Progressive multifocal leukoencephalopathy in a patient with systemic lupus erythematosus

Background/Aims Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease that develops following the reactivation of the John Cunningham virus (JCV) that in rare circumstances can occur in autoimmune disorders such as systemic lupus erythematosus (SLE). We present a 75-year-old female with SLE who had been treated with immunosuppressive therapy (mycophenylate and steroids) for one year. Methods A 75 year-old female presented with sub-acute deterioration of physical and cognitive function over the course of a few months including memory loss, ataxia, dysgraphia, word finding difficulty, confusion, low mood and reduced oral intake. Neurological examination revealed receptive and expressive aphasia, gaze fixation, unilateral weakness, brisk reflexes with positive plantar reflex and rigidity. A diagnosis of PML was made due to the detection of JC virus in the cerebrospinal fluid (234 copies/ml) and brain MRI findings consistent with the disease. Haematology results showed a profound lymphopenia (0.1x10(9) ). Mycophenolate was held and she was commenced on increasing doses of Mirtazapine up to 45mg. Clinical review at four months found marked improvement in her cognitive and physical abilities. Repeat CSF analysis found JC virus to be undetectable. Results PML has a 20-fold greater incidence in SLE when compared with the general population. Lymphopenia is a common finding in patients with SLE and has been found to correlate with both the risk and severity of opportunistic infections. The cause of this can be multifactorial and immunosuppressive drugs are often implicated however SLE in isolation can cause severe CD4+ lymphopenia leading to an increased risk of PML reactivation. This case demonstrates the importance of monitoring lymphocyte counts in SLE. Current guidance suggests adjusting regimes of immunosuppressive therapy if lymphocyte counts fall below 1x10(9) however further guidance on its management may be warranted. The heterogenous manifestation of SLE can make differentiating between the neurological syndromes associated with rheumatic disease and PML challenging. Given the management of PML is vastly different to that of SLE in regards to introduction or withdrawal of immunosuppressive therapies, there should be a high index of clinical suspicion in the early stages of investigation. In vitro studies have explored the possibility of mirtazapine (a 5-HT2A antagonist) providing a low-risk treatment option for those with SLE and this warrants further research into its efficacy in treating or preventing PML in this cohort. Our patient had improved symptomology after cessation of mycophenolate and the commencement of Mirtazapine. Conclusion PML is a rare complication of SLE but should be considered in patients admitted with neuropsychiatric presentations, the use of Mirtazapine may provide a low-risk treatment strategy. Disclosure D. Babla: None. Y. Suleman: None. A. Whittington: None. S. Hamdulay: None.