‘Dural Tap’ – A headache following an epidural
Many women choose to have an epidural – also called regional anaesthesia for pain relief during labour and birth. Most have no problems at all with their epidural and once the numbness has worn off and sensation returns; they soon return to their normal level of activity. For more detailed information also see our article, ‘Pain relief options for labour and birth’.
However, in a much smaller proportion of women (between 0 and 2.6%), having an epidural sited (inserted) can inadvertently result in the dura (the membranes covering the brain and spinal cord) becoming punctured by the epidural needle. This opens up a small hole in the dura through which a small amount of cerebrospinal fluid (CSF) leaks. CSF is a bag of fluid, contained in the dura which cushions and protects the brain and spinal cord. Where the dura is punctured and the CSF leaks out this is referred to as a ‘dural tap’ or ‘post dural puncture headache’ (PDPH). Where an accidental dural tap occurs, there is at least a 75% chance of a PDPH developing soon after the birth. The headache typically develops 12 to 24 hours post birth, but can develop at any time between the first day and seven days’ postnatal. Over the past ten years however, refinements to lumbar (spinal) needle size and shape as well as, developments in procedural techniques have reduced the incidence of PDPH.
Why does this headache develop?
Having an epidural involves injecting local anaesthetic into your back; into the area just outside the dura – called the epidural space. This anaesthetises (numbs) the area so that having the epidural sited is more comfortable. If the dura is punctured and too much CSF leaks out, the pressure in the rest of the CSF surrounding the brain and spinal cord is reduced. If the woman then sits or stands upright, the pressure of the CSF drops even further resulting in a severe ‘throbbing’ headache that is usually felt in the front or back of the head. Women often describe this headache as being like a severe migraine which gets worse when upright, but is relieved by lying completely flat in bed. Some women also report neck pain, photophobia (aversion to bright lights), auditory disturbances – tinnitus (ringing/noise inside the ears), as well as, nausea and vomiting.
What should I do if I feel this way?
If you develop a severe headache soon after the birth, especially following an epidural, it is important that you tell your midwife or doctor straight away. The maternity staff will check you over, including monitoring your blood pressure, temperature, pulse and oxygen saturation levels to check that the headache isn’t being caused by something else such as, pre-eclampsia (high blood pressure); thrombosis (a blood clot) or pyrexia (fever) which can cause similar symptoms. The maternity staff will contact the anaesthetist who will come and see you if you are still on the postnatal ward. If you have already been discharged home; the maternity staff will make arrangements for you to come back into hospital for an anaesthetic review.
How is the headache treated?
There are a number of simple remedies that will be initially offered to help ease a PDPH. The first line of treatment is to ensure the woman lies completely flat in bed for 24 hours (with just one pillow) and gets plenty of rest – maternity staff will help relatives with caring for the baby as needed. The anaesthetist will also prescribe regular pain killers – Paracetamol, as well as, a non-steroidal anti-inflammatory drug (NSAID) – Ibuprofen. These drugs belong to different medication groups and have different properties, which mean they can be used interchangeably, as per manufacturer instructions, to give maximum relief. The anaesthetist will also recommend that the woman drinks plenty of fluids with studies showing that caffeine drinks such as cola, tea and coffee are especially beneficial. Very occasionally, if the woman is dehydrated from labour and/or unable to tolerate oral fluids because of nausea/vomiting, the anaesthetist may suggest that an intravenous infusion (drip) is started to ensure the woman receives adequate fluids while she rests.
What happens if the headache persists?
If the above treatments prove ineffective after 24 hours of therapy, the anaesthetist will suggest a different form of treatment. While the puncture hole in the dura will usually seal itself up after seven days, coping with the severe headache in the intervening days can be extremely debilitating and can make caring for a newborn baby practically impossible. Furthermore, because the CSF acts as a protective cushion for the brain, where the pressure of the CSF remains low and this cushioning-effect is compromised, this can cause a certain type of stroke. Consequently, clinical guidance recommends that PDPHs which fail to resolve after 24 hours are treated promptly with an epidural blood patch. It is recommended that a blood patch is performed after 24 hours post birth wherever possible, as doing a blood patch earlier can be ineffective. Blood patches have been found to be successful in 60-70% of PDPHs.
What does an epidural blood patch involve?
The procedure is performed by an anaesthetist and sometimes with an assisting practitioner; it is very similar to the procedure used to site an epidural. The practitioner(s) will be scrubbed and will wear masks and gowns to ensure the procedure is as aseptic (sterile) as possible. The anaesthetist will explain what having a blood patch involves including, its benefits, disadvantages and associated risks and your informed consent will be sought before the anaesthetist proceeds. It is very common for pain and discomfort to be felt in the back as well as referred pain in the hip or leg during the blood patch and immediately following the procedure. Your observations will be checked to ensure you are not pyrexial (have a raised temperature). If you are found to be pyrexial, this can indicate a possible infection and the anaesthetist will not perform the blood patch.
A small amount of blood (usually 20mls) is taken from a vein in your arm and is then slowly injected into your back, as close to the original epidural puncture site as possible (usually just below it). The blood quickly forms a clot which effectively seals the puncture hole. You will then be asked to lie flat for two hours, after which time, you can gently and cautiously begin to sit up and gradually move around until you are able to remain upright. Many women report a complete disappearance of their headache and associated PDPH symptoms within 24 hours following the blood patch.
What if the blood patch doesn’t work?
A blood patch is effective in 60-70% of cases. However, very occasionally the procedure doesn’t work and the headache persists or the cure is only temporary, with the headache returning. Where this is the case, the anaesthetist will usually recommend a further blood patch. They will however, talk this through with you and where a second blood patch is required this will be undertaken by a Consultant Anaesthetist.
Are there any risks associated with having a blood patch?
As with any clinical procedure there are a few side-effects and risks associated with having a blood patch. The first and most obvious is localised bruising and backache which can persist for a few days. Studies have shown however, that epidurals and blood patches do not cause backache in the longer term. Because the procedure involves a further injection into the back, there is a small risk that a further accidental dural puncture could be sustained. Infection, damage to the nerves (including difficulties passing urine and loss of sensation), and bleeding into the woman’s back are extremely rare complications associated with epidurals and blood patches. If you have any concerns about how you are feeling; particularly, if you are experiencing severe pain or have loss of sensation, it is important that you tell the doctor immediately – these are not normal and will need to be investigated and treated as a matter of urgency.
Following a blood patch, the anaesthetist will advise you to avoid heavy lifting, violent movements or physical straining; all of which, have the potential to dislodge a blood patch – even up to six months after it was performed. Should you have any queries or concerns, or should the headache return, you should always contact the hospital (Delivery Suite or Triage) for advice.