What are the main side effects of the lumbar puncture and how long will they last for?

Some are serious : Sever problems: respiratory arrest. Anaphylactic shock. Minor problems: spinal headache pain around the area of the tap usually those resolve in few days.

Headache: By far the most common side effect is a "post-lp headache." it can last for several days or even a week. The pain tends to get better when you're lying down, and caffeine sometimes helps as well. In severe cases, an epidural blood patch procedure is sometimes performed.