Spinal tap, or lumbar puncture headache occurs in one out of four people undergoing this procedure. Spinal tap is usually done to examine spinal fluid for infections, bleeding, multiple sclerosis, and other conditions. A small percentage of people undergoing epidural anesthesia, which involves placement of the same kind of needle into the same space between vertebrae, also develop a spinal tap headache. This happens because the needle is accidentally placed too far and it causes a leak of spinal fluid. Spinal tap headache is very easy to diagnose – it stops as soon as the person lies down and begins within minutes of sitting up. Normally, the brain floats in cerebrospinal fluid, but if this fluid is drained away by a spinal tap, the brain sags, pulls on the brain coverings, called meninges, and causes a severe headache. The majority of people do not develop this headache after a spinal tap because as soon as the needle is withdrawn, the hole in the dural sac that covers the spinal cord and the brain closes. In some people, especially if it takes a few sticks to get the fluid flowing and with a larger needle, the hole may not close right away and the fluid keeps leaking inside the spine. In most people the headache stops on its own within a day or two. If it doesn’t, the problem can be fixed by a “blood patch” procedure. It involves taking the patient’s own blood from the vein and injecting it into the same space between vertebrae where the spinal tap was done. Patient’s blood clots and seals the persistent leak of the cerebrospinal fluid, which stops the headache, often within minutes.
A similar headache can rarely occur without a spinal tap or even a trauma to the spine. It is called spontaneous low cerebrospinal fluid headache and it is also very positional, meaning that it gets better when the person is lying down. This headache is more difficult to diagnose, but an MRI scan of the brain sometimes shows inflamed meninges around the brain, which suggests this diagnosis. Finding a leak is more difficult and requires looking at the flow of the spinal fluid and searching for a leak. When a single leak is found, a blood patch procedure can help, but with multiple leaks the treatment becomes more complicated. A single case of using Botox to helps this type of headaches was described here last year.
