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

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.

Basic Research Protocol: Exome Sequencing in Adults With Loin Pain Hematuria Syndrome: A Pilot Study

Background

Loin pain hematuria syndrome (LPHS) is a poorly understood clinical syndrome characterized by hematuria and either unilateral or bilateral severe kidney pain in the absence of identifiable urological disease. Loin pain hematuria syndrome imposes a significant health and economic impact with a loss of productivity and quality of life in a young population. Owing to an incomplete understanding of its pathophysiology, treatment has been limited to nonspecific pain management. Nearly 60 years after its initial description, we are no further ahead in understanding the molecular pathways involved in LPHS.

Objective

To outline the study design for exome sequencing in adults with LPHS and their families.

Methods

In this single-center case series, 24 patients with LPHS and 2 additional first-degree family members per participant will be recruited. DNA extracted from venous blood samples will undergo exome sequencing on the Illumina NovaSeq 6000 System at 100× depth and will be assessed for pathogenic variants in genes associated with hematuria (number of genes in: glomerular endothelium [n = 10] and basement membrane [n = 8]), and pain pathways (number of genes in: pain transduction [n = 17], conduction [n = 8], synaptic transmission [n = 37], and modulation [n = 27]). We will further examine identified potentially pathogenic variants that co-segregate with LPHS features among affected families.

Conclusions

This pilot study may identify new directions for an investigation into the molecular mechanisms underlying LPHS.

Endovascular denervation (EDN): From Hypertension to Non-Hypertension Diseases

Recently, the use of endovascular denervation (EDN) to treat resistant hypertension has gained significant attention. In addition to reducing sympathetic activity, EDN might also have beneficial effects on pulmonary arterial hypertension, insulin resistance, chronic kidney disease, atrial fibrillation, heart failure, obstructive sleep apnea syndrome, loin pain hematuria syndrome, cancer pain and so on. In this article we will summarize the progress of EDN in clinical research.

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.

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).