[The treatment of anemia of hemodialysis patients using recombinant human erythropoietin: comparison between intravenous and subcutaneous administration]

Recombinant human erythropoietin (r-huEPO) is now an established therapy for anemia of hemodialysis patients. However, questions remain concerning the optimal maintenance dose as well as the route and frequency of administration. This prospective study was designed to determine whether subcutaneous r-huEPO at a reduced dosage was as effective as intravenous r-huEPO in maintaining constant hemoglobin levels. It involved 12 patients on hemodialysis, previously treated with intravenous r-huEPO for 11.8 +/- 7 months (mean +/- SD). For 3 months hemoglobin was kept at a stable level of 10-13 g/dl with individually titrated intravenous r-huEPO administered thrice weekly after each hemodialysis. Patients were then switched to subcutaneous r-huEPO. Initially, approximately 50% of the previous weekly dose was given as twice weekly subcutaneous injections. During the following 3 months the r-huEPO dosage was adapted to maintain the target hemoglobin level. 3 patients did not complete the second period due to acute intercurrent complications not related to therapy. 9/12 patients completed the study. The hemoglobin concentration was kept at a constant level of (mean +/- SD) 10.5 +/- 1.1, 10.6 +/- 0.9 and 11.1 +/- 0.6 g/dl with 233 +/- 110, 246 +/- 118 and 233 +/- 116 U/kg/week of intravenous r-huEPO for the first 3 months. In the second period hemoglobin was kept at 11.5 +/- 1.2, 11.3 +/- 1.4 and 11.1 +/- 0.9 g/dl with 119 +/- 61, 118 +/- 60 and 137 +/- 78 U/kg/week of subcutaneous r-huEPO. 2 patients required an increase in the r-huEPO dose during the third month of the second period.(ABSTRACT TRUNCATED AT 250 WORDS)

[Treatment of anemia in hemodialysis patients using recombinant human erythropoietin: advantages and disadvantages]

18 anemic patients undergoing maintenance hemodialysis were treated with recombinant human erythropoietin (EPO) 1-3 times per week for 10.7 +/- 3 months. 4 patients underwent renal transplantation whereas 14 patients could be followed up during 12 months of EPO treatment. Hemoglobin concentration rose (from 7.0 +/- 0.7 to 11.0 +/- 1.1 g/dl, p less than 0.001) with an EPO maintenance dose of 298 units/kg/week. Blood transfusions were totally eliminated. 12 patients without iron overload required iron supplements. In the course of an infectious episode and notwithstanding an increase in EPO dosage, 2 patients exhibited a fall in hemoglobin which rose again after successful treatment of the infection. The few complications observed in connection with the rise in hemoglobin were: 1. deterioration of arterial hypertension in 7/18 with hypertensive encephalopathy in 3 patients, 2. thrombotic occlusion of the vascular hemodialysis access (a-v fistula) in 3/18, 3. periarticular inflammation with calcified deposits due to an elevated calcium-phosphorus product of 6.8 mmol/l in 4/18, 4. occurrence of hyperkalemia (6.9 +/- 0.3 mmol/l) in 7/18. These complications were more frequent during the first 3 months. They were corrected with close monitoring, drug therapy for hypertension, and intensification of dialysis and of treatment with phosphate binding substances, with the result that no differences were found in 14 patients before and after 12 months of treatment with EPO (blood pressure 133 +/- 25/77 +/- 9 vs 139 +/- 26/79 +/- 13 mm Hg [ns], potassium 5.4 +/- 0.4 vs 5.6 +/- 1.0 mmol/l [ns] and calcium-phosphorus product 4.3 +/- 1.0 vs 4.6 +/- 1.3 [ns]).(ABSTRACT TRUNCATED AT 250 WORDS)

Human recombinant erythropoietin treatment in transfusion dependent anemic patients on maintenance hemodialysis

