Postudural Puncture Headache (PDPHA) is defined by the International Headache Society as any headache that develops within five days of dural puncture and is not better accounted for by another cause. Classic symptomatology includes a positional headache in the frontal or occipital locations that is worse when upright and relieved by supine positioning. However, there are reports of atypical PDPHA in a small minority of patients that is worsened when lying flat. Accompanying symptoms include neck stiffness and subjective auditory symptoms, visual disturbances, and nausea/vomiting. Most occur within 48 hours of dural puncture, but less than 25% of cases occur later than 3 days afterward. The pathophysiology is felt to be leakage of CSF through the dural puncture site, creating traction on brain structures and cranial nerves.
It is important to note that most postpartum headaches in obstetric patients (which is the population most commonly attributed with PDPHA) is not in fact due to PDPHA. Rather, tension headaches, followed by preeclampsia, are the leading causes of headaches in these patients. The incidence of PDPHA as established by the Serious Complication Repository (SCORE) project of the Society for Obstetric Anesthesia and Perinatology is roughly 1%; however this includes both spinal anesthetics and accidental dural puncture with epidural anesthesia. Young age and female gender have been identified as risk factors for developing PDPHA. Obesity does not increase the risk of developing a headache, and patients with a high BMI may have a lower incidence of PDPHA. Among parturients, cesarean delivery is protective when compared to vaginal delivery. It is theorized that bearing down during the second stage of labor exacerbates CSF leakage.
Once thought a benign complication of neuraxial anesthesia, most PDPHA resolve spontaneously within two weeks. However, several studies have shown that in a small subset of patients, headache persists for greater than six weeks.
While there is no standard method of preventing PDPHA, some anesthesia providers place prophylactic epidural blood patches after difficult epidural placements during which they suspect dural puncture. Studies on this technique have yielded mixed results. Another method which initially showed promise in studies has met with inconsistent results in practice: threading an intrathecal catheter through an epidural needle following known dural puncture. The thought is that the catheter, left in for greater than 24 hours, will staunch CSF leakage and stimulate a fibrotic response which will result in a smaller tear in the dura.
Despite the widespread use of intravenous caffeine in the treatment of PDPHA, only one study has shown a positive effect and no subsequent study has reproduced its results. The emergency medicine literature includes case series of sphenopalatine ganglion blocks using a cotton-tip swab dipped in lidocaine inserted through the nostril as being an effective technique, however this is not widely implemented. Epidural blood patch is the only effective treatment borne out in studies. Optimal volume of sterile blood injected into the epidural space is accepted as 20ml, or until patient complains of back pain. Serious complications are rare, including radicular pain, chronic adhesive arachnoiditis and epidural hematoma. Roughly 10% of patients will require a repeat blood patch.
It behooves anesthesia providers to familiarize themselves with the background and management of PDPHA, a leading cause of lawsuits despite being a fairly well-understood and treatable condition.