115 Cerebral toxoplasmosis in a RA patient receiving biologic therapy

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Background: Biologics therapy has revolutionised the management of autoimmune inflammatory conditions but there is an increased risk of opportunistic infections in this group of patients. A meta-analysis from 2014 concluded that patients with rheumatoid arthritis (RA) on biologics (anti-CD20, anti-TNF, anti-IL6) had a small but significant increased risk of opportunistic infections compared to placebo (1.7 infections per 1,000 patients treated). Most infections reported are with herpes zoster, TB, PCP and aspergillus. There have been a few cases reported on infections with Toxoplasma gondii, but overall, data for prevalence and incidence of toxoplasmosis in patients on biologics is missing and has mainly been reported in advanced HIV disease and immunosuppressed transplant patients. Methods: We report here the case of a 43-year-old veterinary nurse with RA initially diagnosed 2010, who presented to clinic with left superior quadrantanopia in June 2017. She had been treated in the past with various biologics for refractory RA - adalimumab, golimumab, tocilizumab. At the time of presentation, she had been on rituximab (2x1g infusions six-monthly), methotrexate (20mg weekly) and prednisolone (15mg daily), since August 2016. Results: Initial CT head showed no abnormalities, however MRI of the brain requested by the stroke team was reported as infarcts and she was treated with antiplatelets. In spite of this, her visual disturbance worsened and her quadrantanopia progressed to a homonymous hemianopia. Subsequent MRI one month later showed ring enhancing lesions in the right thalamus and right medial temporal lobe. Investigations such as lumbar puncture, blood cultures, T-spot, vasculitic screen, toxoplasma and virology serology including HIV, CT and bronchoscopy failed to give a diagnosis. Mild inflammatory changes in the apical lungs on CT raised the suspicion of TB and she was started on empirical TB treatment. Nonetheless, MRI six weeks later showed progression of the brain lesions. She had a CT guided brain biopsy of the thalamic lesion which was suggestive of toxoplasmosis. Subsequently, repeat toxoplasma serology also tested mildly positive - 64 IU/ml. She was started on sulphadiazine and pyrimethamine and follow-up MRI scans did show improvement, but the field defects remained the same. Conclusion: Toxoplasma gondii infects 350,000 people in the UK each year, of which only 10-20% are symptomatic. In the immunocompromised, toxoplasmosis can have severe manifestations and may present with abnormal neurology, pneumonia, retinochoroiditis and other disseminated systemic disease. This case highlights the difficulties of interpreting serological tests in patients receiving B cell depletion therapies. It also shows the importance of maintaining a high index of clinical suspicion and getting a tissue diagnosis without any delay. Working in a veterinary surgery increased the risk of exposure for this unusual infection. Preventative information and advice needs to be given to this group of patients starting on biologics. Disclosures: A. Sanda Gomez: None. A. Madathil: None. E. Gkrania-Klotsas: None. D. Makkuni: None.

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