Epidural injections involve administering specific medications, such as steroids or local anesthetic agents, into the epidural space of the spinal cord. This offers relief of symptoms such as pain caused by spinal pathologies and can offer anesthesia for scenarios such as giving childbirth.
Unfortunately, there are a few complications that may arise from epidural injections, although they are quite rare occurrences. That being the case, these adverse effects are worth discussing with the doctor who will be performing the procedure in order to discuss the chances of any issues occurring and how many times they have occurred previously in others so that the patient can be informed of the possibilities.
The most common potential risks1 associated with epidural injections include:
- Temporary numbness of the bladder and bowels.
- A dural puncture – this occurs in around 0.5 percent of epidural injections and it may cause a post-dural headache which resolves after a few days. It may be necessary to perform a blood patch if this occurs, which is a procedure that entails removing blood from the patient and immediately injecting it into the epidural space so that it can clot around the punctured dural to stop cerebrospinal fluid from leaking.
- Infection of the membranes making up the epidural space – this is extremely rare with 0.01 to 0.1 percent of injections resulting in this complication.
- Bleeding is a rare adverse event but the chances of this occurring are increased in those who have a bleeding tendency or disorder.
- Nerve damage is an extremely rare scenario but it may occur as a result of direct trauma to the spinal cord by the needle of the injection, or it may occur secondary to the pressure effects caused by bleeding or an infection of the affected site. Arachnoiditis is inflammation of the arachnoid membrane that covers the brain, spinal cord, and nerves of the central nervous system. Besides the mentioned causes, chemical irritation by steroid medications and local anesthetic agents may cause the arachnoid membrane to become inflamed.
- Persistent inflammation of the arachnoid membrane at the site of the epidural injection can lead to scar formation and these are adhesions that cause the nerve fibers and cells to stick together. This is called adhesive arachnoiditis. The resultant effect is severe neurological symptoms and signs which cannot be cured, but rather managed symptomatically.
- Adhesive arachnoiditis can complicate further where the adhesions calcify and become hard. This is referred to as arachnoiditisossificans.
Side effects of epidural steroid medications:
In addition to the risk associated with epidural injections, it is also important to be aware of potential side effects of the steroid medications used in the procedure. These issues do tend to be even rarer and less prevalent than side effects associated with oral steroids. The side effects of epidural steroid medications include:
- Headaches, irrespective of the position the patient is in, which usually resolve within a day.
- Localized increase in pain.
- Flushing of the face.
- Development of a fever the night of when the injection was administered.
- Difficulty falling asleep.
- Elevated blood glucose levels.
- Stomach ulcers and increased gastric acid production.
- A transient suppression of the immune system.
- Severe arthritis of the hips.
- Formation of cataracts in the eyes.
When to request and seek immediate medical attention:
The following conditions or complaints warrant a call to and consultation by a doctor or presentation to an emergency room to seek immediate medical attention:
- Experiencing a fever of 101 degrees F or more for longer than 24 hours.
- The onset of a severe and painful headache when standing up or while sitting and which improves when lying down.
- Lose of sensation or functioning in the arms and/or legs.
- Loss of bladder and/or bowel control after the temporary numbing effect of the local anesthetic agent wears off.
- Severe, burning pain that is not controlled by over-the-counter pain medications.
In general, epidural injections are effective in controlling lower back pain caused by inflammatory processes in the spine where at least 50 percent of patients experience a relief in their symptoms2. The relative safety and efficacy of this procedure make it an important part of the non-surgical management of lower back pain.
- Epstein NE. The risks of epidural and transforaminal steroid injections in the Spine: Commentary and a comprehensive review of the literature. Surgical Neurology International. 2013;4(Suppl 2):S74-S93. doi:10.4103/2152-7806.109446.
- Song SH, Ryu GH, Park JW, et al. The Effect and Safety of Steroid Injection in Lumbar Spinal Stenosis: With or Without Local Anesthetics. Annals of Rehabilitation Medicine. 2016;40(1):14-20. doi:10.5535/arm.2016.40.1.14.