So you might be surprised to hear that lumber functions are now being done
increasingly frequently in the diagnosis of MS. We went through a phase where they
weren't done very often, but just in the last couple of years some new diagnostic
criteria have been suggested which means that lumbar punctures are now back in
the fray, particularly at the very beginning of the illness. So that now
with one MRI scan and one lumbar puncture
you can definitively diagnose MS. So What's a lumbar puncture like? Well the
first thing is that people often have real fears and anxieties about lumbar
punctures they may well have heard terrible stories and if they haven't
heard terrible stories, they've got all sorts of imaginings of huge needles and
terrible pain and all the rest of it. And 99% of people that have lumbar puncture
say "well I really didn't think it was going to be as good as that". So if your
doctor asks you to have a lumbar puncture
then I'd encourage you to accept because it will make the diagnosis of MS or not
or whatever else much more secure and confident. You would only ever have to
have one you know there's no need to have repeated one so this is a one-off
moment to really secure the diagnosis of MS so that you can go into the future
knowing that you do or don't have the disease and make plans accordingly.
Lumbar punctures are done in a hospital setting and the whole process takes half
a day a morning or an afternoon. Where people come in meet the nurse or the
doctor who's doing the lumbar puncture and then the actual lumbar puncture it
take itself takes about half an hour and then people are usually asked to lie on
a bed for one or two hours afterwards, and then they can go. So the the key
thing that can go wrong in a lumbar puncture
and the main cause of side effects is once you've taken the needle out you can
get you've got a hole in the covering around the spinal fluid and some spinal
fluid can leak out of that hole. And if that happens a lot then people can have
a relatively dehydrated brain with less spinal fluid than there should be
which people will notice with a headache. And that headache is particularly
prominent if you stand up, you can imagine the spinal fluid draining down
as you stand up and the brain is dehydrated and the brain doesn't like
that. Now the best thing you can do to avoid that leak is remain relatively
still and relatively flat for a while to allow the leak to clot up literally with
with blood clotting products and not do too much active over the next day or two
after that.
So the procedure is very awkward and uncomfortable.
You have to lie sort of curled up in a ball and you can't see what's going on,
and that is a bit of a worry because you thinking "oh my goodness what's going on"
but if the doctor or nurse who is doing it, is doing their job properly they will
make you feel at ease. The the most painful bit is actually the injection of
the local anesthetic so that's done with an ordinary needle that you would use to
take blood from someone or whatever. And most people have had experience of those
sort of local anaesthetic injections and that's there to numb the back and if
that's done well then the spinal needle itself shouldn't be painful. People can
feel it, and it certainly feels odd to have someone putting a needle through
your skin but it shouldn't be painful. Very occasionally the needle can touch
one of the nerves go into the leg and that can result in a feeling of electric
shock down the leg and people might imagine "oh my goodness something's gone
wrong, you know they
hit my spinal cord" or whatever but actually that's not the case, and it
doesn't mean anything bad has happen, but that can happen and can be a source of
discomfort
Well the key thing about a lumbar puncture is it shows the presence of
something called "Oligoclonal bands" and people will see that phrase a lot
when they look up MS, and all that actually means is a few Oligoclonal
bands of antibodies. So all it's saying is that there are some antibodies in the
spinal fluid that aren't normally there. And 90% or more of people who have
definite MS will have these antibodies in their spinal fluid so if the spinal
fluid is normal that goes a long way to saying someone doesn't have multiple
sclerosis and a very typical example of that where it might be useful is if in
an older person, say someone aged 60 who has some symptoms that might do for MS
their MRI scan may well have a few rather nonspecific blobs on them because
we get those blobs as we get older so the MRI scan is less useful in
discriminating for diagnosis and a CSF, for spinal fluid, a lumbar puncture is
really helpful then, because if it shows these antibodies you can say "yeah that
person has MS" if it doesn't show them you say "no they don't have MS". It's very
helpful. The other situations where lumbar punctures are being used in the
diagnosis of progressive MS, so primary progressive MS or secondary progressive
MS and that's particularly the case now that treatments are starting to be
licensed and being considered to be available for primary progressive MS so
in that context people need to know the diagnosis is secure before giving an
expensive treatment. And then the final situation which is becoming more and
more frequent, is if someone goes to their doctor with just one attack,
let's say of numbness. And an MRI scan shows a few lesions that might be
compatible with MS. The question is "well is this a one-off? Or is this going to
recur and become multiple sclerosis?" Now in the bad old days we would wait for
another attack and there'll be people who can remember being told well you
just have to wait. In the less bad days we would repeat a scan a few months or a
year later and see if anything new it emerged but now we can do a lumbar
puncture then and there and if it shows antibodies in the spinal fluid we say we
don't need to wait you definitely have relapsing remitting
multiple sclerosis even though the person hasn't had relapses or remissions
have just had one attack. And the reason why that's helpful is because
potentially that person could be put on treatment at that point