In this study, we report an obstetric patient case of PR and PC following epidural anesthesia administration and included our findings to a pooled analysis of similar cases published in the literature. Our findings suggest that approximately half of patients reported with PR or PC presented with symptoms of headache; a majority were obstetrical patients. Headaches following epidural anesthesia are not uncommon; secondary causes of headache in obstetrical patients most commonly include post-dural puncture headache (PDPH) which occurs in 0.5% to 1.7% of patients who receive epidural anesthesia.[6] PDPH is classically characterized as a headache or backache developing within days after an epidural procedure as a result of excessive CSF leakage from dural puncture. The pain is exacerbated by head movement and relieved by supine positioning[7]. The PR or PC is much rarer and also commonly presents with headaches; however, it may also have other nonspecific symptoms such as altered mental status, seizure, hemodynamic instability, cerebral cortex focal deficits, lethargy, and loss of consciousness. As routine imaging is not commonly indicated in headaches that occur in the peripartum period, it is possible that obstetrical patients with PR or PC following epidural anesthesia administration are misdiagnosed with PDPH given its more common prevalence. The PR or PC should therefore be considered as a possible etiology of headache in the setting of epidural anesthesia to aid in early diagnosis and treatment for quicker recovery.
Multiple theories regarding the etiology of PR and PC have been proposed, including iatrogenic air administration through epidural anesthesia/analgesia and spontaneous air uptake through the Dandy “ball valve” theory and the Horowitz and Lundsford “inverted-soda-bottle-effect” theory. The Dandy theory hypothesizes that air moves unidirectionally from the atmosphere to inside the cranial cavity.[8] Horowitz and Lundsford suggest that loss of CSF creates a negative intracranial pressure which results in a vacuum formation that traps air inside the cranial space. The loss of CSF as described by Horowitz and Lundsford includes physiologic causes as well, such as during Valsalva maneuvers.[9, 10] During the Valsalva maneuver, intra-abdominal and intrathoracic pressure is increased, which elevates intracranial pressure (ICP) and intrathecal pressure (ITP). The magnitude and duration of ICP and ITP increase depend on the duration and intensity of the maneuver. ICP is then transiently decreased following a Valsalva maneuver, and when paired with a lumbar puncture, causes air to be sucked inside the cranium, resulting in equalization of ICP.[11] This hypothesis regarding air trapping due to increased intra-abdominal pressure may explain the predominance of obstetric patients with PR or PC in the current literature, as patients are instructed to perform Valsalva maneuvers and deep inspiratory breaths during the delivery process for long periods of time. This may also explain the findings of Avellanal et al, whom described a patient with findings of PC during a dural puncture with no air administered by syringe; the patient had a short series of coughs with vigorous inspiratory efforts which may mimic the Valsalva maneuver.[12]
Our study had several strengths, which includes detailing a large series of patients with PR or PC after epidural anesthesia/analgesia. We identified a lack of clarify on establishing causality of the outcomes related to epidural anesthesia/analgesia techniques utilized in obstetric and non-obstetric procedures. Our study also has limitations that should be acknowledged. Firstly, PR or PC were underreported, which may result from selection bias, publication bias, and observer bias. The limited number of case reports available for analysis prevented us from performing a thorough statistical analysis. Secondly, inconsistencies in reporting may have arisen due to the authors’ varying interests and the heterogenicity of patient cases, thus resulting in difficulty in synthesis of evidence and establishing causality. Thirdly, we lacked access to raw data and detailed information on each case, including unknown technique for epidural anesthesia/analgesia administration in 8 of 23 cases and unknown treatment in 3 of 23 cases. Finally, as we only reviewed literature available in English, our findings may not be representative of non-English language sources.
In conclusion, based on our systematic review of the literature from case reports, and including our own case, we have demonstrated that obstetric patients are associated with a higher risk of PR or PC following epidural anesthesia/analgesia. Vaginal delivery is associated with higher risk than cesarean section due to the prevalence of Valsalva maneuver during vaginal delivery. The LORA epidural technique is the more commonly used technique in all cases with PR or PC complications. Further research is needed to explore and identify the optimal labor analgesia techniques and delivery methods.
Data availability: The authors confirm that the data supporting the findings of this study are available within the referenced material of this article and openly accessible through PubMed at https://pubmed.ncbi.nlm.nih.gov.
Conflict of interest: The authors declare that there is no conflict of interest regarding the publication of this article.
Funding Statement: Not applicable
