Loin pain haematuria syndrome 1967-2020: a review

The purpose of this retrospective review is to question the validity of the condition 'loin pain haematuria syndrome' (LPHS). We highlight the possibility that most patients regarded as having LPHS have a psychiatric/psychological basis for their symptoms, particularly loin pain. Because of this, and because it recurs despite treatment, the review also questions the use of treatments that are invasive, expensive, and carry considerable morbidity.

Neuroimmune interplay in kidney health and disease: Role of renal nerves

Renal nerves and their role in physiology and disease have been a topic of increasing interest in the past few decades. Renal inflammation contributes to many cardiorenal disease conditions, including hypertension, chronic kidney disease, and polycystic kidney disease. Much is known about the role of renal sympathetic nerves in physiology - they contribute to the regulation of sodium reabsorption, renin release, and renal vascular resistance. In contrast, far less is known about afferent, or "sensory," renal nerves, which convey signals from the kidney to the brain. While much remains unknown about these nerves in the context of normal physiology, even less is known about their contribution to disease states. Furthermore, it has become apparent that the crosstalk between renal nerves and the immune system may augment or modulate disease. Research from other fields, especially pain research, has provided critical insight into neuroimmune crosstalk. Sympathetic renal nerve activity may increase immune cell recruitment, but far less work has been done investigating the interplay between afferent renal nerves and the immune system. Evidence from other fields suggests that inflammation may augment afferent renal nerve activity. Furthermore, these nerves may exacerbate renal inflammation through the release of afferent-specific neurotransmitters.

Consensus document on autosomal dominant polycystic kindey disease from the Spanish Working Group on Inherited Kindey Diseases. Review 2020

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent cause of genetic renal disease and accounts for 6-10% of patients on kidney replacement therapy (KRT). Very few prospective, randomized trials or clinical studies address the diagnosis and management of this relatively frequent disorder. No clinical guidelines are available to date. This is a revised consensus statement from the previous 2014 version, presenting the recommendations of the Spanish Working Group on Inherited Kidney Diseases, which were agreed to following a literature search and discussions. Levels of evidence mostly are C and D according to the Centre for Evidence-Based Medicine (University of Oxford). The recommendations relate to, among other topics, the use of imaging and genetic diagnosis, management of hypertension, pain, cyst infections and bleeding, extra-renal involvement including polycystic liver disease and cranial aneurysms, management of chronic kidney disease (CKD) and KRT and management of children with ADPKD. Recommendations on specific ADPKD therapies are provided as well as the recommendation to assess rapid progression.

Multidisciplinary management of chronic refractory pain in autosomal dominant polycystic kidney disease

BACKGROUND

Chronic pain is often difficult to manage in autosomal dominant polycystic kidney disease (ADPKD) patients and sometimes even leads to nephrectomy. We analyzed the long-term efficacy of our innovative multidisciplinary protocol to treat chronic refractory pain that aims to preserve kidney function by applying among other sequential nerve blocks.

METHODS

Patients were eligible if pain was present ≥3 months with a score of ≥50 on a visual analog scale (VAS) of 100, was negatively affecting quality of life and if there had been insufficient response to previous therapies, including opioid treatment. Treatment options were, in order, analgesics, cyst aspiration and fenestration, nerve blocks and nephrectomy.

RESULTS

A total of 101 patients were assessed in our clinic (mean age 50 ± 11 years, 65.3% females). Eight patients were treated with medication, 6 by cyst aspiration or fenestration, 63 by nerve blocks and 6 received surgery as the first treatment option. Overall, 76.9% experienced a positive effect on pain complaints shortly after treatment. The VAS score was reduced from 60/100 to 20/100 (P < 0.001) and patients decreased their number of nonopioid and opioid analgesics significantly (P < 0.001, P = 0.01, respectively). A substantial number of the patients (n = 51) needed additional treatment. At the end of follow-up in only 13 patients (12.9%) was surgical intervention necessary: 11 nephrectomies (of which 10 were in patients already on kidney function replacement treatment), 1 liver transplantation and 1 partial hepatectomy. After a median follow-up of 4.5 years (interquartile range 2.5-5.3), 69.0% of the patients still had fewer pain complaints.

