Prevention of nephropathy in patients with type 2 diabetes mellitus

The rising incidence of type 2 diabetes mellitus and of its complications will make it the most important health care challenge in the first quarter of the 21st Century. Diabetic nephropathy left unchecked will overwhelm the renal resources. Simple methods (proper diet and exercise, prevention of obesity) are successful in preventing type 2 diabetes in the great majority of the persons at risk. In patients with established type 2 diabetes, nephropathy can be prevented or greatly delayed by strict metabolic control, strict control of blood pressure using angiotensin-converting enzyme inhibitors and angiotensin receptor blockers as the first line of drugs, tight control of serum lipids using statins as indicated, low protein diet, avoidance of smoking and other nephrotoxic influences, prevention of abnormalities in calcium/phosphorus metabolism, and prevention of renal anemia by the early use of erythropoietin. Current research offers the promise of definitive prevention of both type 2 diabetes and diabetic nephropathy.

Association between calciphylaxis and inflammation in two patients on chronic dialysis

The pathogenesis of calciphylaxis, which has a rising incidence in the chronic dialysis population and a high mortality rate, is poorly understood. Abnormalities in the calcium-phosphorus-parathyroid axis are clinically related to calciphylaxis, but alone, they cannot explain this condition. Here, we present two patients who had chronic inflammatory conditions and hyperparathyroidism and who developed calciphylaxis. A 41-year-old white woman on hemodialysis following scleroderma, hepatitis C, liver transplant, and failed kidney transplant, developed progressive ulcerative lower extremity calciphylaxis lasting more than 3 years. She had evidence of severe hyperparathyroidism and elevated serum C-reactive protein (CRP). A 39-year-old white woman on continuous ambulatory peritoneal dialysis for 6 years for renal failure secondary to lupus nephritis, with sustained lupus activity during the dialysis period, developed rapidly progressing ulcerative calciphylaxis of the lower and upper extremities not responding to adequate treatment of hyperphosphatemia and hyperparathyroidism. Her condition culminated in death within 2 months of the appearance of the skin lesions. Her serum CRP was elevated on a sustained basis before the development of the calciphylaxis and rose to a very high level after appearance of the skin lesions. Inflammation may assist in the development of calciphylaxis through depression of serum levels of fetuin-A, an endogenous inhibitor of calcification that is also a negative acute-phase reactant. The interactions between inflammation-mediated changes in the levels of endogenous inhibitors of calcification and abnormalities in calcium-phosphorus metabolism merit intensive study in the future as potential mechanisms of calciphylaxis.

Serum potassium and acid-base parameters in severe dialysis-associated hyperglycemia treated with insulin therapy

We analyzed the changes in serum potassium concentration ([K]) and acid-base parameters in 43 episodes of dialysis-associated hyperglycemia (serum glucose level > 33.3 mmol/L), 22 of which were characterized as diabetic ketoacidosis (DKA) and the remaining 21 as nonketotic hyperglycemia (NKH). All episodes were treated with insulin therapy only. Age, gender, initial and final serum values of glucose, sodium, chloride, tonicity and osmolality did not differ between DKA and NKH. At presentation, serum values of [K] (DKA 6.2 +/- 1.3 mmol/L; NKH 5.2 +/- 1.5 mmol/L) and anion gap [AG] (DKA 27.2 +/- 6.4 mEq/L; NKH 15.4 +/- 3.5 mEq/L) were higher in DKA, whereas serum total carbon dioxide content [TCO2 ] (DKA 12.0 +/- 4.6 mmol/L; NKH 22.5 +/- 3.1 mmol/L), arterial blood pH (DKA 7.15 +/- 0.09; NKH 7.43 +/- 0.07) and arterial blood PaCO2 (DKA 26.2 +/- 12.3 mm Hg; NKH 34.5 +/- 6.7 mm Hg) were higher in NKH. At the end of insulin treatment, serum values of [K] (DKA 4.0 +/- 0.7 mmol/L, NKH 4.0 +/- 0.5 mmol/L), [AG] (DKA 16.3 +/- 5.4 mEq/L, NKH 14.9 +/- 3.0 mEq/L), [TCO2 ] (DKA 23.5 +/- 5.0 mmol/L, NKH 24.1 +/- 4.2 mmol/L), arterial blood pH (DKA 7.42 +/- 0.09, NKH 7.51 +/- 0.14) and arterial blood PaCO2 (DKA 31.8 +/- 6.7 mm Hg, NKH 34.2 +/- 8.3 mm Hg) did not differ between the two groups. Linear regression of the decrease in serum [K] value during treatment, (Delta[K]), on the presenting serum [K] concentration,([K]2 ), was: DKA, Delta[K] = 2.78 - 0.81 x [K]2 , r = -0.85, p < 0.001; NKH, Delta[K] = 2.44 - 0.71 x [K]2 , r = -0.90, p < 0.001. The slopes of the regressions were not significantly different. Stepwise logistic regression including both DKA and NKH cases identified the presenting serum [K] level and the change in serum [TCO2 ] value during treatment as the predictors of Delta[K] (R2 = 0.81). Hyperkalemia is a feature of severe hyperglycemia (DKA or NKH) occurring in patients on dialysis. Insulin administration brings about correction of DKA and return of serum [K] concentration to the normal range in the majority of the hyperglycemic episodes without the need for other measures. The initial serum [K] value and the change in serum [TCO2 ] level during treatment influence the decrease in serum [K] value during treatment of dialysis-associated hyperglycemia with insulin.

