Francesca Bermond

Cholesterol crystal embolism syndrome in dialysis patients: an emerging clinical diagnosis?

Background: Cholesterol crystal embolism syndrome (CCE) is an increasing end-stage renal disease cause. Few cases have been described on dialysis, despite the high prevalence of the predisposing factors. Methods: The diagnostic criteria of the present study were: skin lesions, myalgia, fatigue, fever and acute inflammatory serologic signs, in the presence of severe vasculopathy. The precipitating factors were: anticoagulation, endovascular intervention and ulcerated atherosclerotic plaque. Results: Between October 2003 and September 2005, CCE was diagnosed in 6 dialysis patients (of 200–210 on chronic treatment): 5 males, 1 female, median age 59.5 years (47–70) and end-stage renal disease follow-up 11.5 years (3–25). All had severe vasculopathy, 5 cardiopathy, and 4 were failed graft recipients. The treatment included: peritoneal dialysis, daily dialysis, ‘conventional’ hemodialysis (2 cases) and hemodiafiltration. The diagnosis was based on the clinical-laboratory picture in 1 patient. In the 5 others clues were present (dicumarol therapy, angioplasty, femoral artery thrombosis, CCE predialysis and ulcerated aortic plaque). The therapeutic approach consisted of corticosteroids (5 cases), statins (4 cases) and prostaglandin analogues (4 cases). Conclusion: The differential diagnosis of CCE should also be considered in dialysis patients (necrotic lesions, limb pain and vasculitis-like signs).

Metabolic diagnosis of nephrolithiasis. Clinical cases (Part II)

This is the second part of an article on the metabolic diagnosis of nephrolithiasis, the first part of which was published in the previous issue of this journal. Here we report on three clinical cases representative of a rational diagnostic workup of nephrolithiasis in specific clinical contexts: secondary hyperuricemia, cystinuria, and primary hyperoxaluria. Nephrolithiasis is one of the most frequent causes of hospitalization in nephrology and urology units in our country and is an important source of discomfort in affected patients. Despite the availability of modern, minimally invasive endourological procedures to remove stones from the urinary tract, prevention of stone recurrences remains an essential strategy. Chemical analysis of stones, whether passed spontaneously or removed surgically, is a crucial step in etiological diagnostics aimed at devising adequate prevention strategies. Modern endoscopic lithotripsy techniques provide complete fragmentation of stones and, compared to extracorporeal shock wave lithotripsy, have the advantage of avoiding painful elimination of fragments through the urinary tract. This means, however, that stone fragments are often unavailable for analysis, thereby depriving the nephrologist of an important tool for diagnosis. As a consequence, metabolic evaluation tends to be the only means of establishing the etiology of stones and preventing their recurrence. We conclude that close collaboration between nephrologists and urologists is a prerequisite for optimizing the diagnosis and treatment of stone disease.

Peritoneal dialysis: marginal dialysis

Peritoneal Dialysis in Italy in 2013: biases and hurdles to its wide diffusion, where are we?

Update on Nephrolithiasis

Many recent papers analyze the association between renal stone disease and other diseases that are typical of industrialized countries. Epidemiology studies from large series indicate that the prevalence of nephrolithiasis is higher among patients with metabolic syndrome, diabetes, and hypertension. Patients with nephrolithiasis also have an increased risk of myocardial infarction and stroke. It has been hypothesized that the common underlying defect could be insulin resistance. This, in turn, alters the urine biochemistry (i.e. more acidic pH and less urine citrate) thereby increasing the propensity of stone forming. In the diabetic rat renal steatosis has been implicated in the reduced production of ammonia, which has been shown to be reversible after PPARγ administration. Furthermore, pioglitazone was shown to be effective in reducing ethylene glycol-induced renal injury. Another significant association concerns gout. Two recent papers report that both calcium and uric acid stone disease are more prevalent among patients with gout. The metabolic derangements found in gouty and non-gouty patients were quite similar. CT imaging in patients with gout indicates that the incidence of nephrolithiasis is underestimated if only based on stone history. Finally, stone episodes may occur many years before the first gouty attack. Another interesting issue is that of a potential adverse effect of calcium and vitamin D supplementation on the risk of stone formation. It has been shown that treated post-menopausal women have a slight but significantly higher risk of forming stones, independently of other interfering variables. From this the recommendation to evaluate the actual benefit of supplementation, even more in the face of its ineffectiveness to prevent fractures in older women. Bariatric surgery is increasingly proposed for managing severe obesity, and in the last few years it has shown a widespread use in the US. Previous procedures of digestive diversion were often complicated by hyperoxaluria and renal oxalosis. More recent techniques, including Roux-en-Y gastric bypass and gastric bending, seem to give better outcomes. Hyperoxaluria and hypocitraturia following these procedures induce only minor increases in the risk of forming stones, but some recent reports of renal oxalosis after gastric bypass deserve attention.