Coagulopathy predicts poor outcome in traumatic brain injury

Introduction

Cerebral damage arising from traumatic brain injury (TBI) can occur primarily at the time of injury or can occur secondarily at a temporally distant time point post insult [1]. Abnormal clotting occurs in 10–20% of head-injured patients and may exacerbate secondary brain injury [2, 3]. It may also be a marker of the degree of the primary injury. Brain tissue is rich in thromboplastin, and activation of clotting pathways following TBI is thought to occur leading to abnormal coagulation. This may result in disseminated intravascular coagulation, cerebral microthrombi and ischaemia, or exacerbation of intracranial haemorrhage [4, 5]. We have studied the admission International Normalised Ratio (INR) in moderate to severe TBI patients, examining its role as a prognostic indicator in these patients.

Methods

All patients admitted to the Queens Medical Centre from 1993 to 2002 with a recorded Glasgow Coma Score of 12 or less within 48 hours of a TBI were included in the Nottingham Head Injury Register. The INR and outcome at 1 year were recorded on the register. We looked at the strength of the association between the admission INR and the outcome at 1 year.

Results

Data were available on 497 patients. Their mean age was 36 years (range 16–91). Seventy-five per cent of the patients were male. Of the 497 patients, 199 died at 1 year. The INR was increased in 60% of patients. Linear regression and logistic regression after group division into dead versus alive and good versus poor outcome were significant for the whole range of increased INR, but particularly striking and clinically relevant outcome difference was found where INR > 1.5 (chi-squared P < 0.001).

Conclusion

A prolonged INR was observed in patients presenting with moderate or severe TBI and was associated with unfavourable outcome. An admission INR > 1.5 is a statistically significant indicator of poor prognosis in moderate to severe TBI patients and may be a useful prognostic marker in these patients. This may be a valuable addition to prognostic scoring systems.