The impact of myasthenia gravis on lower urinary tract functions.

Abstract

To assess the functions of the lower urinary tract (LUT) in patients with myasthenia gravis (MG). A total of 36 patients (18 males and 18 females) with MG and 29 healthy controls were enrolled. Participants completed a 3-day voiding diary and responded to questionnaires "Overactive Bladder Symptom Score" (OABSS) and "International Consultation on Incontinence-Short Form" (ICIQ-SF). All patients underwent uroflowmetry and ultrasonography (US). The data were compared based on the onset of disease and serological status. The most common urinary symptoms were nocturia (80.5%), incontinence (61%) and urgency (47%). OABSS was higher in patients than controls (P=.008). Duration of urinary symptoms was longer, and nocturia was more common in late-onset MG (LOMG) than in early-onset MG (EOMG; P=.029, P=.023). The duration of disease and urinary symptoms statistically increased in ACh-Ab (-) group compared with ACh-Ab (+) group (P=.003, P=.027). Night-time urination frequency significantly increased while daytime voided volume (VV) decreased in LOMG compared with EOMG (P=.003 and P=.01). Residual volume on the US was significantly higher in LOMG than that in EOMG (P=.004). The duration of disease was positively correlated with tQmax and daytime urination frequency (P=.013, r=.48; P=.016, r=.398). A negative association was found between duration of disease and daytime VV (P=.04, r=-.344). LUT dysfunction may manifest disease in MG, particularly in late-onset forms. The lack of ACh-Ab seemed to prolong the duration of disease and urinary disturbances.