Table of Contents
Learn how to perform the procedure too…
Performing a lumbar puncture is covered here!
NB: in bacterial meningitis patients who have had antibiotics prior to LP, CSF may be more lymphocytic and have a normal glucose
Typical Pathogens
- Bacteria in newborns: group B strep, E. coli/coliforms, listeria monocytogenes
- Bacteria in young children: N. meningitidis, strep pneumonia, Haemophilus influenzae
- Bacteria in teens/adults: strep pneumoniae, N. meningitidis, listeria monocytogenes (if >50 years/pregnant)
- Viruses: enterovirus, VZV, HSV, HIV, mumps
- Fungi: cryptococcus neoformans
Additional Tests
- Culture: grow bacteria
- PCR: for viruses e.g. enterovirus, HSV, VZV
- Electrophoresis: oligoclonal bands (MS)
- Acid-fast stain, TB culture and TB PCR: TB
- Xanthochromia: subarachnoid haemorrhage
- India ink stain and cryptococcal antigen test: cryptococcus
- Cytology: to look for malignant cells
Causes for abnormal CSF
- Increased neutrophils: bacterial meningitis, early TB, some viruses (e.g. enterococcus), some fungi (usually <80%), following seizures, following CNS haemorrhage, following CNS infarct, foreign materials, metastatic tumour
- Increased lymphocytes: viral meningitis, viral encephalitis, HIV, partially treated bacterial meningitis, some bacterial meningitides (Listeria, Mycoplasma, Lyme, Syphilis), cryptococcal meningitis, TB meningitis, parasitic meningitis, parameningeal bacterial infections, others uncommon (UTI <3m old, SSPE, MS, encephalopathy due to drugs, sarcoidosis, neoplastic/paraneoplastic, vasculitis, autoimmune encephalitis, other autoimmune conditions e.g. SLE)
- Increased eosinophils: parasitic infections (Angiostrongylus, Gnathostomiasis, Baylisascaris), fungal infections, reaction to foreign material, occasionally bacterial/TB meningitis, lymphoma, sarcoid
Adjusting for… A traumatic tap
- Allow 1 white cell for every 1000 red cells
- Allow 0.01g/L protein for every 1000 red cells