Six anemic hemodialysis patients dependent on regular blood transfusions and with massive iron overload were treated with recombinant human erythropoietin (r-huEPO). The effect on absolute reticulocyte count, hemoglobin and serum ferritin was studied during a twenty-week period. Red-cell volume and red-cell life span were measured with 51Cr-tagged erythrocytes at baseline and after twenty weeks of r-huEPO. Absolute reticulocyte counts and hemoglobin concentration rose markedly (from 55.6 +/- 31.2 to a maximum of 174.9 +/- 31.0 x 10(9)/l at 4 weeks and from 6.8 +/- 0.3 to a maximum of 11.2 +/- 1.3 g/dl at 12 weeks, respectively, p less than 0.001) without any further need for transfusions. Red-cell volumes increased concomitantly (from 58 +/- 4 to 81 +/- 11% of normal, p less than 0.005), in spite of a persistent shortening of red-cell life span (45 +/- 18 and 47 +/- 4 days before and after r-huEPO). Markedly elevated serum ferritin concentrations indicating iron overload decreased slowly from 3,550 +/- 1,615 to 2,721 +/- 1,506 micrograms/l (p less than 0.05). It is concluded that r-huEPO is very effective in treating the anemia of patients maintained on hemodialysis. The favorable effects on hemoglobin and red-cell volumes occur in spite of persistent hemolysis and lead to a slow reduction of iron overload.

[Pathogenesis of anemia due to kidney disease]

Several factors contribute to the pathogenesis of anemia due to renal failure. Hypoproliferation of red cell progenitors may be caused partially by an inhibitory effect of some 'uremic toxins' whose existence certainly is very controversial. Iron deficiency due to gastrointestinal and dialysis-related blood losses and occasionally aluminum intoxication may interfere with the maturation of the erythron. Moderate hemolysis with shortening of red cell survival to some 50% of normal may be an additional factor. The main cause of anemia is, however, inadequate production of erythropoietin by the diseased kidney. This latter factor has now become amenable to treatment.

Effectiveness of single versus double volume exchange transfusion in newborn infants with AB0 hemolytic disease

The effectiveness of early single volume exchange transfusion (ET; 80 ml/kg) was compared with that of early double volume exchange transfusion (160 ml/kg) for treatment of hemolytic disease of the newborn caused by AB0 incompatibility. Twenty full-term infants with AB0 hemolytic disease were randomized into the two treatment groups. The groups were comparable for gestational age, body weight, hemoglobin values, reticulocyte count, maximum serum bilirubin levels, rate of rise of serum bilirubin before ET, antibody titer, and age at time of ET (all p greater than 0.05). The efficacy of treatment was similar in both groups taking into account the mean bilirubin level after ET, post-ET bilirubin, duration of phototherapy following ET, and frequency of second ET (all p greater than 0.05). However, platelet count immediately after ET was lower in the double volume ET group as compared to the single volume ET group (p less than 0.01). Hemoglobin values immediately after ET were higher in the double volume ET group (p less than 0.01). At ten days of life no differences were detectable. The results of this study indicate that the effectiveness of single volume ET for treatment of full-term infants with jaundice due to AB0 incompatibility is at least comparable to that of double exchange ET. Furthermore, the lesser aggressive approach determines less complications such as a decrease of platelet count.

[Cerebrovascular incidents in 4 hemodialysis patients treated with erythropoietin]

Human recombinant erythropoietin (r-huEPO) is very effective in the treatment of anemia of hemodialyzed patients. We describe 4 patients who developed symptoms of central nervous dysfunction during r-huEPO therapy. Three exhibited typical hypertensive encephalopathy, whereas signs of cerebral ischemia were found in the fourth. The increase in blood viscosity with r-huEPO treatment, leading to a rise in peripheral vascular resistance and blood pressure especially in previously hypertensive patients, may be of importance in the pathogenesis of these cerebrovascular incidents; preexistent arteriosclerosis is an possible additional risk factor.

Effect of various therapeutic approaches on plasma potassium and major regulating factors in terminal renal failure

PURPOSE

The development of life-threatening hyperkalemia poses a risk for patients with chronic preterminal renal failure. Various therapeutic options have been suggested for hyperkalemic emergencies in these patients; to date, however, no study has evaluated the relative efficacies of these measures in the presence of renal failure. Our goal was to examine the acute effects of a variety of therapeutic approaches, as well as those of hemodialysis, on plasma potassium levels in a hemodialysis population.

PATIENTS AND METHODS

Ten patients with terminal renal failure undergoing maintenance hemodialysis were enrolled in the study. Blood gas parameters and plasma sodium, potassium, glucose, osmolality, renin, aldosterone, epinephrine, norepinephrine, dopamine, and insulin were measured before, during, and after 60-minute infusions of bicarbonate, epinephrine, and insulin in glucose, and before, during, and after performance of regular hemodialysis for one hour.

