Alberto Martinez-Vea

Severe hyperkalemia with minimal electrocardiographic manifestations: a report of seven cases.

Severe hyperkalemia with minimal or nonspecific electrocardiographic (ECG) changes is unusual. We report data on seven patients with renal failure, metabolic acidosis, and severe hyperkalemia (K+ > or =8 mmol/L) without typical ECG changes. Initial ECGs revealed sinus rhythm and PR and QT intervals in the normal range. QRS intervals were slightly prolonged in two patients (110 ms), and incomplete right bundle branch block was evident in one. Thus, the absence of typical ECG changes does not preclude severe hyperkalemia.

Long-Term Myocardial Effects of Correction of Anemia With Recombinant Human Erythropoietin in Aged Patients on Hemodialysis

Long-term myocardial effects of recombinant human erythropoietin (rhEPO) therapy were investigated in nine hemodialysis (HD) patients greater than 60 years of age. Echocardiographic studies were performed before the administration of rhEPO with a hematocrit of 20.8% +/- 1.9% and repeated after 6 (period I) and 24 months (period II) of treatment, when the hematocrit was increased to 34.1% +/- 2.3% and 32.3% +/- 2.8%, respectively. Left ventricular diameters were not significantly changed by rhEPO, although they tended to decrease at the end of the study (30.6 +/- 5.3 v 27.7 +/- 3.6 mm systole, and 50.3 +/- 3 v 46.5 +/- 3.7 mm diastole). Thickness of the interventricular septum and left ventricular posterior wall remained unaltered, although there was a downward trend (14.5 +/- 5.2 to 12.8 +/- 2.8 mm and 11.7 +/- 1.9 to 10.6 +/- 1.4 mm, respectively). Left ventricular mass index (LVM) progressively decreased from 181.5 +/- 61 to 153.8 +/- 38.3 (period I) and 135.7 +/- 45.6 g/m2 (period II, P less than 0.05). Stroke volume remained unaltered in period I, but it decreased from 93.7 +/- 10 to 65.2 +/- 12.8 mL (P less than 0.001) in period II, resulting in a decrease of cardiac index (CI) from 3.93 +/- 0.86 to 2.54 +/- 0.68 L/min/m2 (P less than 0.001) at the end of the study. Heart rate did not change during the study period. Blood pressure was kept constant, although antihypertensive therapy needed to be adjusted to prevent occurrence or aggravation of hypertension in two patients.(ABSTRACT TRUNCATED AT 250 WORDS)

End-Stage Renal Disease in Systemic Amyloidosis: Clinical Course and Outcome on Dialysis

We studied a group of 48 patients with systemic amyloidosis and end-stage renal disease (ESRD) treated with chronic dialysis to analyze the clinical course and the factors which can influence survival. This group was compared to a control group of 63 nondiabetic patients without amyloidosis with ESRD treated with hemodialysis. The median survival of the experimental group was 52 months; 1-, 2- and 6-year actuarial survival was 72, 62, and 44%, while in the control group it was 95, 91, and 81%, respectively (p less than 0.001). Survival was significantly shorter for patients with amyloidosis who rapidly (less than 3 months) progressed to ESRD or who had an acute deterioration in renal function immediately prior to the need for dialysis. The median survival in these cases was 4 and 1.5 months, respectively. Age, the presence or the degree of renal failure at the moment of diagnosis, and the type of amyloidosis did not affect the survival of these patients. Despite a shorter period of time spent on dialysis, these patients had a similar number of hospital admissions, cardiovascular and infectious events as the control patients, but more gastrointestinal disorders (bleeding and chronic diarrhea) and blood access problems. In conclusion, amyloidotic patients maintained on chronic dialysis have high morbidity and mortality rates. Nevertheless, acceptable survival is predictable in stable patients who progress slowly to ESRD.

