Calcium‐phosphate and parathyroid intradialytic profiles: A potential aid for tailoring the dialysate calcium content of patients on different hemodialysis schedules

Severe hyperparathyroidism is a challenge on hemodialysis. The definition of dialysate calcium (Ca) is a pending issue with renewed importance in cases of individualized dialysis schedules and of portable home dialysis machines with low‐flow dialysate. Direct measurement of calcium mass transfer is complex and is imprecisely reflected by differences in start‐to‐end of dialysis Ca levels. The study was performed in a dialysis unit dedicated to home hemodialysis and to critical patients with wide use of daily and tailored schedules. The Ca‐phosphate (P)‐parathyroid hormone (PTH) profile includes creatinine, urea, total and ionized Ca, albumin, sodium, potassium, P, PTH levels at start, mid, and end of dialysis. “Severe” secondary hyperparathyroidism was defined as PTH > 300 pg/mL for ≥3 months. Four schedules were tested: conventional dialysis (polysulfone dialyzer 1.8–2.1 m²), with dialysate Ca 1.5 or 1.75 mmol/L, NxStage (Ca 1.5 mmol/L), and NxStage plus intradialytic Ca infusion. Dosages of vitamin D, calcium, phosphate binders, and Ca mimetic agents were adjusted monthly. Eighty Ca‐P‐PTH profiles were collected in 12 patients. Serum phosphate was efficiently reduced by all techniques. No differences in start‐to‐end PTH and Ca levels on dialysis were observed in patients with PTH levels < 300 pg/mL. Conversely, Ca levels in “severe” secondary hyperparathyroid patients significantly increased and PTH decreased during dialysis on all schedules except on Nxstage (P < 0.05). Our data support the need for tailored dialysate Ca content, even on “low‐flow” daily home dialysis, in “severe” secondary hyperparathyroid patients in order to increase the therapeutic potentials of the new dialysis techniques.     

Marked improvement in bone metabolism parameters after increasing the dialysate calcium concentration from 2.5 to 3 mEq/L in nonhypercalcemic hemodialysis patients

The optimal dialysate calcium (Ca) concentration for hemodialysis (HD) patients is set at 2.5 mEq/L according to Kidney Disease Outcomes Quality Initiative (K-DOQI) guidelines. This recommendation is opinion-based and could negatively affect secondary hyperparathyroidism. Studies have suggested that a dialysate Ca of 3.0 mEq/L is a compromise between bone protection and cardiovascular risk. The aim of our study was to investigate the effect on bone metabolism parameters after increasing the dialysate Ca concentration from 2.5 to 3.0 mEq/L. The dialysate Ca concentration in our patients was increased from 2.5 to 3.0 mEq/L. Patients with hypercalcemia, normal-high Ca levels with a high Ca-Phosphorus product (Ca x P), excessively suppressed parathyroid hormone (PTH), or a past medical history of calciphylaxis were excluded. Twenty-two patients were studied over 20 weeks. Parathyroid hormone levels decreased significantly (442 +/- 254 vs. 255 +/- 226 pg/mL; p=0.000), without significant changes in serum Ca, P, and Ca x P levels at any sampling point. Better control of secondary hyperparathyroidism allowed us to decrease the paracalcitol dosage in 6 of the 12 patients who had been treated with this drug at the beginning of the study. Other potential factors involved in PTH secretion were not modified. A significant improvement in the rate of patients with 3 or more K-DOQI parameters within the target ranges (8 [36%] vs. 12 [55%]; p=0.026) was observed. In the absence of hypercalcemia or excessively suppressed PTH, an increase from 2.5 mEq to 3.0 mEq/L in dialysate Ca concentration resulted in better control of secondary hyperparathyroidism without affecting Ca, P, and Ca x P levels, thus enabling us to reduce the dosage of vitamin D metabolites.     

