Aderville Cabassi

Hyponatremia is the most frequent electrolyte disorder in hospitalized patients and it is associated with unfavorable clinical outcomes as well as increased hospital costs. Its clinical presentation may be highly variable, ranging from asymptomaticity to neurologic emergencies with seizures or coma as signs of rapidly worsening cerebral edema. In these cases, prompt treatment is mandatory to avoid the patients death. On the other hand, in the case of gradual development of hyponatremia, it is imperative that its correction be also appropriately slow in order to avoid another neurological catastrophe, namely the osmotic demyelination syndrome. Whilst recent international guidelines and expert consensus agree on the approach to the treatment of acute severe and symptomatic hyponatremia, the recommendations on pharmacological therapy in chronic hyponatremia diverge, particularly as to the potential use of vasopressin antagonists. This review is aimed at summarizing essential aspects of epidemiology, pathophysiology and the diagnostic process of hyponatremia, to set the ground for a practical as well as evidence-based approach to treatment. As a guide through the discussion of the available evidence, a clinical case is presented in which the patients history and laboratory data are crucial for identifying the etiology of hyponatremia. The severe neurological signs at presentation justify an emergency treatment with hypertonic saline, as indicated. Subsequently, as the neurological emergency subsides, we discuss the need to revert the trend towards hypercorrection by an apparently counterintuitive approach, based in fact on sound pathophysiological grounds, with continuous infusion of hypotonic solutions and administration of desmopressin.

Colistin (CS) is a polymyxin with bactericidal activity, which is increasingly used in nosocomial infections associated with multidrug-resistant Gram-negative bacteria (MDR-GNB). Intravenous CS is usually administered as a less toxic pro-drug, i.e. colistin sodium methanesulfonate (CMS). In water-containing solutions, CMS undergoes a spontaneous hydrolysis to form a complex mixture of partially sulfomethylated derivatives and CS. Pharmacokinetic of CS is dependent on the route of administration, i.e. parenteral, intramuscular, nebulized, intrathecal/intraventricular. Renal toxicity is the most common adverse effect of CS treatment, as the drug is excreted primarily by the kidney and elevated levels of CS may further impair renal function, with a dose-dependent effect. Clinical manifestations of CS associated nephrotoxicity include acute kidney injury, proteinuria and tubular damage. Only few data are currently available on the effects of different renal replacement therapy modalities on CS pharmacokinetics. In patients undergoing the most efficient forms of renal replacement therapies, the extracorporeal clearance of CMS may result in a substantial removal of the antibiotic. Thus, in this setting, the recommended daily doses should be increased. Future studies should better explore CS pharmacokinetics in patients undergoing different modalities of renal replacement therapy.

Background Severe hypokalemia, defined as serum potassium < 2.5 mEq/L, may lead to neuromuscular, gastrointestinal, and ECG abnormalities. Neuromuscular consequences of hypokalemia include weakness, cramps, rarely paralysis, eventually progressing to rhabdomyolysis. Case presentation We report a case of a 4-year-old girl presenting carpopedal spasm and rhabdomyolysis due to severe hypokalemia associated to hypophosphatemia and hypovolemia. At one month of age she underwent an ileal resection because of a neonatal necrotizing enterocolitis, and a bowel resection at two years of age, because of sub-occlusive episodes. The child had frequent episodes of diarrhoea and was treated with oral white clay (kaolin) and a restrictive diet. Three days prior the admission to the hospital she had numerous episodes of watery diarrhoea. Laboratory tests revealed severe hypokalemia, hypophosphatemia, normal calcium levels associated with marked dehydration. An ECG demonstrated sinus bradycardia, ST-segment depression, T-wave flattening, U-wave, and long-QTc. Symmetric carpal and pedal spasms were observed. A marked rise of creatinine phosphokinase and myoglobin associated to cola colored urine was observed. Intravenous supplementation of potassium phosphate as well as adequate volume repletion led to an improvement of the clinical condition, to the disappearance of carpal and pedal spasms, to normalisation of ECG. Conclusions Careful electrolytes and volume supplementation led to the correction of potential life-threatening arrhythmias and obtained a complete recovery from carpopedal spasm and rhabdomyolysis. Dietary restriction and pharmacological preparations as kaolin have to be administered with caution to treat diarrhea in children and particularly in those who may present other pre-existing risk factors.