Low risk of contrast nephropathy in high-risk patients undergoing spiral computed tomography angiography with the contrast medium iopromide and prophylactic oral hydratation

BACKGROUND Spiral computed tomography angiography (CTA) is a sensitive and specific technique for visualizing renal arteries and diagnosing renal artery stenosis (RAS). Whether spiral CTA is associated with increased risk of contrast nephropathy (CN) in patients with impaired renal function is unknown. METHODS We prospectively studied 50 patients with chronic renal insufficiency (serum creatinine concentration greater than 1.58 mg/dl) who underwent spiral CTA with iopromide, a nonionic, low-osmolar contrast agent. Fourteen patients had diabetes mellitus. Patients were encouraged to drink 1 l of water 12 hours before and 2 l over 24 hours after the procedure. The presence of CN was defined by an increase of 20% or more in the baseline serum creatinine level within or 72 hours after administration of the radio-contrast agent. RESULTS In the entire group, mean serum creatinine levels increased significantly from 2.92 +/- 1.39 to 3.06 +/- 1.55 mg/dl (p = 0.02) and mean creatinine clearance decreased from 29.8 +/- 12.9 to 28.9 +/- 12.8 ml/min (p = 0.009) 72 h after administration of the contrast medium. Two patients experienced an increase in serum creatinine level of 20%. Renal function returned to baseline within seven days in the 2 patients. Absolute changes in creatinine clearance after the administration of radiocontrast medium were similar in nondiabetic and diabetic patients and in the subgroup of patients, with a baseline serum creatinine of < 3 mg/dl and > or = 3 mg/dl. CONCLUSIONS In patients with chronic renal insufficiency, spiral CTA performed with iopromide, a nonionic, low-osmolar contrast medium and a prophylactic oral hydratation, is a minimally invasive technique with low risk of contrast nephropathy.

Left Ventricular Hypertrophy in Hypertensive Patients with Autosomal Dominant Polycystic Kidney Disease: Influence of Blood Pressure and Humoral and Neurohormonal Factors

Left ventricular hypertrophy (LVH) is a common finding in hypertensive autosomal dominant polycystic kidney disease (ADPKD) patients. There are few studies on the influence of blood pressure (BP) and nonhemodynamic factors on LVH in these patients. The aim of this study was to evaluate the relationship between BP, humoral and neurohormonal factors and left ventricular mass (LVM) in hypertensive ADPKD patients. In 20 hypertensive ADPKD patients, ambulatory BP was monitored for 24 h, left ventricular dimensions were estimated by echocardiography, and plasma renin activity (PRA), plasma noradrenaline (NA), angiotensin II (Ang II), aldosterone, atrial natriuretic peptide (ANP) and insulin-like growth factor I (IGF-I) were also determined. Twenty age- and sex-matched essential hypertensive subjects served as controls. Ambulatory BP and LVM index were similar in the two groups, although male ADPKD patients had higher LVM indices than their matched controls. Eight ADPKD patients (40%) and 6 essential hypertensives (30%) showed LVH. PRA, Ang II, aldosterone, ANP and IGF-I levels were similar in the two groups, but plasma NA levels were higher in ADPKD patients than in controls (281 ± 158 vs. 160 ± 62 pg/ml, p = 0.004). ADPKD patients with LVH did not differ from those without LVH with regard to humoral and neurohormonal parameters, but had higher ambulatory BP levels. In ADPKD patients, correlation analysis revealed a significant association between LVM index and 24-hour systolic and diastolic BP, but not with any of the hormonal factors evaluated. On multiple regression analysis, 24-hour diastolic BP was the only independent variable linked to LVM index. In conclusion, ambulatory BP is one of the most important determinants of LVM in hypertensive ADPKD patients. Further studies are warranted to elucidate the role of nonhemodynamic factors in the pathogenesis of LVH in this population.

Abnormalities of Thirst Regulation in Patients with Chronic Renal Failure on Hemodialysis

To determine whether thirst mechanisms are altered in nondiabetic patients with chronic renal failure on hemodialysis, 4 patients with an average weight gain between dialysis sessions of more than 5% of dry body weight (group I), 5 patients with less than 3% weight gain (group II), and a group of 6 healthy subjects (group III) were submitted to infusion of hypertonic saline. After infusion the subjects had free access to water. Thirst was evaluated by visual analogue rating scales. Despite similar increments of effective plasma osmolality during saline infusion, patients of group I were thirstier than groups II and III (p less than 0.005 and p less than 0.01, respectively). Changes in thirst ratings were similar in groups II and III. Osmotic thresholds for thirst onset were similar in groups II and III (288.9 +/- 8.5 and 289.8 +/- 3.4 mosm/kg, respectively), but lower in group I (277.6 +/- 7.6 mosm/kg). Nevertheless, great variations were observed in the latter group. Thus, 2 patients showed thresholds for thirst within the normal range, whereas the others had low osmolar thresholds for thirst and baseline plasma osmolalities and high basal thirst scores. During the drinking period, the patients of group I drank more (14.2 +/- 2.8 ml/kg) than those of groups II (5.3 +/- 1.6 ml/kg; p less than 0.02) and III (10.2 +/- 1.6 ml/kg; n.s.) The plasma levels of angiotensin II in uremic patients were higher than in healthy subjects, although there were no differences between groups I and II and no correlation between basal angiotensin II levels and the interdialytic weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of oxidative stress biomarkers in patients with chronic renal failure: a case control study