Characteristics of end stage renal disease diabetic patients in two countries with different socioeconomic conditions

PURPOSE

To identify differences that may affect morbidity and mortality of type 2 diabetic patients reaching ESRD between countries with different socioeconomic conditions.

METHODS

Comparison of clinical and laboratory features between 21 Nigerian (N) and 57 American patients (A) reaching ESRD over a 30 month period.

RESULTS

Differences were noted in age at ESRD (N, 55.5+/-9.8; A, 64.5+/-9.6 years), duration of diabetes (N, 5.2+/-2.8, A: 14.9+/-4.9 years), body mass index (N, 24.5+/-4.1; A; 27.6+/-6.3 kg/m2), prevalence of left ventricular hypertrophy (N; 14%; A, 89%) and ischemic heart disease (N, 26%; A, 67%), blood pressure (N, [166.2+/-26.7]/[98.6+/-16.5] mmHg; A, [146.8+/-23.6]/[72.5+/-13.3] mmHg), creatinine clearance (N, 6.1+/-3.6; A, 14.8+/-3.5 ml/min), urine protein excretion (N, 1.2+/-0.7; A, 6.1+/-4.9 g/24-h), hematocrit (N, 28.0+/-6.0; A, 35.0+/-5.0%), serum glucose (N, 5.6+/-1.6; A, 10.5+/-5.5 mmol/l), and serum cholesterol (N, 5.32+/-2.57; A, 4.19+/-1.16 mmol/l) (all at P < or = 0.05). Differences were also found in the number of antihypertensive medications (N 1.4+/-0.6; A 2.4+/-1.2 per patient), and use of medications for diabetes (N 29%, A 79%), statins (N zero, A 61 %) and erythropoietin (N zero, A 39%). 72% of the A, but none of the N patients had a functional dialysis access prior to ESRD.

CONCLUSIONS

Between A and N patients reaching ESRD, there are differences in clinical features and laboratory values that may affect morbidity, mortality and impact on the health care resources. These differences indicate areas where further studies that could assist in the planning for ESRD care in both Nigeria and USA are required.

Osmotic Myelinolysis Following Chronic Hyponatremia Corrected at An Overall Rate Consistent with Current Recommendations

Rapid correction of chronic hyponatremia (CH) may lead to the development of osmotic myelinolysis (OM), a condition with high mortality and high incidence of devastating neurological sequelae. Treatment guidelines suggest "safe" overall rates of correction of serum sodium concentration ([Na](s)) over the first 24 and 48 hours of treatment of CH. We report a patient with CH who developed fatal OM despite overall rates of correction of [Na](s) that were within the recommended rates. The potential risk factors for the development of OM in this patient included short (within a few hours) rises in [Na](s) exceeding 0.5 mmol/l per hour and the presence of severe protein malnutrition. We suggest that the rate of correction of [Na](s) in CH should be uniformly slow and that the overall rate of correction should be slower than the currently recommended rate in severely malnourished patients.