The term 'kidney dysfunction' is increasingly used in cardiological literature to indicate different forms of impaired kidney function which can usually be grouped within the broad categories of Acute Kidney Injury (AKI) or Chronic Kidney Disease (CKD). In this review, renal function parameters commonly utilized in patients with acutely decompensated heart failure are illustrated. Some concepts of definition and classification of renal dysfunction in this clinical setting are presented, on the basis of the most recent data in the literature. Aspects of epidemiology and limits of methodologies are explored, in addition to the correct interpretation of findings, and the impact and prognostic value of renal dysfunction within the context of heart failure will be discussed. An impairment of kidney function is frequently observed in patients with heart failure, especially during the acutely decompensated phase (Acutely Decompensated Heart Failure or ADHF). Importantly, this complication may impact negatively on clinical outcomes, as well as directly affecting the choice of therapeutic approach, especially when congestive cardiac failure is present. New, recently proposed bio-markers are indicative of kidney injury and cannot be used to replace classical functional indexes. The evaluation of kidney function, together with the correct interpretation of the significance of clinical findings and the limitations of specific laboratory results, bears major methodological relevance for the care of patients with heart failure. At the present time, more extensive utilization of the new kidney injury bio-markers cannot be recommended in the care of patients with acute decompensated heart failure.

Cerebral blood flow (CBF) decreases during intermittent hemodialysis (HD) in patients with acute kidney injury (AKI). Since cerebral hemodynamics may be impaired in liver cirrhosis (LC), this condition could aggravate cerebral hypoperfusion during HD in patients with AKI. We examined CBF during the first HD session in patients admitted for AKI, with or without LC. CBF was examined by measuring middle cerebral artery mean flow velocity (MCAmfv) with transcranial Doppler at baseline and at the end of the first 4-hour HD session in 11 patients with both AKI and LC (median age 69 years, range 40-87, 7 men). Eleven patients with AKI without LC (median age 77 years, range 69-92, 6 men) served as controls. Median net ultrafiltration volume at the end of the HD session was slightly, albeit not significantly, smaller in the patients with LC than in those without (-0.25 kg [range 0.00 to -1.50] vs. -1.00 kg [range 0.00 to -2.00], p = 0.18). At end of HD session, median MCAmfv had decreased by -5.5 cm/s (range -41.3 to 9.9) in the patients with LC, and by -4.5 cm/s (range -11.0 to -2.5) in those without LC (p = 0.79). At end of HD session, the mean MCAmfv of the 2 groups, adjusted for baseline MCAmfv and net ultrafiltration volume, was 25.7 and 21.1 cm/s in AKI patients with and without LC, respectively (difference between groups: 4.6 cm/sec; 95% confidence interval, -3.8 to +13.0). In patients with AKI, concomitant LC does not confer greater vulnerability to cerebral hypoperfusion during intermittent HD.

In patients with heart failure fluid overload is clinically evident as systemic and/or pulmonary congestion, and represents a key issue in the therapeutic approach to the syndrome. Ultrafiltration, obtained by dedicated machines or standard dialysis machines (isolated ultrafiltration), or by the use of the peritoneal membrane (peritoneal ultrafiltration), has been recently proposed for fluid overload correction. This review is aimed at illustrating the operative background, safety, efficacy and cost issues of the different ultrafiltration modalities in heart failure. We retrieved all full-text non-duplicated articles documenting clinical studies on ultrafiltration in heart failure and describing patient characteristics, ultrafiltration procedures, renal outcome and adverse effects, by searching MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials up to December 31, 2011, with the terms ''heart failure'' and ''ultrafiltration OR hemofiltration'' and ''heart failure'' and "peritoneal dialysis". Isolated ultrafiltration can be considered potentially safe for the heart and the kidney in heart failure, and is efficacious for fluid overload removal. However, the available evidence does not support its widespread use as a substitute for conventional diuretic therapy. Isolated ultrafiltration should be employed neither as a quicker way to achieve mechanical diuresis nor as a remedy for an apparently inadequate response to conventional diuretic therapy. Peritoneal ultrafiltration is a promising ultrafiltration procedure that can be safely and successfully performed in heart failure; however, also in this case larger-scale randomized controlled trials are needed. The available evidence supports the concept of reserving ultrafiltration modalities for selected patients with advanced heart failure and true diuretic resistance, as part of a more integrated strategy aimed at fluid overload control.

