José Abrão Cardeal da Costa

Acute Renal Failure and Hypercalcemia

Hypercalcemia can result from excessive bone resorption, renal calcium retention, excessive intestinal calcium absorption, or a combination of these conditions. Hypercalcemia may also provoke acute renal failure (ARF) or hypertension, or aggravate the tubular necrosis that is frequently found in cases of ARF. The association of ARF and hypercalcemia was studied retrospectively in eight patients based in the data in their charts. Data are expressed as median and percentile (25th; 75th). Our results show that ARF associated with hypercalcemia was related with comorbidity in all cases (cancer, multiple myeloma, hyperparathyroidism, sarcoidosis, vitamin D intoxication, and leprosy). Maximum median serum creatinine levels were 3.3 mg/dL (2.7, 3.8 mg/dL) before treatment and 1.1 mg/dL (0.9, 1.3 mg/dL) after treatment. Maximum total median serum calcium was 15.9 mg/dL (13.5, 19.8 mg/dL) before treatment and 9.1 mg/dL (8.4, 9.7 mg/dL) after treatment. Maximum median ionized serum calcium was 2.1 mmol/L (1.8, 2.2 mmol/L) before treatment and 1.1 mmol/L (1.0, 1.2 mmol/L) after treatment. Different kinds of treatment induced a rapid fall in serum calcium concentration. All patients were treated with hydration and diuretics, and three patients also received calcitonin. Serum creatinine concentration always fell simultaneously with the decrease in serum calcium in all cases. All patients progressed with nonoliguric renal failure. In conclusion, in ARF, patients are frequently hypocalcemic. Usually, the presence of hypercalcemia associated with ARF is indicative of the presence of comorbidity, as observed in all eight patients studied here. There was an improvement of renal function in all cases as serum calcium levels decreased.

Acute tubular necrosis in kidney transplant patients treated with enalapril.

We report two cases of acute renal failure in renal transplant patients using cyclosporine-A (CsA) after the introduction of angiotensin-converting enzyme inhibitor (ACEI) to control arterial hypertension. They had no renal artery stenosis or acute rejection. Both patients presented severe acute tubular necrosis (ATN), which subsided after discontinuation of the ACEI. Synergistic toxic effect of ACEI and CsA on the renal tubules might explain ATN in these two cases.

Total Nitrogen and Free Amino Acid Losses and Protein Calorie Malnutrition of Hemodialysis Patients: Do They Really Matter?’

Background/Aims: Protein calorie malnutrition (PCM) in patients on hemodialysis (HD) is multifactorial; however, HD per se induces nutrient losses. The aim of the present study was to characterize the losses of total nitrogen (TN) and free amino acids (FAs) through the dialysate and to determine the relationship between this loss and PCM, food ingestion, and the characteristics of the hemodialyzer in patients on HD. Methods: In a prospective study, 21 patients submitted to low-flux HD 3 times a week were evaluated within a period of 6 months regarding nutritional status, dietary calorie and protein intake, and losses through the dialysate of TN, FA, and urea nitrogen (UN). The type, surface area and reuses (up to 12) of the dialysis membrane were determined on each occasion, and the adequacy of dialysis was estimated by Kt/V. Results: 50% of the patients were considered malnourished, although the mean protein and energy intakes were similar for the malnourished and nourished patients. Mean TN losses through the dialysate were 16 g/session (60% UN). FA losses varied from 3.8 to 4.2 g/total volume. TN and FA in the dialysate did not differ significantly between malnourished and nourished patients. There was a positive correlation between membrane (polysulfone) area and TN (p <0.05) and ultrafiltrate volume and TN (p < 0.05), and a nonsignificant correlation between reuse of the dialysis membrane and TN. Conclusions: TN and FA losses through the dialysate were similar for malnourished and non-malnourished patients on chronic HD, thus they do not act as indicators of nutritional status impairment.

The Evaluation of Renal Osteodystrophy with Cortical Quantitative Ultrasound at Various Bone Sites

Background: In this study we evaluated bone abnormalities of patients with chronic renal failure (CRF) by cortical quantitative bone ultrasound (QUS) measurements at different bone sites because these abnormalities may be of variable etiology and may start before symptoms or radiological changes are manifested. Methods: Of fifteen patients with chronic renal failure, seven had moderate–severe disease and eight had been on chronic hemodialysis from 5 to 17 years, with renal osteodystrophy (ROD) confirmed by bone biopsies. Twelve normal subjects of similar age and gender volunteered for the control group. Results: Patients and controls differed in creatinine clearance, in serum phosphate levels and in serum total alkaline phosphatase. Mean intact‐PTH levels differed significantly amongst the three groups of subjects. All patients with ROD had intact‐PTH higher than 200 pg/mL. The cortical ultrasound parameter, speed of sound (SOS), was slower in patients with more severe renal failure at all bone sites measured. The group with ROD had significantly lower cortical ultrasound values than the other patients and the control group at all sites. SOS values at the proximal phalanx, distal radius and midtibial sites were positively and significantly correlated. Cortical ultrasound measurements at the radial site correlated with midtibial and phalangeal sites but the correlation between midtibial and phalangeal sites did not reach significance. IPTH levels correlated negatively and significantly with cortical QUS values at all sites being the correlations higher at phalangeal and radial sites than at the midtibial region. Conclusions: The differences in cortical ultrasound observed indicate the potential clinical application of this methodology to evaluate bone abnormalities in chronic renal failure, especially in patients on chronic hemodialysis.

