Neurochemical and neuroendocrine correlates of overactive bladder at first demyelinating episode

Bladder dysfunction is frequent during the course of multiple sclerosis (MS), observed in up to 75% of patients. Urinary symptomatology can be a feature of the first episode of MS in a minority of cases, and most often shows characteristics of an overactive bladder (OAB), with voiding symptoms seen less frequently, often in combination with OAB. The neural control of micturition is complex, involving systems located in the brain, spinal cord, and periphery, and implicating central noradrenergic, serotonergic, and dopaminergic activities. Urinary disorders are also linked to anxiety and depression, conditions connected to hypothalamus-pituitary-adrenal axis activity. In this study we aimed to investigate neurochemical and neuroendocrine correlates of bladder dysfunction in early MS.

We included 101 patients at first demyelinating episode suggestive of MS that were drug-free at assessment. We evaluated the presence of urinary symptomatology and estimated CSF levels of the main metabolites of noradrenaline, serotonin, and dopamine, as well CSF-ACTH and serum cortisol.

In total, 15 patients (15%) reported urinary dysfunction suggestive of OAB. Four of these had coexistent voiding symptomatology. The serotonin metabolite 5-HIAA was significantly reduced (P = 0.017) in patients with OAB syndrome, while there were no differences in the metabolites of noradrenaline (MHPG) and of dopamine (HVA). Additionally, significantly lower serum cortisol (P = 0.009) and borderline lower CSF-ACTH (P = 0.08) were found in patients with OAB.

MS patients with OAB syndrome at the first demyelinating episode show reductions in central serotonergic activity and stress hormones. Whether the same changes persist at later disease stages remains to be investigated. Neurourol. Urodynam. 35:955-958, 2016. © 2015 Wiley Periodicals, Inc.