I had a steroid injection for sciatica caused by a herniated disc. Three weeks later I was in the hospital with meningitis. Is there any connection between the two events?

Although this is rare, it can happen. If you had an epidural steroid injection, the needle goes through the skin so that the tip of the needle is in the epidural space. This space is the area between the bony ring of the spine and the covering of the spine called the dura. The dura is the sac that encloses the spinal fluid and nerves of the spine.

Once the needle is in place, a liquid mixture of cortisone and lidocaine (a type of novacaine) is injected. The epidural space is normally filled with fat and blood vessels. Fluid such as the lidocaine and cortisone flows up and down the spine and inside the epidural space. It coats the nerves that run inside the spinal canal.

The result is to reduce inflammation and swelling. Pain relief is the goal.

But there are potential complications. Anytime a hole is punctured in the protective lining of the spinal canal, bacteria can be introduced. Local infection with an abscess can occur. Or a more serious systemic infection such as meningitis can develop.