Clouding Jolt Accentuation by Cloudy Clinical Setting for Lumbar Puncture

I read with interest a recent report by Sato et al, who attempted to demonstrate the possibility of meningitis in the absence of jolt accentuation by asking “Can we rule out meningitis from negative jolt accentuation? ” Jolt accentuation (JA) is an exacerbation of headache induced by rotation of the head horizontally twice or three times per second, which has been reported in patients with meningitis, brain tumor, or migraine. Our original prospective study of JA was designed to address a clinical question “how to select reasonable candidates for lumbar puncture in a relatively homogeneous group of patients presenting with recent-onset headache (within two weeks after onset) and fever (more than 378) without neurological deficits. Because this set of criteria enhances the pretest probability of meningitis and lowers the pretest probability of other possibilities such as brain tumor, severe encephalitis, or migraine, it was proved that positive JA in this selected cohort may enhance the probability of meningitis. Even though the population of our initial study was small (n 5 54), this original study was successful in demonstrating that JA is the most sensitive sign of pleocytosis over classical meningeal signs. Now, Sato et al challenge this diagnostic value of JA by asking “Can we rule out meningitis from negative jolt accentuation? ” in an extended retrospective cohort without such patient selection. Because negative JA in patients with pleocytosis has been noted in a patient with Sjogren syndrome in the initial study and has been since confirmed by subsequent retrospective studies, the answer to the authors’ question is apparently “No.” The results on JA have been variable due to population bias (where the study was performed), how the patients were recruited to the study (recruitment bias), how the data were collected, and how the data were interpreted (interpretation bias) to settle clinical questions. Anyway, it was fortunate that this simple method has been routinely used in an emergency setting to raise suspicion of meningitis. Unfortunately, however, this simple method was extended to the cohorts with or without fever, headache, or those with neurological deficits. As expected, application of JA to such heterogeneous cohorts might have greatly reduced the original sensitivity and specificity of JA initially obtained in a relatively homogeneous cohort. Because lumbar puncture is potentially harmful, evaluation of its benefits in reference to potential risks may be necessary for improved management of these patients suspected of meningitis. Theoretically, it is justified to perform lumbar puncture to patients suspected of meningitis. How to suspect meningitis is still, however, a matter of considerable debate, one that remains to be standardized. Indeed, the clinical impression of caring physicians is not helpful in predicting pleocytosis in these patients. Therefore, patients’ recruitment based on the non-standardized clinical suspicion of meningitis, as entertained in the study by Sato et al, could not only expand heterogeneity but also is hard to reproduce by other institutes. Operational criteria for indication of lumbar puncture independent of subjective clinical impression, such as suspicion of meningitis, may be necessary. Otherwise, the study results cannot be extrapolated to clinical settings conducted differently by different physicians in various clinical settings. In short, external validity of this clinical study may not be qualified with such poorly defined recruitment. Moreover, the methods section stated “We evaluated the sensitivity and specificity of JA in febrile patients with and without headache,” which is different from the abstract “Jolt accentuation (was? ) evaluated in patients with fever, headache. ” Therefore, this cohort might include heterogeneous patients with and without headache, which Address all correspondence to T. Uchihara, Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan. email: uchihara-ts@igakuken.or. jp