33. A case of ocular ischaemic syndrome caused by severe giant cell arteritis

INTRODUCTION: This case describes a very aggressive form of giant cell arteritis (GCA) complicated by ocular ischaemic syndrome (OIS), complete bilateral visual loss and bilateral scalp muscle necrosis, despite treatment with high dose intravenous steroids. OIS, defined as ischaemia of all intraorbital and intraocular structures, is rare, estimated at 7.5 cases per million. This case also highlights the use of PET CT in management of complex cases of GCA. CASE DESCRIPTION: A 79-year-old lady presented with sudden onset pain above her right eye. A month earlier she had undergone curative surgery for infiltrating adenocarcinoma of the colon. 6 months earlier she had complained of bilateral shoulder pain. A month earlier she had developed pain on chewing and was unable to fully open her mouth. The next day she was reviewed in the eye hospital due to 24hrs of intermittent blurred vision. CT head was normal. Fundoscopy was normal and she was diagnosed with ocular migraine. Later that evening she lost vision in the right eye. Bloods showed CRP 58 and ESR 43. She was given 5 days of IV methylprednisolone (5x1g). Despite this she developed a right 6(th) nerve palsy. 2 days later her left eye developed visual loss, complete ptosis and loss of eye movements in all directions. MRI head with gadolinium showed temporoparietal juxtacortical diffuse white matter signal abnormalities. She underwent extensive investigation. ANCA was negative, lumbar puncture normal and temporal artery biopsy showed extensive fibrinoid necrosis of the vessel wall, with possible granulomata but no eosinophilia. Oral cyclophosphamide (2mg/kg) was started. 5 days later she developed severe bi-temporal pain and a rash which progressed to severe scalp necrosis. There were no vesicles to suggest shingles. Ten days later she suffered an upper gastro-intestinal bleed requiring a 4 unit transfusion. Gastroscopy showed mild gastritis. After this, cyclophosphamide was withheld, following discharge on steroids alone. Bilateral scalp necrosis remained a problem, complicated by pseudomonas infections. When a decreased left radial pulse was noted a PET CT was arranged. This showed active extensive vasculitis of the aorta. At this point methotrexate 15mg per week was added. The scalp lesions rapidly healed and the radial pulse returned to normal. The CRP has remained consistently below 5. DISCUSSION: An antiplatelet agent, clopidogrel was started due to the ischaemic cerebral findings on MRI, but it probably contributed, along with steroids, to her upper GI bleed. Antiplatelet therapy is no longer recommended routinely in the management of GCA. However in this case the diagnosis was still uncertain. None of us had ever seen orbital infarction syndrome as a complication of GCA. Perhaps a PET CT earlier on in the course of this lady’s disease would have made us more secure in the diagnosis. It could be argued that given the severity of her disease, methotrexate or even tocilizumab should have been commenced earlier. In fact, cyclophosphamide was used initially as it wasn’t clear if this was a medium vessel vasculitis. This was withheld when she had a large upper GI bleed (Hb dropped to 76). Once recovering, her CRP was down to 10. By this time the temporal artery biopsy was available, the ANCA was negative and GCA was felt to be the most likely diagnosis. It was also felt that given the bilateral visual loss, the most feared complication of GCA had already occurred so what was there to gain by using such strong immunosuppression? Hence cyclophosphamide was discontinued, and she was discharged on steroids alone. The addition of methotrexate had an impressive effect in terms of healing her weeping, secondarily infected scalp necrosis. Methotrexate was added in light of the PET CT which showed active large vessel vasculitis. The scalp necrosis, on reflection was due to an ongoing vasculitis that was being undertreated. There were missed opportunities for starting steroids earlier in the course of the disease: polymyalgic symptoms 6 months earlier, jaw claudication a month earlier. However it remains uncertain whether or not earlier treatment would have altered the course of this aggressive, severe disease. KEY LEARNING POINTS: Scalp necrosis, which very easily can be mistaken for shingles or infections complicating steroid treatment, can be a feature of GCA. Orbital infarction syndrome can be a feature of GCA. Early PET CT might have clarified the diagnosis. Methotrexate should probably have been started once the limited response to IV steroids was apparent. Antiplatelet agents are no longer recommended in the updated BSR guidelines for managing GCA. CONFLICTS OF INTEREST: The authors have declared no conflicts of interest.