Serum tonicity, extracellular volume and clinical manifestations in symptomatic dialysis-associated hyperglycemia treated only with insulin

The absence of osmotic diuresis modifies the effects of hyperglycemia on body fluids in patients with advanced renal failure. To determine the relationship between clinical manifestations and abnormalities in tonicity and extracellular volume in such patients, we analyzed 43 episodes of severe dialysis-associated hyperglycemia (serum glucose exceeding 600 mg/dL) treated only with insulin. The main manifestations were dyspnea in 22 cases (pulmonary edema in 19), nausea and vomiting in 15, coma in 13 and seizures in 3, while 5 patients had no symptoms. Treatment with insulin resulted in a decrease in serum glucose value from 913 +/- 197 mg/dL to 170 +/- 78 mg/dL, an increase in serum sodium level from 125 +/- 5 to 136 +/- 5 mmol/L, and a fall in calculated serum tonicity value from 300 +/- 13 to 282 +/- 11 mmol/kg (all at p < 0.001). The ratio of the change in serum sodium level over change in serum glucose concentration was -1.50 +/- 0.22 mmol/L per 100 mg/dL. The percent increase in extracellular volume secondary to hyperglycemia developing from the prior euglycemic state and calculated from changes in serum sodium and chloride concentrations, was 10.9% +/- 4.6% (1.5% +/- 0.6% per 100 mg/dL increase in serum glucose level). All clinical manifestations dissipated after correction of hyperglycemia in 42 patients. One woman developed during treatment a fatal myocardial infarction. Dialysis patients with severe hyperglycemia may develop symptoms as a result of hypertonicity and extracellular expansion. Insulin alone may be sufficient treatment for these symptoms. The changes in serum tonicity and electrolytes during treatment are consistent with theoretical predictions.

Lack of precision of indirect estimates of body water affects urea kinetic analysis in chronic peritoneal dialysis

To test the precision of estimates of body water and urea clearance in peritoneal dialysis (PD), we compared, in 925 PD patients who underwent formal urea kinetics studies, estimates of V and Kt/V urea obtained by the use of the Watson, Hume, and Sahlgrenska anthropometric formulas and two novel formulas, one (Vcreat) computed using fat-free mass (FFM) estimated from creatinine kinetics as 0.73 x FFMcreat, and the other (VBMI) calculated as 0.73 x FFM(BMI) where FFM(BMI) was obtained by the Gallagher formula, which estimates body composition as a function of body mass index (BMI). Comparisons by twos were performed using the paired t-test and the Wilcoxon sign rank test with the Bonferroni correction for multiple (n=10) comparisons. The results for V (liters) were Watson, 36.7 +/- 7.1; Hume, 37.3 +/- 7.3; Sahlgrenska, 36.8 +/- 7.6; Vcreat, 32.2 +/- 9.8; and VBMP 37.2 +/- 7.8. With the exception of V(BMI) and V(Hume) which did not differ, all other values differed (p < 0.001) from one another regardless of whether a parametric or nonparametric comparison was performed. The results for weekly total Kt/V urea were Watson, 2.05 +/- 0.57; Hume, 2.03 +/- 0.57; Sahlgrenska, 2.06 +/- 0.59; from Vcreat 2.42 +/- 0.71; and from V(BMP) 2.03 +/- 0.58. All of those values differed from one another (p < 0.001) by both methods of comparison. Using cut-off values (1.50, 1.75, and 2.00) as indices of adequate total weekly Kt/V urea, the discrepancies between any two estimates by the five studied formulas varied in the range 1.1% - 34.2%. Despite numerically close mean values, estimates of V based on various anthropometric formulas differ substantially and cause substantial discrepancies in the classification of Kt/V urea as inadequate or adequate. This lack of precision, added to the known lack of accuracy of the estimates, confounds the interpretation of the clinical relevance of urea kinetic estimates in PD.