RESULTS

Hypertonic as well as isotonic intravenous bicarbonate (2 to 4 mmol/minute) induced a marked rise in plasma bicarbonate and pH, but failed to lower the plasma potassium level (5.66 versus 5.83 mmol/liter before and after). Epinephrine, 0.05 microgram/kg/minute administered intravenously, decreased plasma potassium only slightly from 5.57 to 5.25 mmol/liter, and five patients showed no decline. On the other hand, insulin in glucose, 5 mU/kg/minute intravenously, effectively lowered plasma potassium levels from 5.62 to 4.70 mmol/liter, and hemodialysis induced the most rapid decline from 5.63 to 4.29 mmol/liter. Plasma aldosterone was elevated before treatment; it correlated with plasma potassium and dropped during intravenous bicarbonate administration or hemodialysis. Pretreatment plasma renin activity, insulin, epinephrine, norepinephrine, and dopamine levels were generally normal.

CONCLUSION

We conclude that in patients with terminal renal failure undergoing maintenance hemodialysis, intravenous bicarbonate is ineffective in lowering plasma potassium rapidly, and epinephrine is effective in only half the patients, whereas insulin in glucose is a fast and reliable form of therapy for hyperkalemic emergencies. Plasma aldosterone levels are appropriate in relationship to plasma potassium levels, and levels of other potassium-influencing hormones are generally normal.

Lethal osteogenesis imperfecta: abnormal collagen metabolism and biochemical characteristics of hypophosphatasia

We have examined collagen from a patient with the rare type IIC form of perinatally lethal osteogenesis imperfecta, in whom biochemical characteristics of hypophosphatasia were also apparent. In addition to normal alpha 1(I) and alpha 2(I) chains, there were chains overmodified along their lengths. Unexpectedly, the thermal stability of molecules containing these chains was normal. This suggests the existence of a structural mutation causing delayed triple helix formation, situated in either the alpha 1(I) or alpha 2(I) C-terminal propeptide. Since collagen synthesised by fibroblasts from each of the patient's parents was normal, the mutation was probably newly arising and dominant. In contrast to other reported cases of lethal osteogenesis imperfecta, not only was the secretion of collagen by cultured fibroblasts considerably retarded, but that of non-collagenous proteins was also severely impaired.

Long-term treatment of central precocious puberty with an intranasal LHRH analogue: control of pituitary function by urinary gonadotropins

Daily subcutaneous doses of luteinizing hormone-releasing hormone (LHRH) analogues are a well-established therapy for gonadotropin-dependent precocious puberty. Reports on intranasally administered analogues, however, are controversial. We studied the effect of intranasal D-Ser(TBU)6-LHRH(BUS) on growth rate, skeletal maturation, and urinary gonadotropins in five girls and one boy with central precocious puberty (CPP) who had been treated for 1.4-2.3 years (mean 1.9). Because of the potential antifertility effects of LHRH analogues, testicular histology was analysed in the boy. In the five children with accelerated growth, the bone age-related velocity of height gain decreased from 10.58 +/- 2.77 to 5.82 +/- 1.8 cm/year (means +/- SD, P less than 0.01), and the ratio of change in bone age to change in chronological age fell below 1. Basal luteinizing hormone (LH), and LHRH-stimulated LH and follicle stimulating-hormone, at pubertal levels before treatment, decreased significantly in all children, normalizing in four (P less than 0.04). During therapy, pituitary function was best controlled by urinary LH, which correlated with clinical data. After 13 months of therapy, testicular histology showed degenerated Sertoli cells, and absence of B- and Ap-spermatogonia and of primary spermatocytes in the boy. We conclude that: (1) Efficient long-term suppression of central precocious puberty--including accelerated growth and skeletal maturation--can be maintained by intranasal dosage of BUS. (2) Urinary LH reflects pituitary function and proves to be a reliable guide to adjustment of the LHRH-analogue dose regimen.(ABSTRACT TRUNCATED AT 250 WORDS)

Human recombinant erythropoietin in anaemic patients on maintenance haemodialysis. Secondary effects of the increase of haemoglobin

