Lumbar puncture is an important part of any neurologist’s toolkit. But patients who need an evaluation of their CSF are already struggling with symptoms of some kind that necessitated the procedure.

No one wants to add to their discomfort. This is why understanding the etiology of post-dural puncture headache (PDPH) is so important to the field of neurology.

PDPH, which occurs in 32 percent of cases, can last for days and may be incapacitating. This makes understanding the cause important for obtaining the best diagnostic information while avoiding morbidity. Young adults and females are at greatest risk for PDPH, as are those with lower body mass or undergoing procedures with larger needles or multiple punctures.

According to the International Classification of Headache Diagnoses, 3rd Edition (ICHD-3), PDPH is a subcategory of ICHD 7.2: “Headache attributed to low cerebrospinal fluid pressure.”

It can only be diagnosed if it occurs within five days of the procedure with documented intracranial hypotension or CSF leakage evident on imaging. However, this relationship between low CSF pressure and PDPH remains unproven, and recent studies have examined this concept and found it wanting.

In the first study, published in Frontiers in Neurology, researchers in South Korea prospectively enrolled 103 patients who needed CSF examination for suspected meningitis. They gathered data on opening pressure (OP), closing pressure (CP), cerebrospinal elastance (ECS), and the pressure-volume index (PVI) for all patients.

Analysis showed that none of the pressure factors were correlated with PDPH, even though CP was significantly lower than OP. Outcomes were controlled for demographics, presence of aseptic meningitis, and procedural differences. Researchers concluded that factors related to CSF pressure “might not be related to the development of PDPH.”

In a second study, published in Headache, researchers from across the U.S. performed a systematic literature review. Studies included in the review looked at headache incidence in relation to OP, CP or volume of CSF removed (V). They also performed a retrospective, case-control study to examine these associations. Researchers found no evidence connecting OP or CP with PDPH. In a minority of the studies reviewed, if a large volume of CSF removed there was an association with PDPH.

Based on this evidence, opening and closing pressure differentials have less impact on headache development than standard preventive practices (such as using atraumatic needles) to minimize CSF leakage after LP. Researchers suggest revisiting the ICHD criteria so that intracranial hypotension is not a diagnostic requirement.

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