Temporal summation to thermal stimuli is elevated in women with overactive bladder syndrome

Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN): An introduction to the Urinary Urgency Phenotyping Protocol LURN II

AIMS

The Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) is undertaking a new cohort study in LURN II including cases and controls.

METHODS

This new cohort was enrolled to specifically study urinary urgency and urgency urinary incontinence, lower urinary tract symptoms (LUTSs) that are often difficult to treat due to a lack of understanding of their phenotypes and pathophysiologies.

RESULTS

This paper will focus on the motivation for the second iteration of LURN and highlight the new research techniques and plans for more thorough phenotyping of this population.

CONCLUSIONS

This paper will outline the gaps in understanding in treating LUTSs, specifically urinary urgency.

Black box in overactive bladder: Central sensitization and its relationship with urinary symptom severity and quality of life

AIM

To examine central sensitization (CS), and to investigate the relationship between CS, and urinary symptom severity, and quality of life (QoL) in women with overactive bladder (OAB).

MATERIALS AND METHODS

A total of 144 women with OAB included the study. CS with the Central Sensitization Inventory (CSI), urinary symptom with the Overactive Bladder Questionnaire-Version 8 (OAB-V8), bladder diary and Patients' Perception of Intensity of Urgency Scale (PPIUS) and QoL with the King's Health Questionnaire (KHQ) were assessed.

RESULTS

It was found that 47.9% (n = 69) of women with OAB had CS. It was observed that the CSI score was related to the OAB-V8 score (ρ = 0.327; p < 0.001) and the average number of voids/day (ρ = 0.291; p < 0.001). Additionally, urgency severity was higher in women with OAB with CS than in women with OAB without CS (p = 0.006). There was a relationship between the CSI score and KHQ-incontinence impact (ρ = 0.250; p = 0.012), KHQ-personal relationship (ρ = 0.253; p = 0.002), KHQ-sleep/energy (ρ = 0.180; p = 0.031), KHQ-emotional state (ρ = 0.310; p < 0.001) and KHQ-severity measurement scores (ρ = 0.391; p < 0.001).

CONCLUSION

In this study, it was observed that the majority of women with OAB had CS. It was found that more severe symptoms of CS were associated with worse urinary symptom severity and QoL in these patients. It may be beneficial to evaluate CS in the management of OAB and to consider CS when determining treatment strategies.

Musculoskeletal Pain, a Possible Indicator of Central Sensitization, Is Positively Associated With Lower Urinary Tract Symptom Progression in Community-Dwelling Older Men

BACKGROUND

Musculoskeletal pain, a possible marker of central sensitization, is associated with higher prevalence of lower urinary tract symptoms (LUTS) among older men. We investigated whether musculoskeletal pain is associated with LUTS progression.

METHODS

Participants were 5 569 men age ≥65 years enrolled in the prospective, multicenter Osteoporotic Fractures in Men (MrOS) Study. Self-reported musculoskeletal pain within 12 months before baseline was categorized as any pain and multilocation pain. Pain interference within 4 weeks of baseline was assessed with the SF-12 questionnaire. LUTS were assessed repeatedly with the American Urological Association Symptom Index (AUA-SI). Men with severe LUTS at baseline were excluded. LUTS progression was defined as the first occurrence of a ≥4-point AUA-SI increase during a 2-year follow-up interval. Incidence rate ratios (IRR) and 95% confidence intervals (CI) were estimated using multivariable pooled logistic regression.

RESULTS

LUTS progression was 37% higher among men with any musculoskeletal pain compared with men without pain (IRR 1.37, 95% CI: 1.21, 1.54). Positive associations were also observed between LUTS progression and pain at 1 (IRR 1.31, 95% CI: 1.13, 1.48) and ≥2 locations (IRR 1.42, 95% CI: 1.24, 1.60). Compared with men without pain interference, men with quite a bit/extreme pain interference were most likely to experience LUTS progression (minimal interference IRR 1.15, 95% CI: 1.03, 1.26; moderate interference IRR 1.28, 95% CI: 1.11, 1.45; quite a bit/extreme interference IRR 1.47, 95% CI: 1.22, 1.71).

CONCLUSIONS

Among men initially without severe LUTS, musculoskeletal pain is associated with an increased risk of LUTS progression. Studies using validated measures of central sensitization and LUTS progression among men are warranted.

Assessment of bladder pressure and discomfort symptoms: How do overactive bladder differ from interstitial cystitis/bladder pain syndrome patients?