Risk of extracellular volume expansion in long-term peritoneal dialysis

Although direct evidence is unavailable, indirect evidence strongly suggests that the risk of extracellular (EC) volume expansion increases with long-term peritoneal dialysis (PD). Long-term PD patients routinely develop loss of residual renal function (RRF) and often develop increased rates of peritoneal solute transport. Loss of RRF is associated with hypervolemia and increased risk of death. It is also indirectly linked both to development of high peritoneal transport (through the prescription of larger hypertonic dextrose loads) and to further limitations of peritoneal sodium removal [through automated PD (APD), which is often prescribed as a means of increasing peritoneal clearances as renal clearances decrease, and which causes, through its shortened dwell periods, low rates of peritoneal sodium removal]. High peritoneal solute transport limits peritoneal ultrafiltration and sodium removal; it is a recognized risk factor for hypervolemia. Many cross-sectional studies measuring EC volume have documented moderate to severe hypervolemia in large numbers of PD patients. In long-term PD, hypervolemia has severe consequences including morbidity and mortality. Preventing hypervolemia in PD patients requires a focus on maintaining sodium balance. The means include lowering the dialysate sodium concentration for APD exchanges, using icodextrin, and, primarily, reducing dietary sodium intake to a level determined by monitoring the patient's sodium removal rate in urine plus dialysate. Periodic measurements of sodium removal rates and appropriate adjustments of dietary sodium intake should be considered measures of adequacy in PD.

Serum potassium concentration in hyperglycemia of chronic dialysis

We analyzed abnormalities in serum potassium ([K]) in 40 episodes of diabetic ketoacidosis (DKA)--6 episodes in peritoneal dialysis (PD) and 34 episodes in hemodialysis (HD)--and in 245 episodes of nonketotic hyperglycemia (NKH)--70 episodes in PD and 175 episodes in HD. Serum glucose ([Glu]) was 25 mmol/L or higher in all episodes. We compared the PD and HD hyperglycemic episodes separately for DKA and NKH. For DKA, [Glu] was 55.5 + 4.8 mmol/L in PD and 51.9 +/- 12.2 mmol/L in HD [p = nonsignificant (NS)], and [K] was 6.4 +/- 1.5 mmol/L in PD and 6.3 +/- 1.1 mmol/L in HD (p=NS). Also for DKA, [K] was 5.5 mmol/L or higher in 4 episodes (66.7%) in PD and in 26 episodes (76.5%) in HD (p=NS), and 6.0 mmol/L or higher in 3 episodes (50.0%) in PD and in 22 (episodes 64.7%) in HD (p=NS). For NKH, [Glu] was 39.4 +/- 14.7 mmol/L in PD and 37.8 +/- 12.4 mmol/L in HD (p=NS), and [K] was 4.3 +/- 0.9 mmol/L in PD and 5.1 +/- 0.8 mmol/L in HD (p < 0.001). Also for NKH, [K] was 5.5 mmol/L or higher in 7 episodes (10.0%) in PD and in 55 episodes (31.4%) in HD (p < 0.001), and 6.0 mmol/L or higher in 4 episodes (5.7%) in PD and in 31 episodes (17.7%) in HD (p = 0.023). Serum sodium, tonicity, urea, osmolality, creatinine, chloride and anion gap, and arterial blood pH and partial pressure of carbon dioxide did not differ between PD and HDfor either DKA or NKH episodes, but serum total carbon dioxide content was lower in PD than in HD DKA episodes (6.5 + 3.8 mmol/L vs. 9.5 + 2.8 mmol/L, p = 0.038), and higher in PD than in HD NKH episodes (22.5 + 6.0 mmol/L vs. 20.9 + 4.4 mmol/L, p = 0.004). Although PD and HD DKA episodes appear not to differ in [K], the mean [K] and the frequency of hyperkalemia are both lower in PD than in HD NKH episodes. Differences between PD and HD in acid-base balance and, probably, in other factors affecting [K] (such as mineralocorticoid metabolism and blood levels) may account for the differences in [K] between PD and HD NKH episodes.

