Treatment of Metformin Intoxication Complicated by Lactic Acidosis and Acute Kidney Injury: The Role of Prolonged Intermittent Hemodialysis.

Metformin intoxication with lactic acidosis, a potentially lethal condition, may develop in diabetic patients when the drug dose is inappropriate and/or its clearance is reduced. Diagnosis and therapy may be delayed due to nonspecific symptoms at presentation, with severe anion gap metabolic acidosis and elevated serum creatinine values being the most prominent laboratory findings. Confirmation requires measurement of serum metformin by high-performance liquid chromatography-tandem mass spectrometry, but this technique is available only at specialized institutions and cannot be relied on as a guide to immediate treatment. Thus, based on strong clinical suspicion, renal replacement therapy must be started promptly to achieve efficient drug clearance and correct the metabolic acidosis. However, because metformin accumulates in the intracellular compartment with prolonged treatment, a rebound in serum concentrations due to redistribution is expected at the end of dialysis. We report a case of metformin intoxication, severe lactic acidosis, and acute kidney injury in a diabetic patient with pre-existing chronic kidney disease stage 3, treated effectively with sustained low-efficiency dialysis. We discuss the pathophysiology, differential diagnosis, and treatment options and highlight specific pharmacokinetic issues that should be considered in selecting the appropriate modality of renal replacement therapy.

Effects of continuous renal replacement therapy on linezolid pharmacokinetic/pharmacodynamics: a systematic review.

BACKGROUND: Major alterations in linezolid pharmacokinetic/pharmacodynamic (PK/PD) parameters might be expected in critically ill septic patients with acute kidney injury (AKI) who are undergoing continuous renal replacement therapy (CRRT). The present review is aimed at describing extracorporeal removal of linezolid and the main PK-PD parameter changes observed in critically ill septic patients with AKI, who are on CRRT. METHOD: Citations published on PubMed up to January 2016 were systematically reviewed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. All authors assessed the methodological quality of the studies and consensus was used to ensure studies met inclusion criteria. In-vivo studies in adult patients with AKI treated with linezolid and on CRRT were considered eligible for the analysis only if operational settings of the CRRT machine, membrane type, linezolid blood concentrations and main PK-PD parameters were all clearly reported. RESULTS: Among 68 potentially relevant articles, only 9 were considered eligible for the analysis. Across these, 53 treatments were identified among the 49 patients included (46 treated with high-flux and 3 with high cut-off membranes). Continuous veno-venous hemofiltration (CVVH) was the most frequent treatment performed amongst the studies. The extracorporeal clearance values of linezolid across the different modalities were 1.2-2.3 L/h for CVVH, 0.9-2.2 L/h for hemodiafiltration and 2.3 L/h for hemodialysis, and large variability in PK/PD parameters was reported. The optimal area under the curve/minimum inhibitory concentration (AUC/MIC) ratio was reached for pathogens with an MIC of 4 mg/L in one study only. CONCLUSIONS: Wide variability in linezolid PK/PD parameters has been observed across critically ill septic patients with AKI treated with CRRT. Particular attention should be paid to linezolid therapy in order to avoid antibiotic failure in these patients. Strategies to improve the effectiveness of this antimicrobial therapy (such as routine use of target drug monitoring, increased posology or extended infusion) should be carefully evaluated, both in clinical and research settings.

[Ultrafiltration in heart failure]. / Ultrafiltrazione nello scompenso cardiaco.

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.

Reliability of bedside ultrasound for measurement of quadriceps muscle thickness in critically ill patients with acute kidney injury.