Doppler echocardiograph evaluation of pulmonary hypertension in patients undergoing hemodialysis

Pulmonary hypertension (PH) has been reported in hemodialysis (HD) patients, but data regarding its incidence and mechanisms are scarce. The aims of this study was to evaluate the prevalence of unexplained PH in long-term HD patients, and to examine some possible etiologic factors for its occurrence. The prevalence of PH was estimated by Doppler echocardiography in a cohort of 86 stable patients on HD via arteriovenous access for more than 12 months. All the patients underwent full clinical evaluation, chest radiography, and a standard 12-lead echocardiograph. Laboratory investigation included a mean of 12 months (serum calcium, phosphorus, parathormone (PTH), alkaline phosphatase, lipids, and hemoglobin). Pulmonary hypertension was defined as pulmonary artery systolic pressure >35 mmHg as determined by Doppler echocardiography using the modified Bernoulli equation. Pulmonary hypertension was detected in 23 patients (26.74%). Of those with PH, left ventricular hypertrophy was seen in 13 patients (56.52%), and valvular calcifications in 6 patients (26.08%). There were no significant differences between both groups with regard to age, sex, duration of dialysis, shunt location, and all the biological parameters of the study. The presence of PH was not related to the level of PTH, or the severity of other metabolic abnormalities. This study demonstrates a high prevalence of PH among patients with ESRD receiving long-term HD via surgical arteriovenous access. The role of the vascular access, anemia, or secondary hyperparathyroidism as the etiology of PH in HD patients did not hold in this study.     

Clinical Experiences Calcium and phosphate balance in children on home nocturnal hemodialysis (NHD)

Objective: To evaluate and describe biochemical indices of bone metabolism in 4 children on NHD. Method: The children, aged 12, 13, 14, and 16 yrs, have been treated exclusively on NHD for 6, 9, 9, and 15 mos. Subsequently, Pt 1 converted to a hybrid program of 4 nights on home nocturnal plus 1 session of in center conventional HD per week. Biochemical indices of bone metabolism have been collected prospectively. Results: All baseline pre‐dialysis calcium levels were within normal ranges and each patient was started on a dialysis calcium concentration of 3.0 mEq/L. However, over time the number of asymptomatic biochemical hypocalcaemic episodes increased. The dialysate calcium concentration was increased to 3.5 mEq/L in one and decreased to 2.0 mEq/L in another who was hypercalcemic and receiving concurrent calcitonin for bone pain related to osteoporosis. In Pt 1, the dialysate calcium was increased to 3.5 mEq/L during nocturnal and continued on hybrid therapy. Including an evaluation of dietary intake, all 4 patients had a net positive calcium balance, ranging between 9.8 to 23.5 mmol (393–942 mg). A significant reduction in the predialysis phosphate level was observed in all 4 patients, and none required dietary restrictions or the use of phosphate binders within 2 months or vitamin D within 6 months of HND. In addition, phosphate was added to provide a dialysate concentration of 2.4–6.1 mEq/L to prevent hypophosphatemia. This is reflected by significant reductions in intact PTH levels to the desired range (twice the normal range) in all 4, but the level continued to drop to the normal range and below in 2. In Pt 1, after introduction of hybrid therapy, both levels of phosphate and PTH rose, necessitating recommencement of phosphate binders and vitamin D. Likewise, the (Ca × PO₄) dropped and remained <55 in all 4 patients exclusively on NHD, but started to climb in Pt 1 during hybrid therapy. Conclusion: In our cohort of patients, NHD rapidly lowered plasma phosphate and PTH levels. With NHD, additional dialysate phosphate and possibly calcium may be necessary to prevent chronic losses and development of renal osteodystrophy, and caution is required to prevent either oversuppression of PTH and extraskeletal calcification.     

Treating mineral metabolism disorders in patients undergoing long hemodialysis: A search for an optimal strategy

In hemodialysis (HD) patients, mineral metabolism (MM) disorders have been associated with an increased mortality rate. We report the evolution of MM parameters in a stable HD population undergoing long hemodialysis by performing an annual cross-sectional analysis for every year from 1994 to 2008. The therapeutic strategy has changed: the dialysate calcium concentration has decreased from a mean of 1.7 ± 0.1 to 1.5 ± 0.07 mmol/L and has been adapted to parathyroid hormone serum levels (from 1 to 1.75 mmol/L). The use of calcium-based and aluminum-based phosphate binders has decreased and they have been replaced by sevelamer; alfacalcidol has partly been replaced by native vitamin D. The percentage of patients with a parathyroid hormone serum level between 150 and 300 pg/mL has increased from 9% to 67% (P<0.001); the percentage of patients with phosphataemia between 1.15 and 1.78 mmol/L has increased from 39% to 84% (P<0.001). The percentage of those with albumin-corrected calcemia between 2.1 and 2.37 mmol/L has increased from 29% to 61% (P<0.001), and that of patients with a calcium-phosphorous product (Ca × P) level >4.4 mmol/L decreased from 8.8% to 2% (P=0.02). Although patients undergo long and intensive HD treatment, MM disorders are common. However, an appropriate strategy, mostly consisting of native vitamin D supplementation, progressive replacement of calcium-based phosphate binders with non–calcium-based ones, and individualization of dialysis session duration and dialysate calcium concentration, would result in a drastic improvement.     