Severe proximal myopathy in advanced renal failure. Diagnosis and management

Myopathies encountered in uremic patients may have different pathogenetic mechanisms and treatment. Secondary hyperparathyroidism may cause uremic myopathy responding to specific treatment. This study aimed at presenting a case illustrative of the clinical features, diagnosis and management of uremic parathyroid myopathy. A 66-year old man with renal failure from membranous nephropathy developed sensory signs of uremic neuropathy and progressive painless weakness of the pelvic girdle muscles bilaterally. Motor nerve conduction velocity was normal, electromyogram was consistent with a myopathic pattern, while muscle biopsy showed a pattern of atrophy more consistent with a neuropathic pattern. Serological tests for collagen vascular diseases and hyperthyroidism were negative, while serum muscle enzymes were not elevated and serum phosphate levels were not low. Serum parathyroid hormone level was grossly elevated, while serum calcium was mildly elevated in a small fraction of the measurements, serum alkaline phosphatase showed a progressive rise and skeletal bone survey did not disclose osteopenia or signs of parathyroid bone disease. A course of calcitriol failed to improve the myopathy, which responded promptly and dramatically to parathyroidectomy. Uremic parathyroid myopathy, which has a characteristic clinical picture, must be differentiated from other neuropathic or myopathic conditions that require specific treatments. Progressive parathyroid myopathy is, by itself, an indication for parathyroidectomy, which is curative in this case.

Chronic hemodialysis in a Nigerian teaching hospital: practice and costs

The incidence of end-stage renal disease (ESRD) is on the rise in developing countries. To identify issues related to renal replacement therapy in ESRD patients in the developing world, we analyzed the practice and costs of hemodialysis in Nigerian ESRD patients. Ten ESRD patients were dialyzed at the Jos University Teaching Hospital, Jos, Plateau State, Nigeria, between June 15 and July 15, 2003. In these patients, we analyzed initiation, vascular access issues, frequency, duration, adequacy and economics of chronic hemodialysis. The Nigerian patients were referred to the nephrologist for the first time only when they had developed frank uremia. No patient had a permanent vascular access at the time dialysis was initiated. Only two patients had a functioning dialysis fistula, while the other eight patients were dialyzed through temporary femoral vein catheters that were removed after each dialysis. Frequency of dialysis was three times weekly in 2 patients, twice weekly in 1 patient and once weekly or less frequently in 7 patients. The duration of a dialysis session was prescribed to be 4 hours, but sessions often lasted for as long as 10 hours because of breakdowns of the antiquated dialysis machines. The urea reduction ratio was 45.3 +/- 8.6%. In every case, the cost of dialysis was borne by the patients and their families. Comparison of the cost of dialysis, with extensive re-use of supplies, to monthly incomes of Nigerians with different professions revealed that the great majority of Nigerians cannot afford three times weekly dialysis. Underdialysis in Nigerian ESRD patients is common and caused by socioeconomic factors and technologic deficits. One step towards correction of underdialysis could be sharing of the cost of dialysis by the public.

Neurological manifestations of uraemia and chronic dialysis

BACKGROUND

The management of uraemic neurological manifestations is a major target of the treatment of the uraemic syndrome. Chronic dialysis is associated with novel neurological manifestations.

OBJECTIVE

To describe the clinical characteristics, pathogenesis and management of the main neurological syndromes encountered in uraemia and chronic dialysis.

METHODS

Review of the pertinent literature. Selected references, which have been critical in the understanding of the topic, were included in this review.

RESULTS

The main neurological manifestations of uraemia include encephalopathy, neuropathy that can affect cranial, peripheral and autonomic nerves, and proximal myopathy. Retention of uraemic toxins is the main putative cause of uraemic encephalopathy and neuropathy. Arrest or prevention of uraemic encephalopathy and neuropathy are main targets of the dialytic treatment and constitute major criteria of its adequacy. The main cause of uraemic myopathy is secondary hyperparathyroidism and parathyroidectomy is its main treatment. Chronic dialysis is associated with three main neurological syndromes, the disequilibrium syndrome, seen usually in the first few haemodialysis sessions and prevented by starting dialysis with a low dose and progressively increasing the dialysis dose in subsequent dialysis sessions, dialysis dementia, which results from aluminium overloading and is prevented by reducing exposure of the dialysis patients to aluminium, and nerve entrapment, particularly carpal tunnel syndrome, which is caused by beta2-microglobulin amyloidosis and may be prevented by the use of high-flux dialysers which provide relatively high clearance for beta2-microglobulin or by daily haemodialysis.

