Ottawa subarachnoid haemorrhage rule for investigation of new non-traumatic severe headaches
| Inclusion criteria |
|---|
| Age >15 years |
| New severe headache with maximum intensity within 1 hour |
| No known brain tumour, intracranial aneurysm or previous SAH |
| No previous chronic or recurrent headaches (3 or more similar headaches in last 6+ months) |
| Criteria for further investigations of headache |
| Age >40 years |
| Thunderclap headache |
| Headache onset during exertion |
| Neck pain or stiffness |
| Witnessed loss of consciousness |
| Limited neck flexion on examination |
Patients must fulfil all inclusion criteria before the rule can be applied. Then if any of the criteria for further investigations are positive, a CT scan of the brain is indicated. Applied as stated, sensitivity up to 100%, with specificity 15%. Taken from Perry et al.14
CT = computed tomography; SAH = subarachnoid haemorrhage