- There are a number of important causes of headache that may not be identified on plain CT brain.
- If there is remaining clinical suspicion other modalities such as CTA, CTV, MRA, MRV need to be considered. Seek specialist advice.
- Small sub-arachnoid haemorrhage
- Cerebral vein thrombosis (sinus venous thrombosis, cavernous sinus thrombosis)
- Meningitis / Encephalitis
- Posterior reversible encephalopathy syndrome (previously known as hyptertensive encephalopathy)
- Benign intracranial hypertension