CONCLUSIONS

These data indicate that our multidisciplinary treatment protocol appears effective in reducing pain in the majority of patients with chronic refractory pain, while postponing or even avoiding in most patients surgical interventions such as nephrectomy in most patients.

Renal denervation does not affect hypertension or the renin-angiotensin system in a rodent model of juvenile-onset polycystic kidney disease: clinical implications

We examined the effect of total and afferent renal denervation (RDN) on hypertension and the renin-angiotensin system (RAS) in a rodent model of juvenile-onset polycystic kidney disease (PKD). Lewis Polycystic Kidney (LPK) and control rats received total, afferent or sham RDN by periaxonal application of phenol, capsaicin or normal saline, respectively, and were monitored for 4-weeks. Afferent RDN did not affect systolic blood pressure (SBP) determined by radiotelemetry in either strain (n = 19) while total RDN significantly reduced SBP in Lewis rats 4-weeks post-denervation (total vs. sham, 122 ± 1 vs. 130 ± 2 mmHg, P = 0.002, n = 25). Plasma and kidney renin content determined by radioimmunoassay were significantly lower in LPK vs. Lewis (plasma: 278.2 ± 6.7 vs. 376.5 ± 11.9 ng Ang I/ml/h; kidney: 260.1 ± 6.3 vs. 753.2 ± 37.9 ng Ang I/mg/h, P < 0.001, n = 26). These parameters were not affected by RDN. Intrarenal mRNA expression levels of renin, angiotensinogen, angiotensin-converting enzyme (ACE)2, and angiotensin II receptor type 1a were significantly lower, whereas ACE1 expression was significantly higher in the LPK vs. Lewis (all P < 0.05, n = 26). This pattern of intrarenal RAS expression was not changed by RDN. In conclusion, RDN does not affect hypertension or the RAS in the LPK model and indicates RDN might not be a suitable antihypertensive strategy for individuals with juvenile-onset PKD.

Establishing a core outcome measure for pain in patients with autosomal dominant polycystic kidney disease: a consensus workshop report

Background

Pain is the highest prioritized patient-reported outcome in people with autosomal dominant polycystic kidney disease (ADPKD) but remains infrequently and inconsistently measured in clinical trials and poorly managed in clinical settings. A recently completed systematic review of pain in ADPKD identified 26 different outcome measures. None of these measures were considered appropriate as a core outcome measure due to the lack of patient-important dimensions, inadequate content, relatively long duration of completion time and limited evidence to support psychometric robustness.

Methods

We convened an international Standardized Outcomes in Nephrology–Polycystic Kidney Disease consensus workshop involving 21 patients/caregivers and 40 health professionals (clinicians, nurses, researchers, policy makers and industry representatives) from 18 countries to discuss the identification or development of a core outcome measure for pain.

Results

Four themes were identified highlighting fundamental issues for the measurement of pain in ADPKD: distressing and disrupting life participation; variability and ambiguity in defining pain; stigma, frustration and adaptation to pain; and ensuring validity and feasibility of pain measures.

Conclusions

Existing measures were found to be insufficient in capturing pain as a core outcome and there was consensus on the need for a new validated measure that is simple, succinct and addresses the impact of pain on life participation. This measure will facilitate the appropriate prioritization of pain in all trials and guide clinical decision making in people with ADPKD.

Treatment and Management of Loin Pain Hematuria Syndrome

PURPOSE OF REVIEW

Loin pain hematuria syndrome (LPHS) is rare and seldom diagnosed, yet it has a particularly significant impact on those affected. This is a review of the latest and seminal evidence of the pathophysiology and diagnosis of LPHS and presents the typical clinical presentation and treatment options available.

