What information can be reached with cerebrospinal fluid after doing a lumbar puncture??

Question

What information can be reached with cerebrospinal fluid after doing a lumbar puncture??

Answer 1

The first thing you can learn is whether or not there is increased pressure on the brain, and you find that out by measuring the opening pressure--how hard the CSF comes out when you make the puncture.

You can then see whether the fluid is bloody, cloudy or clear.  If it's bloody, you may have an intracranial bleed (or you may just have a bloody tap--no Champagne for you).  If it's cloudy, that can indicate an infection.  If it's clear, you keep looking.

You can put some of the CSF on a slide and do a stain called a Gram stain looking for cells that soak up that particular stain.  If you find them, your CSF has organisms that are Gram positive.  That tells you something about the kind of organism it could be.  You can also do an India ink stain to look for cryptococcus, but I'm not sure how often they do that one any more now that they have antigen testing.

You can then send the CSF off to the lab where they will look for red blood cells, white blood cells, protein and glucose.  There are always some of the latter three (there shouldn't be any red blood cells, strictly speaking), but the numbers of the latter three will also give you some clues about what kind of process might be going on.

You can then run further studies on those things to find out what kind of white blood cells you have (a viral infection will have an increase in one type while a bacterial infection will show more of another; very high numbers might suggest a neoplastic process) or what kind of protein it is (monoclonal or polyclonal, for example).  There is always some glucose, but again, whether it is higher or lower than normal tells you something--when it is high you tend to have certain disease processes and when it is low you have others.

You can do cultures to try and grow out any bacteria, fungi or viruses that are present so they can be positively identified.

And there are a bunch of other things you can look for:  chloride, glutamine, lactate...

So, lots of information.  *g*