Blood lead level: an overlooked risk of carpal tunnel syndrome in hemodialysis patients

Assessing Cross-Sectional Association of Uremic Pruritus with Serum Heavy Metal Levels: A Single-Center Study

(1) Background: Uremic pruritus (UP) is a common and taxing symptom in patients on maintenance hemodialysis (MHD). We have previously shown that blood lead levels (BLLs) and blood aluminum levels (BALs) were separately positively associated with UP in MHD patients. We also found that blood cadmium levels (BCLs) were positively associated with all-cause mortality and cardiovascular-related mortality in MHD patients. We wondered whether there is any correlation between BCLs and UP after adjusting for BLLs and BALs. (2) Methods: Patients enrolled in this study were all from three hemodialysis (HD) centers at Chang Gung Memorial Hospital, Lin-Kou Medical Center, including both the Taipei and Taoyuan branches. Correlations between UP and BLLs, BALs, BCLs, and other clinical data were analyzed. (3) Results: Eight hundred and fifty-three patients were recruited. Univariate logistic regressions showed that diabetes mellitus, hepatitis B virus infection, hepatitis C virus infection, HD duration, hemodiafiltration, dialysis clearance of urea, normalized protein catabolic rate, non-anuria, serum albumin levels, log (intact-parathyroid hormone levels), total serum cholesterol levels, serum low-density lipoprotein levels, log (blood aluminum levels), and log (blood lead levels) were associated with UP. Although log BCLs were not significantly associated with UP (p = 0.136) in univariate analysis, we still included log BCLs in multivariate logistic regression to verify their effect on UP given that our aim in this study was to verify associations between serum heavy metals and UP. Multivariate logistic regressions showed that log BLLs (OR: 27.556, 95% CI: 10.912-69.587, p < 0.001) and log BALs (OR: 5.485, 95% CI: 2.985-10.079, p < 0.001) were positively associated with UP. The other logistic regression, which stratified BLLs and BALs into high and low BLLs and BALs, respectively, showed that high BLLs or high BALs (low BLLs and low BALs as reference) (OR: 3.760, 95% CI: 2.554-5.535, p < 0.001) and high BLLs and high BALs combined (low BLLs and low BALs as reference) (OR: 10.838, 95% CI: 5.381-21.828, p < 0.001) were positively correlated with UP. (4) Conclusions: BLLs and BALs were positively correlated with UP. BCLs were not correlated with UP. Clinicians should pay more attention to the environmental sources of lead and aluminum to prevent UP.

Hepatitis C virus and carpal tunnel syndrome in hemodialysis patients: a single center cross-sectional study

OBJECTIVES

Carpal tunnel syndrome (CTS) is a common complication in maintenance hemodialysis (MHD) patients and leads to disabilities and increased risk of mortality. Hepatitis C virus (HCV) infection is associated with inflammatory and oxidative stress, and HCV infection can be cured. This study aimed at evaluating the association of HCV infection with CTS.

METHODS

Using a cross-sectional design, anthropometric and laboratory data were collected. Serum β₂-microglobulin, HCV antibody and HCV-RNA were measured. CTS was diagnosed according to clinical manifestation, electrophysiological test or ultrasonography. The related factors for CTS were analyzed by multivariate logistic regression.

RESULTS

This study included 113 participants, of whom 33 (29.2%) patients were positive for HCV antibody and 18 (15.9%) were positive for HCV antibody and HCV-RNA. Thirty-two (28.3%) patients were diagnosed with CTS. There were significant differences in the dialysis vintage, age of onset of MHD, high-sensitivity C-reactive protein, serum β₂M, anti-HCV-positive, HCV-RNA-positive, HCV load values and urine volume category between the CTS group and non-CTS group (p < 0.05). High-sensitivity C-reactive protein (OR: 1.238, 95% CI: 1.071-1.431, p = 0.004), dialysis vintage (OR: 1.017, 95% CI: 1.008-1.026, p < 0.001) and HCV-RNA-positive (OR: 5.929, 95% CI: 1.295-27.132, p = 0.022) rather than anti-HCV-positive were related factors for CTS.

CONCLUSIONS

High-sensitivity C-reactive protein, dialysis vintage and HCV-RNA replication but not previous HCV-infection were related factors for CTS in MHD patients. Further studies are needed to clarify whether intervention is beneficial for preventing and delaying the progression of CTS in MHD patients with HCV-RNA replication.

