Q: I had a persistent headache after a spinal tap. The fluid taken out during the tap was normal. My doctor has suggested a blood patch. What is this?
A: Epidural blood patching is a procedure used to treat people who develop a persistent headache caused by a spinal tap (lumbar puncture).
To do a spinal tap, the doctor inserts a very skinny needle into the fluid space inside the spine. After the spinal fluid is collected, the needle is pulled straight back and out. This helps avoid a leak.
But even with excellent technique, spinal fluid may continue to leak for several days or even weeks afterward. When spinal fluid leaks, it lowers the fluid pressure around the brain and spinal cord. A fall in pressure puts tension on the membranes around the brain. Then nerves in the membranes send out pain signals, causing the headache.
This type of headache is called a post-dural puncture headache (or post LP headache). Typically the headache is worse with standing and relieved by lying down. The first way to treat it is to remain flat in bed for a couple of days. You need to drink plenty of fluids, preferably with caffeine. For pain relief, start with acetaminophen or ibuprofen. But you may need prescription-strength pain medicine.
Epidural blood patching is done as an outpatient procedure. The doctor finds the place in the lower back where the patient had the initial needle puncture. Then, he or she sterilizes the area and slowly advances the spinal needle until it enters the epidural space between the vertebrae in the lower back.
The nurse draws a small amount of blood, less than two teaspoons, from the patient's arm. The doctor then injects this blood, the patient's own blood, into the space to close up the leak.
This procedure often relieves persistent post-dural puncture headache.
(Howard LeWine, M.D., is a practicing internist at Brigham and Women's Hospital, Boston, Mass., and Chief Medical Editor of Internet Publishing at Harvard Health Publications, Harvard Medical School.)
(For additional consumer health information, please visit http://www.health.harvard.edu.)