Clinical Management of Bladder Pain Syndrome/Interstitial Cystitis: A Review on Current Recommendations and Emerging Treatment Options

Bladder pain syndrome (BPS) is a chronic condition characterized by pelvic pain or pressure which is perceived to be originating from the bladder, accompanied by one or more urinary symptoms, including frequency, urgency and nocturia. The precise etiology of BPS is not fully understood. Chronic bacterial infection, defective glycosaminoglycan (GAG) layer of the bladder urothelium, inappropriate activation of mast cells in the suburothelial layer of the bladder, autoimmune-mediated mechanisms and autonomic nervous system dysfunction have all been implicated. Treatments targeted at each of these mechanisms have been developed with mixed outcomes. High-quality research into the treatment options is lacking and it is difficult to draw definite conclusions. The treatment approach is multimodal and should be patient specific, targeting the symptoms which they find most bothersome. Conservative treatment, including patient education, behavioural modification, dietary advice, stress relief and physical therapy is an essential initial management strategy for all patients. If no response is observed, oral treatments such as amitriptyline are likely to offer the greatest response. Cystoscopy is essential to phenotype patients, and Hunner lesion directed therapy with fulguration or resection can be performed at the same time. Intravesical instillation of DMSO or lidocaine, detrusor injections of botulinum toxin A and neuromodulation can be used if initial management fails to improve symptoms. Oral cyclosporin can be trialled in those experienced with its use; however, it is associated with significant adverse events and requires intense monitoring. Lastly, radical surgery should be reserved for those with severe, unremitting BPS, in which quality of life is severely affected and not improved by previously mentioned interventions. Future work investigating exact aetiological factors will help target the development of efficacious treatment options, and several promising oral and intravesical treatments are emerging.

Interventions for treating people with symptoms of bladder pain syndrome: a network meta-analysis

BACKGROUND

Bladder pain syndrome (BPS), which includes the condition of interstitial cystitis, is a poorly understood clinical condition for which patients present with varying symptoms. Management of BPS is challenging for both patients and practitioners. At present, there is no universally accepted diagnosis and diverse causes have been proposed. This is reflected in wide-ranging treatment options, used alone or in combination, with limited evidence. A network meta-analysis (NMA) simultaneously comparing multiple treatments may help to determine the best treatment options for patients with BPS.

OBJECTIVES

To conduct a network meta-analysis to assess the effects of interventions for treating people with symptoms of bladder pain syndrome (BPS).

SEARCH METHODS

We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL, in the Cochrane Library), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and handsearched journals and conference proceedings (searched 11 May 2018) and the reference lists of relevant articles. We conducted a further search on 5 June 2019, which yielded four small studies that were screened for eligibility but were not incorporated into the review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of interventions for treating adults with BPS. All types of interventions (including conservative, pharmacological and surgical) were eligible.

DATA COLLECTION AND ANALYSIS

We assessed the risk of bias of included studies using Cochrane's 'Risk of bias' tool. Primary outcomes were the number of people cured or improved, pain, frequency and nocturia. For each outcome, random-effects NMA models were fitted using WinBUGS 1.4. We monitored median odds ratios (ORs) for binary outcomes and mean differences (MDs) for continuous outcomes with 95% credible intervals (Crls). We compared results of the NMA with direct evidence from pairwise meta-analysis of head-to-head trials. We used the CINeMA tool to assess the certainty of evidence for selected treatment categories.

MAIN RESULTS

We included 81 RCTs involving 4674 people with a median of 38 participants (range 10 to 369) per RCT. Most trials compared treatment against control; few trials compared two active treatments. There were 65 different active treatments, and some comparisons were informed by direct evidence from only one trial. To simplify, treatments were grouped into 31 treatment categories by mode of action. Most studies were judged to have unclear or high risk of bias for most domains, particularly for selection and detection bias. Overall, the NMA suggested that six (proportion cured/improved), one (pain), one (frequency) and zero (nocturia) treatment categories were effective compared with control, but there was great uncertainty around estimates of effect. Due to the large number of intervention comparisons in this review, we focus on three interventions: antidepressants, pentosan polysulfate (PPS) and neuromuscular blockade. We selected these interventions on the basis that they are given 'strong recommendations' in the EAU Guidelines for management of BPS (EAU Guidelines 2019). We found very low-certainty evidence suggesting that antidepressants were associated with greater likelihood of cure or improvement compared with control (OR 5.91, 95% CrI 1.12 to 37.56), but it was uncertain whether they reduced pain (MD -1.27, 95% CrI -3.25 to 0.71; low-certainty evidence), daytime frequency (MD -2.41, 95% CrI -6.85 to 2.05; very low-certainty evidence) or nocturia (MD 0.01, 95% CrI -2.53 to 2.50; very low-certainty evidence). There was no evidence that PPS had improved cure/improvement rates (OR 0.14, 95% CrI 0.40 to 3.35; very low-certainty evidence) or reduced pain (MD 0.42, 95% CrI -1.04 to 1.91; low-certainty evidence), frequency (MD -0.37, 95% CrI -5.00 to 3.44; very low-certainty evidence) or nocturia (MD -1.20, 95% CrI -3.62 to 1.28; very low-certainty evidence). There was evidence that neuromuscular blockade resulted in greater cure or improvement (OR 5.80, 95% CrI 2.08 to 18.30) but no evidence that it improved pain (MD -0.33, 95% CrI -1.71 to 1.03), frequency (MD -0.91, 95% CrI -3.24, 1.29) or nocturia (MD -0.04, 95% CrI -1.35 to 1.27). The certainty of this evidence was always very low.

