Stress-Related Urinary Incontinence Common With Myasthenia Gravis

Urinary incontinence (UI) and overactive bladder (OAB) are more common adverse health outcomes in patients who have myasthenia gravis (MG), leading investigators to conclude that these patients tend to exhibit more stress UI symptoms.

Spurred to investigate these health impacts in the MG patient population by the lack of information on them, the study authors explained the discrepancy by noting that the immune-mediated chronic neuromuscular junction typically manifests with ocular symptoms, bulbar involvement, trunk and limb weakness, and dyspnea.¹ Previous reports, they add, have been limited to small cohorts when investigating UI and OAB in MG, they wrote in Neurological Sciences.²

They matched 86 patients living with MG (mean [SD] age, 59.6 [16.5] years) to 90 inpatient controls (mean age, 59.5 [16.9] years) for age and sex who did not have a primary neurological diagnosis who filled out the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-UI SF; score > 6, strong indicator of UI) regarding the presence, severity, and impact of UI on daily life and the Overactive Bladder Symptom Score (OABSS; higher scores equate to greater severity) to report OAB symptom severity. They were evaluated with the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale and subdivided into 3 populations according to the age of MG symptom onset.

Top comorbidities in each group were being multiparous (MG group, 26.74%, and control group, 27.77%), having diabetes (25.6% and 24.4%, respectively), having benign prostatic hyperplasia (16.2% and 8.9%), having a history of pelvic surgery (14.0% and 12.2%), and having a history of smoking (9.3% and 8.9%). Serology was positive for anti-acetylcholine receptor (AChR) antibodies (7.9%), negative for AChR antibodies (9.3%), and positive for anti-muscle specific tyrosine kinase antibodies (5.8%). MG treatments encompassed immunotherapies alone (45.3%), pyridostigmine and immunotherapies (40.7%), and pyridostigmine only (10.5%).

More than 4 times as many patients with MG vs controls demonstrated potential UI, with an ICIQ-UI SF score of 6 or higher (52.3% vs 12.2%; P > .001). Among the subdivided populations, the highest prevalence was 63.2% of those with late-onset MG (aged 50 to younger than 65) vs the lowest rate of 46.2% in those with very-late-onset MG (65 years and older).

In addition, more patients with MG vs controls reported slight (4.7% vs 2.2%; P = .358), moderate (15.1% vs 10.0%; P = .292), severe (32.6% vs 2.2%; P < .001), or very severe (4.7% vs 0.05; P = .039) UI severity. Stress UI was reported by 31.4% of patients compared with 6.7% of controls (P < .001), and 8 or more episodes of UI per day were seen in 19.8% vs 14.4% (P = .331). For nighttime frequency, 3 or more episodes of UI were reported by 27.9% of patients with MG vs 11.1% of controls (P = .004) and 2 episodes in 25.6% vs 14.4% (P = .054); the controls reporting 1 episode of UI outnumbered the patients with MG (40.0% vs 24.4%; P = .025). Overall, any nighttime episode was reported by 77.9% and 65.5%, respectively (P < .001).

Median (IQR) OABSS were 6 (1-10) in the patients with MG vs 1 (0-3) in the control patients (P < .001).

Urgency percentages trended similarly. The numbers for this were higher across all groupings for patients with MG vs control individuals:

• Once a week or more: 3.5% vs 2.2% (P = .611)
• About once per day: 11.6% vs 5.6% (P = .129)
• 2 to 4 times per day: 19.8% vs 1.1% (P < .001)
• 5 times per day or more: 18.6% vs 1.1% (P < .001)

Drilling down to male patients vs female patients in the study, the UI numbers were again higher for those with MG-related UI (43.8% vs 14.0% and 63.2% vs 10.0%, respectively).

There were modest correlations between total ICIQ-UI SF score and OABSS (r = 0.863; P = .001) and daytime and nighttime voiding frequency (both P = .001), and MG-ADL score had a modest association with ICIQ-UI SF score (r = 0.863; P = .001) and OABSS (r = 0.863; P = .001). Predictors of UI comprised higher MG-ADL scores on univariate analysis (OR, 2/57; P = .050) and multivariate analysis (adjusted OR, 2.38, 95% CI 1.04-5.46; P = .041). The fastest progression to UI was experienced by patients with late-onset MG, at 3.8 years; the slowest progression was experienced by patients with early-onset MG (19.5 years).

Limitations on the authors’ findings are the absence of urodynamics testing; lack of data on pyridostigmine dosing, timing relative to assessment, and treatment duration; incomplete information on body mass index, which the authors explained could influence urinary symptoms; and recall bias regarding timing of first UI symptoms. Still, the authors are positive about their findings.

“This research may offer insights into the neuromuscular mechanisms underlying urinary control, emphasizing the broader clinical implications of MG beyond its classically recognized muscle involvement,” they conclude. “Our findings highlight the importance of inquiring about urinary symptoms in routine clinical evaluation of MG patients to enhance patient care and quality of life.”

References

1. Kuks JBM. Clinical presentations of myasthenia gravis. In: Kaminski HJ, Kusner LL, eds. Myasthenia Gravis and Related Disorders, 3rd Edition. Humana; 2018;85-100.
2. Shihada K, Gorenshtein A, Wolfe GI, Shelly S. Urinary dysfunction in myasthenia gravis: a cross-sectional case control study. Neurol Sci. 2026 Jan 3;47(1):91. doi: 10.1007/s10072-025-08588-8