Uraemic pruritus is not related to plasma histamine concentrations

Chronic Intractable Pruritus in Chronic Kidney Disease Patients: Prevalence, Impact, and Management Challenges - A Narrative Review

Chronic kidney disease (CKD) is recognized as a leading public health problem and causes numerous health complications. One of the most common and burdensome dermatological symptoms affecting patients undergoing dialysis is CKD-associated pruritus (CKD-aP). This condition not only has a negative impact on sleep, mood, daily activities, and quality of life but also increases the mortality risk of hemodialyzed patients. Despite that, this condition is greatly underestimated in clinical practice. Due to the complex and still not fully understood etiopathogenesis of CKD-aP, the choice of an effective therapy remains a challenge for clinicians. Most common therapeutic algorithms use topical treatment, phototherapy, and various systemic approaches. This review aimed to summarize most recent theories about the pathogenesis, clinical features, and treatment of CKD-aP.

Pruritus Features in Children with End-Stage Renal Disease Underwent Dialysis: A Cross-Sectional Study

Objective

Evaluation of the pruritus features in children with end-stage renal disease (ESRD) who underwent dialysis at an academic tertiary pediatric dialysis center.

Methods

This cross-sectional study was conducted at an academic tertiary pediatric dialysis center, Isfahan, Iran. The reviewed medical records of the children included their characteristics, dialysis properties, and laboratory parameters. The 4-item itch questionnaire was utilized to assess distribution, severity, frequency, and associated sleeping disorders.

Results

Thirty ESRD patients with pruritus, including 23 males (76.7%) with a mean age of 11.7 ± 3.64 years, were recruited. The most common cause of CKD was nephronophthisis (23.3%). The median total score of pruritus was 5 (range: 3-15). The distribution score of pruritus was directly correlated with the age (Spearman's rho = 0.42, P = 0.02) and serum level of parathyroid hormone (PTH) (Spearman's rho = 0.42, P = 0.04). In the reduced multiple logistic regression model, the increasing level of serum calcium was associated with increased odds of having total pruritus score ≥ 5 (OR (odds ratio): 4.5; 95% CI 1.12 to 18.05). In addition, an increase in age for one year was found to be associated with 50% higher odds of having total pruritus score ≥ 5 (OR: 1.5; 95% CI 1.03 to 2.18).

Conclusion

Increased level of serum Ca and higher age were associated with increased odds of having more severe pruritus score in children.

Chronic Kidney Disease-Associated Itch (CKD-aI) in Children-A Narrative Review

Chronic kidney disease (CKD) is a condition of widespread epidemiology and serious consequences affecting all organs of the organism and associated with significant mortality. The knowledge on CKD is rapidly evolving, especially concerning adults. Recently, more data is also appearing regarding CKD in children. Chronic itch (CI) is a common symptom appearing due to various underlying dermatological and systemic conditions. CI may also appear in association with CKD and is termed chronic kidney disease-associated itch (CKD-aI). CKD-aI is relatively well-described in the literature concerning adults, yet it also affects children. Unfortunately, the data on paediatric CKD-aI is particularly scarce. This narrative review aims to describe various aspects of CKD-aI with an emphasis on children, based on the available data in this population and the data extrapolated from adults. Its pathogenesis is described in details, focusing on the growing role of uraemic toxins (UTs), as well as immune dysfunction, altered opioid transmission, infectious agents, xerosis, neuropathy and dialysis-associated aspects. Moreover, epidemiological and clinical aspects are reviewed based on the few data on CKD-aI in children, whereas treatment recommendations are proposed as well, based on the literature on CKD-aI in adults and own experience in managing CI in children.

Development and Validation of a Uremic Pruritus Treatment Algorithm and Patient Information Toolkit in Patients With Chronic Kidney Disease and End Stage Kidney Disease

CONTEXT

Uremic pruritus (UP) affects up to half of all patients with kidney disease and has been independently associated with poor patient outcomes. UP is a challenging symptom for clinicians to manage as there are no validated guidelines for its treatment.

OBJECTIVES

The study aimed to develop and validate an algorithm and patient information toolkit for the treatment of UP in patients with kidney disease.