RECENT FINDINGS

LPHS is typically found in young women with characteristic symptoms, including severe recurrent flank pain and gross or microscopic hematuria. The majority of patients will experience crippling pain for many years without effective therapy, often requiring frequent use of narcotic medication. However, the lack of conclusive pathophysiology, in conjunction with the rarity of LPHS, has prohibited the development and trial of definitive treatment options. Nevertheless, in order to combat this rare but severe disease, management strategies have continued to evolve, ranging from conservative measures to invasive procedures. This review presents an overview of the current hypotheses on the pathophysiology of LPHS in addition to summarizing the management strategies that have been utilized. Only 30% of LPHS patients will experience spontaneous resolution, whereas the majority will continue to face chronic, crippling pain. Several methods of treatment, including invasive and non-invasive, may provide an improved outcome to these patients. Treatment should be individually tailored and multi-disciplinary in nature. Further research is required to further elucidate the pathophysiology and develop new, specific, treatment options.

Renal denervation: where do we stand and what is the relevance to the nephrologist?

Catheter-based renal denervation to reduce high blood pressure (BP) has received well-deserved attention after a recent series of sham-controlled trials reported significant antihypertensive efficacy and very favourable tolerability and safety of the intervention. This emerging treatment option is of high relevance to nephrologists. Patients with chronic kidney disease (CKD) are at elevated risk of cardiovascular adverse events and often present with hypertension, which is very difficult to control with medication. Renal denervation promises a new tool to reduce BP and to prevent loss of renal function in this population. The current review considers the role of the kidney and neurohormonal activation in the development of hypertension and the rationale for renal denervation. The current state of the evidence for the effectiveness and tolerability of the procedure is considered from the nephrologists’ perspective, with a focus on the potential future role of renal denervation in the management of CKD patients with hypertension.

Interventional Approaches for Loin Pain Hematuria Syndrome and Kidney-Related Pain Syndromes

PURPOSE OF REVIEW

Loin pain hematuria syndrome (LPHS) frequently presents with severe chronic pain that poses a clinical challenge. Current treatment approaches are mostly empirical and include a wide range of therapeutic strategies such as physical therapy, local and systemic analgesia, interventional and surgical approaches usually flanked by psycho-behavioral therapy, and other strategies. LPHS often impacts negatively on quality of life particularly in patients who are refractory to treatment.

RECENT FINDINGS

With recent advances in catheter-based treatment approaches and better understanding of the pathophysiology of LPHS, intraluminal renal denervation (RDN) has been proposed as a valuable treatment option for kidney-related pain syndromes. The present review provides a brief overview of the clinical challenges associated with LPHS, highlights recent insights into its underlying mechanisms, and summarizes currently available data on the use of RDN in the context of LPHS and kidney-related pain syndromes. Renal denervation via various approaches including surgical and catheter-based techniques has shown promise in alleviating kidney-related pain syndromes. Randomized controlled trials are now required to better define its role in the management of these conditions.

Feasibility Study of a Randomized Controlled Trial Investigating Renal Denervation as a Possible Treatment Option in Patients With Loin Pain Hematuria Syndrome

Background:

Loin Pain Hematuria Syndrome (LPHS) is a poorly understood clinical condition characterized by severe pain localized to the kidney but in the absence of identifiable urinary tract disease. There is no consensus on optimal treatment strategies for LPHS. Case reports and series have shown renal denervation via catheter-based radiofrequency ablation to be an effective therapeutic option for the treatment of LPHS. To determine whether catheter-based renal denervation is a meaningful addition to the treatment options in these often-difficult-to-treat LPHS patients, a randomized clinical trial is needed. Prior to conducting a definitive trial that focuses on patient outcomes, ensuring the feasibility of undertaking such a trial is required. As such, we will conduct a single-center randomized control feasibility trial designed to determine viability and provide framework and direction for a larger trial.

Objective:

The objective of the study is to determine whether conducting a randomized trial of renal denervation versus sham procedure is feasible in terms of recruitment and eligibility, and adequacy of follow-up in LPHS patients.

Design:

Single-center double-blinded, parallel-group, partial crossover, sham-controlled, randomized feasibility trial of 10 LPHS patients.

Setting:

Regina General Hospital in Regina, Saskatchewan, Canada.

Patients:

Ten LPHS patients who require opioid therapy.

