[A case of acute renal failure secondary to late-onset McArdle's disease]. / Un caso di insufficienza renale acuta secondaria a malattia di McArdle ad esordio tardivo.

INTRODUCTION: Mc Ardles disease, also known as Type V glycogen storage disease, is a rare deficiency of the enzyme glycogen phosphorylase in muscle cells, inherited as an autosomal recessive trait. In the absence of this enzyme, muscles cannot break down glycogen during exercise, so in patients affected by McArdles disease even moderate physical activity produces cramps, pain and fatigue. Anaerobic activity leads to severe fixed contractures and rhabdomyolisis with myoglobinuria and raised serum creatine-kinase, which, in turn, can lead to acute renal failure. Disease onset is usually in early childhood, although diagnosis is often not made until the second or third decade. CASE REPORT: We present the case of a 68-year-old man who presented to the Emergency Room with fatigue, vertigo, diarrhea and oliguria. The patient underwent five daily hemodialysis sessions, diuresis reappeared and there was progressive recovery of renal function. The patient described episodes of fatigue and muscular pain occurring since childhood: the positive personal history, together with persistently raised CPK levels in the absence of any infective or toxic cause of myositis, led us to suspect the presence of this rare metabolic disease, which was subsequently confirmed by muscle biopsy. CONCLUSION: To date, there is no specific treatment for type V glycogenosis, although a diet rich in protein and saccarose, vitamin B6 supplementation and creatine administration are generally recommended. Moderate physical activity can help manage symptoms by improving exercise tolerance and blood supply to the muscles, ensuring provision of glucose and free fatty acids for the muscle fibers.

[Collaboration between nephrologists, cardiologists and diabetologists and the importance of early diagnosis of chronic kidney disease]. / Interazione nefrologo-cardiologo-diabetologo e necessita' della diagnosi precoce di IRC.

The incidence and prevalence of kidney disorders is high in patients with cardiac disease or diabetes, and this requires close collaboration between nephrologists, cardiologists and diabetologists. Renal function disorders and signs of kidney disease have been demonstrated to be independent cardiovascular risk factors. At the same time, even very initial reductions of renal function have been shown to be an independent risk factor for cardiovascular death. Diagnosing progressive renal disease and chronic kidney disease at an early stage is thus very important. Thanks to interspecialist collaboration, early diagnosis will delay the progression of renal disease and reduce the associated cardiovascular risk. As regards chronic kidney disease and other diabetic complications, the need for early diagnosis is linked to their high costs for patients, society, and health-care organizations. Micro- and macroalbuminuria are well-known independent risk factors both for chronic kidney disease and cardiovascular disease. Thus, reducing albuminuria should be considered a crucial goal in the treatment and secondary prevention of progressive renal disease.

[Low-protein dietary therapy in patients with chronic kidney disease]. / Terapia dietetica ipoproteica del paziente con IRC.

Several prospective studies and meta-analyses including the recent Cochrane meta-analysis have demonstrated that reducing the protein content in the diet delays renal death and the start of dialysis in patients with chronic kidney disease (CKD). Reducing the dietary protein intake offers other benefits such as lowering accumulation of uremic toxins and circulating phosphates and improving symptoms and metabolic derangements. Following the publication of the Cochrane meta-analysis, some of the most renowned experts in Italy on dietary therapy in the CKD patient established a working group within the Italian Society of Nephrology (SIN), the ''Nephrontieres'' project. The current supplement of GIN presents the views of the members of the ''Nephrontieres'' group on a range of issues related to dietary therapy in CKD. A CME program for Italian nephrologists also originated from the collaborative work of the group.

[Low-protein diet in Italy today: the conclusions of the Working Group from the Italian Society of Nephrology]. / La dieta ipoproteica oggi in Italia: le conclusioni del Gruppo di Lavoro SIN.