Background

To better understand the sensation of bladder “pressure” and “discomfort”, and how they are similar or distinct from the “pain” and “urgency” symptoms in IC/BPS and OAB.

Methods

IC/BPS and OAB patients rated their bladder pain, pressure, discomfort, and urinary urgency on separate 0–10 numeric rating scales (NRS). Their NRS ratings were compared between IC/BPS and OAB, and Pearson correlations were performed.

Results

Among IC/BPS patients (n = 27), their mean numeric ratings of pain, pressure, discomfort, and urinary urgency were almost identical (6.6 ± 2.1, 6.0 ± 2.5, 6.5 ± 2.2, and 6.0 ± 2.8 respectively). The three-way correlations between pain, pressure, or discomfort were very strong (all > 0.77). Among OAB patients (n = 51), their mean numeric ratings of pain, pressure, and discomfort (2.0 ± 2.6, 3.4 ± 2.9, 3.4 ± 2.9) were significantly lower than urgency (6.1 ± 2.6, p < 0.001). The correlations between urgency and pain, and between urgency and pressure were weak in OAB (0.21 and 0.26). The correlation between urgency and discomfort was moderate in OAB (0.45). The most bothersome symptom of IC/BPS was bladder/pubic pain, while the most bothersome symptom of OAB was urinary urgency and daytime frequency.

Conclusions

IC/BPS patients interpreted bladder pain, pressure, or discomfort as the similar concepts and rated their intensity similarly. It is unclear whether pressure or discomfort provide additional information beyond pain in IC/BPS. Discomfort may also be confused with urgency in OAB. We should re-examine the descriptors pressure or discomfort in the IC/BPS case definition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-01164-8.

Experimental Pain and Auditory Sensitivity in Overactive Bladder Syndrome: A Symptoms of the Lower Urinary Tract Dysfunction Research Network (LURN) Study

PURPOSE

The objective of this study was to investigate the presence of nonbladder sensory abnormalities in participants with overactive bladder syndrome (OAB).

MATERIALS AND METHODS

Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) study participants with OAB symptoms and controls were recruited from 6 U.S. tertiary referral centers. Quantitative sensory testing (QST) was performed to determine pressure pain sensitivity at the thumbnail bed and auditory sensitivity. Fixed and mixed effect multivariable linear regressions and Weibull models were used to compare QST responses between groups. Pearson correlations were used to assess the relationship between QST measures. Associations between QST and self-reported symptoms were explored with linear regression.

RESULTS

A total of 297 participants were analyzed (191 OAB, 106 controls; 76% white, 51% male). OAB cases were older than controls (57.4 vs 52.2 years, p=0.015). No significant differences in experimental thumbnail (nonbladder) pain or auditory sensitivity were detected between OAB cases and controls. Correlations between pressure and auditory derived metrics were weak to moderate overall for both groups, with some significantly stronger correlations for cases. Exploratory analyses indicated increased pressure pain and auditory sensitivity were modestly associated with greater self-reported bladder pain and pain interference with physical function.

CONCLUSIONS

As a group, no significant differences between OAB cases and controls were observed in experimental nonbladder pain or auditory sensitivity during QST. Associations between QST outcomes and clinical pain raise the possibility of centrally mediated sensory amplification in some individuals with OAB.

Lower urinary tract symptoms are associated with musculoskeletal pain among older men: Preliminary evidence for central sensitization as a mechanism?

AIMS

Features of central sensitization (CS) are present in almost all chronic pain conditions, including painful urinary conditions and back pain. Recently CS was proposed as a mechanism of nonpainful lower urinary tract symptoms (LUTS). Using musculoskeletal pain as an indicator of CS, we investigated whether the prevalence of musculoskeletal pain is greater among community-dwelling men with moderate or severe LUTS compared to those with mild LUTS.

METHODS

We conducted a cross-sectional study of 5966 men ≥65 years who attended the Osteoporotic Fractures in Men Study baseline visit. LUTS were assessed with the American Urological Association Symptom Index (AUA-SI) and categorized as none/mild (0-7), moderate (8-19), or severe (≥20). Self-reported back, neck, hip, or knee pain within the 12 months before baseline was categorized as any pain and multilocation pain. We tested our hypothesis using odds ratios (OR) and 95% confidence intervals (CI) estimated from multivariable logistic regression models.

RESULTS

The adjusted odds of any pain were higher among men with moderate (OR 1.49, 95% CI: 1.29-1.72) and severe LUTS (OR 1.76, 95% CI: 1.28-2.40) compared to those with no/mild LUTS. The adjusted odds of pain at ≥ 2 locations were 69% higher among men with moderate (OR 1.69, 95% CI: 1.45-196) and more than double among men with severe LUTS (OR 2.24, 95% CI: 1.62-3.10) compared to men with no/mild LUTS.

