Can we lower the platelet threshold of ≥ 50 × 109/L for performing a lumbar puncture safely in patients with hematological malignancies?

Thrombocytopenia and Adverse Bleeding Events in Neonatal Lumbar Punctures in the Emergency Department

OBJECTIVE

Lumbar punctures are performed as part of a routine evaluation of neonates with fever in the emergency department. Current recommendations regarding performing a lumbar puncture in the presence of thrombocytopenia exist for children with leukemia and other cancers; however, there are no such recommendations for the general neonatal population. This study assesses the frequency of thrombocytopenia and adverse bleeding events in neonates who undergo a lumbar puncture to determine whether a complete blood count, and specifically the platelet count, should be reviewed before performing the lumbar puncture.

METHODS

This is a retrospective chart review of neonates 30 days or younger presenting to a single freestanding pediatric emergency department who received a lumbar puncture over the course of 11 years. The complete blood count was reviewed for thrombocytopenia, determined to be platelet count of less than 150,000/μL. The chart was reviewed for any documented adverse bleeding events associated with the lumbar puncture.

RESULTS

A total population of 2145 was studied with 56 patients determined to be thrombocytopenic. Seven total bleeding events were identified: 1 in the thrombocytopenic group and 6 in the nonthrombocytopenic group. All bleeding events were deemed to be clinically significant, either resulting in prolonged hospital stay or required further workup and medical intervention. The percentage of clinically adverse bleeding events that were related to the lumbar puncture was 0 (0.0%; 95% confidence interval, 0.0%-6.4%) and 2 (0.1%; 95% confidence interval, 0.0%-0.3%) ( P = 1.0) in the thrombocytopenic and nonthrombocytopenic groups, respectively.

CONCLUSIONS

Our results demonstrated a very low risk of bleeding events associated with lumbar punctures in neonates, with no increased risk in the thrombocytopenic group. As such, we conclude that waiting for the results of a complete blood count before performing the lumbar puncture in neonates without a known bleeding disorder is unnecessary.

Patterns and prognostic impact of CNS infiltration in adults with newly diagnosed acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is highly associated with central nervous system (CNS) infiltration and can be associated with higher risk of relapse. Conventional cytology (CC) is the traditional method for diagnosing CNS infiltration, although the use of immunophenotyping by flow cytometry (FC) has gained prominence in recent years due to its higher sensitivity. Also, some authors have proposed that CSF contamination by a traumatic lumbar puncture (TLP) could have a clinical impact. This retrospective study accessed the impact of CNS infiltration by CC or FC on overall survival, event-free survival, and relapse rate. In a cohort of 105 newly diagnosed ALL patients, CNS1, CNS2, and CNS3 status were found in 84%, 14%, and 2%, respectively. We found that extramedullary disease at the diagnosis, higher leukocyte counts, and higher blast percentage were associated with a positive CC. Sensitivity and specificity of CC were 53% and 98%, respectively. Three-year overall survival was 42.5%. Conversely, TLP was not associated with a positive CC nor had an impact on relapse rates. In multivariate analysis, a positive CC was associated with an increased relapse rate (HR 2.074, p = 0.037), while its detection by FC did not associate with this endpoint. Survival rates seem to be increasing over the last years by the adoption of a stratified CNS prophylaxis risk strategy. CSF contamination does not represent a major concern according to our report, as it did not increase CNS involvement or relapse rates.