Arteriovenous Fistula Puncture: An Essential Factor for Hemodialysis Efficiency

Objective. To determine the blood recirculation ratio in the vascular access of patients on hemodialysis, and to calculate the Kt/Vs obtained with the different techniques of arteriovenous fistula punctures. Materials and Methods. A total of 174 patients were divided according to the technique used for arteriovenous fistula puncture: group 1, needles in opposite directions and with a distance of 5 cm or more between them; group 2, needles in opposite directions but with a distance of less than 5 cm; group 3, unidirectional needles with both directed to the heart and with a distance of 5 cm or more; group 4, unidirectional needles but separated by a distance of less than 5 cm between needles; and group 5, patients carrying a temporary venous catheter. Blood samples were collected for urea analysis, pre and post-dialysis for Kt/V rate, and other samples for calculation of the access recirculation. Results. Group 1 presented the lowest rate of access recirculation (8.51 ± 4.90%) and the best Kt/V (1.71 ± 0.36), while group 4 presented the worst access recirculation (20.68 ± 4.92%) and Kt/V (1.16 ± 0.26). All groups differed significantly from group 4 (p < 0.05), except group 5 with regard for Kt/V parameter. Discussion. The technique of arteriovenous fistula puncture is an essential factor to decrease the access recirculation and assure better results of measurement of hemodialysis adequacy. On the basis of the results obtained, insertion of the needles in the same direction and with a distance of less than 5 cm between them should be avoided.

Increase in BMI Over Time Is Associated With Fluid Overload and Signs of Wasting in Incident Peritoneal Dialysis Patients

OBJECTIVES Peritoneal dialysis (PD) patients may suffer changes in nutritional status after starting PD. Several markers can be used to evaluate these modifications, such as body mass index (BMI), serum albumin, and serum creatinine. Fluid overload should be considered because it can overestimate or underestimate nutritional status. The objective of this study was to evaluate the BMI changes over time in incident PD patients and identify interactions among BMI, signs of fluid overload, serum albumin, and serum creatinine. DESIGN The study included a cohort of 1,997 incident PD patients of the BRAZPD recruited from 2004 to 2007. Sociodemographic data and BMI classification were obtained at baseline. The evolutions of BMI and body weight were assessed over a period of 29 months. Changes in the evolution were analyzed when a patient presented with albumin < 3.8 g/dL, creatinine < 7.0 mg/dL, or the presence of edema. Data analysis was performed using linear mixed-effects regression models as the main statistical procedure. RESULTS BMI increased over time (29 months) by an average of 0.05 kg/m(2) per month, and body weight increased by 0.11 kg/month for a total increase of 3.08 kg. BMI decreased by 0.12 kg/m(2) in the presence of albumin < 3.8 g/dL and by 0.38 kg/m(2) in the presence of creatinine < 7.0 mg/dL. BMI increased by 0.61 kg/m(2) in the presence of edema. BMI increased in the presence of edema and albumin < 3.8 mg/dL or edema and creatinine < 7.0 mg/dL. CONCLUSIONS There is a mean increase in the BMI of incident PD patients over time, and these changes may be, at least partly, due to fluid overload, leading to distortions of body weight. When the patients presented with lower serum albumin or creatinine levels, the BMI values were reduced, suggesting that a reduction in lean mass and an increase in fat mass may be occurring in these patients.

Study of Protein Oxidative Stress, Antioxidant Vitamins and Inflammation in Patients Undergoing either Hemodialysis or Peritoneal Dialysis

BACKGROUND The influence of dialysis modality on oxidative stress (OS) and inflammation is not yet clear. Elucidating this influence could provide novel therapy concepts for cardiovascular diseases. AIM To compare protein OS, antioxidant vitamins and inflammation in patients undergoing either hemodialysis (HD) or peritoneal dialysis (PD). METHODS A cross-sectional study was performed with 19 PD and 21 HD patients treated for ≥ 6 months. The control group was composed of 17 healthy individuals. Advanced oxidation protein products (AOPP), advanced glycation end products (AGEs), vitamins C, A and E, C-reactive protein and interleukin 6 were measured in plasma samples. RESULTS OS was higher in the dialysis group when compared with controls, but HD patients showed higher AOPP compared with PD (HD:141.9 ± 75.2 µmol/L; PD: 112.5 ± 69.3 µmol/L, P< 0.01) and AGEs (HD: 32.2 ± 10.6 AU x10³; PD: 26.6 ± 4.9 AUx10³, P< 0.05). There was no difference in inflammation and vitamin levels among dialysis patients. In HD patients, AGEs correlated moderately with serum vitamin C (r = 0.46; P< 0.05). CONCLUSION The dialysis modality adopted influences protein OS, but it has no effect on antioxidant status or inflammation. Hemodialysis probably exacerbates OS due to the increased bioincompatibility of the dialysis procedure, and this scenario seems to be related to the intravenous supplementation of vitamin C. Peritoneal dialysis allows for a better oxidative balance, which may reduce cardiovascular risk.

The Role of Nutrition and Supplementation in Dialysis Patient Health: Specific Nutritional Recommendations and Evidence of the Functional Effects of Food and Supplements in the Health of Chronic Kidney-Disease Patients on Dialysis

Chronic kidney disease (CKD) is a public health problem that affects millions of people throughout the world. Advanced stage CKD patients require dialysis and a specific diet to control the disease and maintain a good nutritional status. Several studies were conducted to determine the nutrient recommendation values for this population. However, there are still few studies that have investigated the functional effects of foods and supplements in patients with CKD. Researchers have associated the use of functional supplements, such as omega-3, vitamins E and D, conjugated linoleic acid (CLA), polyphenols, l -carnitine, creatine, prebiotics, and probiotics, with decreased inflammatory markers, increased antioxidant defenses, and clinical and nutritional improvement in CKD patients. The findings from a single study or even from many studies regarding the functional effects of some elements in the CDK should be interpreted cautiously. Further investigation is needed to confirm the benefits of these foods and supplements and, thereafter, to safely recommend them in clinical practice.