Urinary Storage Symptoms Common in Thyrotoxicosis and Improve After Treatment

People newly diagnosed with thyrotoxicosis frequently report urinary symptoms, and those symptoms improve markedly once thyroid hormone levels return to normal, according to a prospective controlled study published in BMC Urology. The findings suggest that lower urinary tract complaints in patients with an overactive thyroid may be overlooked in clinical practice, even though they appear to be common and largely reversible.

Thyroid hormone excess increases beta-adrenergic activity and disturbs the balance of the autonomic nervous system, an effect that has been studied most extensively in the cardiovascular system. Because bladder storage and voiding depend on a balance between sympathetic and parasympathetic activity, researchers have long suspected that thyrotoxicosis could also affect lower urinary tract function. Until now, however, the evidence has been limited to a few small studies with inconsistent findings, and it remained unclear whether symptoms and objective measures of bladder function change after euthyroidism is restored.

To address this gap, the researchers enrolled 40 patients aged 18 to 50 years with newly diagnosed thyrotoxicosis and compared them with 37 healthy controls matched for age, sex and body mass index. Patients were assessed at baseline, before any treatment took effect, and again after they had achieved normal thyroid function. The study evaluated symptoms with the International Prostate Symptom Score, a validated questionnaire, and measured bladder function objectively using uroflowmetry and ultrasonographic assessment of post-void residual urine volume.

The symptom findings were striking. At baseline, 28 of the 40 patients, or 70 percent, had moderate urinary symptoms. After treatment, 38 patients, or 95 percent, had only mild symptoms. The mean symptom score fell from 7.03 to 1.95, a mean change of minus 5.08 points with a 95 percent confidence interval of minus 6.10 to minus 4.05, and the improvement was statistically significant.

Importantly, the improvement held up under statistical scrutiny. It remained significant after multivariable adjustment for measured confounders, and it was similar in patients who were not receiving antithyroid drugs, suggesting that the symptom relief was tied to the restoration of normal thyroid function rather than to a direct effect of medication. The researchers also noted that the symptoms were almost exclusively storage symptoms, mainly urinary frequency and nocturia, rather than problems with emptying the bladder.

Objective measures told a different story. Uroflowmetric parameters, which assess the speed and pattern of urine flow, and post-void residual volumes did not change after treatment and did not differ from those of healthy controls at any point.

One intriguing secondary finding was a borderline inverse correlation between pre-treatment free thyroxine levels and maximum flow rate, with a Spearman correlation coefficient of minus 0.31 and a confidence interval of minus 0.57 to minus 0.00, just reaching statistical significance at p equals 0.050. This hints that higher thyroid hormone levels might be associated with slower urine flow, but the authors themselves call for urodynamic assessment and larger samples to clarify such relationships.

The study’s authors conclude that lower urinary tract symptoms are common in thyrotoxicosis and improve significantly after treatment, independently of the confounders they measured, whereas uroflowmetric parameters and post-void residual volume do not change within a short follow-up. They suggest that the symptom score may be a useful tool for assessing urinary complaints in this patient group. As a prospective controlled cohort study of 40 patients with a relatively short follow-up, the work cannot establish long-term outcomes or mechanisms, and the researchers explicitly note that larger studies with longer follow-up and formal urodynamic assessment are needed before firm clinical conclusions can be drawn.

For patients, the study offers reassurance that such symptoms are recognized, measurable and, in this cohort, largely resolved after treatment. The open-access article, published on 29 October 2026, adds to a growing appreciation that thyroid hormone excess can affect organ systems well beyond the heart and metabolism.

Subject of Research: Lower urinary tract symptoms and bladder function in newly diagnosed thyrotoxicosis before and after treatment

Article Title: Evaluation of bladder function in newly diagnosed thyrotoxicosis patients: a prospective controlled study

Article References: Şahin, B., Kılıç, G. E., Bayraktar, A. B., Yılmaz, M. B., Özgür, B. C., & Kuşkonmaz, Ş. M. (2026). Evaluation of bladder function in newly diagnosed thyrotoxicosis patients: a prospective controlled study. BMC Urology. https://doi.org/10.1186/s12894-026-02450-5

Image Credits: AI Generated

DOI: 10.1186/s12894-026-02450-5

Keywords: thyrotoxicosis, bladder function, lower urinary tract symptoms, IPSS, uroflowmetry, post-void residual, autonomic nervous system, euthyroidism, nocturia, urinary frequency, BMC Urology, prospective controlled study