CONCLUSIONS

Musculoskeletal pain, especially at multiple locations, is associated with greater LUTS severity among older men. CS may represent a novel shared mechanism of pain and LUTS.

Clustering of patients with overactive bladder syndrome

BACKGROUND

Overactive bladder is a heterogenous condition with poorly characterized clinical phenotypes. To discover potential patient subtypes in patients with overactive bladder (OAB), we used consensus clustering of their urinary symptoms and other non-urologic factors.

METHODS

Clinical variables included in the k-means consensus clustering included OAB symptoms, urinary incontinence, anxiety, depression, psychological stress, somatic symptom burden, reported childhood traumatic exposure, and bladder pain.

RESULTS

48 OAB patients seeking care of their symptoms were included. k-means consensus clustering identified two clusters of OAB patients: a urinary cluster and a systemic cluster. The systemic cluster, which consisted of about half of the cohort (48%), was characterized by significantly higher psychosocial burden of anxiety (HADS-A, 9.5 vs. 3.7, p < 0.001), depression (HADS-D, 6.9 vs. 3.6, p < 0.001), psychological stress (PSS, 21.4 vs. 12.9, p < 0.001), somatic symptom burden (PSPS-Q, 28.0 vs. 7.5, p < 0.001), and reported exposure to traumatic stress as a child (CTES, 17.0 vs. 5.4, p < 0.001), compared to the urinary cluster. The systemic cluster also reported more intense bladder pain (3.3 vs. 0.8, p = 0.002), more widespread distribution of pain (34.8% vs. 4.0%, p = 0.009). The systemic cluster had worse urinary incontinence (ICIQ-UI, 14.0 vs. 10.7, p = 0.028) and quality of life (SF-36, 43.7 vs. 74.6, p < 0.001). The two clusters were indistinguishable by their urgency symptoms (ICIQ-OAB, OAB-q, IUSS, 0-10 ratings). The two OAB clusters were different from patients with IC/BPS (worse urgency incontinence and less pain).

CONCLUSIONS

The OAB population is heterogeneous and symptom-based clustering has identified two clusters of OAB patients (a systemic cluster vs. a bladder cluster). Understanding the pathophysiology of OAB subtypes may facilitate treatments.

Cognitive components of behavioral therapy for overactive bladder: a systematic review

INTRODUCTION AND HYPOTHESIS

Behavioral therapy is the first-line treatment for overactive bladder (OAB); however, the cognitive components of behavioral therapy for OAB have not been evaluated. The purposes of this systematic review were to describe the cognitive components of behavioral therapy for OAB and evaluate their effectiveness as well as to describe their rationale and origins.

METHODS

Searches were conducted on the PubMed, CINAHL, Web of Science, Cochrane and PEDro databases. Inclusion criteria were single-arm or randomized controlled trials on OAB treatment that utilized behavioral therapy, with a description of a cognitive component of the behavioral therapy. Study participants were neurologically intact adults (n = 1169). Study methodological quality was assessed with the PEDro and Newcastle-Ottawa scales.

RESULTS

Five studies were included, published between 2009 and 2020. Methodological quality was variable. All studies reported a reduction of symptoms in participants receiving behavioral therapy. Cognitive components of behavioral therapy were not extensively described. Distraction was the most common cognitive strategy for managing urgency. The relative impact of the cognitive aspect of behavioral therapy could not be evaluated, and the cognitive aspects of behavioral therapy appear to be accepted wisdom, traceable to several key authors, that has not been subjected to scientific investigation.

CONCLUSIONS

Behavioral therapy for OAB appears useful, but its cognitive components are not well described, their relative importance has not been evaluated or ascertained, nor have they been rigorously studied.

Sensory and pain modulation profiles of ongoing central neuropathic extremity pain in multiple sclerosis

BACKGROUND

Central neuropathic extremity pain (CNEP) is the most frequent type of pain in multiple sclerosis (MS). The aim of the present study was to evaluate sensory and pain modulation profiles in MS patients with CNEP.

METHODS

In a single-centre observational study, a group of 56 CNEP MS patients was compared with 63 pain-free MS patients and with a sex- and age-adjusted control group. Standardized quantitative sensory testing (QST) and dynamic QST (dQST) protocols comprising temporal summation and conditioned pain modulation tests were used to compare sensory profiles.