The high estimated prevalence of chronic kidney disease (CKD) forcefully supports the need for collaboration among nephrologists, cardiologists, diabetologists and general practitioners, to reduce the cardiovascular risk of CKD patients and delay the start of dialysis. Many studies confirm that reducing the dietary intake of proteins improves uremia as well as acid-base and phosphorus disorders without exposing the CKD patient to the risk of malnutrition. The possibility of delaying renal death and the start of dialysis by almost one to two years is also recognized, thanks in part to the antiproteinuric effect of low-protein diets supplemented with keto acids and essential amino acids. Reducing the dietary protein intake delays the start of dialysis independently of the effect of renin-angiotensin system (RAS)-active antihypertensive drugs. Reduction of the dietary protein intake is indicated in patients with a glomerular filtration rate <25 mL/min (CKD stages 4 and 5). Some situations may, however, require an earlier switch to a low-protein diet, e.g., high proteinuria, renal function worsening at more than 5 mL/min/year, diabetes, and metabolic decompensation. If well designed and properly carried out, reduction of the dietary intake of proteins is not associated with low serum albumin levels or malnutrition, and does not affect patients death. Today, highly palatable, high-quality reduced protein preparations are widely available to reduce the protein intake of CKD patients.

Dietary therapy in chronic renal failure. (A comedy of errors).

Controversies still exist about the use and the effects of low protein diets in chronic renal failure. The contrasting - sometimes opposite - results published over the last 30 years in several studies can be read and explained by a series of errors included in those studies. The new Comedy of Errors starts from the misinterpretation of experimental studies, the lack of appropriacy of clinical trials' design; it continues with neglecting the role of patients' compliance as well as of other clinical findings, here included the role of blood pressure. Finally pitfalls in the intrepretation of the results of clinical trials and meta-analyses were identified.

Hypertension and progression of renal disease.

That systemic hypertension is involved in the progression of human renal disease is mostly suggested by the way anti-hypertensive treatment affects the course of the disease. Clinical evidence has been obtained from observational studies as well as from studies of dietary protein restriction. In addition, several trials have compared the effects of different antihypertensive agents. The angiotensin-converting-enzyme inhibitors have the best renoprotective effect when compared to conventional agents and calcium channel blockers. In most studies, ACE-inhibitors approximately halved the risk of progressive renal functional deterioration in patients with non-diabetic nephropathies; this protection was associated with a significant reduction in systemic blood pressure and proteinuria. Statistical analysis, however, also suggests a direct effect of ACE-inhibitors on the kidney.

The role of systemic hypertension in the progression of nondiabetic renal disease.

BACKGROUND: A role for hypertension in the progression of renal disease has been convincingly shown in experimental animals only. In human studies, the relation between hypertension and progression is difficult to demonstrate due to several confounding factors: age, gender, race; the difficult choice of blood pressure (BP) parameters that correlate with progression; the abnormal circadian BP pattern; and the many non-hemodynamic factors of progression. An important role for hypertension in progressive nondiabetic renal disease has been suggested by observational studies and clinical trials originally intended to evaluate the effect of dietary protein restriction on progression. In addition, several studies, summarized by a recent meta-analysis, have shown that pharmacological agents which lower both BP and proteinuria, mainly the angiotensin-converting enzyme inhibitors (ACEI), significantly slow the rate of progression in these diseases. METHODS: In this article we review the effect of lowering BP on the progression of nondiabetic chronic renal disease, the patient characteristics that are associated with a greater or lesser benefit of blood pressure reduction, and the choice of antihypertensive regimens associated with better outcomes in patients with renal disease. RESULTS: Lower levels of achieved BP are associated with a slower decline in renal function, both in patients with and without proteinuria. ACEI are effective BP lowering agents and are associated with better preservation of renal function as opposed to antihypertensive regimens without ACEI. This protective effect of ACEI is in addition to their BP and urine protein lowering effects. The protective effect of ACEI on renal function is more pronounced in patients with proteinuria. CONCLUSION: In patients with nondiabetic renal disease and proteinuria, the risk of progression can be minimized by lowering both BP and proteinuria. ACEI have an additional beneficial effect.

Management of hypertension in renal disease.

