CNS Infections for UPSC CMS: Meningitis, Encephalitis and Brain Abscess

Bacterial Meningitis#

Organisms: S. pneumoniae (adults), N. meningitidis (children/young adults), H. influenzae (post-Hib vaccine: rare).

CSF: Turbid, WBC >1000 (neutrophils), protein high, glucose low (<40), Gram stain.

Treatment: Dexamethasone + Ceftriaxone + Vancomycin. Ampicillin if Listeria risk (elderly, immunocompromised, pregnancy).

TB Meningitis#

CSF: Clear/fibrinous, WBC 50-500 (lymphocytic), protein high, glucose very low. Long track signs, basal exudates on imaging.

Treatment: HRZE (isoniazid, rifampicin, pyrazinamide, ethambutol) + steroids.

Viral Encephalitis#

HSV-1: Temporal lobe involvement on MRI. Treatment: Acyclovir IV. JEV: Japanese encephalitis, rice fields, pigs.