An atypical presentation of immune reconstitution inflammatory syndrome (IRIS) in a patient with cryptococcal meningitis in the setting of fingolimod therapy for multiple sclerosis.

Central nervous system (CNS) cryptococcosis in the setting of fingolimod therapy for multiple sclerosis is an increasingly recognised, and often fatal entity. Furthermore, some patients may develop immune reconstitution inflammatory syndrome (IRIS) after the initiation of anti-fungal therapy and cessation of fingolimod. Clinical and radiological progression despite appropriate antifungal treatment often leads to a therapeutic dilemma of whether to use corticosteroids if IRIS is suspected. We present a case of a patient with CNS IRIS that responded to oral prednisolone treatment, in the setting of CNS cryptococcal infection and background fingolimod therapy. Interestingly, our patient had a normal CD4 and total peripheral lymphocyte count. This case serves as a reminder that a high index of suspicion is needed when patients who are being treated with fingolimod, present with subtle symptoms and signs of meningitis, and, additionally, it provides further evidence that IRIS in HIV negative patients, may respond to corticosteroid treatment.