Objective: To report a rare case of biopsy-proven giant cell arteritis (GCA) involving the intracerebral vessels, and to highlight the need for early and aggressive immunosuppressive treatment.

Method/Results: The case is a 78 year old woman who presented with a subacute history of headache and monocular blindness due to anterior ischaemic optic neuropathy. CT and conventional angiography showed changes consistent with cerebral vasculitis and superficial temporal artery biopsy confirmed GCA. Despite treatment with high dose corticosteroids, she developed a progressive left hemiplegia and MRI showed multiple regions of acute ischaemia in both cerebral hemispheres. Pulse intravenous cyclophosphamide was then added, after which her condition stabilised.

Conclusions: This case highlights several issues:
1. In rare cases, GCA can cause an aggressive cerebral vasculitis.
2. Non-invasive imaging of the cerebral circulation (eg. CTA, MRA) should be considered in cases of biopsy-proven GCA.
3. If imaging findings consistent with cerebral vasculitis are found, early and aggressive immunosuppressant treatment should be given.
4. Even with such treatment, the outcome may be poor.