Haemodialysis in 'hepatorenal syndrome': report on two cases

Management of Renal Complications of Liver Disease

Included among the most important renal complica tions of liver disease is progressive sodium retention leading to the formation of edema and ascites and the hepatorenal syndrome (HRS). When ascites is refractory to conventional treatment, the use of invasive proce dures such as reinfusion or dialytic ultrafiltration of as cites or the peritoneovenous shunt may be indicated. The possibility that continuous arteriovenous hemo filtration may be useful in removing fluid in patients who would not otherwise tolerate traditional hemodialysis has, because of its recent availability, been raised. Ther apy of HRS continues to be one of the most intriguing and vexing problems in clinical medicine. The use of hemodialysis with polyacrylonitrile membranes may be helpful in certain patients with HRS, especially in those with acute reversible liver injury. Although the peri toneovenous shunt has been reported to correct the renal functional disturbance, the results of the only two controlled studies available are inconclusive.

Liver disease is frequently accompanied by a variety of alterations in renal function and electrolyte me tabolism [1]. These complications of liver disease range in severity from the clinically unimportant to problems requiring prompt and vigorous thera peutic intervention. In the present review, empha sis is placed on the management of the abnor malities of renal sodium handling and on acute intrinsic renal failure (ATN) and the hepatorenal syndrome (HRS), which often supervene in patients with severe liver disease. The reader is referred to Epstein [1,2] and Perez and colleagues [3] for more detailed expositions of the use of dialysis and ultrafiltration in treating renal complications of liver disease.

Practical recommendations for the treatment of ascites and its complications

Ascites is one of the earliest and most common complications of patients with cirrhosis, and is associated with complications such as dilutional hyponatraemia, renal dysfunction and spontaneous bacterial peritonitis. The treatment of ascites has been based on the combination of a low-sodium diet and the administration of diuretics. The reintroduction of paracentesis and the recent introduction of the transjugular intrahepatic portosystemic shunt (TIPS) are the most relevant innovations in the treatment of ascites during the past 2 decades. The development of ascites is closely related to renal disturbances of functional origin, including the hepatorenal syndrome. A new definition of hepatorenal syndrome has been proposed recently and 2 different types have been defined (type I or progressive, and type III or stable). Although no effective therapy exists for this syndrome, the use of therapeutic methods (TIPS, vasoconstrictor agents, dialysis) to temporarily improve renal function and act as a 'bridge' to liver transplantation, may be of most benefit. The use of potent and safe antibiotics has improved the resolution rate and survival of patients with spontaneous bacterial peritonitis. In addition, the use of oral antibiotics will simplify the management of this condition in the near future. Finally, prophylactic antibiotic regimens represent a major step forwards in the prevention of spontaneous bacterial peritonitis in subsets of cirrhotic patients with a great risk of developing this complication.

Risk factors and outcome of 107 patients with decompensated liver disease and acute renal failure (including 26 patients with hepatorenal syndrome): the role of hemodialysis

The prognosis of acute renal failure in patients with preexisting liver decompensation is poor, and hemodialysis is considered futile, especially for hepatorenal syndrome (HRS). Since we observed a more favorable outcome in some patients, we retrospectively evaluated 107 patients with decompensated liver disease and acute renal failure (serum creatinine > 200 mumol/L) treated at the medical department of a university hospital in a 10-year period (1980-1990). HRS in the strict sense (urine-Na < 20 mmol/L while on furosemide) was diagnosed in 26 of 107 patients (24%). Renal function remained compensated in 25 patients, while 82 patients fulfilled the criteria for dialysis treatment (creatinine > 500 mumol/L and/or diuresis < 500 mL/day). In contrast to the current doctrine, 38 of the 82 patients were given hemodialysis (46%). Using the Cox proportional hazard model, the relative risk (presence vs. absence of a risk factor) of dying was increased 8.2-fold (3.9-17.2) in patients with thrombocytopenia < 100/nL, 3.9-fold (1.4-11.3) in those with hepatic encephalopathy and prothrombin time < 30%, 2.8-fold (1.6-4.8) in patients with malignoma, and 2.7-fold (1.5-4.8) in patients not submitted to dialysis despite its indication. In the CART statistics (classification and regression trees), the 33 patients with the poorest outcome were characterized exclusively by thrombocytopenia < 100/nL. HRS in the strict sense was not an independent risk factor. The CART group of 43 patients with favorable prognosis (compensated renal failure or treatment by hemodialysis, absent malignancy) had a 1-year survival rate of 38%. We conclude that thrombocytopenia, encephalopathy, and malignoma, but not HRS per se, are fatal signs that make hemodialysis futile in patients with acute renal failure and decompensated liver disease.