Dialysate calcium and calcium/phosphate balance in hemodialysis

The changing pattern of pharmaceutical use in dialysis patients has resulted in several alterations to dialysate calcium concentration over the past 40 years. Non‐calcium–containing phosphate binders and calcimimetics are the most recent examples of drugs that influence the overall calcium balance in dialysis patients. Renal osteodystrophy, vascular disease, and mortality are believed to be linked in patients with chronic kidney disease (CKD), although to date most of the evidence is based only on statistical associations. The precise pathophysiology of vascular calcification in end‐stage renal disease is unknown, but risk factors include age, hypertension, time on dialysis, and, most significantly, abnormalities in calcium and phosphate balance. Prospective studies are required before “cause and effect” can be established with certainty, but it is an active metabolic process with inhibitors and promoters. Serum calcium levels are clearly influenced by dialysate calcium and may therefore play an important role in influencing vascular calcification. Clinical management of hyperphosphatemia is being made easier by the introduction of potent non‐calcium–based oral phosphate binders such as lanthanum carbonate. Short‐term and long‐term studies have demonstrated its efficacy and safety. Vitamin D analogs have been a disappointment in the control of serum parathyroid hormone (PTH) levels, but evidence is emerging that vitamin D has other important metabolic effects apart from this, and may confer survival advantages to patients with CKD. Calcimimetics such as cinacalcet enable much more effective and precise control of PTH levels, but at the cost of a major financial burden. While it is unreasonable to expect that any one of these recent pharmacological developments will be a panacea, they provide researchers with the tools to begin to examine the complex interplay between calcium, phosphate, vitamin D, and PTH, such that further progress is fortunately inevitable.     

Aerobic exercise increases phosphate removal during hemodialysis: A controlled trial

Previous studies have suggested that exercise during hemodialysis (HD) could increase the efficacy of solute removal, although this hypothesis has not been conclusively evaluated. The goal of this study was to compare the removal of low‐molecular weight solutes between HD sessions, with and without aerobic exercise. It was a controlled clinical trial, including HD patients in a randomly cross‐over design, such that each patient received a HD session with exercise (intervention) and the next one without exercise (control), three times each. In the exercise sessions, patients pedaled on a cycle ergometer for 60 minutes. The total mass of removed urea, potassium, creatinine, and phosphate were calculated from the solutes concentration in dialysate (continuous spent sampling of dialysate). This was evaluated in a total of 132 HD sessions of patients with a mean age of 54 ± 15 years, 75% male and HD vintage of 3 (2–13) years. Phosphate removal in dialysate during intervention sessions was significantly higher (5.6 [2.5–18.9] vs. 5.1 [1.5–11.2] mg/min) than during control sessions, P = 0.04. The median mass of phosphate removed during control HD session was 1226 (367.8–2697.2) vs. 1348.6 (613.0–4536.2) mg/session during intervention sessions. The exercise did not modify the removal of urea (control 122.6 [61.3–286.0] vs. exercise 112.4 [51.1–250.3] mg/min, P = 0.44), creatinine (control 5.6 [2.5–13.8] vs. exercise 5.6 [2.5–12.8] mg/min, P = 0.49), or potassium (control 13.3 [11.2–15.8] vs. exercise 13.8 [6.6–15.8] mEq/min, P = 0.49). Aerobic exercise during HD increases the efficacy of phosphate removal, without changing urea, creatinine and potassium removal. The implications of this finding in mineral and bone disease and cardiovascular disease need to be evaluated on future clinical trials.     