MAIN PROBLEM: In patients with Acute Kidney Injury there is a lack of nutritional variables that can assess nutritional status, more specifically lean body mass (LBM) and skeletal muscle mass, at the individual level. In this clinical setting, ultrasound (US)) of the quadriceps femoris could represent a widely available, non-invasive, affordable, and reliable tool to evaluate skeletal muscle. METHODS: We performed a cross-sectional observational study in adult critically ill patients with KDIGO stage 3 AKI on dialysis. Quadriceps rectus femoris and vastus intermedius thickness were measured by two assessors. Intra- and interobserver reliability was evaluated using the intraclass correlation coefficient (ICC). The same US measures were obtained before and after dialysis. RESULTS: We enrolled 34 patients, 22 (65%) were male and the mean APACHE II score was 22.7 (±5.6). In the intraobserver reliability study, assessor 1 performed 288 paired measurements and assessor 2 performed 430 paired measurements in 34 patients, with an ICC equal to 0.99 and 1.00, respectively. There were 238 paired measurements (34 patients) in the interobserver reliability study, with an ICC = 0.92. No difference was found in the measurements obtained before and after dialysis (11.5 (4.2) vs 11.4 (4.1) mm, P = 0.2498), independently from acute body weight changes due to fluid removal. CONCLUSION: In patients with AKI, US of quadriceps femoris could represent a simple, accurate, and non-invasive method to evaluate quantitative changes in skeletal muscle.

[Metformin-associated lactic acidosis and acute kidney injury]. / Acidosi lattica associata a metformina e insufficienza renale acuta.

Metformin is recommended as the treatment of choice in patients with type 2 diabetes mellitus because of its efficacy, general tolerability and low cost. Recent guidelines have extended the use of metformin to patients with Chronic Kidney Disease (CKD) up to stage III. However, in the recent literature, cases of MALA (metformin-associated lactic acidosis) are increasingly reported. MALA is the most dangerous side effect of the drug, with an incidence rate of 2-9 cases per 100000 person-years of exposure. We report on two patients with accidental metformin overdose, severe lactic acidosis and acute kidney injury. In both cases, the usual dose of metformin was inappropriate with respect to the level of kidney dysfunction (CKD stage III). As both patients met the criteria for renal replacement therapy in metformin poisoning, they were treated effectively with sustained low-efficiency dialysis until normalization of serum lactate and bicarbonate values. Clinical status and kidney function improved and both patients could be discharged from the hospital.

[Pathophysiology of Acute Kidney Injury in sepsis]. / Fisiopatologia dell'insufficienza renale acuta nella sepsi.

Sepsis is a serious medical condition often complicated by multiorgan failure, especially in the intensive care unit setting. Acute renal failure is a frequent complication of sepsis, leading to increased hospital mortality risk and worsening of patient outcome. Despite recent advances in the treatment of sepsis and acute renal failure, the pathophysiological mechanisms of acute renal failure in sepsis is still not fully ascertained. The aim of this review is to illustrate the pathophysiological mechanisms that are involved in the development of acute renal failure in sepsis, with special regard to the systemic hemodynamic alterations, renal microvascular and inflammatory/immunological mechanisms.

[Metabolic acidosis]. / Acidosi metabolica.

Metabolic acidosis is frequently observed in clinical practice, especially among critically ill patients and/or in the course of renal failure. Complex mechanisms are involved, in most cases identifiable by medical history, pathophysiology-based diagnostic reasoning and measure of some key acid-base parameters that are easily available or calculable. On this basis the bedside differential diagnosis of metabolic acidosis should be started from the identification of the two main subtypes of metabolic acidosis: the high anion gap metabolic acidosis and the normal anion gap (or hyperchloremic) metabolic acidosis. Metabolic acidosis, especially in its acute forms with elevated anion gap such as is the case of lactic acidosis, diabetic and acute intoxications, may significantly affect metabolic body homeostasis and patients hemodynamic status, setting the stage for true medical emergencies. The therapeutic approach should be first aimed at early correction of concurrent clinical problems (e.g. fluids and hemodynamic optimization in case of shock, mechanical ventilation in case of concomitant respiratory failure, hemodialysis for acute intoxications etc.), in parallel to the formulation of a diagnosis. In case of severe acidosis, the administration of alkalizing agents should be carefully evaluated, taking into account the risk of side effects, as well as the potential need of renal replacement therapy.