47. Claudication, Cerebral infarct and Cyclophosphamide

Introduction We present a severe and rare case of GCA involving the right middle cerebral artery (MCA) resulting in an ischaemic stroke. Our patient presented in 2017, before tocilizumab was approved as a treatment option in refractory GCA. Intravenous cyclophosphamide was used as a glucocorticoid-sparing agent in this patient with good response. This case contributes to our current limited evidence base in the treatment and prognosis of intracranial GCA. Case description The patient was 75 years old when referred by his GP with a four-month history of left temporal headache, jaw claudication and weight loss in August 2017. He had type 2 diabetes and hypertension. He also had a stroke in 2015 and was subsequently found to have paroxysmal atrial fibrillation so was commenced on rivaroxaban. His bloods showed ESR of 66 and CRP 18. ESR had been persistently raised for two months. Ophthalmology assessment revealed bilateral cataracts only. A clinical diagnosis of GCA was made and he was commenced on prednisolone 60mg daily. A biopsy of his left temporal artery was performed six days later and the histology showed transmural inflammation with multinucleated giant cells. His headache and jaw claudication improved with prednisolone but he was still experiencing localised temporal artery tenderness. In the last week of September 2017, he presented to the Emergency Department with a two-day history of incoordination and left arm weakness. MRI of his head showed small foci of infarcts in the right MCA territory. He had suffered an ischaemic stroke likely secondary to GCA despite being treated with high dose oral glucocorticoid. He was given three pulses of intravenous methylprednisolone followed by intravenous cyclophosphamide. Subsequent CT angiogram (CTA) confirmed the involvement of intracranial arteries – circumferential thickening of the right internal carotid artery with near complete occlusion of right cavernous and intracranial segments. There was also mural thickening involving the left vertebral artery. He went on to have five more cycles of cyclophosphamide and responded well to treatment. Oral methotrexate 15mg weekly was added in two weeks after the last course of cyclophosphamide. During his last clinic visit, he was taking prednisolone 2mg daily and the plan was to taper the dose down to zero over eight weeks. Discussion Though uncommon, GCA can affect vertebrobasilar arteries causing strokes. The involvement of intracranial arteries, on the other hand, is thought to be extremely uncommon in GCA due to their increased wall thickness. There is only a limited number of intracranial GCA cases reported in the medical literature. A review of nearly 500 patients with a diagnosis of central nervous system vasculitis at the Mayo Clinic identified only two patients with convincing evidence of intracranial GCA. Our patient’s MRI and CTA were reviewed in the neuroradiology multidisciplinary meeting and the consensus was that there was a near complete occlusion of the right MCA due to a vasculitic process. Importantly, his GCA went into remission and he has not had any relapses thus far (21 months since his initial presentation). He has also improved from the stroke point of view. We have been able to reduce his prednisolone dose to a minimal level. The use of oral or intravenous cyclophosphamide in the treatment of refractory GCA have been reported. It was found to be effective in inducing a sustained remission in a majority of patients in a series of 35 patients in Germany. However, significant adverse events were reported in one third of the patients. Our patient tolerated intravenous cyclophosphamide therapy well. He was given fluconazole and co-trimoxazole as prophylactics. He did not report any major infections or adverse events during the four-month period when he was on cyclophosphamide. Key learning points This case represents a severe variant of GCA. Our patient was only referred to secondary care after being unwell for several months. It illustrates the importance of promptly initiating investigations and treatment when GCA is suspected. This case demonstrates the importance of following up with patients closely as well as working closely with the multispecialty team in managing patients with GCA. Conflicts of interest The authors have declared no conflicts of interest.