The utilization of renal replacement therapies in cardiac patients has received increasing attention in recent years. In fact, isolated ultrafiltration has been proposed in patients with heart failure as a means for rapidly relieving fluid overload while preserving renal function; moreover, periprocedural hemofiltration (HF) has been suggested for radiocontrast-induced nephropathy (RCIN) prophylaxis. As a matter of fact fluid overload, with the ensuing systemic and pulmonary congestion, remains a major problem in patients with heart failure, and diuretic resistance is not an uncommon feature in the more advanced stages of the syndrome. In the same way, RCIN is increasingly indicated as a major complication of the use of iodinated contrast media, accounting for a significant number of hospital-acquired acute kidney injury episodes; moreover, it is thought to be associated with short- and long-term adverse effects on patient prognosis and increased economic burden. This article is aimed at reviewing the background of renal replacement therapies in the clinical context of cardiology wards, with special regard to isolated ultrafiltration and HF, as well as the current evidence regarding the safety and efficacy of these procedures, and their economic impact. From a theoretical point of view, isolated ultrafiltration could have a number of potential heart- and kidney-related advantages if compared to standard therapy (mainly diuretics). However, currently available clinical evidence does not support these concepts for its widespread utilization. Thus, isolated ultrafiltration should be reserved for selected patients with advanced heart failure and diuretic resistance, as part of a more complex strategy devoted to the control of fluid retention. There is currently no sound evidence for routinely recommending periprocedural HF in coronary angiography procedures, even in patients at high risk for RCIN.

Experimental and clinical evidence supports the involvement of inflammation and innate immunity in chronic renal disease. Immune dysfunction in end-stage renal

Objective and methods Left ventricular hypertrophy in human and experimental hypertension is not always associated with pressure overload but seems to precede an increase in blood pressure. In this study, performed in male 5-week-old prehypertensive spontaneously hypertensive rats (SHR; n = 65) and age-matched Wistar–Kyoto rats (n = 56), the relationship between myocardial structure and activation of the adrenergic and nitric oxide systems was evaluated. Results Body weight, blood pressure and heart rate were similar in both groups. A higher left ventricle/body weight ratio was found in SHR, as a result of greater mononuclear (+47%) and binuclear (+43%) myocyte volumes, without changes in interstitial collagen. Both adrenergic and nitric oxide pathways were activated in SHR, as expressed by higher myocardial norepinephrine content, tyrosine hydroxylase activity, myocardial nitric oxide synthase 3 expression and protein nitration, indicating greater peroxynitrite (ONOO⁻) generation from nitric oxide and superoxide. No difference was measured in nitric oxide synthase 1 expression, whereas nitric oxide synthase 2 was undetectable. A positive correlation between myocardial tyrosine hydroxylase activity and protein nitration was observed in SHR (r² = 0.328; P < 0.01). Early treatment with a superoxide dismutase mimetic, 4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl, from the third to the fifth week of age, reduced ONOO⁻ generation, protein nitration and sympathetic activation in SHR without changes in myocardial structure. Conclusion In prehypertensive SHR, left ventricular hypertrophy is associated with adrenergic and nitrosative imbalance. Early superoxide dismutase mimetic treatment in SHR effectively reduces higher myocardial ONOO⁻ generation, sympathetic activation, and heart rate without affecting the development of myocardial hypertrophy.

Advanced heart failure is characterized by increased activation of the renin-angiotensin system and the development of cachexia. Angiotensin II (Ang II) has been proposed as a lipid metabolism regulator. The effects of exogenous Ang II (osmotic minipump, 525 ng/kg/min for 12 d) on interstitial sc glycerol and norepinephrine levels, indexes of lipolysis, and sympathetic activation, respectively, were measured in Sprague Dawley rats by consecutive microdialysis performed in vivo in white adipose tissue. Higher sustained interstitial glycerol and norepinephrine levels were found after 7 and 12 d of Ang II infusion. Triglyceride to DNA content ratio and adipocyte diameter were reduced in sc and visceral (retroperitoneal and epididymal) fat tissues of Ang II-infused rats, whose body weight was lower and blood pressure higher. Losartan, an Ang II receptor 1 blocker, and carvedilol, an α1-nonselective-β1,2,3-adrenergic blocker, but not doxazosin, an α1-selective-adrenergic blocker, lowered glycerol and norepinephrine levels, preventing lipolysis and weight loss. Our results indicate that Ang II stimulates lipolysis in sc and visceral adipocytes by sympathetic activation and β-adrenergic-receptor stimulation. Nonselective-β-adrenergic and Ang II-receptor1 blockade markedly attenuated the rise of norepinephrine, preventing catabolic effects. The metabolic benefits of carvedilol and losartan, in addition to recognized protective cardiovascular effects, may be relevant in cachectic patients with advanced heart failure.