15: CSF Analysis Flashcards
What makes up the BBB?
Choroid plexus
What makes up the blood-CSF barrier?
Arachnoid
What makes up the CSF-brain barrier?
Ependyma and pia
Why is CSF low cellularity?
Plasma ultrafiltrate and membrane secretion
Why should you not collect CSF if increased intracranial pressure?
Causes brain herniation
What do you use for cell count and cytology?
EDTA
What do you use for protein albumin and serology?
Protein albumin and serology
What time after collection is CSF analysis best?
Within 30 mins
If keeping longer than 30 mins, what do you need to add to CSF?
Serum/albumin or cells were burst
Why do you need hemocytomer for CSF analysis?
Cell numbers too low for automated count
What stain do you use for CSF?
None
How do you concentrate cells from CSF?
Centrifuge, membrane filter selection, gravity sedimentation, then air dry and count
How do you measure CSF protein?
Urine dipstick
What does high CSF protein suggest?
Inflammation or tumour
WHat does an Ig index do?
Compares CSF to serum Ig numbers
What else do you measure in CSF?
Albumin, Igs, virus specific Ag, PCR
How much RBC and WBC should there be in CSF?
No RBC, very little WBC
How can RBCs enter the CSF?
Contamination, haemorrhage, iatrogenic
How can WBCs enter the CSF?
Inflammation or blood contamination
How do you correct for blood contamination in CSF?
Remove 1 WBC for every 500 RBC
What will be present in the CSF if haemorrhage is fresh?
Platelets
Which contrast agents do you use for CAT and MRI scans?
Iodine
Why do you take cell count before injecting contrast agents?
Affects cells counts - neutrophils and macrophages will increase within 24 hours
How long can cell changes last after contrast contrast agent use?
5-10 days
Which cells are in normal CSF?
Mononuclear cells, choroid/ependymal cells, rare neutrophils and eosinophils
What kind of macrophages are abnormal in CSF?
Foamy/reactive
What colour can CSF be in bacterial meningitis?
Clear to turbid
What parameters are increased in bacterial meningitis?
Cells, proteins, IgG index
What % neutrophils do you see in bacterial meningitis?
over 75% degenerate
What kind of animals especially get bacterial meningitis?
Young
Which cells/parameters do you see increased in fungal meningitis?
Mixed cell pleocytosis, increased protein, sometimes eosinophils
How common is fungal meningitis?
Rare
What is correlation between CSF and blood eosinophils?
None
What does eosinophils in CSF indicate?
The meningitis is fungal or immune mediated
What are two forms of parasitic meningitis?
Common protozoal myelitis or verminous encephalomyelitis
What species gets verminous encephalomyelitis?
Horse
Which other parasites can cause meningitis?
Neospora or toxoplasma
Which cell changes do you see in parasitic meningitis?
Mixed pleocytosis
Which kind of meningoencephalomyelitis does parasitic meningitis cause?
Multifocal granulomatous
What kind of inflammation do you see in viral disease?
Non-suppurative
What cell/parameter changes do you see in viral disease?
Increased cell numbers, protein and IgG index, xanthochromia, mononuclear pleocytosis
What cell/parameter changes does herpes give?
Increased IgG and IgA, increased pleocytotic lymphocytes
What can CSF be like in rabies?
Normal
Should you collect CSF if rabies is suspected?
No
What colour is CSF in immune-mediated disease?
Clear to hazy
What is a symptom of immune-mediated disease?
headache
In which species is immune-mediated disease common?
Dogs
Which cell/parameter changes do you see in immune-mediated disease?
Increased cells and proteins, pleocytosis of any cell types
What may you see in CSF following intervertebral disc disease?
Cartilaginous emboli
What can CSF be like in intervertebral disc disease?
Normal
What are two different CSF changes you may see in IVDD?
Mild mononuclear pleocytosis, foamy macrophages, increased protein OR pleocytosis, normal protein, albumin and IgG
What can CSF be like in neoplasia?
Normal, but commonly there is increased protein and albumin and pleocytosis with abnormal cells
What is the usual neoplasia causing CSF changes?
Lymphoma, or meningioma or choroid plexus tumour
