Progressive encephalomyelitis with rigidity and myoclonus: Resolution after thymectomy

Abstract

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a disorder of subacute onset presenting with widespread rigidity, painful spasms, and prominent myoclonus.1 PERM is probably related to stiff-person syndrome (SPS). In both conditions, most patients have anti-glutamic acid decarboxylase (anti-GAD) antibodies, and both can be paraneoplastic. However, PERM differs from SPS by the presence of brainstem and long tract signs and its aggressive course. Initially, PERM was considered as uniformly fatal.2 More recently, partial improvement of PERM has been reported in rare cases.3,4 We describe a patient with PERM and glycine receptor antibodies who completely recovered after resection of a thymoma. ### Classification of evidence. This case report provides Class IV evidence that thymectomy for a thymoma resulted in resolution of PERM. ### Case report. On September 15, 2008, a 49-year-old farmer without significant medical history developed pain in his right leg, which became intolerable within 5 days. Lumbosacral spine MRI was normal. He then developed involuntary, painful extension spasms of the right leg, left arm stiffness, speech and swallowing difficulties, intermittent diplopia, dry mouth, constipation, urinary retention, and excessive sweating. He could no longer fully open his mouth, and was referred to our hospital with a tentative diagnosis of tetanus, 8 days after onset. On admission, he was …