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S-100b protein levels as a predictor for long-term disability after head injury
  1. John-Paul Lomas, House Officer,
  2. Joel Dunning, Clinical Research Fellow
  1. Department of Emergency Medicine, Manhester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK; Kevin.mackway-jonesman.ac.uk

    Abstract

    A short cut review was carried out to establish whether levels of S-100b were predictive of long-term disability after head injury. 200 papers were found using the reported searches, of which 12 presented the best evidence to answer the clinical question. The author, date, and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these best papers are tabulated. It is concluded that a raised level of S-100b is a marker of poorer long-term outcome after both major and minor head injury.

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    Report by John-Paul Lomas, House OfficerSearch checked by Joel Dunning, Clinical Research Fellow Manchester Royal Infirmary, Manchester, UK

    Clinical Scenario

    A 17 year old male presents to the Emergency Department after a road traffic accident. His GCS was 8 on arrival but an immediate CT scan showed no focal abnormality. His GCS returned to 14 after 4 hours. You are talking to his mother who is reassured that he does not need urgent neurosurgery, but she asks whether he will suffer any long term consequences from this injury. You tell her that it is difficult to predict. You have recently heard that S-100 protein measurement is available in your hospital for research purposes. You wonder whether S-100 could help predict his long term prognosis.

    Three part question

    In [patients with a head injury] do [levels of S-100B protein] predict [long-term disability]?

    Search strategy

    Medline 1966-Week 4 August 2005 using the OVID interface [(exp S100 Proteins/ OR s100.mp OR s-100.mp) AND (exp Brain Injuries/ OR brain injury.mp OR exp Craniocerebral trauma/ OR head inj$.mp)] Embase 1980-2005 week 37 [exp Protein S 100/ OR s100.mp OR s-100.mp] AND [exp Brain Injury/ OR brain injury.mp. OR craniocerebral trauma.mp. or exp Head Injury/] LIMIT to Human and English Language The Cochrane Library Issue 3 2005 Exp Brain injuries [MeSH] OR exp Craniocerebral trauma [MeSH] AND exp S100 proteins [MeSH]

    Search outcome

    200 papers were found of which 13 were found to be relevant. Two relevant papers described the same patient population. The remaining 12 papers are shown in the table.

    Comments

    All studies were under 200 patients in size and most were under 100 patients. The studies find sensitivities from 27%–95% and specificities from 70% to 97%. The reasons for this great variation in findings may in large part be due to the small sample sizes. The specificities seem to perform better than the sensitivities and thus the finding of a high S-100 may indicate that your patient is at high risk of long term disability. The cut-points for a significant S-100 level differ between studies also and are generally much higher when applied to patients after a severe head injury. Most studies agree that S-100 levels must be taken within 6 hours of head injury.

    CLINICAL BOTTOM LINE

    A high S-100 level is a marker of poorer long term outcome following minor and major head injury.

    Table 3

    Report by John-Paul Lomas, House OfficerSearch checked by Joel Dunning, Clinical Research Fellow Manchester Royal Infirmary, Manchester, UK

    References

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