A negative head CT in a neurologically normal patient, with a thunderclap headache presentation, a clear time of onset, and a modern CT scanner performed within 6 hours of onset read by an attending radiologist results in a post test risk of SAH of 1 – 2/1000 patients. A shared decision strategy should be used to balance the risk and benefits of performing a lumbar puncture versus a negative CT within 6 hours being sufficient to rule out SAH.
- Symptoms of arm ischemia or paresthesias with syncope – Subclavian steal syndrome
- Chest pain that is acute, radiates, tearing/sharp, involves symptoms above and below diaphragm with syncope – Aortic dissection
- Tachypnea, pleuritic chest pain, shortness of breath with syncope – PE
- Neurologic deficit with syncope – TIA/stroke
- Headache that is sudden in onset, maximal at onset, worst of life with syncope – Subarachnoid hemorrhage
- Minor trauma with head or neck pain and syncope – Carotid/vertebral artery dissection
- Abdominal/flank pain in older patient with syncope – Ruptured AAA