Twelve anaemic patients on haemodialysis were treated with recombinant human erythropoietin, starting with 72 IU/kg/week. The dose was doubled after 2 weeks until an increase of 2 g/dl of haemoglobin was observed. The effects on various parameters were studied during a 3-month period. Haemoglobin increased from 6.70 +/- 0.74 to 10.49 +/- 1.04 g/dl (mean +/- SD, P less than 0.001), potassium from 5.51 +/- 0.50 to 6.06 +/- 0.65 mmol/l (P less than 0.005), phosphate from 1.78 +/- 0.40 to 2.17 +/- 0.40 mmol/l (P less than 0.001) and the calcium phosphorus product from 4.3 to 5.2 (P less than 0.001). Three patients developed marked periarticular inflammation due to calcified deposits with a high calcium-phosphorus product of 6.8. An increase in arterial blood pressure was observed in three previously well-controlled hypertensive patients, one of whom developed hypertensive encephalopathy. We conclude that recombinant human erythropoietin is very effective in treating the anaemia of end-stage renal failure on haemodialysis. Regular estimations of serum potassium and phosphate are mandatory. In hypertensive individuals a further increase in blood pressure is possible.

[Diagnosis of glomerular and non-glomerular erythrocyturia using phase contrast microscopy of the urine sediment]

Recently the appearance of deformed polymorphous erythrocytes in the urinary sediment has been described as characteristic of glomerular bleeding. We studied 30 patients with histologically confirmed glomerular disorders and 25 patients with urological diseases and with hematuria. In the sediment of 10 ml urine 200 erythrocytes were counted under phase-contrast microscopy and evaluated relative to their morphology. The number of glomerular erythrocytes was expressed as a percentage. In all groups of glomerular disorders (mesangial-proliferative, membranous and membrano-proliferative glomerulonephritis, focal segmental glomerulosclerosis, glomerulonephritis of systemic disease, thinning of the glomerular basement membrane) the percentage of glomerular erythrocytes varied widely between 2 and 100%. In 7 cases less than 10% of glomerular erythrocytes were found. There was no correlation between the percentage of glomerular erythrocytes and the degree of renal insufficiency, hematuria or proteinuria. On the other hand, in patients with hematuria from the lower urinary tract, erythrocytes were uniformly non-glomerular in shape (95-100%). We conclude that 10-20% or more of glomerular erythrocytes in the urinary sediment are a good indicator of glomerular disease, whereas lower figures do not definitely rule out a glomerular origin for hematuria.

Behavior of beta 2-microglobulin in patients with chronic renal failure undergoing hemodialysis, hemodiafiltration and continuous ambulatory peritoneal dialysis (CAPD)

beta 2-microglobulin (beta 2-m) is the major component of a new form of amyloid deposit found in carpal tunnel syndrome and dialysis arthropathy of long-term hemodialysis patients. In 52 patients on maintenance hemodialysis, serum beta 2-m concentration was elevated to 37.9 +/- 1.4 (normal 1.2 +/- 0.6) mg/l. It was correlated with the time on hemodialysis (r = 0.43, p less than 0.01) and was inversely correlated with residual renal function (r = 0.87, p less than 0.001). In 20 patients on CAPD, beta 2-m likewise was increased to 31.6 +/- 2.3 mg/l; daily elimination by dialysate was only 34 mg (normal 150 mg). Hemodialysis with a cuprophane membrane caused a rise in serum beta 2-m, whereas hemodiafiltration with a polysulfone membrane performed in 5 patients over 2 1/2 months was accompanied by a decrease in serum beta 2-m from 39.5 +/- 0.7 to 29.7 +/- 1.0 mg/l predialysis (19.1 +/- 1.1 postdialysis). On the other hand, beta 2-m elimination reached only approximately 100 mg per day in spite of markedly elevated serum levels. It is concluded that serum beta 2-m is massively elevated in long-term hemodialysis and CAPD patients; contrary to routine hemodialysis with cuprophane membranes, newer more permeable membranes will permit some elimination of beta 2-m. However, based on quantitative considerations it seems difficult to obtain beta 2-m concentrations in the high normal or moderately elevated range with present day techniques.

