Visceral and cutaneous sensory testing in patients with painful bladder syndrome

Our aims were to determine whether subjects with painful bladder syndrome (PBS) demonstrate characteristics of visceral pain syndromes: visceral hyperalgesia, expanded loci of referral of bladder sensation, increased bladder pain with repetitive filling, lower thresholds to cutaneous stimulation in relevant dermatomes, abnormal response to repetitive cutaneous stimulation in relevant dermatomes, and also to develop easily applied measures for PBS pain evaluation and management.

We recruited PBS subjects and control subjects with no bladder pain and with either stress urinary incontinence (SUI) or no incontinence. Subjects underwent three bladder fills up to maximum 300 ml and mapped bladder fullness/discomfort, rating any pain present. Cutaneous current perception thresholds (CPTs) were tested at 2000 Hz, 250 Hz, 5 Hz at C5, T6, T10, T12, S3 dermatomes. Repetitive supra-threshold stimulation in trains of 15 stimuli 2 sec apart were then administered to T12, S3 dermatomes.

PBS subjects demonstrated hyperalgesia to bladder filling and tended to sense bladder discomfort at both suprapubic and vulvar/urethral sites. There was no difference in CPTs at any dermatome at any stimulating frequency. PBS and SI subjects tended not to habituate to repetitive stimuli, while asymptomatic controls tended to habituate to repetitive stimulation.

PBS subjects demonstrate bladder hyperalgesia and may sense bladder discomfort at sites other than suprapubic. Rating of bladder discomfort and sensory mapping during cystometry usefully distinguishes between PBS subjects and controls.