Ans. c. Lymphocytosis, low glucose, high protein (Ref: Harrison 19/e p1111, 18/e p3414)Presence of significant basal exudates, together with dilated ventricles (hydrocephalus) in a young female with prolonged history of fever and headache suggests a diagnosis of tubercular meningitis. Tubercular meningitis is characterized by lymphocytic pleocytosis (Pleocytosis is the presence of both neutrophils and lymphocytes in CSF), low glucose and high proteins within the CSF."The pathological hallmark of Tubercular Meningitis is predominant involvement of basal cisterns that are observed by the presence of basal inflammatory tissue exudate."CSF changes in Infection of CNSParameters (Normal values)Bacterial MeningitisTuberculous MeningitisViral MeningitisPressureRaisedQRaisedQRaisedQGross appearanceTurbidQClear (may clot)ClearQProtein (Normal: 20-50 mg/dL)HighQVery highQSlightly highQGlucose (40-70 mg/dL)Very LowQLowQNormalQChloride (116-122 mg/dL)LowQVery LowQNormalQCells < 5/mLNeutrophilsQPleocytosisQLymphocytosisQTubercular MeningitisClassic CSF Abnormalities in Tubercular Meningitis* Elevated opening pressure* Elevated protein concentration (Range of 1 to 5 g/L or 10 to 500 mg/dL)* Decreased glucose concentration (Range of 1.1 to 2.2 mmol/L or 20 to 40 mg/dL)* Lymphocytic pleocytosis (10-500 cells/mL)* Mononuclear cells (except early infection when PMN cells are seen)* Chloride level: usually reducedThe pathological hallmark of Tubercular Meningitis is predominant involvement of basal cisterns that are observed by the presence of basal inflammatory tissue exudate.Classical Radiological Features (CT/MRI) in Tubercular Meningitis* Basal exudates/Obliteration of Basal cisternsQ (Tubercular exudates are primarily located in the vicinity of basal cisterns that are obscured by presence of inflammatory tissue exudate.)* Subarachnoid space is involved by the exudate (i.e. subarachnoiditis is present)Q* Abnormal leptomeningeal enhancement (Usually most pronounced in the basal cisterns)* Involvement is mainly of the leptomeninges i.e. Pia- arachnoid: Duramater is usually sparedQ.* Hydrocephalus (Usually communicating although non-communicating may also be seen)* Ischemic/Vasculitic infarcts (Basal ganglia and/or Internal capsule)* Tuberculomas (Granulomas)* Calcification is commonly seen in the meninges at the base of the brain.* Ventriculitis may be seen, but it is not common