[Glomerulonephritis in chronic bacterial infections]

Five patients with chronic bacterial infections (two with osteomyelitis, two with infected vascular prostheses, one with soft tissue abscess), but without endocarditis, developed signs of glomerulonephritis and renal failure. Histological examination in three revealed mainly proliferative glomerular alterations. The outcome of glomerulonephritis paralleled the course of infection. Recovery or marked improvement occurred in three patients in whom the infection was cured, one case with smoldering infection eventually developed endstage renal failure, and one with persistent infection died from severe complications with acute renal failure. If renal failure occurs in the setting of suppurative infection, so-called infection-associated glomerulonephritis must be considered. Prompt and effective eradication of infection has an important bearing on the course of renal function.

[Early recognition of and treatment possibilities in diabetic nephropathies]

Diabetic nephropathy due to glomerulosclerosis develops in 40% of patients with type I diabetes (in type II the incidence is only around 5%). Two mechanisms are of pathogenetic importance: hemodynamic changes with glomerular hyperfiltration leading to glomerulosclerosis and proteinuria, and biochemical alterations of the glomerular basement membrane consisting of an increase and glycosylation of collagen IV as well as a decrease in negatively charged proteoglycans and sialic acid. Diabetic nephropathy runs through several stages, the first being characterized by hyperfunction and hypertrophy. The appearance of microalbuminuria after 10-15 years of diabetes seems to be a good indicator of the later development of clinically overt nephropathy with large urinary protein losses and decreasing renal function. Successful treatment of hypertension may slow the decrease of renal function. For those patients who have reached terminal renal failure, the treatment modalities of hemodialysis, continuous ambulatory peritoneal dialysis (CAPD) and renal transplantation offer a reasonable chance of prolonging life, although the results are generally less good than in non-diabetic renal patients of the same age group. However, the ultimate goal of therapy must remain the successful prevention of the devastating late sequelae of diabetes, including diabetic nephropathy.

[Hemoglobin A1c in patients under periodic hemodialysis or continuous ambulatory peritoneal dialysis]

In 44 dialyzed patients (27 nondiabetic hemodialysis, 10 CAPD patients and 7 diabetics) hemoglobin A1c (HbA1c) concentrations were measured comparatively by column chromatography (using Bio-Rad columns) and the thiobarbituric acid (TBA) method. With column chromatography the values were significantly higher in each patient group than in healthy controls. In the diabetics, who on average showed elevated blood glucose levels, HbA1c concentrations were higher than in the other dialysis patients, although there was some overlap. On the other hand, concentrations measured in non-diabetic patients with the TBA method were only marginally higher than in controls. It is well known that column chromatography measures carbamylated hemoglobin with HbA1c, and for this reason false high concentrations are found in renal failure. The TBA method is precise and specific in this situation but unfortunately is too time-consuming for routine determinations. The simple column chromatographic method is of only limited value in the control of diabetics with renal failure; nevertheless, unequivocally elevated concentrations of greater than or equal to 7% HbA1c are a good indicator of unsatisfactory metabolic control.

[Acute rhabdomyolysis following administration of succinylcholine]

Acute rhabdomyolysis without hyperthermia, after anesthesia including succinylcholine, is described in a father and son. Rhabdomyolysis-associated acute renal failure was mild in the son but severe in the father. Known enzymatic muscular defects were excluded as cause. The clinical picture of anesthesia-associated rhabdomyolysis is discussed on the basis of these two cases and a review of the literature.

Oxygen affinity of erythrocytes and pulmonary gas exchange in patients on continuous ambulatory peritoneal dialysis

In 11 patients on continuous ambulatory peritoneal dialysis 2,3-diphosphoglycerate, oxygen (O2) affinity of red cells (P50), blood gases, ventilation, and O2 consumption were studied. Contrary to patients on maintenance hemodialysis, 2,3-diphosphoglycerate and P50 were normal in patients on continuous ambulatory peritoneal dialysis; they were correlated with each other. Arterial O2 pressure was normal; under the conditions of dialysis with 35 mmol lactate per liter dialysis fluid a slight metabolic acidosis persisted; it was combined with a moderate respiratory alkalosis. Position had no influence upon pulmonary gas exchange with the exception of the alveolo-arterial gradient which was elevated when the abdominal cavity was filled with dialysis fluid and the patients assumed the supine position. Ventilation was in the normal range, whereas O2 consumption was low, possibly due to a reduction in muscle mass in some of the patients. It is concluded that pulmonary gas exchange and erythrocyte O2 transport were normal and that O2 requirements tended to be low in this group of patients on continuous ambulatory peritoneal dialysis.