AN UNDER-RECOGNISED COMPLICATION OF LEUKAEMIA TREATMENT

Patients undergoing treatment for haematological malignancies can present to neurological services with complications from the disease or the treatment. We present a case displaying a complication that is rarely diagnosed by adult neurologists. A 20 year old student undergoing treatment with vincristine, daunorubicin, asparaginase and intra-thecal methotrexate for Acute Lymphoblastic Leukaemia (ALL) originally presented with featureless headaches and visual disturbance. She was extensively investigated for inflammatory, metabolic, nutritional and vascular causes of pathology with MRI, LP, serological and autoimmune investigations all proving normal or negative. The symptoms resolved over several weeks. She deteriorated again 4 weeks following her initial recovery with a rapid onset of an encephalopathy: displaying roving eye movements, trismus and rapidly deteriorating conscious level. She required admission to intensive care for monitoring. Ultimately the clinical picture, negative ancillary investigations and repeat imaging enabled a diagnosis of methotrexate induced encephalopathy to be made. Methotrexate induced encephalopathy is seen in a significant minority of patients in clinical trials for ALL, and predominantly occurs in older children and young adults. Various approaches to treatment based on hypothesised pathophysiology of the condition, and small case series have been used.