Hepatorenal syndrome: an update

Update on hepatorenal Syndrome: Definition, Pathogenesis, and management

Hepatorenal syndrome (HRS) is acute kidney injury (AKI) that occurs without evidence of structural abnormalities in the kidneys in patients with liver disease. It is thought to be due to splanchnic vasculature dilatation that is associated with intense increase of renal arteries' tone, leading to renal cortex ischemia and AKI. Nitric oxide, endotoxins, neurohormonal changes, bacterial infection, high serum bilirubin and bile acids are examples for factors contributing to HRS development. Nevertheless, other unknown factors may have role in HRS pathophysiology. Hence, further discussion and research are needed to clearly understand HRS. Plasma volume restoration and vasoconstrictors are the cornerstone of HRS treatment. Others such as octreotide, noradrenaline, infection control, systemic inflammatory response prevention, shunting, and renal replacement therapy are currently used to manage HRS. Liver or combined liver and kidney transplantation is currently the ultimate cure for HRS. This review was written to help in better understanding the pathogenesis, diagnosis, and treatment options for HRS.

Pharmacokinetic determinants for the right dose of antiarrhythmic drugs

INTRODUCTION

Antiarrhythmic drugs (AADs) show a narrow therapeutic range and marked intersubject variability in pharmacokinetics (PK), which may lead to inappropriate dosing and drug toxicity.

AREAS COVERED

The aim of the present review is to describe PK properties of AADs, discussing the main changes in different clinical scenarios, such as the elderly and patients with obese, chronic kidney, liver, and cardiac disease, in order to guide their right prescription in clinical practice.

EXPERT OPINION

There are few data about PK properties of AADs in a special population or challenging clinical setting. The use and dose of AADs is commonly based on physicians' clinical experience observing the clinical effects rather than being personalized on the individual patients PK profiles. More and updated studies are needed to validate a patient centered approach in the pharmacological treatment of arrhythmias based on patients' clinical features, including pharmacogenomics, and AAD pharmacokinetics.

Hepatorenal Syndrome: Diagnosis and Treatment - newsreel

Hepatorenal syndrome (HRS) is defined as renal failure that occurs in the presence of severe acute or chronic liver disease in the absence of underlying renal pathology. Due to the functional nature of the disease and the absence of specific diagnostic markers, HRS diagnosis is determined based on positive criteria associated with excluding other causes of renal failure in patients with liver cirrhosis and ascites. Differentiation from other types of acute or chronic renal disease is extremely difficult and therapeutic options are limited, prophylactic behavior is most appropriate in patients with severe hepatic disease and risk factors for the installation of hepatorenal syndrome. Highlighting all precipitating factors of acute renal insufficiency and therapeutic modalities in order to minimize adverse events is an important step in improving the follow-up of the patients with liver cirrhosis. The prognosis is reserved especially for type 1 HRS. Liver transplantation is the best option for patients without contraindications. The therapies introduced in recent years, such as vasoconstrictor drugs or transjugular intrahepatic portosystemic shunt are effective methods in the renal function improvement.

Metastatic testicular cancer presenting with liver and kidney dysfunction treated with modified BEP chemotherapy combined with continuous hemodiafiltration and rasburicase

A 25-year-old man was admitted to our hospital complaining of right scrotal pain and upper abdominal pain. A computed tomographic scan indicated a right scrotal mass, a huge liver mass, and multiple lung masses, although there was no enlarged retroperitoneal lymph node swelling. Laboratory tests showed severe liver and kidney dysfunction and high levels of serum α-fetoprotein (11 997 ng/ml). Although needle biopsies of the testicular and liver masses were performed, the tissues were insufficient for a pathological diagnosis. As liver and kidney function worsened, we started chemotherapy with bleomycin, etoposide, and cisplatin (BEP chemotherapy), which was modified because of the liver and renal dysfunction. We also used continuous hemodiafiltration and rasburicase to prevent tumor lysis syndrome. After induction of chemotherapy, the liver and kidney dysfunction improved immediately and the high orchiectomy was performed on day 8 after chemotherapy. The pathological diagnosis was a yolk sac tumor. He underwent four courses of the BEP regimen and five courses of the TIN regimen (paclitaxel, ifosphamide, and nedaplatin), followed by the resection of liver metastases. There was no evidence of viable cells in the resected liver and no recurrence was evident at 1 year postoperatively.

