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Three Part Question

In [anticoagulated patients who sustain a minor head injury] is [a CT scan indicated] to [rule out intra-cranial injury]?

Clinical Scenario

A 68yr old man, on warfarin for a mechanical aortic valve replacement, is brought into A&E after a minor head injury. He has a haematoma over the occipital region, however has no symptoms relating to his head injury. On examination, his GCS is 15/15 and there is no focal neurological deficit. You wonder if a CT scan of the head is indicated in this situation to safely rule out any significant intracranial injury.

Search Strategy

Medline 1966 – June 2005 through the OVID interface.
(Head Injury) AND (CT scan) AND (anticoagulants). Limited to English and human.

Search Outcome

14 papers were found in this search, 3 of which are relevant to this BET.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Gittleman et al, 2005, USA	89 patients on warfarin who underwent CT scan for HI. Low and moderate risk head injuries were included in the study.	Retrospective	Normal or Abnormal CT result.	Group 1 82 patients with normal CT scan. Average GCS 14.8. No neurology Group 2 7 patients with abnormal CT scans. Average GCS 12 Focal neurology present Conclusions Pts with GCS 15 and no neurology do not require CT scan	Retrospective design Small study population Low and moderate risk HI included in study
Li et al, 2001, USA	144 patients who sustained minor HI while on warfarin. Exclusion criteria: New neurology, reduced GCS, multi trauma and penetrating injury.	Retrospective	Normal or Abnormal CT result.	144 pts scanned.10 abnormal scans with significant intracranial injury.7% of pts with apparently low risk head injury who have abnormal CT scan. Conclusions CT scan required for all patients who sustain minor HI while anticoagulated to exclude significant intracranial injury.	Small numbers Selection bias
Garra et al, 1999, USA	65 patients on warfarin who sustained minor head injury as defined by no focal neurology or LOC. 39 patients CT scanned. 26 followed up clinically.	Retrospective	Normal or abnormal CT result. Clinical follow up in the group who did not under go CT scan	Group 1 39 pts with minor HI who were CT scanned. All CT scans were normal Group 2 26 pts who did not receive CT scan after HI were followed up by phone. No evidence of complications related to HI Conclusions CT scan is not required in patients with no new neurology and no LOC.	Retrospective design Clinical follow up limited Loosely defined 'minor' head injury.

Comment(s)

3 papers studied the incidence of intracranial injury post head injury in anticoagulated patients. All studies were retrospective in design and used normal or abnormal CT scans as outcome measurements. 1 study (Garra) also included patients who had not been CT scanned and followed this group up clinically

Clinical Bottom Line

The evidence in this BET is inconclusive. 2 studies (Gittleman, Garra) concluded that in the absence of reduced conscious level and a new focal neurological deficit, CT scanning is not required to exclude a significant intracranial haemorrhage. However, Li et. al. arrived at a differing conclusion. This study found that anticoagulated patients with an apparently low risk head injury had an increased chance of sustaining significant intracranial injury (Risk=7% 95%CI). There was no significant demographic or case characteristic differences between the patients with normal and abnormal CT scans, this included INR. This study recommended 'intracranial imaging during emergency assessment for head trauma in all patients receiving anticoagulants'. Further studies are required to clarify the need for CT scanning in this group of patients. Ideally they should involve larger numbers and be prospective in design.

References

1. Gittleman AM. Ortiz AO. Keating DP et al. Indications for CT in patients receiving anticoagulation after head trauma. American Journal of Neuroradiology 26(3):603-6, 2005 Mar.
2. Li J. Brown J. Levine M. Mild head injury, anticoagulants, and risk of intracranial injury. Lancet 357(9258):771-2, 2001 Mar 10.
3. Garra G. Nashed AH. Capobianco L. Minor head trauma in anticoagulated patients. Academic Emergency Medicine. 6(2):121-4, 1999 Feb.