METHODS

The study involved a literature search and development of an initial draft algorithm, followed by content and face validation of this algorithm. Validation entailed three rounds of interviews with six nephrology clinicians per round. Participants assessed the relevance of each component of the algorithm and then rated a series of statements on a scale of 1-5 to assess face validity of the algorithm. After each round, the content validity index (CVI) of each algorithm component was calculated, and the algorithm was revised by the study team in response to findings. This process was followed by a second study that developed and validated a patient information pamphlet and video.

RESULTS

Algorithm validation participants were affiliated with three institutions and included seven physicians, four registered nurses, three nurse practitioners, three pharmacists, and a dietician. The average CVI of the algorithm components across all three rounds was 0.89, with 0.80 commonly cited as the lower acceptable limit for content validation. More than 78% of participants rated each face validity statement as "Agree" or "Strongly Agree". For the patient information tools, five clinicians and 15 patients were included in validation. The average CVI was 1.00 for both tools, and the average face validity was 92%.

CONCLUSION

A treatment algorithm and patient information toolkit for managing UP in patients with kidney disease were developed and validated through expert review. Further research will be conducted on implementation of the treatment algorithm and evaluating patient-reported outcomes.

Uremic Pruritus

Renal itch is a localized or generalized itch, affecting patients with chronic renal failure, where there is no primary skin disease and no systemic or psychological dysfunction that might cause pruritus. Uremic pruritus (UP) is an unpleasant sensation, rarely appearing in earlier stages of chronic kidney disease. Renal transplantation is the definite solution for that problem. The prevalence of UP has been reduced during the last years, possibly, due to a more efficient dialysis, with more biocompatible filters.

During the last decades a big number of substances were considered to be etiologic factors of UP, and an even bigger number of therapeutic substances appeared with promising potentials and conflicting results in the course of their use. The main reason for this disorientation is the lack of sound evidence on the pathogenetic mechanisms that may potentiate UP.

‘Inflammatory’ and ‘opioid’ hypothesis are the best studied and the reduction of UP is a fact. Nevertheless the mechanisms of the pathogenesis of UP are still under investigation and a long way has to be done in order to achieve more definite results.

Pruritus in Systemic Diseases: A Review of Etiological Factors and New Treatment Modalities

Pruritus is the most frequently described symptom in dermatology and can significantly impair the patient's quality of life. In 10–50% of adults with persistent pruritus, it can be an important dermatologic clue for the presence of a significant underlying systemic disease such as renal insufficiency, cholestasis, hematologic disorder, or malignancy (Etter and Myers, 2002; Zirwas and Seraly, 2001). This review describes the presence of pruritus in different systemic diseases. It is quite important to discover the cause of pruritus for providing relief for the patients experiencing substantial morbidity caused by this condition.

Is pruritus in chronic uremic patients related to peripheral somatic and autonomic neuropathy? Study by R-R interval variation test (RRIV) and by sympathetic skin response (SSR)

The problem of pruritus in uremic dialysed patients remains unsolved. The etiology of pruritus has not been precisely explained, and sometimes no efficient treatment is available. The aim of this study was to analyse the relationship between somatic neuropathy and pruritus as well as the relationship between pruritus and dysautonomia. Fifty-one patients with end-stage renal failure underwent basic neurological examination, nerve conduction velocity studies, and pruritus assessment by means of a questionnaire. Two tests were used to assess the autonomic nervous system, namely the R-R interval variation test in basal and profound breath conditions (RRIV) and the sympathetic skin response (SSR). Pruritus was found in 63% patients of the sample. Most of them had clinical symptoms and signs of peripheral sensorimotor neuropathy and dysautonomia. About 59% of uremic patients revealed abnormally reduced RRIV. About 45% of patients had abnormal (delayed or absent) SSR. The pruritus in uremic patients occurred significantly more frequently (P < 0.01) in patients with paresthesia. A nonsignificant but sizeable trend towards a relationship of pruritus with hypohidrosis and pathological SSR results was also observed. There was no relationship between the pruritus presence and RRIV results. According to our results the activity of the nervous system might play an important role in the mechanism of uremic pruritus, but paradoxically this latter appeared more tightly related to somatic neuropathy than to autonomic dysfunction. Our results also suggest that SSR may become a useful technique for the assessment of autonomic dysfunction in uremic patients.