Effect of renal function impairment on the mortality of cirrhotic patients with hepatic encephalopathy: a population-based 3-year follow-up study

Kidney is an important organ to clear neurotoxic substance in circulation. However, it is still unknown about the effect of renal function impairment (RFI) on the mortality of cirrhotic patients with hepatic encephalopathy (HE). We used the Taiwan National Health Insurance Database to identify 4932 cirrhotic patients with HE, hospitalized between January 1, 2007 and December 31, 2007. The enrolled patients were followed up individually for 3 years to identify their 3-year mortalities. There were 411 (8.3%) patients with RFI and 4521 (91.7%) patients without RFI. The adjusted hazard ratio (HR) of RFI for 3-year mortality was 2.03 (95% CI, 1.82-2.27). In RFI group, there were 157 (38.2%) patients with acute renal failure (ARF), 61 (14.8%) with hepatorenal syndrome (HRS), 93 (22.6%) with chronic kidney disease (CKD), and 100 (24.3%) with end-stage renal disease (ESRD). Compared with the non-RFI group, the adjusted HR of ARF for 3-year mortality was 2.57 (95% CI, 2.17-3.06), CKD 1.93 (95% CI, 1.55-2.40), ESRD 1.26 (95% CI, 1.01-1.57), and HRS 3.58 (95% CI, 2.78-4.63). Among ESRD patients, there were 99 patients receiving hemodialysis regularly. Compared with the CKD group, the adjusted HR of ESRD with hemodialysis for 3-year mortality was 0.664 (95% CI, 0.466-0.945). RFI increased the 3-year mortality of cirrhotic patients with HE, especially ARF and HRS. HE patients with ESRD receiving hemodialysis had better 3-year survival rate than those with CKD.

Hepatorenal syndrome and novel advances in its management

Hepatorenal syndrome is a complication of end stage liver disease. It is a unique form of functional renal failure related to kidney vasoconstriction in the absence of underlying kidney pathology. Hepatorenal syndrome is classified into 2 types: type-1 HRS shows a rapid and progressive decline in renal function with a very poor prognosis (median survival of about 2 weeks); type-2 HRS has a more stable kidney failure, with a median survival of 6 months; its main clinical manifestation is refractory ascites. The most appropriate therapy for HRS is liver transplantation but only a minority of HRS patients undergo the procedure due to the high mortality; survival among liver transplant recipients is lower in HRS than among their counterparts without HRS. A large body of evidence, based on observational studies and randomized controlled trials, has been accumulated in the last decade showing that terlipressin represents a milestone in the management of HRS. According to our meta-analysis of randomized trials comparing terlipressin vs. placebo (five trials, n=243 patients), the pooled rate of patients who reversed HRS by terlipressin was 8.09 (95% CI, 3.52; 18.59) (P<0.001). Among vasoconstrictors, terlipressin (a V1 vasopressin agonist) is the most widely used; however, noradrenaline is another good choice. Vasoconstrictor drugs alone or with albumin reduce mortality compared with no intervention or albumin (RR of mortality, 0.82; 95% Confidence Intervals, 0.70; 0.96) (P<0.01). Two series of patients with HRS recurrence after the first treatment have recently shown that long-term therapy with terlipressin and albumin is beneficial as a bridge to liver transplant. Nevertheless, recovery of renal function can be achieved in less than 50% of patients with HRS after terlipressin use and the recovery of renal function may also be partial in patients who are defined full responders. Renal replacement therapy should not be considered a first-line therapy for HRS Clinical trials are under way in order to assess efficacy and safety of novel therapeutic agents for the treatment of type-1 and type-2 HRS.

Pathophysiology of ascites formation in liver cirrhosis

Liver cirrhosis has a high morbidity and poses a large threat to human health worldwide. In China, viral hepatitis, especially hepatitis B, is the main pathogenic factor of liver cirrhosis. Ascites formation in cirrhosis is the result of combined action of portal hypertension and liver function impairment, and it is the most prominent clinical manifestation of decompensated cirrhosis. The understanding of pathophysiology of ascites formation can help provide more accurate treatment of this condition so as to alleviate patients' mental and economic burdens.

