Department of Pulmonology, University Hospital Gasthuisberg, K.U. Leuven, Belgium. rob.van.klaveren@uza.uia.ac.be

STUDY OBJECTIVES: To investigate whether the localization of multiple sclerosis (MS), the duration of the disease, and the level of neurologic functioning in patients with MS predispose them to disturbed breathing control.

DESIGN: Case-control study.

SETTING: Outpatient pneumology department of a university hospital. PATIENTS: Twenty-three MS patients and 51 healthy control subjects.

MEASUREMENTS AND RESULTS: Resting mouth occlusion pressure at 0.1 s after onset of inspiratory effort (P0.1) was measured during the hypercapnic response (HCR) and the hypoxic response (HR) in all subjects. The Kurtzke expanded disability status scale and the functional system score were used to describe the level of neurologic functioning of the MS patients. Predictors of HCR and HR were assessed by multiple regression analysis. Low maximal inspiratory pressure (MIP) values correlated with low resting P0.1 values (r = 0.44; p = 0.05), although in neuromuscular diseases, high resting P0.1 values are usually found to compensate for low MIPs. Detrusor-sphincter dyssynergia (DSD) was the only predictor for lower ventilatory HCR (p = 0.006; r2 = 0.52), lower P0.1 HCR (p = 0.004; r2 = 0.47), lower ventilatory HR (p = 0.04; r2 = 0.28), and lower P0.1 HR (p = 0.04; r2 = 0.10); low MIPs and pyramidal tract involvement had no role.

CONCLUSIONS: (1) Impaired control of breathing in some MS patients is related mainly to central defects. (2) DSD is the most important predictor of disturbed ventilatory control, presumably because the micturition and pneumotaxic center are closely related and located in the rostral pons. (3) No relationship with the duration of the MS disease could be demonstrated, which can be explained by the variable course of MS itself.

Source: Chest 1999 Jun;115(6):1539-45