Dialysate saving by automated control of flow rates: comparison between individualized online hemodiafiltration and standard hemodialysis

Cost reduction and quality improvement seem to be conflicting issues. However, online hemodiafiltration (oHDF) with new automatic functions offers a cost‐efficient therapy compared to hemodialysis (HD). Seven dialysis centers conducted a randomized clinical trial with cross‐over design: high‐flux HD vs. postdilutional oHDF with functions coupling both dialysate and substitution flow rates to blood flow rates. During the 6 weeks of the study, all treatment parameters remained unchanged for HD and oHDF, apart from dialysate and substitution flow rate. Treatment data were recorded during each treatment, and predialytic and postdialytic concentrations of urea were recorded at the end of each study phase. The analysis involved 956 treatments of 54 patients. The mean dialysate consumption was 123.2 ± 6.4 l for HD and 113.4 ± 14.9 l for oHDF (p < 0.0001), the mean dialysis dose was 1.42 ± 0.23 for HD and 1.47 ± 0.26 for oHDF (p < 0.0001); oHDF resulted in a lower dialysate consumption (8.0% less) and a slightly increased dialysis dose (Kt/V 3.5% higher) compared to HD. oHDF with the investigated automatic functions offers substantial savings in dialysate consumption without decreasing dialysis dose.     

Switch from calcitriol to paricalcitol in secondary hyperparathyroidism of hemodialysis patients: Responsiveness is related to parathyroid gland size

Paricalcitol is more effective than calcitriol in hemodialysis patients (HD) with secondary hyperparathyroidism (SHPT), but it is not effective in some of them. We have investigated the relationship between paricalcitol responsiveness and parathyroid gland (PTG) size. Thirty HD with SHPT treated previously with calcitriol for at least 6 months were switched to paricalcitol (1:4 conversion ratio). Parathyroid gland number and size (maximum longitudinal diameter [MLD] of largest PTG) was measured by ultrasonography. Patients were divided into 2 groups: group A (MLD ≤9.0 mm [17 HD]); and group B (MLD >9.0 mm [13 HD]). They were defined responder if both the last 2 monthly determinations of inhibit parathyroid hormone (iPTH) were within the target (<300 pg/mL) according to National Kidney Foundation Kidney Disease Outcomes Quality Initiative recommendations. Twenty‐six and 20 HD completed 6‐month and 12‐month paricalcitol therapy, respectively. After 6 months of paricalcitol treatment, 23.5% HD of group A and 7.7% of group B were responders. At 12 months, 41.2 % of group A and 7.7% of group B were responders. Throughout paricalcitol therapy, serum calcium and phosphorus concentrations slightly increased in all HD but more significantly in group B. The baseline iPTH and MLD of the largest PTG were significantly correlated with final iPTH levels. Paricalcitol is more effective than calcitriol in SHPT, but the responsiveness to paricalcitol and hypercalcemia are related to PTG size. The measurement of MLD by ultrasonography may be useful for predicting responsiveness to paricalcitol, avoiding an unnecessary and expensive therapy.     

Calcium phosphate metabolism and bone mineral density with nocturnal hemodialysis

An elevated calcium x phosphate product (Ca x P) is an independent risk factor for vascular calcification and cardiovascular death in dialysis patients. More physiological dialysis in patients undergoing nocturnal hemodialysis (NHD) has been shown to produce biochemical advantages compared with conventional hemodialysis (CHD) including superior phosphate (P) control. Benefits of dialysate with greater calcium (Ca) concentration are also reported in NHD to prevent Ca depletion and subsequent hyperparathyroidism, but there are concerns that a higher dialysate Ca concentration may contribute to raised serum Ca levels and greater Ca x P and vascular disease. The NHD program at our unit has been established for 4 years, and we retrospectively analyzed Ca and P metabolism in patients undergoing NHD (8-9 h/night, 6 nights/week). Our cohort consists of 11 patients, mean age 49.3 years, who had been on NHD for a minimum of 12 months, mean 34.3 months. Commencement was with low-flux (LF) NHD and 1.5 mmol/L Ca dialysate concentration, with conversion to high-flux (HF) dialyzers after a period (mean duration 18.7 months). We compared predialysis serum albumin, intact parathyroid hormone, P, total corrected Ca, and Ca x P at baseline on CHD, after conversion to LF NHD and during HF NHD. We also prospectively measured bone mineral density (BMD) on all patients entering the NHD program. Bone densitometry (DEXA) scans were performed at baseline (on CHD) and yearly after commencement of NHD. With the introduction of HF dialyzers, the Ca dialysate concentration was concurrently raised to 1.75 mmol/L after demonstration on DEXA scans of worsening osteopenia. Analysis of BMD, for all parameters, revealed a decrease over the first 12 to 24 months (N = 11). When the dialysate Ca bath was increased, the median T and Z scores subsequently increased (data at 3 years, N = 6). The mean predialysis P levels were significantly lower on LF NHD vs. CHD (1.51 vs. 1.77 mmol/L, p = 0.014), while on HF NHD P was lower again (1.33 mmol/L, p = 0.001 vs. CHD). Predialysis Ca levels decreased with conversion from CHD to LF NHD (2.58 vs. 2.47 mmol/L, p = 0.018) using a 1.5 mmol/L dialysate Ca concentration. The mean Ca x P on CHD was 4.56 compared with a significant reduction of 3.74 on LF NHD (p = 0.006) and 3.28 on HF NHD (p = 0.001 vs. CHD), despite the higher dialysate Ca in the latter. We conclude that an elevated dialysate Ca concentration is required to prevent osteopenia. With concerns that prolonged higher Ca levels contribute to increased cardiovascular mortality, the optimal Ca dialysate bath is still unknown. Better P control on NHD, however, reduces the overall Ca x P, despite the increased Ca concentration, therefore reducing the risk of vascular calcification.     