Hepatorenal syndrome: beyond liver failure

Critical care nurses occasionally confront patient conditions that are not common. One such condition is hepatorenal syndrome (HRS). Three primary processes contribute to regional alterations in circulation in the renal and splanchnic beds. These processes include effective hypovolemia from the massive release of vasoactive mediators, thereby underfilling circulation, systemic and splanchnic vasodilation along with renal vasoconstriction, and hyperdynamic circulation. A "second-hit" hypothesis, whereby a triggering event causes intravascular volume depletion, likely initiates the development of HRS. The idea of a second hit focuses the attention of the health care team on surveillance strategies to prevent or limit HRS in patients with advanced cirrhosis and ascites. The treatment goal is to restore systemic and splanchnic vasoconstriction, while promoting renal vasodilation, balance sodium, and achieve euvolemia. The critical care nurse must maintain ongoing education to care for the patient with this complex syndrome in order to prevent complications and death.

Acute kidney injury after hepatic ischemia and reperfusion injury in mice

Hepatic ischemia reperfusion (IR) is the leading cause of acute liver failure (ALF) during the perioperative period and patients with ALF frequently develop acute kidney injury (AKI). There is no effective therapy for AKI associated with ALF because pathomechanisms are incompletely characterized, in part due to the lack of an animal model. In this study, we characterize a novel murine model of AKI following hepatic IR. Mice subjected to approximately 70% liver IR not only developed acute liver dysfunction, but also developed severe AKI 24 h after liver injury. Mice subjected to liver IR developed histological changes of acute tubular injury including focal proximal tubular cell necrosis involving the S3 segment, cortical tubular ectasia, focal tubular simplification and granular bile/heme cast formation. In addition, there was focal interstitial edema and hyperplasia of the juxtaglomerular apparatus. Inflammatory changes in the kidney after hepatic IR included neutrophil infiltration of the interstitium and upregulation of several proinflammatory mRNAs (tumor necrosis factor-alpha, keratinocyte-derived cytokine, monocyte chemotactic protein-1, macrophage inflammatory protein-2, intercellular adhesion molecule-1). In addition, marked renal endothelial cell apoptosis was detected involving peritubular interstitial capillaries, accompanied by increased renal vascular permeability. Finally, there was severe disruption of renal proximal tubule epithelial filamentous-actin. Our results show that AKI rapidly and reproducibly develops in mice after hepatic IR and is characterized by renal tubular necrosis, inflammatory changes and interstitial capillary endothelial apoptosis. Our murine model of AKI after liver injury closely mimics human AKI associated with ALF and may be useful in delineating the mechanisms and potential therapies for this common clinical condition.

Antiarrhythmics: elimination and dosage considerations in hepatic impairment

Many drugs, including most antiarrhythmics (some of which are now of limited clinical use) are eliminated by the hepatic route. If liver function is impaired, it can be anticipated that hepatic clearance will be delayed, which can lead to more pronounced drug accumulation with multiple dosing. Consequently, the potential risks of adverse events could be increased, especially as antiarrhythmics have a narrow therapeutic index. The present review summarises the available pharmacokinetic data on the most popular antiarrhythmic drugs to identify the enzymes involved in the metabolism of the various agents and confirm whether liver disease affects their elimination. Despite long usage of some of these drugs (e.g. amiodarone, diltiazem, disopyramide, procainamide and quinidine), surprisingly few data are available in patients with liver disease, making it difficult to give recommendations for dosage adjustment. In contrast, for carvedilol, lidocaine (lignocaine), propafenone and verapamil, sufficient clinical studies have been performed. For these drugs, a marked decrease in systemic and/or oral clearance and significant prolongation of the elimination half-life have been documented, which should be counteracted by a 2- to 3-fold reduction of the dosage in patients with moderate to severe liver cirrhosis. For sotalol, disopyramide and procainamide, renal clearance contributes considerably to overall elimination, suggesting that dosage reductions are probably unnecessary in patients with liver disease as long as renal function is normal. The hepatically eliminated antiarrhythmics are metabolised mainly by different cytochrome P450 (CYP) isoenzymes (e.g. CYP3A4, CYP1A2, CYP2C9, CYP2D6) and partly also by conjugations. As the extent of impairment in clearance is in the same range for all of these agents, it could be assumed that they have a common vulnerability and that, consequently, hepatic dysfunction will affect CYP-mediated phase I pathways in a similar fashion. The severity of liver disease has been estimated clinically by the validated Pugh score, and functionally by calculation of the clearance of probe drugs (e.g. antipyrine). Both approaches can be helpful in estimating/predicting impairments in drug metabolism, including antiarrhythmics. In conclusion, hepatic impairment decreases the elimination of many antiarrhythmics to such an extent that dosage reductions are highly recommended in such populations, especially in patients with cirrhosis.