Respiratory dysfunction in multiple sclerosis: A prospective analysis of 60 patients

Abstract

This study aimed to determine the relationship between pulmonary function, respiratory muscle function and neurological function in multiple sclerosis (MS). Sixty patients (27 males and 33 females) aged 27-75 yrs (mean ± SD 48 ± 12 yrs) were prospectively studied. The Kurtzke Expanded Disability Status Scale (EDSS; range 0-10) score was 6.5 ± 1.5; and the different Functional Systems Scores (FSS; ranges 0-5 and 0-6) were: pyramidal 3.4 ± 1.1; brain stem 1.9 ± 1.2; mental 1.3 ± 0.9; cerebellar 2.2 ± 1.0; sphincter 1.8 ± 1.5; visual 1.4 ± 1.4; and sensory 2.0 ± 1.5. Results of lung function tests were: vital capacity (VC) 80 ± 23% of predicted; single-breath transfer factor of the lung for carbon monoxide (TL,CO,sb) 83 ± 17% pred; maximal static expiratory mouth pressure (MEP) 30 ± 16% pred; and maximal static inspiratory mouth pressure (MIP) 47 ± 23% pred, indicating a marked respiratory muscle dysfunction, with a minor restrictive defect. In 70% of the patients, a transcutaneous oxygen saturation (Stc,O2) of less than 92% at night was found. Comparison of lung function and disability scores showed that the abnormalities in both tended to be correlated to each other, and that this was significant for EDSS versus lung volumes, for most FSS with VC, and also for some FSS with MEP and/or MIP. Duration of disease was significantly correlated with the EDSS, but not with the different FSS scores (with the exception of mental status) and not with lung function. Multiple sclerosis leads to lung function abnormalities attributable to respiratory pump dysfunction.