Delayed radicular pain following two large volume epidural blood patches for post-lumbar puncture headache: a case report.

INTRODUCTION Postdural puncture headache (PDPH) is a known complication of diagnostic lumbar puncture. Multiple factors including needle size, type, and needle bevel orientation, have been postulated to contribute to the development of PDPH. The presentation of PDPH tends to have classic symptoms that include a postural headache, nausea, vomiting, tinnitus, and ocular disturbances. Conservative treatment measures include bed rest, intravenous hydration or caffeine, and analgesics. Resistant cases might require an epidural blood patch (EBP). Though complications are rare, cases of immediate post-procedural pain and subdural epidural hematoma have been reported. Here we present a case of PDPH treated with sequential EBPs that resulted in delayed radicular pain. CASE REPORT A 29-year-old female presented to the emergency room with a severe frontal headache of several days duration. She underwent a diagnostic lumbar puncture as a part of her work-up. Then, 24-48 hours later she developed a severe postural headache unresponsive to conservative care. Two days later she underwent an epidural blood patch with 20 mL of autologous blood. Her symptoms did not abate, prompting a repeat EBP within 24 hours with an additional 20 mL of autologous blood. Five days later the patient began experiencing muscle spasms and radicular pain in the buttocks and left posterior leg that radiated to her posterior calf. The patient was initially started on pregabalin 25mg 3 times daily, and underwent a gadonlinum-enhanced MRI of the lumbar spine. She followed up 5 days later with unchanged symptoms and a negative MRI. She was then started on a methylprednisolone taper and continued the pregabalin. At the 10-day follow-up, there was 90% resolution of symptoms and a pain intensity of 1/10 on NRS. At this time she is continuing the pregabalin with plans to discontinue medication. DISCUSSION Although EBP is typically a safe procedure, complications might occur. An inflammatory response, secondary to the injection of blood, or mechanical compression, due to the total volume of blood injection, are highlighted as possible causative agents in the development of this complication. The role of fluoroscopic imaging, particularly in patients who have failed an initial EBP, must also be examined. Given the rates of false loss of resistance (17-30%) reported in the literature, the use of real-time imaging to ensure proper needle placement and subsequent injectate spread should be considered.