Phosphate removal model: an observational study of low-flux dialyzers in conventional hemodialysis therapy

Precise assessing phosphate removal by hemodialysis (HD) is important to improve phosphate control in patients on maintenance HD. We reported a simple noninvasive model to estimate phosphate removal within a 4‐hour HD. One hundred sixty‐five patients who underwent HD 4 hours per session using low‐flux dialyzers made of polysulfone (1.2 m²) or triacetate (1.3 m²) were enrolled. Blood flows varied from 180 to 300 mL/min. Effluent dialysate samples were collected during the 4‐hour HD treatment to measure the total phosphate removal. Predialysis levels of serum phosphate, potassium, hematocrit, intact parathyroid hormone, total carbon dioxide (TCO₂), alkaline phosphatase, clinical and dialysis characteristics were obtained. One hundred thirty‐five observations were randomly selected for model building and the remaining 30 for model validation. Total amount of phosphate removal within the 4‐hour HD was mostly 15–30 mmol. A primary model (model 1) predicting total phosphate removal was Tpo₄ = 79.6 × C₄₅ (mmol/L) ? 0.023 × age (years) + 0.065 × weight (kg) ? 0.12 × TCO₂ (mmol/L) + 0.05 × clearance (mL/min) ? 3.44, where C₄₅ was phosphate concentration in spent dialysate measured at the 45 minute of HD and clearance was phosphate clearance of dialyzer in vitro conditions offered by manufacturer's data sheet. Since the parameter TCO₂ needed serum sample for measurement, we further derived a noninvasive model (model 2):Tpo₄ = 80.3 × C₄₅ ? 0.024 × age + 0.07 × weight + 0.06 × clearance ? 8.14. Coefficient of determination, root mean square error, and residual plots showed the appropriateness of two models. Model validation further suggested good and similar predictive ability of them. This study derived a noninvasive model to predict phosphate removal. It applies to patients treated by 4‐hour HD under similar conditions.     

Citrate vs. acetate dialysate on intradialytic heparin dose: A double blind randomized crossover study

Introduction Citrate containing dialysate has a calcium‐binding anticoagulant effect compared to standard acetic acid containing dialysate. We performed a randomized, double‐blind, crossover trial in maintenance HD patients to determine if citrate dialysate (“citrate”) safely allows for a lower cumulative heparin dose (“heparin dose”). Methods Intradialytic heparin was adjusted to the minimum during a 2‐week run‐in phase. Patients remaining on heparin at the end of the run‐in phase were then randomized to two weeks of HD with acetate dialysate (“acetate”) followed by two weeks of citrate (sequence 1) or two weeks of citrate followed by two weeks of acetate (sequence 2). We estimated a minimum of 14 patients are required to show a 30% reduction in heparin dose per HD session with citrate compared with acetate. Twenty‐five patients entered the run‐in phase, 20 were randomized, and 19 completed the study. Findings The mean heparin dose was reduced by 19% (656 units, 95% CI ?174 to ?1139 units, P = 0.011) in the acetate group, and 30% (1046 units 95% CI ?498 to 1594 units, P < 0.001) in the citrate group. There was no difference in the mean heparin dose reduction between the two dialysates (P > 0.05). The intradialytic ionized calcium in the citrate group was lowered by 0.10 mmol/L (95% CI 0.07 to 0.14 mmol/L, P < 0.001), and remained unchanged in the acetate group. Discussion Although citrate is a safe alternative to acetate, it does not result in additional heparin dose reduction.     

