Quantitative assessment of nonpelvic pressure pain sensitivity in urologic chronic pelvic pain syndrome: a MAPP Research Network study.

Experimental pain sensitivity was assessed in individuals with urologic chronic pelvic pain syndrome (UCPPS) as part of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network. A series of computer-controlled pressure stimuli were delivered to the thumbnail bed, an asymptomatic site distant from the area of UCPPS pain that is considered to be indicative of overall body pain threshold. Stimuli were rated according to a standardized magnitude estimation protocol. Pain sensitivity in participants with UCPPS was compared with healthy controls and a mixed pain group composed of individuals with other chronic overlapping pain conditions, including fibromyalgia, chronic fatigue, and irritable bowel syndromes. Data from 6 participating MAPP testing sites were pooled for analysis. Participants with UCPPS (n = 153) exhibited an intermediate pain sensitivity phenotype: they were less sensitive relative to the mixed pain group (n = 35) but significantly more sensitive than healthy controls (n = 100). Increased pain sensitivity in patients with UCPPS was associated with both higher levels of clinical pain severity and more painful body areas outside the pelvic region. Exploratory analyses in participants with UCPPS revealed that pain sensitivity increased during periods of urologic symptom flare and that less pressure pain sensitivity at baseline was associated with a greater likelihood of subsequent genitourinary pain improvement 1 year later. The finding that individuals with UCPPS demonstrate nonpelvic pain hypersensitivity that is related to clinical symptoms suggests that central nervous system mechanisms of pain amplification contribute to UCPPS.

A longitudinal analysis of urological chronic pelvic pain syndrome flares in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network.

OBJECTIVE: To describe the frequency, intensity and duration of urological chronic pelvic pain syndrome symptom exacerbations ('flares'), as well as risk factors for these features, in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain Epidemiology and Phenotyping longitudinal study. PARTICIPANTS AND METHODS: Current flare status ('urological or pelvic pain symptoms that are much worse than usual') was ascertained at each bi-weekly assessment. Flare characteristics, including start date, and current intensity of pelvic pain, urgency and frequency (scales of 0-10), were assessed for participants' first three flares and at three randomly selected times when they did not report a flare. Generalized linear and mixed effects models were used to investigate flare risk factors. RESULTS: Of the 385 eligible participants, 24.2% reported no flares, 22.9% reported one flare, 28.3% reported 2-3 flares, and 24.6% reported ≥4 flares, up to a maximum of 18 during the 11-month follow-up (median incidence rate = 0.13/bi-weekly assessment, range = 0.00-1.00). Pelvic pain (mean = 2.63-point increase) and urological symptoms (mean = 1.72) were both significantly worse during most flares (60.6%), with considerable within-participant variability (26.2-37.8%). Flare duration varied from 1 to 150 days (94.3% within-participant variability). In adjusted analyses, flares were more common, symptomatic, and/or longer-lasting in women and in those with worse non-flare symptoms, bladder hypersensitivity, and chronic overlapping pain conditions. CONCLUSION: In this foundational flare study, we found that pelvic pain and urological symptom flares were common, but variable in frequency and manifestation. We also identified subgroups of participants with more frequent, symptomatic, and/or longer-lasting flares for targeted flare management/prevention and further study.