RT Journal Article SR Electronic T1 Hypothyroid ataxia complicating monoclonal antibody therapy JF Practical Neurology JO Pract Neurol FD BMJ Publishing Group Ltd SP practneurol-2017-001713 DO 10.1136/practneurol-2017-001713 A1 Abdul Badran A1 Carla Moran A1 Alasdair J Coles YR 2017 UL http://pn.bmj.com/content/early/2017/08/04/practneurol-2017-001713.abstract AB We present a case of cerebellar dysfunction due to severe hypothyroidism induced by pembrolizumab, a member of the ‘immune checkpoint inhibitor’ class of cancer immunotherapies. Thyroxine replacement completely resolved his symptoms and signs. We also discuss the neurological immune-related complications of checkpoint inhibitors.