Source / episode info

• **Episode:**263
• **Title:**Divine Intervention Episode 263 – The Clutch CNS Infection Podcast (+ 2CK course/NBME test taking strategies reminder).
• **Published:**2020-09-20
• Source:Episode page

One-liner

This episode provides a comprehensive review of CNS infections, emphasizing the differential diagnosis based on CSF analysis (e.g., differentiating bacterial vs. viral vs. fungal meningitis) and highlighting high-yield associations for specific pathogens like Cryptococcus, Toxoplasma, HSV, and Neisseria meningitidis.

High-yield summary

• CSF Differentiation: Bacterial meningitis typically shows low glucose, high protein, and a predominance of neutrophils; viral meningitis usually has normal glucose/protein with lymphocytic pleocytosis.
• Cryptococcus neoformans: Characterized by very high opening pressure, very low CSF glucose, and very high CSF protein in HIV patients (especially those with CD4 < 100). Diagnosis requires India ink stain or latex particle aggregation assay.
• Toxoplasmosis: Classically presents as ring-enhancing lesions on imaging, especially calcifications around the basal ganglia (choroid plexus, putamen, globus pallidus) in HIV patients. Treatment involves Pyrimethamine + Sulfadiazine (or Spiramycin during pregnancy).
• HSV/CMV Differentiation: HSV meningitis often involves the temporal lobes and is associated with a high number of red blood cells (RBCs) in the CSF; CMV can cause intra-nuclear inclusions, while rabies causes intracytoplasmic inclusions (Negri bodies).
• Meningococcal Meningitis: Requires prompt treatment with third-generation cephalosporins (e.g., Ceftriaxone), and crucially, prophylactic antibiotics must be given to all close contacts (Rifampin preferred, unless pregnant).
• Neonatal Meningitis: The most common causes in the first 20 days of life are Streptococcus agalactiae (GBS), followed by Listeria monocytogenes, and then E. coli.

Learning objectives

• Differentiate the CSF profile of bacterial, viral, fungal, protozoal, and arboviral meningitis.
• Identify the key pathogens associated with CNS infections in immunocompromised hosts (e.g., HIV).
• Recognize the classic imaging findings for Toxoplasma and CMV encephalitis.
• State the appropriate empirical antibiotic/antiviral regimens for suspected bacterial or fungal meningitis.
• Understand the public health implications of meningococcal disease, including prophylaxis for close contacts.