Levodopa-responsive progressive encephalomyelitis with rigidity and myoclonus associated with glycine receptor antibodies

Facial Palsy as Initial Symptom in Glycine Receptor Antibody Positive Progressive Encephalomyelitis With Rigidity and Myoclonus: A Case Report

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare and disabling syndrome characterized by painful spasms, myoclonic jerks, hyperekplexia, brainstem signs, and dysautonomia, which is considered to be a severe form of stiff person spectrum disorder (SPSD) and is mostly associated with glycine receptor antibodies. The PERM has an acute or subacute course, with complex and varied initial symptoms mainly manifest as stiffness and pain. The authors present the case of a male patient admitted for intractable stiffness and paroxysmal myoclonus of the lower extremities preceded by a 5-day history of facial weakness. After admission, his symptoms deteriorated rapidly. He developed progressive generalized hypertonia and painful spasms, which quickly spread to the upper extremities, and he suffered frequent paroxysmal myoclonus. Serum and cerebrospinal fluid (CSF) were tested by a cell-based assay, and both were positive for glycine receptor antibodies (GlyR-Abs). The patient developed complications, such as crushed teeth, lumbar vertebral compression fractures, and psoas major muscle abscess, during rapid disease progression, although he responded well after being treated with intravenous methylprednisolone and immunoglobulin. This report of PERM, initiated as facial palsy followed by acute progression, helps to expand the clinical spectrum of this rare autoimmune disorder and raise awareness of the prevention of complications.

Progressive encephalomyelitis with rigidity: A Taiwanese case and review of literature

INTRODUCTION

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare disorder. However, the outcome is still variable with different serological and tumor associations, and the elements to good response with less relapse is yet to be elucidated.

METHOD

We present a case and obtain a literature review of patients with PERM and make comparisons based on different serological groups. We also analyze patients with idiopathic PERM that had detailed medical records.

RESULTS

81 patients were collected and analyzed. The largest group were glycine receptor-antibody (GlyR-Ab)-positive (70%), and the seropositive-GlyR-Ab-negative group had better response to immunotherapy. Malignancy can occur up to 2 years from the presentation of PERM. Among the 18 cases with detailed records, the patients who had good outcome initiate immunotherapy within 2 months from presentation. 9 of the 12 patients who experienced no relapse had non-steroid immunotherapy. The maximal interval time of relapse was 24 months.

CONCLUSION

We recommend tumor surveillance up to 2 years in patients with PERM and early administration of immunotherapies and maintain with non-steroid immunotherapy with or without oral corticosteroid for a minimum of 2 years to reduce the risk of relapse in GlyR-Ab-positive patients.