Measurements:

The main feasibility outcome measures include proportion of target patients who undergo the procedure (treatment or sham) within 6 months; proportion of randomized participants (treatment or control) who entirely complete the follow-up measures at 6 weeks, 3 and 6 months; proportion of the participants who were randomized to control group, cross over after 6 months and opt-in renal denervation treatment; proportion of the crossover participants who complete the follow-up measures at 6 weeks, 3 and 6 months. Pain will be assessed using Brief Pain Inventory Score, McGill Pain Questionnaire, and a pain diary. Mood, disability, and quality of life will be measured by Center for Epidemiologic Studies Depression Scale, Oswestry Disability Index, EuroQol-5D, and Short Form Health Survey Questionnaire, respectively.

Methods:

Eligible participants will be randomized into either renal denervation (treatment group) or a sham treatment (control group). Data (pain, quality of life, mood, disability) will be collected from both groups at baseline, 6 weeks, 3 and 6 months after the intervention. After the initial 6-month follow-up is over, the participants who received the sham procedure will cross over into the treatment group and will be followed for an additional 6 months in the same manner as the treatment group. Descriptive statistics will be used to report outcomes for all patients.

Limitations:

Single-center study, small sample size.

Conclusions:

The lessons learnt from this trial will lay the framework and direction for conducting a multisite randomized controlled trial involving a larger cohort of patients.

Trial registration:

ClinicalTrials.gov (NCT04332731).

Polycystic kidney disease

Cystic kidneys are common causes of end-stage renal disease, both in children and in adults. Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are cilia-related disorders and the two main forms of monogenic cystic kidney diseases. ADPKD is a common disease that mostly presents in adults, whereas ARPKD is a rarer and often more severe form of polycystic kidney disease (PKD) that usually presents perinatally or in early childhood. Cell biological and clinical research approaches have expanded our knowledge of the pathogenesis of ADPKD and ARPKD and revealed some mechanistic overlap between them. A reduced 'dosage' of PKD proteins is thought to disturb cell homeostasis and converging signalling pathways, such as Ca²⁺, cAMP, mechanistic target of rapamycin, WNT, vascular endothelial growth factor and Hippo signalling, and could explain the more severe clinical course in some patients with PKD. Genetic diagnosis might benefit families and improve the clinical management of patients, which might be enhanced even further with emerging therapeutic options. However, many important questions about the pathogenesis of PKD remain. In this Primer, we provide an overview of the current knowledge of PKD and its treatment.

Successful Use of Renal Denervation in Patients With Loin Pain Hematuria Syndrome-The Regina Loin Pain Hematuria Syndrome Study

Introduction

Loin pain hematuria syndrome (LPHS) is characterized by severe unilateral or bilateral loin pain that suggests a renal origin but occurs in the absence of identifiable or relevant urinary tract disease. Hematuria can either be microscopic or macroscopic, but the renal abnormalities responsible for the hematuria are unexplained. Debilitating pain refractory to conventional pain medications is the main cause of morbidity.

Methods

We conducted a single-arm, single-center study. Twelve patients between the ages of 21 and 62 years (11 female, 1 male) with LPHS underwent endovascular ablation of the renal nerves between July 2015 and November 2016, using the Vessix renal denervation system. The primary objective was to achieve 30% reduction in self-reported pain with the McGill Pain Questionnaire (MPQ) at 6 months. The secondary objectives were to measure changes in disability (Oswestry Disability Index [ODI]), mood (Geriatric Depression Scale [GDS]), and quality of life (EuroQol-5D [EQ-5D] and the MOS 36-Item Short Form Survey [SF-36]) scores from baseline to 6 months postprocedure.

Results

Ten of 12 patients at 3 months and 11 of 12 patients at 6 months reported a >30% reduction in pain based on the MPQ at 3 and 6 months. We found consistent improvements in MPQ, ODI, GDS, EQ-5D, and SF-36 scores from baseline to 6 months postprocedure.

Conclusion

We conclude that renal denervation is associated with a considerable improvement in pain, disability, quality of life, and mood. Our results suggest that percutaneous catheter−based delivery of radiofrequency energy is a safe, rapid treatment option that should be considered in all patients with LPHS.