RESULTS

Loss-type QST abnormalities in both thermal and mechanical QST modalities prevailed in both MS subgroups and correlated significantly with higher degree of disability expressed as Expanded Disability Status Scale (EDSS). Comparison of sensory phenotypes disclosed a higher frequency of the 'sensory loss' prototypic sensory phenotype in the CNEP subgroup (30%) compared with pain-free MS patients (6%; p = .003).

CONCLUSION

The role of aging process and higher lesion load in the spinothalamocortical pathway might be possible explanation for pain development in this particular 'deafferentation' subtype of central neuropathic pain in MS. We were unable to support the role of central sensitization or endogenous facilitatory and inhibitory mechanisms in the development of CNEP in MS.

SIGNIFICANCE

This article presents higher prevalence of the 'sensory loss' prototypic sensory phenotype in multiple sclerosis patients with central extremity neuropathic pain compared to pain-free patients. Higher degree of disability underlines the possible role of higher lesion load in the somatosensory pathways in this particular 'deafferentation' type of central neuropathic pain.

Lack of Exercise-Induced Hypoalgesia to Repetitive Back Movement in People with Chronic Low Back Pain

PURPOSE

To investigate whether people with chronic low back pain (LBP) show dysfunctional exercise-induced hypoalgesia (EIH) in response to repeated contractions of their back muscles during a lifting task.

METHODS

In this cross-sectional observational study conducted on asymptomatic participants (n = 18) and participants with chronic LBP (n = 21), quantitative sensory testing (QST) was applied extensively over the lumbar region and a remote area before and after a repeated task that involved lifting a 5-kg box for ~7 minutes. QST included pressure pain thresholds (PPTs), thermal detection, pain thresholds, and measures of temporal summation. Topographical maps of the percentage change in PPT detected at 16 locations over the lumbar region were generated to explore regional differences and compared between groups.

RESULTS

Mean (standard deviation) PPTs measured from 16 sites over the lower back changed significantly in asymptomatic participants (+29.78 kPa [41.4]) following task completion, indicative of EIH, whereas no significant change was observed for the low back pain (LBP) group (-14.87 kPa [61.2]). No changes were detected at the remote site for either group. No changes were revealed for the thermal tests. Temporal summation data revealed decreasing pain sensitivity as the test progressed, but the test response did not change after the exercise for either group.

CONCLUSION(S)

Unlike asymptomatic individuals, participants with LBP lacked EIH over the lumbar erector spinae muscles following repeated lifting. Although these results should be considered in relation to the study limitations, particularly the absence of a control group, the findings support impaired EIH in patients with LBP.

The Severity and Distribution of Nonurologic Pain and Urogenital Pain in Overactive Bladder are Intermediate Between Interstitial Cystitis and Controls

OBJECTIVES

(1) To compare the severity and distribution of nonurologic and urogenital pain between overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS) and controls, and (2) To examine the relationships between the severity of urogenital pain and severity of urinary symptoms among patients with OAB.

SUBJECTS AND METHODS

Fifty-one OAB patients, 27 IC/BPS patients, and 30 controls were recruited. Nonurologic pain was assessed using a whole body map and Brief Pain Inventory. Urologic pain was assessed using the Interstitial Cystitis Symptom and Problem indexes, Genitourinary Pain Index, and 0-10 pain scale. Urogenital pain was assessed using a genital map, and report of pain related to bladder filling and urination.

RESULTS

Among OAB patients, 6% reported pelvic pain only while 28% reported pelvic pain and beyond. 18% reported widespread pain. The distribution of nonurologic pain and urogenital pain in OAB patients were intermediate between IC/BPS and controls (IC/BPS>OAB>controls, P all <.05). The intensity of pain reported by OAB patients was intermediate between controls and IC/BPS (average 2.3 vs 0.8 vs 4.3 out of 10, P <.001). Among OAB patients, the pain severity (GUPI-pain, ICSI-pain, ICPI-pain) was positively correlated with urinary severity (UDI-6, IIQ-7, OABq-SS, OABq-QOL, P all < .05). OAB patients with pelvic pain have worse urinary symptoms and psychosocial health (anxiety, depression) compared to OAB patients without pelvic pain.

CONCLUSION

A subset of OAB patients has pain inside and/or outside the pelvis. The intensity and distribution of pain in OAB was intermediate between IC/BPS and controls. Systemic processes such as central sensitization should be examined in this population.

Painful Bladder Symptoms Related to Somatic Syndromes in a Convenience Sample of Community Women with Overactive Bladder Symptoms

PURPOSE

We investigated the relationship of painful bladder filling and urinary urgency to somatic and chronic pain symptoms in women with overactive bladder without an interstitial cystitis/bladder pain syndrome diagnosis.

