An unexpected effect of traumatic and bloody lumbar puncture among patients with primary headaches in emergency department.

Background: This study aimed to investigate the association between traumatic tap and the incidence of post-dural puncture headache (PDPH) following lumbar puncture (LP) among patients who underwent LP with a primary discharge diagnosis of primary headache in the emergency department (ED).

Methods: We retrospectively reviewed the medical records of patients who visited a single tertiary ED with the symptom of a headache and underwent LP for cerebrospinal fluid (CSF) analysis between January 2012 and January 2022. Patients who met the definition of PDPH and revisited the ED or outpatient clinic within 2 weeks of discharge were included. For comparative analysis, we divided the groups according to CSF RBC counts (group 1, CSF RBC <10 cells/μL; group 2, 10-100 cells/μL; group 3, ≥100 cells/μL). The primary outcome was the difference in CSF RBC counts between the ED or outpatient clinic revisiting patients who underwent LP within 2 weeks after discharge from the ED. The secondary outcomes were the admission rate and risk factors for PDPH; sex, age, needle size, and CSF pressure.

Results: Data from 112 patients were collected; PDPH was reported in 39 patients (34.8%), and 40 (35.7%) patients were admitted. The median (interquartile range) CSF RBC count was 10 [2-100.8] cells/μL. One-way analysis of variance test of the mean differences among the three groups showed no differences in age, the duration of headache before LP, PLT counts, PT, or aPTT among the groups. There were differences in the number of admitted patients (30 vs. 7 vs. 3, P < 0.001) and the incidence of PDPH (29 vs. 6 vs. 4, P < 0.003). In the comparison of the PDPH and non-PDPH groups, there were differences in age (28.7 ± 8.4 years vs. 36.9 ± 18.4 years, P = 0.01) and the admission rate (85% vs. 9%, P < 0.001).

Conclusions: Notably, our results suggest that traumatic LP may be an unexpected factor in reducing the occurrence rate of PDPH. Consequently, the admission rate for PDPH was significantly reduced among patients with traumatic LP and those with primary headaches. In this study, we collected and analyzed the data from a relatively small sample size of 112 patients. Further studies are needed to evaluate the relationship between traumatic LP and PDPH.