Fibromyalgia: its prevalence and impact on the quality of life on a hemodialyzed population

Fibromyalgia syndrome (FMS) is characterized by widespread musculoskeletal pain. It has negative effects on quality of life and has been poorly investigated in specific populations. Our aim was to determine the prevalence of FMS in Brazilian hemodialysis (HD) patients and to investigate its effects on the quality of life. We investigated 311 patients on HD who were submitted to physical examination towards the classification of FMS. All subjects from FMS and control groups were submitted to laboratorial investigation and completed questionnaires of quality of life. The prevalence of FMS was 3.9%, which was close to that of the general population. Most patients were females and from non-Caucasian races. No difference between FMS and control groups was observed regarding race, dialysis adequacy, nutritional status and level of schooling. Ionized calcium was higher in the FMS group than in the control group. There was no association between FMS and secondary hyperparathyroidism. On the other hand, FMS was associated with worse quality of life, depression and anxiety. In conclusion, the prevalence of FMS in HD patients was similar to that of the general population. It was associated with decreasing quality of life in HD patients, in addition to higher degrees of depression and anxiety. No laboratory tests could identify FMS patients on HD. Fibromyalgia syndrome subsequently follows without a well-established mechanism of pathogenesis, and seems to be due to multifactorial causes. Its true impact on the quality of life of HD patients deserves more attention by nephrologists.     

Overview of clinical studies in hemodiafiltration: What do we need now ?

Despite several technical advances in dialysis treatment modalities and a better patient care management including correction of anemia, suppression of secondary hyperparathyroidism, lipid and oxidative stress profiles improvement, the morbidity and the mortality of dialysis patients still remain still elevated. Recent prospective interventional trials in hemodialysis (HEMO study and 4D study) were not very conclusive in showing any significant improvement in dialysis patient outcomes. High-efficiency convective therapies, such as online hemodiafiltration (HDF), are claimed to be superior to conventional diffusive hemodialysis (HD) in improving the dialysis efficacy and in reducing intradialytic morbidity and all-cause and cardiovascular mortality in dialysis patients. The aim of this report was, first, to review the evidence-based facts tending to prove the superiority of HDF vs. HD in terms of efficacy and tolerance, and, second, to analyze the needs to prove the clinical superiority of HDF in terms of reducing morbidity and all-cause mortality of dialysis patients. A systematic review of studies comparing HDF and HD has been performed in the microbiological safety of online production, the solute removal capacity of small and medium-size uremic toxins, and its implication in the reduction of the bioactive dialysis system vs. patient interaction. Major planned randomized international studies comparing HDF and HD in terms of morbidity and mortality have been reviewed. To conclude, it is thought that these long-term prospective randomized trials will clarify on a scientific evidence-based level the putative beneficial role of high-efficiency HDF modalities on dialysis patient outcomes.     

Parathyroidectomized patients have impaired capacity of peripheral vascular constriction during hemodialysis

Parathyroidectomy (PTx) seems to improve cardiovascular outcomes and reduce blood pressure levels. However, the effect of PTx on hemodynamic changes during hemodialysis (HD) is still overlooked. This was a prospective cohort design. Patients with end‐stage renal disease on maintenance HD were included. Diabetes and nonsinusal rhythm were exclusion criteria. History of PTx was recorded. Finometer monitor was used to access parameters immediately pre‐ and post‐HD sessions. Cardiac index (CI) variation (ΔCI) and peripheral arterial resistance variation (ΔPAR) were the variables of interest. Biochemical and echocardiographic data were also obtained. PTx patients (n = 11) were matched to non‐PTx patients (n = 20). ΔPAR was lower in PTx group in comparison with non‐PTx group (P = 0.039), which was independent of parathyroid hormone (PTH) levels. Multiple regression analysis showed that PTx, ΔCI, and dialysate calcium remained independently associated with PAR variation and even adjusted for ultrafiltration rate (adjusted r² = 0.64). In conclusion, parathyroidectomized patients have impaired capacity of vasoconstriction in response to ultrafiltration, an effect independent of serum PTH levels. Further studies are needed to elucidate mechanisms explaining the interaction between PTx and systemic vascular tonus.     

