ARTICOLO ORIGINALE   

La Rivista Italiana della Medicina di Laboratorio 2020 Giugno;16(2):108-13

DOI: 10.23736/S1825-859X.20.00065-1

Copyright © 2020 EDIZIONI MINERVA MEDICA

language: Italian

A study of protein S100B levels in minor head injury patients receiving oral anticoagulant therapy

Marina BRUGIA ¹, Lucia BABINI ¹ ✉, Fabiana PASQUINI ¹, Alessandra CALCINARI ¹, Marianna PAVANI ¹, Vincenzo G. MENDITTO ², Aldo SALVI ², Marco MORETTI ¹

¹ Laboratorio Biochimica Clinica e Microbiologia, Azienda Ospedaliero Universitaria Ospedali Riuniti, Ancona, Italia; ² Pronto Soccorso e Medicina d’Urgenza, Azienda Ospedaliero Universitaria Ospedali Riuniti, Ancona, Italia

BACKGROUND: Minor head injury is one of the most frequently observed traumas in emergency departments of Western countries. Several publications and international guidelines have focused on the decision of which of these patients should undergo computerized axial brain tomography (CT). However, there are limited data available to characterize the risk of adverse outcome in patients receiving oral anticoagulant therapy. Over the last two decades, there has been increasing interest in several serum proteins that could potentially predict the presence of a brain injury from head trauma. The most promising marker for the stratification of the risk of bleeding in these patients appears to be the S100B protein. The purpose of this paper was to correlate the S100B level in serum with the presence of brain injury in patients treated with oral anticoagulant therapy upon arrival at the Emergency Department.
METHODS: 100 patients were enrolled in the period from April 2018 to August 2019. Patients enrolled had to meet these criteria: age >14 years; Injury Severity Score (ISS) <15; head injury Glasgow Coma Scale (GCS) between 14-15; trauma occurrence within 48 hours; oral anticoagulant therapy at the time of the trauma. Enrolled patients underwent CT at the entrance and control CT at 24 hours (±6 hours); blood samples were taken within 6 hours of arrival in the emergency room (PS). The determination of S100B was performed with an automated system (limit of detection: 0.004 µg/L, cut-off 0.2 µg/L). Ten of the enrolled patients were excluded from the study because the first or the second CT were not performed. Of the 90 patients studied, 37 (41%) were males and 53 (59%) were females, the age ranged from 46 to 95 years old, the mean age was 82.
RESULTS: Seventy-six (84%) patients had negative CT both at the entrance and at 24 hours; 29 (38% of the patients with negative CT) of these patients had S100B values above the cut-off. Four (4.4%) patients had negative CT at the entrance and positive CT 24 hours later, and 2 of these showed S100B values above the cut-off. 6 (6.6%) patients had positive CT at the entrance and negative control CT at 24 hours, 3 of these had S100B values above the cut-off. Finally, 4 (4.4%) patients had entrance CT and control CT both positive and they showed elevated S100B values. The negative predictive value (VPN) and the positive predictive value (VPP) of the S100B protein assay 6 hours after the trauma, in relation to the outcome of the first or second CT, are 100% and 18.4% respectively with 0.2 μg/L cut-off (sensitivity 100%, specificity 62.7%).
CONCLUSIONS: The introduction of the S100B protein assay in patients with mild head injury could help in identifying patients with an elevated risk of post-traumatic cerebral hemorrhage, avoiding unnecessary hospitalizations and instrumental investigations, and facilitating the rule out of patients. However, analyzing a higher number of samples and completing the follow-up of enrolled patients will help to clarify further the utility of this biomarker.

KEY WORDS: S100B protein, human; Brain injuries; Warfarin