*CPOT: Critical Pain Observation Tool
**MME: Morphine Milligram Equivalents
Outcome and Follow-up:
The patient reported a significant decrease in pain after insertion of the epidural. His CPOT score went from 8/10 the day before insertion to a score of 2/10. He also tolerated the discontinuation of the lidocaine infusion as well as a significant reduction in opioid use. As per the stated initial goals, after a pain break of a few days, the epidural was discontinued to reduce the risk of any complications with a subsequent increase in CPOT scores back to 8/10 and an increased need for opioids. The patient was subsequently decannulated on day 63 since onset of symptoms and by day 74 his pain was much improved with a CPOT of 2/10 daily. From day 77, the patient was discharged from ICU to a bed on the ward to continue rehabilitation. He was discharged from hospital to a rehabilitation center on day 115 needing only gabapentin 1200mg daily, venlafaxine 75 mg daily and nortriptyline 35 mg daily.
Discussion:
Pain is a common complicating factor in GBS. However, severe refractory pain is relatively uncommon but can complicate the course of some patients with GBS. There is limited data on how to best treat these patients. Data on the use of an epidural for refractory pain relief in GBS is even further limited. The potential benefit is a reduction in refractory pain which can have a psychological impact on patients (and families). Moreover, the use of an epidural could potentially spare the use of other medications such as opioids with their multitude of side effects and dependence as well as the use of other medications which may have varied effects such as QT prolongation, which in itself can increase mortality. Furthermore, most of these medications cause respiratory depression which may prolong the time that a GBS patient is on a ventilator which has its own risks such as deconditioning, ventilator induced diaphragm dysfunction, ventilator induced lung injury, stress ulcers, decubitus ulcers, and ventilator associated pneumonia. This host of side effects to traditionally used pain management plans have prompted the development of safer therapeutic modalities.[8] The potential risks of an epidural include that of localized infection or bleeding which may go unnoticed especially in a patient that is already paralyzed and unable to sense. However, this risk is approximately 1/18,000 for epidural hematomas and an incidence of 0.2 to 2.8 cases per 10,000 for an epidural abscess and potentially could be reduced further with daily screening ultrasounds to look for localized fluid collections.[9][10] Furthermore, a tunneled epidural could further reduce the risk of infection though evidence is lacking in GBS patients.[11] Studies have supported the use of tunneled epidurals to provide not only timely, but extended analgesia for cancer patients.[12] In our case, the epidural produced a significant improvement in the refractory dysesthetic pain for our patient. The epidural was only kept in situ for five days to prevent infection. Most case studies documenting the use of epidural after failure of routine analgesics in GBS were documented in the late 80’s and 90’s. All used morphine sulphate epidurals in previously healthy adults. A short report from 1991 showed that 8/9 patients benefited from a morphine epidural to treat refractory pain with minimal side effects with the most common being urinary retention and pruritis.[13] Again, in 1992, a case study successfully reported the long-term use of a bupivacaine and fentanyl epidural, however, after day 24, opioid requirements increased suggesting development of tachyphylaxis.[14] Our case is novel in that more data has emerged since the 1990’s in the use of adjunct therapies for pain control in GBS. In our case, our patient was already on what would be considered the contemporary management of pain in GBS with multiple adjunct agents. Even in the setting of being on all these drugs, the patient still had refractory pain. Despite this, the epidural was highly effective, which is in contrast to all previous studies from the 1980’s where epidurals were used with very little adjunct medication on board. Further data is required on epidurals in GBS. Additionally, larger, well designed randomized control trials are required to further investigate the safety of potential interventions for patients with pain in GBS.[15] The present case report gives some observational evidence to the potential benefit of epidurals in GBS and may be a steppingstone to considering a trial of epidurals (or tunnelled epidurals) in patients with GBS and refractory pain.
Learning points:
Pain is common in the acute phase of Guillain-Barré Syndrome and rarely can be severe and refractory.
Pain in GBS may not always respond to contemporary pain and adjunct therapy.
An epidural can potentially be considered for the treatment of refractory pain after a careful patient-centered discussion with the patient about risks.