Study Finds Increased Risk for Intracranial Subdural Hematomas in Postpartum Women with Post-Dural Puncture Headaches
By Christine Lehmann
October 17, 2019
Article In Brief
Women who had a post-dural puncture headache after neuraxial anesthesia in childbirth had a small but significantly higher risk for intracranial subdural hematoma. Independent experts said while the absolute risk is low, clinicians should remain vigilant about potential complications in women who have acute headaches in late-stage pregnancy and the postpartum period.
Women who develop post-dural headaches after childbirth from cerebrospinal fluid (CSF) leaks associated with needle punctures from neuraxial anesthesia may have a small but significantly increased risk for potentially life-threatening subdural hematomas, according to a paper published online in the September 16 issue of JAMA Neurology.
Up to 3 percent of women may experience post-dural puncture headaches after neuraxial anesthesia in childbirth, the study authors noted. But while case reports in the medical literature have described subdural hematomas in women who had post-dural headache after childbirth, few studies have determined if there was a significant association between the conditions.
“This is the first study to identify and quantify the risk of developing intracranial subdural hematomas post-partum in women with post-dural headaches,” the lead investigator Albert R. Moore, MD, associate professor of anesthesiology at McGill University in Montreal, told Neurology Today.
The researchers found that among more than 22 million deliveries, culled from a large database in the US, the post-dural puncture headache rate was 309 per 100,000 deliveries and the subdural hematoma rate was in 1.5 per 100,000 deliveries. But the subdural hematoma rate for women with post-dural puncture headache increased significantly to 147 per 100,000 deliveries.
Dr. Moore encouraged clinicians to be more vigilant of postpartum patients with post-dural puncture headaches and to advise these patients of the “very small but significant risk of developing a brain blood clot. Most of these headaches develop in young healthy women—it would be devastating for them to have a hematoma,” he said.
A neurologist who was not involved with the study agreed that the findings underscored the need for vigilance for this potentially dangerous association in late-stage pregnant and postpartum patients with acute headaches in general, but he emphasized that the message to patients should be that the absolute risk for subdural headaches is still very low.
To determine the association between post-dural puncture headaches and subdural hematomas, Canadian researchers collected hospital discharge and readmission records in the US Agency for Healthcare Research and Quality National Readmission Database. The database includes data on women who gave birth from 2010 to 2016, and the research team analyzed the data from 2018 to 2019.
They included patients who had two months of follow-up data and had not undergone a diagnostic lumbar puncture. Only the first delivery for a calendar year was studied. The team compared outcomes for 68,374 women who had had post-dural headaches with 22,062,441 women without headaches.
Adjusting for confounders, the post-dural headache group had an absolute risk increase of 130 hematoma cases per 100,000 deliveries and an adjusted odds ratio of 199 for subdural hematoma.
Additional risk factors associated with subdural hematomas included a patient's history of anticoagulation, blood vessel abnormalities, and chronic hypertension including severe preeclampsia.
However, Caesarean sections and obesity showed a negative association with subdural hematomas, noted Dr. Moore. “A possible explanation for the c-sections is that we provide anesthesia through a smaller needle puncture in the spine rather than in the dura because women don't experience labor.”
The investigators also found no association between the administration of an epidural blood patch to fix the spinal fluid leak and subdural hematomas although “the blood patches that were delayed until the patients were readmitted showed an increased risk. This suggests that the patches given earlier may be protective,” said Dr. Moore.
The main limitation was the retrospective nature of the database, which could only determine that post-dural headaches were associated with rather than caused subdural hematomas. “We also didn't know what type of anesthetic the women had, for example, whether it was epidural or spinal or an analgesic,” said Dr. Moore.
He suggested that other databases could be used in future research to corroborate and further determine causation.
“This is the first paper in the literature to show a clear association between post-dural puncture headaches and subdural hematomas and quantify the risk,” said Naida Cole, MD, an obstetric anesthesiologist at Brigham and Women's Hospital and an instructor in anesthesia at Harvard Medical School, who was not involved in the study.
“I was surprised by how high the odds ratio was (199) and the magnitude of the risk difference (145) in women with post-dural puncture headaches compared to women without them. Even with the increased relative risk, the absolute risk for subdural hematoma is still very low, since these are incredibly rare events. Nonetheless, because the paper documents an increased risk, I would be careful about advising patients with post-dural headaches that the condition is benign,” said Dr. Cole.
Clinicians can use a simple test to diagnose post-dural puncture headaches. “A cardinal symptom is whether the headache improves when patients lie down flat and worsens when they sit up or stand up. If a patient's headache meets this criterion, the definitive treatment is an epidural blood patch. A trial of conservative therapy such as pain medications may also be appropriate in some cases, to relieve mild symptoms,” said Dr. Cole.
She noted that at her institution, epidural blood patches are given without delay to patients diagnosed with post-dural headaches. “A secondary finding of this study was that delaying treatment with a blood patch was associated with an increased risk of having a subdural hematoma.”
Most neurologists know that there are risks, including potentially debilitating post-dural puncture headaches, associated with dural punctures, whether from a diagnostic lumbar puncture or for analgesic purposes, said Matthew S. Robbins, MD, FAAN, FAHS, neurology residency program director at Weill Cornell Medicine, New York Presbyterian Hospital, to Neurology Today in an email.
Many studies have demonstrated that subdural fluid collections and hematomas can be an additional complication from intracranial hypotension/hypovolemia caused by CSF leaks, added Dr. Robbins.
“Although the results raise alarms about reinforcing such a rare but serious consequence, we can frame the results in a reassuring way for pregnant women offered such anesthesia for labor and delivery. The absolute risk of subdural hematoma related to post-dural puncture headache remains low. In addition, this study found that more than three-fourths of patients with subdural hematomas did not require any neurosurgical intervention, which is in line with our clinical experience of patients with spontaneous CSF leaks,” said Dr. Robbins.
Nonetheless, the finding of a small but increased risk of subdural hematomas “reinforces the need for diagnostic vigilance in late-stage pregnant and postpartum patients with acute headaches in general,” said Dr. Robbins. He and his co-researchers drew a similar conclusion in their studies of pregnant women with acute headaches receiving neurological consultations.
Dr. Robbins suggested that more studies be performed “to capture the factors and clinical features of patients with post-dural puncture headaches who develop subdural hematomas as a complication compared to patients who do not experience this complication.”
Drs. Moore, Cole, and Robbins had no disclosures.