Prediction of disease progression in Miller Fisher and overlap syndromes

Background Patients with Miller Fisher syndrome (MFS) may have a relatively mild clinical course or progress to Guillain-Barre syndrome with limb weakness (MFS-GBS overlap syndrome). Other variants in this spectrum are GBS with ophthalmoparesis and Bickerstaff's Brainstem encephalitis (BBE). Aim To compare the clinical course of MFS and overlap syndromes and to identify predictors of disease progression. Methods In a prospective study of 170 patients with GBS and variant forms, 37 (22%) had a MFS, MFS-GBS overlap syndrome, ophthalmoplegic GBS or BBE. The clinical, serological and electrophysiological features were compared. Results Twenty-three patients presented with MFS, of which 10 (43%) developed limb weakness (MFS-GBS overlap syndrome). All these transitions occurred in the first week after onset of symptoms. There were no differences in the clinical, electrophysiological and serological features at entry between MFS and MFS-GBS. Twelve patients had ophthalmoplegic GBS and the disease severity at nadir and outcome was worse than in the patients with a MFS-GBS overlap syndrome. Conclusion No early predictors for progression from MFS to MFS-GBS overlap syndrome were found. All transitions occurred in the first week. This finding implicates that all patients with MFS need careful monitoring for at least one week.