title: Evaluation of S100B in the diagnosis of suspected intracranial hemorrhage after minor head injury in patients who are receiving platelet aggregation inhibitors and in patients 65 years of age and older.
abstract: OBJECTIVE
  Cranial CT (CCT) scans and hospital admission are increasingly performed to rule out intracranial hemorrhage in patients after minor head injury (MHI), particularly in older patients and in those receiving antiplatelet therapy. This leads to high radiation exposure and a growing financial burden. The aim of this study was to determine whether the astroglial-derived protein S100B that is released into blood can be used as a reliable negative predictive tool for intracranial bleeding in patients after MHI, when they are older than 65 years or being treated with antiplatelet drugs (low-dose aspirin, clopidogrel).
  
  
  METHODS
  The authors conducted a prospective observational study in 2 trauma hospitals. A total of 782 patients with MHI (Glasgow Coma Scale Score 13-15) who were on medication with platelet aggregation inhibitors (PAIs) or were age 65 years and older, independent of antiplatelet therapy, were included. Clinical examination, bloodwork, observation, and CCT were performed in the traumatology emergency departments. When necessary, patients were admitted and observation took place on the ward; in these patients, CCT was performed during their hospital stay. Patients with severe trauma, focal neurological deficits, posttraumatic seizures, anticoagulant therapy, alcohol intoxication, coagulation disorder, blood sampling more than 3 hours after trauma, and unknown time of the trauma were excluded from the study. The median age of the patients was 83 years, and 69% were female. Sensitivity, specificity, and positive and negative predictive values of S100B with reference to CCT findings were calculated. The cutoff of S100B was set at 0.105 μg/L.
  
  
  RESULTS
  Of the 782 patients, 50 (6.4%) had intracranial bleeding. One patient with positive results on CCT scan showed an S100B level below 0.105 μg/L. Of all patients, 33.1% were below the cutoff. S100B showed a sensitivity of 98.0% (CI 89.5%-99.7%), a negative predictive value of 99.6% (CI 97.9%-99.9%), a specificity of 35.3% (CI 31.9%- 38.8%), and a positive predictive value of 9.4% (CI 7.2%-12.2%).
  
  
  CONCLUSIONS
  Levels of S100B below 0.105 μg/L can accurately predict normal CCT findings after MHI in older patients and in those treated with PAIs. Combining conventional decision criteria with measurement of S100B can reduce the CCT scan and hospital admission rates by approximately 30%.
authors.affiliation: Trauma Hospital Meidling;
authors.forename: Heinrich Wolfgang
authors.initials: HW
authors.lastname: Thaler
authors.affiliation: Department of Traumatology, Donauspital; and.
authors.forename: Jochen
authors.initials: J
authors.lastname: Schmidsfeld
authors.affiliation: Trauma Hospital Meidling;
authors.forename: Michael
authors.initials: M
authors.lastname: Pusch
authors.affiliation: Trauma Hospital Meidling;
authors.forename: Simon
authors.initials: S
authors.lastname: Pienaar
authors.affiliation: Trauma Hospital Meidling;
authors.forename: Jörg
authors.initials: J
authors.lastname: Wunderer
authors.affiliation: Trauma Hospital Meidling;
authors.forename: Paul
authors.initials: P
authors.lastname: Pittermann
authors.affiliation: Department of Radiology, Kaiser-Franz-Josef-Spital, Vienna; and.
authors.forename: Rosmarie
authors.initials: R
authors.lastname: Valenta
authors.affiliation: Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Gleiss
authors.affiliation: Trauma Hospital Meidling;
authors.forename: Christian
authors.initials: C
authors.lastname: Fialka
authors.affiliation: Department of Traumatology, Donauspital; and.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mousavi
mesh_terms: D000328:Adult; D000368:Aged / Q000502:physiology; D000369:Aged, 80 and over; D001241:Aspirin / Q000009:adverse effects; D015415:Biomarkers / Q000032:analysis; D000077144:Clopidogrel; D006259:Craniocerebral Trauma / Q000150:complications*; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D020198:Intracranial Hemorrhage, Traumatic / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D011237:Predictive Value of Tests; D011446:Prospective Studies; D064568:S100 Calcium Binding Protein beta Subunit / Q000737:chemistry / Q000378:metabolism*; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives
chemical_list: D015415:Biomarkers; D010975:Platelet Aggregation Inhibitors; D064568:S100 Calcium Binding Protein beta Subunit; C579160:S100B protein, human; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: CCT = cranial CT; ED = emergency department; GCS = Glasgow Coma Scale; IQR = interquartile range; MHI = minor head injury; NPV = negative predictive value; PAI = platelet aggregation inhibitor; PPV = positive predictive value; S100B; intracranial hemorrhage; minor head injury; older patients; platelet aggregation inhibitors; traumatic brain injury