Cerebrospinal Fluid (CSF)

Overview

Parameters

• Protein

• Glucose

• Opening Pressure

• Microscopy: lymphocytes, neutrophils

• Culture

• Oligoclonal bands

Core Differentials

• Bacterial Meningo-encephalitis

• Viral Meningo-encephalitis

• Tuberculosis

• Mumps

• Cryptococcus

• Malignancy infiltration

• Multiple sclerosis

• Idiopathic intracranial hypertension (IIH)

Diagnosis

Bacterial Meningo-encephalitis (septic)

• Low glucose, raised protein

• Neutrophils raised

• CSF culture: bacteria

• Meningococcal: ceftriaxone

Viral Meningo-encephalitis (aseptic)

• Normal glucose/ protein

• Raised lymphocytes (90%)

• CSF culture: virus

• MRI: HSV inflammatory changes, bitemporally

Tuberculosis

• Subacute presentation +/- cough/ haemoptysis 

• Normal to low glucose, normal to raised protein

• Mildly raised pressure 20-30

• CSF: raised lymphocytes

• MRI: basal inflammatory changes

Mumps

• Presentation: cervical lymphadenoapthy, unvaccinated

• CSF: raised monocytes

Cryptococcus

• raised pressure 30+

Malignancy infiltration

• Raised protein

• Lymphocytes

Multiple Sclerosis

• Oligoclonal bands

• Usually normal protein/ glucose

Idiopathic Intracranial Hypertension (IIH)

• Opening pressure > 30

• Other parameters normal

• Presentation: headache raised ICP & visual symptoms

References and Resources. 

Written in 2025.