A spinal tap, also called a lumbar puncture, sounds scary. However for most people, it is not anything to be particularly worried about.
Along with blood tests, your neurologist may order a spinal tap when they are trying to diagnose a neurological disease. In my case, Doc Fundamental performed the LP right in his office. The doctor will anesthetize the area around your lower back and have you sit on the table, leaning forward. He will then insert a needle into your spine, puncturing the dura mater and draining some of the spinal fluid from inside of it. The dura is a tough sack encasing the spinal cord and brain.
When someone has multiple sclerosis, it is believed that their immune system attacks the myelin coating on the nerve cells. When this happens, the breakdown of the myelin creates certain antibodies as a byproduct. The antibodies don’t stay in your spinal fluid for too long so if the spinal tap result comes back positive for these antibodies, it indicates that your immune system may currently be attacking the myelin. In my case, the results were not off the charts and horribly abnormal, but they did show the presence of the antibodies.
A positive result by itself does not mean that you have MS and a negative result does not clear you from it. There are significant type 1 and 2 errors for you stats folks. It is just one more piece of evidence leading towards a diagnosis, one way or the other.
Post puncture they will have you lay still for a couple of hours. You will be instructed to drink a lot of fluids and to take it easy for the next 24 to 48 hours. However, a lucky 40% of us develop severe headaches when we sit or stand upright after the procedure. Unlike the EMG, I’m not sure that this one does beat a sharp stick in the eye. Thankfully, there was a creative treatment and that will be the topic of my next post.