponema pallidum (syphilis), can present with meningitis but are less common and typically have distinct clinical contexts or additional symptoms.
- Parasitic Meningitis: In rare cases, parasitic infections can cause meningitis. These are often associated with specific travel histories or exposure risks and can have a more subacute presentation.