Efficacy of Lumbar Puncture

[jason80]

Dear Doctor,
I have various symptoms of MS/Lyme that began ~ 2 years ago. To date, various tests (e.g., two MRIs w/o contrast, nerve tests, VEP, battery of blood work, etc.) have been inconclusive for any neurologic or infectious disease (e.g., Lyme). I have not done Lumbar Puncture.

My question: What is the efficacy of a LP for ruling out Lyme and any other neurologic disease? (My neurologist had some concern that it might induce a headache (I have suffered from chronic/dizzy headache in the past and I am free of that now). Will LP definitely rule out neurologic and Lyme?

Thanks in advance,
Jason

[Craig Brooker]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.

A lumbar puncture (LP) is one part of many of the work up of various neurological diseases and an LP alone cannot rule out all neurological diseases.  In the setting of possible Multiple Sclerosis (MS) 3 serological tests are often ordered including Myelin Basic Protein, Oligoclonal bands, and Tourtelloutes.  None of these entities is perfectly sensitive nor specific so these results alone don't make the diagnosis.  In Lyme Disease (a relatively common mimic of many neurological diseases) LP tests are also imperfect but using a few different studies looking for Lyme can increase the probability that one does or doesn't have Lyme.  

So while an LP can add significant additional information, much of these depends on clinical suspicion based on history and examination.  For example, if you're not from an area where Lyme Disease is common, you haven't had any known tick bites (or risks for them like camping), you haven't had a rash at any time (much less the typical "bull eye" rash) these would all make Lyme disease less likely (though as I mentioned above, it is a common mimic of many other neurological diseases).   Similarly if you don't have the typical history or exam findings of MS and all of the tests you mention above are specifically normal (you say inconclusive which is harder to interpret without the details), the LP is less likely to be very useful.  

LPs are often feared in the public realm but when done by an experienced neurologist, they are generally well tolerated.  Many lay people believe they are very painful but when given local anesthetic appropriately, LPs usually only have pressure and minimal if any pain associated with them.  Potential complications (which will be discussed more fully with you by your doctor before such a procedure) include most commonly headache.  Headache occurs in ~10% of patients (thought to be related to fluid continuing to leak after the LP) but this risk can be minimized by using a small bore needle, being well hydrated prior to the LP, the needle bevel position, and possibly by laying still for a little while or at least by taking the rest of the day "easy" (e.g. no contact sports, etc).  Is it possible to have a post-LP headache trigger your prior chronic headache?  Yes, potentially.  I'm not aware of good research on that in particular and I think would be difficult to study since the causes of chronic headache are numerous.  Most post-LP headaches can be treated successfully with hydration, caffeine, and laying flat (this last item often improving the headache dramatic quickly).  Post-LP headaches refractory to these treatments occasionally require a "bloodpatch" in which another needle is inserted into the spinal canal and a small amount of blood added which is believed to block the needle holes, prevent leak, and allow the headache to resolve.  

[jason80]

Thank you for your detailed reply, including headache info.

I've had an MS specialist and an ID doctor tell me that the LP would be VERY conclusive for ruling out CNS Lyme.

Whereas I've had a neurologist and a Lyme Dr. tell me that it is virtually useless for ruling out CNS Lyme.

What do you think?  (My focus is on ruling out CNS Lyme is because I'm debating whether or not to take IV- antibiotics).

Thanks again,
Jason