Hepatorenal syndrome (HRS) is a severe complication that can arise in individuals with advanced liver disease. It is a specific type of kidney failure where the kidneys are not initially damaged but cease to function correctly due to a failing liver. This condition is a functional issue, meaning the problem lies in how the kidneys are operating rather than in their physical structure. This distinction explains why treatments are aimed at both the kidneys and the liver.
How Liver Failure Causes Kidney Failure
The development of hepatorenal syndrome begins with the consequences of severe liver disease, most often cirrhosis. A failing liver leads to the widening of blood vessels in the splanchnic circulation, the network of arteries supplying abdominal organs like the stomach, intestines, and spleen. This vasodilation causes a significant amount of the body’s blood to pool in this expanded circulatory system.
This pooling effect results in a drop in overall blood volume and pressure. The body’s internal systems misinterpret this change as a massive loss of blood. In response, hormonal and nerve signals are triggered to preserve blood flow to essential organs, such as the brain and heart.
This protective mechanism has a detrimental effect on the kidneys. To increase blood pressure elsewhere, the body severely constricts the blood vessels that supply the kidneys. This renal vasoconstriction dramatically reduces blood and oxygen reaching the kidney tissues, impairing their ability to filter waste from the blood and leading to their functional failure.
Recognizing Symptoms and Underlying Causes
The primary trigger for hepatorenal syndrome is advanced liver disease. Cirrhosis, which is scarring of the liver, is the most common precursor. This scarring can result from chronic conditions like long-term alcohol misuse, viral hepatitis B or C, and nonalcoholic fatty liver disease. Acute liver failure can also precipitate HRS, although this is less common.
Symptoms of HRS are often layered on top of the existing signs of chronic liver disease. A primary indicator is a sharp reduction in urine output, which leads to fluid retention. This causes rapid weight gain, swelling in the legs (edema), and a significant buildup of fluid in the abdomen, a condition known as ascites.
Other symptoms reflect the underlying liver failure, such as jaundice (a yellowing of the skin and eyes), persistent fatigue, and confusion or mental fogginess, referred to as hepatic encephalopathy.
The Diagnostic Process
Diagnosing hepatorenal syndrome is a process of elimination, as there is no single test to confirm it. Physicians must first rule out other potential causes of acute kidney injury. This involves reviewing the patient’s medical history to exclude factors such as shock, bacterial infections, or the use of medications that are toxic to the kidneys (nephrotoxic drugs).
The diagnosis relies on a set of established criteria. A patient must have advanced liver disease with ascites and a documented rapid decline in kidney function, measured by a rise in serum creatinine levels. Another step involves administering intravenous albumin and discontinuing any diuretic medications for at least 48 hours.
If kidney function does not improve after these measures, and other causes have been excluded, a diagnosis of HRS is made.
Treatment Approaches for Hepatorenal Syndrome
The management of hepatorenal syndrome is focused on two simultaneous goals: reversing immediate kidney dysfunction and addressing the underlying liver disease. The only definitive, long-term solution for HRS is a liver transplant, which corrects the root cause. However, not all patients are candidates for a transplant, and this option is not immediately available, so other treatments are used to stabilize the patient.
For immediate management of kidney failure, a combination of medications is used to counteract the circulatory changes. This involves administering vasoconstrictors, which are drugs that narrow blood vessels, like terlipressin, often paired with intravenous albumin infusions. The vasoconstrictors help correct the widening of the splanchnic blood vessels, while albumin helps increase the volume of fluid within the bloodstream, improving blood flow to the kidneys.
In some cases, a transjugular intrahepatic portosystemic shunt (TIPS) procedure may be considered. A TIPS procedure creates a new connection between blood vessels in the liver, redirecting blood flow to relieve pressure in the portal vein. This can serve as a bridge to a liver transplant or as a palliative measure.
For patients whose kidney function does not recover with medical therapy, renal replacement therapy, such as dialysis, might be used. This is also seen as a temporary bridge to a liver transplant and does not improve long-term survival on its own.