Association between low serum prealbumin levels and carpal tunnel syndrome in maintenance hemodialysis patients

Aims

Carpal tunnel syndrome (CTS) and low serum prealbumin concentration are common in maintenance hemodialysis patients. In this study, we focused on the association between low serum prealbumin levels and carpal tunnel syndrome in maintenance hemodialysis (MHD) patients using low-flux dialysis reuse.

Materials and methods

Serum prealbumin levels were assessed to determine the association between low serum prealbumin levels and CTS in 373 prevalent MHD patients (the mean age was 45 years old, hemodialysis duration was 46 months). The patients were divided into 2 groups: the CTS group with 44 patients and the non-CTS group with 329 patients.

Results

The prevalence of CTS was 11.8%. Serum prealbumin showed a good prognostic value to predict CTS in MHD patients using low-flux dialysis reuse (the Area Under the Curve = 0.841, p < .001; cutoff value: 26.5 mg/dL with sensitivity = 72.7% and specificity = 79.9%).

Conclusions

Serum prealbumin was a good prognostic biomarker of CTS in MHD patients using low-flux dialysis reuse.

Median nerve swelling is an independent risk factor of carpal tunnel syndrome in chronic hemodialysis patients

Carpal tunnel syndrome (CTS) has a wide variety of underlying causes and occurs in association with dialysis. Early diagnosis is essential to prevent permanent nerve damage and functional sequelae. We evaluated the association between CTS and cross-sectional area (CSA) of the median nerve in chronic hemodialysis (HD) patients. Patients with end-stage renal disease on maintenance HD via arteriovenous fistula were enrolled. We divided 43 patients into two groups; patients diagnosed with CTS (n = 19) and patients without CTS (n = 24). The median nerve CSA was measured at the wrist (CSA-W) and forearm (CSA-F) by ultrasonography. Median nerve swelling was assessed by the wrist-to-forearm ratio (WFR). There were no significant differences in the underlying causes of chronic kidney disease and adequacy of dialysis between the two groups (p = NS). The patients with CTS showed significantly higher WFR than the patients without CTS (p = 0.001). Univariate Cox regression analysis revealed that WFR >1.25 (odds ratio, 6.30; 95% confidence interval, 1.44-27.45; p = 0.014) was associated with CTS in HD patients. The factors traditionally associated with CTS such as age, sex, diabetes, vintage of HD, β2-MG, intact PTH, and Kt/V were not associated with CTS. After adjustment for age and sex, we found a strong correlation between CTS and the WFR >1.25 (odds ratio, 10.8; 95% confidence interval, 1.85-62.4; p = 0.008). High WFR was associated with the development of CTS, and median nerve swelling was an independent risk factor of CTS in chronic HD patients.

[Carpal tunnel syndrome: Rare causes and associated forms behind a common and stereotyped affection]

Carpal tunnel syndrome (CTS) is too common a condition not to daily interact with the practitioner, if only because of its entanglement to other pathologies, causal or chance association. The typical symptomatology, with hand paresthesia and morning pain upon waking, is related to a median nerve injury in the confined space of the carpal tunnel, more often by local inflammation and tenosynovitis of the finger flexors (repetitive activity of the hands). SCC may be secondary to situations (pregnancy) or conditions (edema, hypothyroidism…), which exaggerate the ordinary pathophysiology or cause deposits in the channel (amyloidosis, mucopolysaccharidoses, etc.). Otherwise, SCC is favored by all neuropathies that cause nerve fragility (especially diabetes). It is sometimes the first sign of these various affections of which it can allow early diagnosis. Electroneuromyographic examination (ENMG) is a key examination to confirm the diagnosis (slowing of sensitive and motor conduction of the median nerve through the carpal tunnel, due to local demyelination), to look for a predisposing neuropathy and for signs of seriousness (amplitude reduction of electrophysiological signals) that indicate axonal loss. In SCC forms with only slowed conduction without sign of seriousness, a splint or infiltration treatment may be attempted. If this medical treatment does not bring healing, or if there are signs of seriousness or unbearable pains, a decompression surgery is indicated. Whether it is performed traditionally or endoscopically, it provides fast relief, even immediate.