MATERIALS AND METHODS

Women who met overactive bladder criteria based on symptoms were recruited, including 183 (83.9%) from the community and 35 (16.1%) from the urology clinic to complete validated questionnaires assessing urinary symptoms, somatic symptoms and pain syndromes. Participants were categorized into 1 of 3 groups, including 1) neither symptom, 2) either symptom or 3) both symptoms, based on their reports of painful urinary urgency and/or painful bladder filling. Multivariable regression analyses were performed to determine factors predictive of having painful urgency and/or painful filling.

RESULTS

Of 218 women with overactive bladder 101 (46%) had neither painful bladder filling nor urinary urgency, 94 (43%) had either symptom and 23 (11%) had both symptoms. When controlling for age, women with either or both urological pain symptoms were more likely to have irritable bowel syndrome, chronic pelvic pain and temporomandibular disorder than women in the neither group. Additionally, these women had higher pain intensity and somatic symptoms scores than women with neither symptom.

CONCLUSIONS

The majority of women with overactive bladder who had not been diagnosed with interstitial cystitis/bladder pain syndrome reported painful urgency and/or painful filling. Experiencing painful urgency and/or filling was associated with an increased somatic symptom burden and greater pain intensity. These findings support the hypothesis that overactive bladder and interstitial cystitis/bladder pain syndrome diagnoses may represent a continuum of bladder hypersensitivity.

The LURN Research Network Neuroimaging and Sensory Testing (NIST) Study: Design, protocols, and operations

The Neuroimaging and Sensory Testing (NIST) Study of the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) is a cross-sectional, case-control study designed to investigate whether disrupted brain connectivity and sensory processing are associated with abnormal lower urinary tract symptoms (LUTS) in patients with overactive bladder syndrome (OAB). The NIST Study tests the hypotheses that patients with urinary urgency will demonstrate: (1) abnormal functional and structural connectivity of brain regions involved in urinary sensation on magnetic resonance imaging (MRI), and (2) hypersensitivity to painful (pressure) and non-painful (auditory) sensory stimuli on quantitative sensory testing (QST), compared to controls. Male and female adults (18 years or older) who present at one of the six participating LURN clinical centers for clinical care of their LUTS, with symptoms of urinary urgency with or without urgency urinary incontinence, are eligible to participate. The NIST Study is the largest MRI and QST study of its kind, yielding a neuroimaging and sensory testing dataset unprecedented in OAB research. Advanced multi-modal techniques are used to understand brain functional and structural connectivity, including gray matter volume, and sensory function. Unlike previous MRI studies which involved invasive catheterization and repeated cycles of non-physiologic bladder filling and emptying via a catheter, we use a water ingestion protocol to mimic more physiological bladder filling through natural diuresis. Furthermore, these data will be used in concert with other phenotyping data to improve our understanding of clinically meaningful subtypes of patients with LUTS in order to improve patient care and management outcomes.

Women Undergoing Third Line Overactive Bladder Treatment Demonstrate Elevated Thermal Temporal Summation

PURPOSE

We sought to determine whether women with overactive bladder who required third line therapy would demonstrate greater central sensitization, indexed by temporal summation to heat pain stimuli, than those with overactive bladder.

MATERIALS AND METHODS

We recruited 39 women with overactive bladder from the urology clinic who were planning to undergo interventional therapy for medication refractory overactive bladder with onabotulinumtoxinA bladder injection or sacral neuromodulation. We also recruited 55 women with overactive bladder who were newly seen at our urology clinic or who responded to advertisements for study participation. Participants underwent quantitative sensory testing using a thermal temporal summation protocol. The primary study outcome was the degree of temporal summation as reflected in the magnitude of positive slope of the line fit to the series of 10 stimuli at a 49C target temperature. We compared the degree of temporal summation between the study groups using linear regression.

RESULTS

Women in the group undergoing third line therapy showed significantly higher standardized temporal summation slopes than those in the nontreatment group (β = 1.57, 95% CI 0.18-2.96, t = 2.25, p = 0.027). On exploratory analyses a history of incontinence surgery or hysterectomy was associated with significantly greater temporal summation.

CONCLUSIONS

In this study the degree of temporal summation was elevated in women undergoing third line overactive bladder therapy compared to women with overactive bladder who were not undergoing that therapy. These findings suggest there may be pathophysiological differences, specifically in afferent nerve function and processing, in some women with overactive bladder.