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Aspirin and the risk of intracranial complications following head injury

Three Part Question

In [adults with head injury] does [pre-injury aspirin] adversely [affect clinical outcome]?

Clinical Scenario

A 65 year old man on aspirin presents to the emergency department having fallen sustaining a minor head injury. You wonder whether he is at higher risk of intracranial bleeding due to aspirin.

Search Strategy

Medline using the OVID interface 1966- August Week 4 2005 Embase 1980–2005 week 37
The Cochrane Library Issue 3 2005
Medline: [exp brain injuries/ OR brain injur$.mp. OR exp craniocerebral trauma/ OR head injur$.mp.] AND [exp aspirin/ OR OR exp acetylsalicylic acid/ OR antithromb$.mp.] Limit to humans and English
Embase: [craniocerebral OR exp Head Injury/ OR exp Brain Injury/ OR brain injur$.mp] AND [ or exp Acetylsalicylic Acid/ OR antithrom$.mp] LIMIT to Human, English Language and (adult <18 to 64 years> or aged <65+ years>)
The Cochrane Library: Exp Aspirin [MeSH] AND exp brain injuries [MeSH] OR exp craniocerebral trauma [MeSH]

Search Outcome

Altogether 103 were found in Medline and 104 in Embase. Three were relevant to the three part question, these are shown in the table below:

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Reymond MA et al,
189 patients with severe head injuryRetrospective Risk analysisChronic subdural haematomaAspirin is a risk factor for chronic subdural haematomaRetrospective nature of the study
Mina AA et al,
37 patients admitted with intracranial injury on anticoagulants 37 case matched patientsRetrospective case controlledMortality due to head injuryHigher percentage of those on aspirin than any other anticoagulant diedRetrospective, Subgroup analysis, and small sample size
Spektor S et al,
Mild (GCS13-15) and moderate (GCS 9-12) head injuries in 231 patients >60 years old. 110 of which were on aspirin therapyProspective cohort studyIntracranial haemorrhageNo difference in frequency or type of ICH whether on aspirin or notSmall sample size. Mild & moderate injuries included


There was conflicting evidence that prior chronic use of aspirin increases the risk of intracranial haemorrhage following minor head injury. However, there is some evidence to suggest that there is increased risk of chronic subdural haemorrhage. A well designed prospective cohort study with adequate sample size and follow up is needed to address such important and common problem.

Clinical Bottom Line

Pre-injury aspirin may increase the risk of intracranial complications following head injury. More research is needed.


  1. Reymond MA. Marbet G. Radu EW. Gratzl O. Aspirin as a risk factor for haemorrhage in patients with head injuries. Neurosurg Rev 15(1):1992;21-25.
  2. Mina AA. Knipfer JF. Park DY. Bair HA et al. Intracranial complications of preinjury anticoagulation in trauma patients with head injury. J Trauma 53(4):2002;668-672.
  3. Spektor S. Agus S. Merkin V. Constantini S. Low –dose aspirin prophylaxis and risk of intracranial hemorrhage in patients older than 60 years of age with mild or moderate head injury: a prospective study. J Neurosurg 99(4):2003;661-665.