CONCLUSIONS

Specific neurological manifestations are part of the uraemic syndrome and may complicate chronic dialysis. The diagnosis of these manifestations, their differentiation from other neurological syndromes that can complicate the course of renal failure or dialysis, and their specific treatment require clinical acumen and represent a major challenge for physicians treating patients with chronic renal failure or undergoing chronic dialysis.

Pyocystis in patients on chronic dialysis. A potentially misdiagnosed syndrome

Pyocystis is an important complication of non-functioning urinary bladder, which often poses diagnostic difficulties. We present a case of pyocystis in a patient on chronic hemodialysis who was anuric for one year. The patient was initially diagnosed with diverticulitis. An abdominal C-T scan suggested the diagnosis of pyocystis, which was confirmed by bladder catheterization. The patient was treated with bladder drainage and a prolonged antibiotic course, followed by intermittent saline washing of the bladder.

Obesity and patient survival in chronic dialysis

Obesity shortens survival in the general population. In hemodialysis (HD), obesity is associated with improved short-term survival (around 3 years). The discrepancy in the survival of obese patients between HD and the general population may be attributable to survival bias. (Only a small percentage of patients with renal failure survive until HD, and they may have certain survival advantages, including obesity.) Bias is introduced through the mixture of prevalent and incident HD patients in most studies, better nutrition in obese HD patients, malnutrition-inflammation complex syndrome causing weight loss, or other reasons. In studies of peritoneal dialysis (PD), obesity has been associated with decreased patient survival, no noticeable effect on survival, and increased survival. Potential reasons for the differences include bias in the selection of PD for obese patients, effects of race, chronic inflammation in obese PD patients, differences in nutrition and adequacy of PD, adverse effects of the increased PD dose needed to achieve adequate small-solute clearances, differences in body composition, and time discrepancies among risk factors having opposite effects on PD patient survival. Some evidence exists that in the long-term (> 10 years), obesity is a risk factor for death in both HD and PD. Further studies are needed to identify the short- and long-term risks and benefits of obesity in the two dialysis modalities.

Estimates of body water, fat-free mass, and body fat in patients on peritoneal dialysis by anthropometric formulas

BACKGROUND

Anthropometric formulas that are used to estimate body water in peritoneal dialysis patients can also be used to estimate fat-free mass and body fat. Evaluation of body composition by the anthropometric formulas rests on two assumptions: (1) fat contains no water, and (2) the water content of the fat-free mass is constant (72%).

METHODS

We compared estimates of body water, fat-free mass, and body fat by anthropometric formulas to estimates employing dilution of tracer substances to measure body water and standard methods to analyze body composition in studies performed on peritoneal dialysis patients. We also analyzed the potential errors of the estimates of body composition by the formulas.

RESULTS

Estimates of the average body composition provided by the anthropometric formulas agreed with estimates provided by the standard methods. However, these formulas have the potential of introducing large errors when estimating body composition in individuals differing from the average subject, either because the anthropometric formulas do not account for major determinants of body composition, such as physical exercise, nutrition, and catabolic illness, or because these formulas systematically overestimate body water in subjects who are obese or experiencing volume excess.

CONCLUSION

Anthropometric formulas currently in existence can provide only approximations of body composition and may be the sources of large errors in evaluating body composition in peritoneal dialysis patients. The potential errors include estimates of body water. These errors may alter the interpretation of urea kinetic studies in certain categories of peritoneal dialysis patients (e.g., obese subjects).

Classification of the degree of obesity by body mass index or by deviation from ideal weight

BACKGROUND

The purpose of this study was to compare classifications of subjects as underweight, normal weight, or obese by body mass index (BMI) and the ratio of body weight to ideal weight (W/IW).

METHODS

We performed a theoretical comparison of the 2 indices. We compared classifications of the degree of obesity in 1839 women and 5914 men who were followed up in the primary care clinics of a United States federal hospital. Information was extracted from computerized records. Subjects were classified as underweight (BMI < 18.5 kg/m2, W/IW < 0.9), obese (BMI > or = 30.0 kg/m2, W/IW > or = 1.2), or normal weight (BMI, W/IW values between the cutoff values for underweight and obesity). W/IW values were computed assuming small, medium, and large skeletal frame for all. We compared the classifications of subjects as underweight, normal weight, or obese by BMI and W/IW. We used Cohen's kappa ratio to evaluate the agreement between these classifications.

