Assistant Professor, Physical Medicine and Rehabilitation University of Pittsburgh Medical Center Pittsburgh, Pennsylvania, United States
Case Diagnosis: Progressive Encephalomyelitis with Rigidity and Myoclonus (PERM)
Case Description: A 6-year-old girl presented with four days of progressively worsening whole body spasms and rigidity, confusion, gait difficulties, and hyperekplexia. Labs were notable for elevated transaminases and CPK. CSF studies were notable for lymphocytic pleocytosis, elevated protein, and oligoclonal bands. Glycine receptor antibodies were found in the serum and CSF. EEG, MRI studies, and EMG were unremarkable. She was diagnosed with glycine receptor antibody positive PERM and treated with four doses of IVIG. Symptoms also improved with lorazepam trial; she was subsequently transitioned to clonazepam and baclofen. She showed significant clinical improvement in self-care and mobility at discharge but continued to demonstrate balance and cognitive deficits. She was discharged home with pediatric rehabilitation medicine follow up and outpatient PT, OT, and SLP.
Discussions: Stiff-person syndrome (SPS) is rare and progressive neurological autoimmune disorder resulting in muscular rigidity, painful spasms, gait difficulties, and falls. PERM is a severe variant of SPS further characterized by encephalopathy, seizures, myoclonus, hyperekplexia, autonomic dysfunction, flare-ups, and remissions. PERM is a clinical disease. MRI, CSF, and EMG are typically normal. PERM is often associated with anti-GAD antibodies, glycine receptor antibodies, and NMDA receptor antibodies. Early diagnosis and treatment with corticosteroids, IVIG, PLEX, and/or cyclophosphamide can result in dramatic clinical improvement. Benzodiazepines and baclofen are also utilized for symptomatic management. Rigidity and stiffness can lead to contractures of the affected joints, resulting in impairments in mobility and self-care. Rehabilitation should focus on management of rigidity and stiffness, primarily through persevering range of motion and contracture prevention.
Conclusions: Children with PERM require prompt diagnoses, medical management, and comprehensive rehabilitation to address self-care, mobility, and cognitive deficits. The Pediatric Rehabilitation Medicine team plays an essential role in managing children with PERM given the disease’s chronic, progressive, fluctuating, and recurring nature.