AUTHORS' CONCLUSIONS

We are uncertain whether some treatments may be effective in treating patients with BPS because the certainty of evidence was generally low or very low. Data were available for a relatively large number of trials, but most had small sample sizes and effects of treatments often could not be estimated with precision. An NMA was successfully conducted, but limited numbers of small trials for each treatment category hampered our ability to fully exploit the advantages of this analysis. Larger, more focused trials are needed to improve the current evidence base.

Hyperbaric oxygen significantly improves frequent urination, hyperalgesia, and tissue damage in a mouse long-lasting cystitis model induced by an intravesical instillation of hydrogen peroxide

AIM

To investigate whether hyperbaric oxygen (HBO) is effective for the pathophysiological findings in an IC/PBS-like mouse model induced by intravesical hydrogen peroxide (H₂ O₂ ).

METHODS

Six-week-old ICR female mice (N = 16) were divided into four experimental groups: (1) sham control with intravesical vehicle instillation twice, and without subsequent treatment (N = 4); (2) H₂ O₂ instillation twice, followed by HBO (100% O₂ , 2 ATA, 30 min per session) (N = 4); (3) H₂ O₂ instillation twice, followed by dummy hyperbaric treatment (air, 2ATA, 30 min per session) (N = 4); and (4) H₂ O₂ instillation twice, followed by no treatment (N = 4). Body weight, voiding frequency, tidal voiding volume, and individual bladder pain threshold using the von-Frey test were measured. Whole body uptake of an inflammation-specific fluorescent pan-cathepsin was assessed by an in vivo imaging. Immunohistochemical staining and the mRNA expression of several biomarkers associated with chronic inflammation in resected bladders were evaluated.

RESULTS

The HBO-treated group showed significant improvement in voiding frequency, tidal voiding volume, and the individual bladder pain threshold. Moreover, HBO markedly suppressed H₂ O₂ -induced inflammation, edema, and fibrosis in bladder wall, concomitant with a significant decrease in mRNA expressions of inflammation biomarkers and a significant increase in endothelial nitric oxide synthase expression. HBO also inhibited the expression of transient receptor potential channels induced by H₂ O₂ instillation.

CONCLUSION

These results suggest that HBO contributes to elimination of H₂ O₂ -induced long-lasting cystitis through the repair of chronically inflamed bladder tissue and inhibition of the bladder sensory system.

Dimethyl sulfoxide (DMSO) as intravesical therapy for interstitial cystitis/bladder pain syndrome: A review

AIMS

The purpose of this review is to update the current understanding of dimethyl sulfoxide (DMSO) and its role in the treatment of interstitial cystitis (IC).

METHODS

A systematic review was conducted using the PRIMSA checklist to identify published articles involving intravesical DMSO for the treatment of IC.

RESULTS

Thirteen cohort studies and three randomized-controlled trials were identified. Response rates relying on subjective measurement scores range from 61 to 95%. No increased efficacy was found with "cocktail" DMSO therapy. Great variation existed in diagnostic criteria, DMSO instillation protocols and response measurements.

CONCLUSIONS

The current evidence backing DMSO is a constellation of cohort studies and a single randomized-controlled trial versus placebo. The optimal dose, dwell time, type of IC most likely to respond to DMSO, definitions of success/failure and the number of treatments are not universally agreed upon. Improvements in study design, phenotyping patients based on symptoms, as well as the emergence of reliable biomarkers of the disease may better guide the use of DMSO in the future.

Clinical guidelines for interstitial cystitis and hypersensitive bladder updated in 2015

Clinical guidelines for interstitial cystitis and hypersensitive bladder have been updated as of 2015. The guidelines define interstitial cystitis by the presence of hypersensitive bladder symptoms (discomfort, pressure or pain in the bladder usually associated with urinary frequency and nocturia) and bladder pathology, after excluding other diseases explaining symptoms. Interstitial cystitis is further classified by bladder pathology; either Hunner type interstitial cystitis with Hunner lesions or non-Hunner type interstitial cystitis with mucosal bleeding after distension in the absence of Hunner lesions. Hypersensitive bladder refers to a condition, where hypersensitive bladder symptoms are present, but bladder pathology or other explainable diseases are unproven. Interstitial cystitis and hypersensitive bladder severely affect patients' quality of life as a result of disabling symptoms and/or comorbidities. Reported prevalence suggestive of these disorders varies greatly from 0.01% to >6%. Pathophysiology would be an interaction of multiple factors including urothelial dysfunction, inflammation, neural hyperactivity, exogenous substances and extrabladder disorders. Definite diagnosis of interstitial cystitis and hypersensitive bladder requires cystoscopy with or without hydrodistension. Most of the therapeutic options lack a high level of evidence, leaving a few as recommended therapeutic options.

From bladder to systemic syndrome: concept and treatment evolution of interstitial cystitis

Interstitial cystitis, presently known as bladder pain syndrome, has been recognized for over a century but is still far from being understood. Its etiology is unknown and the syndrome probably harbors different diseases. Autoimmune dysfunction, urothelial leakage, infection, central and peripheral nervous system dysfunction, genetic disease, childhood trauma/abuse, and subsequent stress response system dysregulation might be implicated. Management is slowly evolving from a solo act by the end-organ specialist to a team approach based on new typing and phenotyping of the disease. However, oral and invasive treatments are still largely aimed at the bladder and are based on currently proposed pathophysiologic mechanisms. Future research will better define the disease, permitting individualization of treatment.