RESULTS

Theoretically, the cutoff values of BMI and W/IW for underweight and obesity are not in agreement. Patient data revealed substantial differences in the classifications of subjects as underweight, normal weight, or obese. Kappa ratios ranged between 0.18 (poor agreement) and 0.71 (reasonable, but not high degree of agreement). In general, kappa ratios were higher when assuming large or medium skeletal frame versus small frame.

CONCLUSIONS

There are substantial discrepancies in classifying the subjects of a population as underweight, normal weight, or obese by BMI or W/IW. These discrepancies may cause confusion when 2 or more indices are used simultaneously to classify the degree of obesity.

Estimates of body water, fat-free mass, and body fat in patients on peritoneal dialysis by anthropometric formulas

BACKGROUND

Anthropometric formulas that are used to estimate body water in peritoneal dialysis patients can also be used to estimate fat-free mass and body fat. Evaluation of body composition by the anthropometric formulas rests on two assumptions: (1) fat contains no water, and (2) the water content of the fat-free mass is constant (72%).

METHODS

We compared estimates of body water, fat-free mass, and body fat by anthropometric formulas to estimates employing dilution of tracer substances to measure body water and standard methods to analyze body composition in studies performed on peritoneal dialysis patients. We also analyzed the potential errors of the estimates of body composition by the formulas.

RESULTS

Estimates of the average body composition provided by the anthropometric formulas agreed with estimates provided by the standard methods. However, these formulas have the potential of introducing large errors when estimating body composition in individuals differing from the average subject, either because the anthropometric formulas do not account for major determinants of body composition, such as physical exercise, nutrition, and catabolic illness, or because these formulas systematically overestimate body water in subjects who are obese or experiencing volume excess.

CONCLUSION

Anthropometric formulas currently in existence can provide only approximations of body composition and may be the sources of large errors in evaluating body composition in peritoneal dialysis patients. The potential errors include estimates of body water. These errors may alter the interpretation of urea kinetic studies in certain categories of peritoneal dialysis patients (e.g., obese subjects).

A 100-kg man on peritoneal dialysis (PD) with a borderline kt/V: to PD or not to PD

The determinants of the PD prescription for adequate dialysis are residual renal clearance, target clearance, patient size (gender, height, weight, and, in men only, age), and some information about peritoneal transport characteristics, usually obtained from a PET (anticipated D/P, anticipated Vuf). With this information, PD schedules providing adequate clearances can be calculated for most large anuric patients. This is part of the information that should be provided to large patients before they decide on their dialysis modality. If the patient chooses PD, dialysis prescription may need to be modified over time and one must be attentive to the patient's needs to prevent burnout.

Oliguric acute renal failure in mycosis fungoides with lymphomatous infiltrates in the kidneys

OBJECTIVE

To present the clinical picture of acute renal failure in patients with mycosis fungoides (MF) and renal lymphomatous infiltrates. To analyze the pathogenesis of renal failure.

METHODS

Correlation of clinical picture, urinary findings, imaging reports and autopsy findings in two patients with long-standing MF who died with renal failure.

CASE SUMMARIES

Both subjects had sustained oliguria in the last 2 weeks. One patient had persistent hypotension, normal urinalysis, normal renal sonogram, and scarce interstitial lymphomatous infiltrates with preservation of renal parenchymal architecture. He was thought to have ischemic acute renal failure not directly linked to the lymphomatous infiltrates. The second patient developed hypertension one month prior to death, and had moderate proteinuria, hematuria, pyuria, grossly enlarged kidneys with hypoechoic masses, and extensive replacement of the renal parenchyma by lymphomatous infiltrates. This picture is typical of renal failure secondary to lymphomatous replacement of the kidneys.

CONCLUSIONS

The development of oliguric renal failure in MF with renal lymphomatous infiltrates may have varying clinical and imaging manifestations and pathogeneses. Potentially reversible pathogenic mechanisms should be systematically investigated, particularly if the overall clinical picture is not characteristic of renal failure secondary to lymphomatous replacement of the parenchyma.