The treatment of systemic hypertension in chronic renal disease is now mostly based on the administration of drugs which are able to reduce proteinuria and to slow down the progressive functional deterioration. Angiotensin-converting-enzyme inhibitors (ACEI), which lower both proteinuria and blood pressure, have emerged as drugs of choice in proteinuric patients with either normal renal function or mild to moderate chronic renal failure. In non proteinuric nephropathies no controlled studies exist demonstrating the superiority of ACEI over other drugs. In these conditions calcium antagonists might also be used. The approach to patients with hypertension and renal disease should always take into consideration the quality of the results that are to be achieved. If the aim is to control blood pressure and to protect other organs at risk, then a variety of drugs can be used. If the aim is to reduce proteinuria and slow down progression, then ACEI, possibly associated with calcium antagonists, are the drugs of choice.

6th Verona Seminar on Nephrology, Verona, Italy, September 19-21, 1996.

The Veronese biennial meeting aimes to provide an up-to-date overview on topics of recent interest and progress. In 1996 the Scientific Committee devised a programme which spent the spectrum from basic science to very practical clinical problems.

Low-dosage ibopamine treatment in progressive renal failure: a long-term multicentre trial.

A multicentre trial (11 nephrology centres) was carried out to test the effects of ibopamine, an orally active dopamine-like drug, on the progression of chronic renal failure. For a 2-year period 189 chronic renal failure patients (serum creatinine level 1.5-4.0 mg/dl) were observed. They were homogeneous for basic nephropathy, degree of residual renal function, blood pressure, and proteinuria. The patients were randomly divided into two groups: 96 took ibopamine at a dosage of 100 mg/day (group A) and 93 served as controls (group B). All were on a low-protein diet (mean 0.8 g/kg body weight). By the end of the observation period, the rate of decrease of the renal function indexes in time proved significantly slower (1.8 times) in group A than in group B. The survival curves for renal function (pre-established end points were creatinine level increases equal to or > 20% and equal to or > 40% of the basal values) proved significantly better (p < 0.02 and p < 0.002 respectively) in group A than in group B. The mean plasma creatinine values rose by 17% in group A and by 36% in group B. The creatinine clearance decreased by 5% in treated patients and by 14% in the controls. Statistical analysis ruled out any possible centre effect. The trial suggests that low-dosage ibopamine administration may be used as a valid and safe pharmacological adjunct for retarding the progression of renal failure in patients with mild or moderate chronic renal impairment.

Renal reserve in patients with solitary kidneys.

The first part of this article focuses on the risk of functional deterioration in subjects with solitary kidneys; the long-term clinical outcome of various subgroups of patients is reviewed. Thereafter, the pathophysiology of the renal functional reserve in subjects with a 50% reduction in renal parenchyma and the results coming from studies eliciting the renal reserve in these subjects are summarized. Finally, the clinical significance of the renal functional reserve and its usefulness in clinical practice are critically discussed.

Nutrition and the kidney: how to manage patients with renal failure.

Nutrition is believed to play a key role in the management of chronic and acute renal failure. Considerable evidence suggests that unrestricted protein diets accelerate the progression of chronic renal failure. As a result, recommendations have evolved limiting the quantity and quality of nitrogen intake with the goal of slowing the progression to dialysis dependency. Acute renal failure offers different challenges in view of its common association with hypermetabolic states. With respect to nitrogen substrate administration, the use of mixed formulations of essential plus nonessential amino acids seems to be as effective as essential amino acids alone.

[Risk factors for the progression of chronic kidney failure]. / I fattori di rischio per la progressione dell'insufficienza renale cronica.

Virtually all renal diseases progress, although at different rates, to end-stage renal failure. The main clinical factors which may explain such relentless progression are reviewed and include: the underlying renal pathology, with the most rapid progression rate observed in glomerular disease and in polycystic kidney disease; systemic hypertension, a significant risk factor for progression in any renal disease; the magnitude and duration of proteinuria with the fastest progression rate found in the nephrotic syndrome; the degree of functional renal deterioration at which so called conservative treatment is prescribed. The proper identification of these risk factors may result in rational dietary and non-dietary intervention with the aim of slowing the progression of chronic renal disease.