Lumbar Puncture in Thrombocytopenia: The Floor Is Not Firm.

Objective Lumbar puncture (LP) is a diagnostic procedure that accesses the spinal subarachnoid space to measure the opening pressure of the cerebrospinal fluid (CSF) and obtain samples of CSF for analysis. Although commonly performed, LPs are associated with the risk of morbidity and mortality. In addition, thrombocytopenia is thought to increase the risk of LP complications, particularly spinal bleeds. This study compares rates of complications among patients who received LPs with and without thrombocytopenia in hopes of establishing more evidence-based platelet thresholds for an LP. Methods The TriNetX multi-institutional electronic health record database was used to perform a retrospective propensity score-matched analysis of clinical outcomes of two cohorts of patients who underwent LPs - those with thrombocytopenia (defined as a platelet level of 10,000-50,000 platelets {plts}/μL) and those without thrombocytopenia. The outcomes of interest were the new occurrence of subdural hematoma, epidural hematoma, subarachnoid hemorrhage, receipt of a blood patch, new onset of paralysis, and requirement of spinal decompression. Results The risk of developing a spinal bleed following an LP was 1.496% (42 of 2,808) for the cohort with thrombocytopenia versus 1.09% (31 of 2,843) for the cohort without thrombocytopenia. The risk difference, risk ratio, and odds ratio of patients from these two cohorts experiencing a spinal bleed following an LP were insignificant at 0.05. The risk of receiving a blood patch following an LP was 7.844% for those with thrombocytopenia compared to 1.421% for those without thrombocytopenia. The odds ratio of receiving a blood patch between the two cohorts was 5.906, significant to the 0.05 level (95% CI: 4.213-8.279). There was no significant difference in the cohorts' risk of developing paralysis or requiring spinal decompression following an LP. Conclusion In support of recent findings against conventional platelet count thresholds prior to LP, it was observed in the present study that the incidence of post-LP spinal bleeding in the 30 days after LP is not associated with platelet counts below the guideline threshold of 50,000 plts/μL. Patients with thrombocytopenia are also not significantly more likely to require spinal decompression or develop new onset paralysis. However, thrombocytopenia is associated with a significantly increased likelihood of receiving a blood patch following an LP.