National Trends in Lumbar Puncture from 2010 to 2018: A Shift Reversal from the Emergency Department to the Hospital Setting for Radiologists and Advanced Practice Providers

Lowering Platelet Threshold to 20,000/μL for Fluoroscopy-Guided Lumbar Puncture Does Not Result in Observed Clinical Adverse Outcomes

PURPOSE

Fluoroscopic-guided lumbar puncture (FG-LP) is a common neuroradiologic procedure. Traditionally, a minimum platelet count (MPC) of 50,000/μL for this procedure has been required; however, we recently adopted a lower MPC threshold of 20,000/μL. The purpose of this study was to compare adverse events in patients undergoing FG-LP with MPCs above to those below the conventional 50,000/μL threshold.

MATERIALS

This was an institutional review board-approved, retrospective study on adult patients with hematologic malignancy undergoing FG-LP in the neuroradiology division between May 2021 and December 2022, after lowering the minimal required MPC to 20,000/μL. Recorded data included indication for FG-LP, preprocedure and postprocedure MPC, need for and number of platelet transfusions within 24 hours of FG-LP, presence of traumatic tap, FG-LP-related complications, and any platelet transfusion-related adverse event. Patients were classified into 2 groups based on MPC: (1) those above 50,000/μL and (2) those below 50,000/μL. Descriptive statistics were used comparing these 2 groups.

RESULTS

One hundred twenty-eight patients underwent FG-LP, with 46 having an MPC between 20,000 and 50,000/μL and 82 having an MPC above 50,000/μL. No postprocedural complications were encountered in either group. Traumatic taps occurred in 10/46 (22%)​ with MPC below 50,000/μL versus 10/82 (12%)​ in those with MPC above 50,000/μL. Forty of 46 patients (87%) were transfused with platelets within 24 hours prior to FG-LP. One patient developed a transfusion-related reaction.

CONCLUSION

Lowering the MPC threshold from 50,000/μL to 20,000/μL for FG-LP did not result in a higher incidence of spinal hematoma.

Cryptococcal Meningitis Diagnosed With Lumbar Puncture in an Emergency Department Patient With Acute Delirium

Cryptococcal meningitis is a life-threatening fungal infection of the central nervous system. It primarily affects immunocompromised individuals, particularly those with advanced HIV/AIDS, but can occur in people of all ages. Risk factors include solid organ transplantation, hematological malignancies, immunosuppressive medications, and primary immunodeficiency disorders. We describe a case of a 68-year-old male with atypical risk factors for cryptococcal meningitis who presented acutely delirious with a negative diagnostic workup aside from a positive cerebrospinal fluid (CSF) meningitis screen reporting Cryptococcus neoformans/gattii. While the rate of lumbar puncture (LP) in the ED has drastically decreased over the years, we emphasize the importance of considering its diagnostic value in emergency department settings in patients with atypical presentations.

Charting the Next Road Map for CSF Biomarkers in Alzheimer's Disease and Related Dementias

Clinical prediction of underlying pathologic substrates in people with Alzheimer's disease (AD) dementia or related dementia syndromes (ADRD) has limited accuracy. Etiologic biomarkers - including cerebrospinal fluid (CSF) levels of AD proteins and cerebral amyloid PET imaging - have greatly modernized disease-modifying clinical trials in AD, but their integration into medical practice has been slow. Beyond core CSF AD biomarkers (including beta-amyloid 1-42, total tau, and tau phosphorylated at threonine 181), novel biomarkers have been interrogated in single- and multi-centered studies with uneven rigor. Here, we review early expectations for ideal AD/ADRD biomarkers, assess these goals' future applicability, and propose study designs and performance thresholds for meeting these ideals with a focus on CSF biomarkers. We further propose three new characteristics: equity (oversampling of diverse populations in the design and testing of biomarkers), access (reasonable availability to 80% of people at risk for disease, along with pre- and post-biomarker processes), and reliability (thorough evaluation of pre-analytical and analytical factors influencing measurements and performance). Finally, we urge biomarker scientists to balance the desire and evidence for a biomarker to reflect its namesake function, indulge data- as well as theory-driven associations, re-visit the subset of rigorously measured CSF biomarkers in large datasets (such as Alzheimer's disease neuroimaging initiative), and resist the temptation to favor ease over fail-safe in the development phase. This shift from discovery to application, and from suspended disbelief to cogent ingenuity, should allow the AD/ADRD biomarker field to live up to its billing during the next phase of neurodegenerative disease research.

An evaluation of the practice of image-guided lumbar puncture

OBJECTIVE

The purpose of this study was to evaluate the technical success and complication rates of image-guided lumbar puncture (IGLP) and to evaluate for differences in approach employed to help establish the optimum technique.

METHODS

A retrospective search of the hospital picture archiving and communications system was performed to identify all IGLPs that had taken place over a 5-year period. Radiology reports and the electronic medical record were examined to identify technical parameters and complications associated with each procedure.

RESULTS

The technical success rate was 96% (219/228). 69.4% (n = 161) had a previously failed bedside attempt. The rate of complications was 0.01% (n = 2). No major complications were observed. There was no difference in the rates of failure (2.4% vs  3.6%, p = 0.68) or complications (0.008% vs  0.012%, p = 1) between interlaminar and interspinous approaches.

CONCLUSION

IGLP is a safe procedure with a high rate of technical success. Where a difficult bedside attempt is anticipated, it is reasonable to forego this and proceed directly to IGLP.

ADVANCES IN KNOWLEDGE:

This paper helps to confirm what is already assumed about a common radiological procedure. This is important as there has been a shift from bedside technique to most lumbar punctures being performed via image guidance.

Lumbar Puncture: Indications, Challenges and Recent Advances

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