Successful management of severe hyponatremia in CKD‐VD: In a cost limited setting

Patients with end stage renal disease (ESRD) and severe hyponatremia always pose a challenge to manage. It is necessary to correct biochemical parameters, advanced azotemia, and fluid overload with conventional haemodialysis (HD) but it may correct serum sodium (Na) rapidly resulting in neurological complications like seizures and osmotic demyelination syndrome. Continuous renal replacement therapy (CRRT) is an ideal modality to manage such patients. However, most of the centers in the developing or underdeveloped nations do not have CRRT facility. We present two cases of ESRD, who had advanced azotemia requiring dialysis, also had persistent vomiting and severe hyponatremia (one with Na 107, another with Na 109 mEq/L), both cases were managed with conventional HD using dialysate Na concentration of 128 mEq/L (lowest permissible level of Na in a traditional HD machine) and keeping the blood flow of 50 mL/min. The serum Na increased by 1 mEq/L/h during first HD session, during the next session blood flow increased to 100 mL/min, and serum Na increased by two mEq/L/h. At the end of 48 hours, we were able to successfully correct serum Na by 18 mEq/L, with complete resolution of uremic manifestations and no neurological deficits. The current reports highlight management of hyponatremia in newly diagnosed ESRD in a cost limited setting.     

Cervical tumoral calcinosis with secondary hyperparathyroidism in a chronic hemodialysis patient

Tumoral calcinosis is an uncommon and severe complication of chronic renal failure. It is generally associated with the presence of a high‐serum calcium‐and‐phosphorus product. We report here a case of a patient on maintenance hemodialysis who presented with progressively increasing, solitary, tumor‐like swelling over the nape of the neck. A 50‐year‐old female on thrice weekly maintenance hemodialysis for the last 3 years presented with a small swelling over the nape of the neck that had been progressively increasing over the last 1 year to cricket ball size. The patient was investigated and diagnosed as having tumoral calcinosis. The metastatic calcification occurring in the patient was most likely related to high calcium × phosphate product with coexistent secondary hyperparathyroidism possibly aggravated by vitamin D therapy. The patient was treated with withdrawal of vitamin D therapy, strict control of serum phosphate levels with noncalcemic phosphate binders, and subtotal parathyroidectomy. The neck swelling started decreasing in size after 2 months of parathyroidectomy and there was marked clinical improvement with drop in serum parathormone levels, over a period of 6 months. After 2 years of parathyroidectomy, the neck swelling again started increasing in size with increase in serum parathormone levels. The patient was treated with cinacalcet and the neck swelling gradually decreased in size along with control of serum parathormone and phosphate levels.     

Uremic pleuritis in chronic hemodialysis patients

Chronic hemodialysis (HD) patients are predisposed to several complications associated with pleural effusion. In addition, uremia can directly cause pleuritis. However, there are inadequate data about pathogenesis and natural course of uremic pleuritis. In this study, 76 chronic HD patients with pleural effusion admitted to the Respiratory Center of Masih Daneshvari Hospital, in Tehran, Iran between June 2005 and May 2011 were evaluated to figure out the etiology of their pleural disease. Among these patients, patients with uremic pleuritis were identified and studied. The rate of uremic pleuritis was 23.7%. Other frequent etiologies of pleural effusion were parapneumonic effusion (23.7%), cardiac failure (19.7%), tuberculosis (6.6%), volume overload, malignancy, and unknown. In patients with uremic pleuritis, dyspnea was the most common symptom, followed by cough, weight loss, anorexia, chest pain, and fever. Compared to patients with parapneumonic effusion, patients with uremic effusion had a significantly higher rate of dyspnea and lower rate of cough and fever. Pleural fluid analysis showed that these patients had a significantly lower pleural to serum lactic dehydrogenase ratio, total pleural leukocytes, and polymorphonuclear count compared to patients with parapneumonic effusion. Improvement was achieved in 94.1% of patients with uremic pleuritis by continuation of HD, chest tube insertion or pleural decortication; an outcome better than the previous reports. Despite the association with an exudative effusion, inflammatory pleural reactions in patients with uremic pleuritis may not be as severe as infection‐induced effusions. Owing to the advancement in HD technology and other interventions, outcome of uremic pleuritis may be improved.