BackgroundOxidative stress is related to several diseases, including chronic renal insufficiency. The disequilibrium in the oxidant-antioxidant balance is the result of several metabolic changes. The majority of studies to-date have evaluated the grade of oxidative stress with a single biomarker, or a very limited number of them.FindingsThe present study used several important biomarkers to establish a score relating to oxidative stress status (glutathione S-transferase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, reduced and oxidized glutathione, thiobarbituric acid reactive substances and hemolysis test). The score of oxidative stress (SOS) was then applied to a group of patients with renal insufficiency not on hemodialysis, and compared to healthy control individuals.The score for patients with chronic renal insufficiency was significantly different from that of the healthy control group (0.62 ± 1.41 vs. -0.05 ± 0.94; p < 0.001). The comparison between patients with chronic renal insufficiency and control individuals showed significant differences with respect to changes in the enzymatic antioxidant systems (glutathione S-transferase, glutathione reductase), non-enzymatic antioxidant system (oxidized glutathione) and oxidizability (hemolysis test) indicating significant oxidative stress associated with chronic renal insufficiency.ConclusionsPatients with chronic renal insufficiency not on hemodialysis are susceptible to oxidative stress. The mechanisms that underlie this status are the consequence of changes in glutathione and related enzymes. The SOS scoring system is a useful biochemical parameter to evaluate the influence of oxidative stress on the clinical status of these patients.

Microalbuminuria in normotensive patients with autosomal-dominant polycystic kidney disease

Microalbuminuria (MA) is present in hypertensive autosomal-dominant polycystic kidney disease (ADPKD) patients, but has not been reported in normotensive ADPKD patients. We examined the prevalence of MA and the effect of different determinants on urinary albumin excretion in a group of 42 normotensive ADPKD patients. Metabolic parameters, plasma renin activity and aldosterone and serum angiotensin-converting enzyme (ACE) activity were determined. A 24-h urine sample two or three times over a 6-month period was collected to evaluate MA. Each patient underwent an echocardiography to measure left ventricular mass. Eight patients (19%) showed MA (61.6 mg/day, range 37-164), whereas 34 patients (81%) were normoalbuminuric (8.8 mg/day, range 2-29). The groups were matched for all possible confounding variables, but microalbuminuric patients showed a tendency towards greater systolic blood pressure, plasma renin activity and left ventricular mass. There was no correlation between MA and age, sex, body mass index, systolic or diastolic blood pressure, plasma renin activity, serum ACE levels or left ventricular index. The present study demonstrates a high prevalence of MA in normotensive ADPKD patients. MA may be a predictor of early renal and vascular damage in these patients.

Minimal-change glomerulopathy and carcinoma. Report of two cases and review of the literature

We describe 2 patients with minimal-change glomerulopathy (MCG) associated with an undifferentiated carcinoma of unknown origin and urothelial carcinoma. Oliguric acute renal failure and histopathological changes consistent with acute tubular necrosis were also observed. Fourteen other cases of MCG complicating solid tumors reported in the literature are reviewed. MCG should be included in the nephropathies which cause nephrotic syndrome in adult patients with carcinoma.

IgA Nephropathy and Polycystic Kidney Disease

We report a patient with polycystic kidney disease, advanced renal failure, and nephrotic-range proteinuria. Kidney biopsy revealed IgA nephropathy with lesions of focal and segmental glomerular sclerosis. This association had not been previously described and is probably coincidental. This case supports the assumption that the nephrotic-range proteinuria observed in some polycystic patients could be the consequence of another superimposed glomerular disease. This glomerulopathy can worsen the course of azotemia in these patients.