Immunohistochemical distribution of renal prostaglandin endoperoxide synthase and prostacyclin synthase: diminished endoperoxide synthase in the hepatorenal syndrome

To evaluate possible causes of the diminished prostaglandin production in advanced hepatorenal syndrome, prostaglandin endoperoxide synthase and prostacyclin synthase were localized and semiquantitated by immunofluorescence in postmortem, biopsy and nephrectomy renal tissues. In normal kidneys, antiprostacyclin synthase serum caused intense staining in peritubular capillaries, in the adjacent renal interstitial cells and in glomerular mesangial regions. Antiprostaglandin endoperoxide synthase serum caused staining of collecting duct epithelial cells, cells of the thin ascending limb and possibly glomerular mesangial cells. Prostacyclin synthase-positive staining was graded 5+ (scale of 0+ to 5+) in all kidney samples. Medullary collecting tubule prostaglandin endoperoxide synthase-positive staining was graded 4+ or 5+ in kidney samples from patients with acute tubular necrosis or acute tubulointerstitial nephritis and from patients with liver failure without the hepatorenal syndrome. However, prostaglandin endoperoxide synthase-positive staining was markedly diminished or absent (average 1+) in patients with the hepatorenal syndrome. These data suggest that loss of the medullary prostaglandin endoperoxide synthase is the cause of diminished urinary prostaglandin E2 excretion in the hepatorenal syndrome.

Calcium-channel blockers and the hepatorenal syndrome

It is suggested that calcium-channel blockers may be the agents of choice for treating the renal dysfunction associated with the hepatorenal syndrome because these agents may be effective in reversing the episodic renal vasospasm which characterizes this disorder.

Pharmacology and therapeutic use of low-dose dopamine

The renal pharmacologic effects of intravenous dopamine in doses of 0.5-3.0 micrograms/kg/min include increases in renal blood flow, glomerular filtration rate, solute excretion, and urine flow. Clinical studies revealed that low-dose dopamine can reverse oliguria, but these studies were poorly controlled, were confounded by the use of other diuretics, had small patient populations, and often did not evaluate mortality or long-term renal function. When used in low doses, side effects are rarely seen. Because of dopamine's effect on hepatic and renal function, changes in drug clearance may occur. Low-dose dopamine may be considered in the early course of oliguric patients; however, specific advantages over other diuretic therapy have not been established.

Role of renal prostaglandins and the effects of nonsteroidal anti-inflammatory drugs in patients with liver disease

Renal prostaglandins have several key functions in patients with severe liver disease and ascites. Increased activity of vasodilatory prostaglandins counters the underlying impairment in renal perfusion and the effects of vasoactive hormones. Prostaglandins also participate in renin secretion, renal diluting ability, sodium excretion, the action of diuretics, and, possibly, the development of the hepatorenal syndrome. Nonsteroidal anti-inflammatory drugs inhibit these compensatory actions of prostaglandins and cause a functional reduction in glomerular filtration rate and an impairment in sodium and fluid excretion. The severity of these nephrotoxic effects depends on the potency of the drug in inhibiting renal prostaglandins and on patient susceptibility. Patients with ascites and avid sodium retention, sodium-restricted diets, or concurrent diuretic use are most at risk. If nonsteroidal anti-inflammatory drugs must be administered to these patients, the type of drug should be carefully selected and renal function should be closely monitored.