Hepatorenal Syndrome: Causes, Symptoms, Diagnosis, Treatment, and Prevention
People with advanced cirrhosis or acute liver failure can suffer from hepatatorenal syndrome (HRS), a serious complication of liver disease characterized by a malfunctioning kidney. HRS is a type of acute kidney injury (AKI) that requires urgent medical attention and is life-threatening.
Causes of Hepatorenal Syndrome
HRS is caused by a combination of factors that affect the blood flow and function of the kidneys. These factors include:
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As a result of scarring and damage to the liver, portal hypertension occurs when the blood pressure in the portal vein (which connects the digestive organs to the liver) is too high. The blood supply to the kidneys is reduced when blood bypasses the liver and flows into other veins due to portal hypertension.
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An abdominal blood vessel (the splanchnic circulation) becomes widened and relaxed due to portal hypertension and other factors when it becomes splanchnic vasodilated. As a result, more blood pools in the abdominal organs, reducing the blood flow to the kidneys.
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Low blood pressure and low blood volume cause systemic vasoconstriction, which occurs when blood vessels in the body (the systemic circulation) become narrowed and constricted. As a result, the body attempts to preserve blood flow to the vital organs, such as the brain and heart, at the expense of the kidneys.
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A condition called renal vasoconstriction occurs when the blood vessels in the kidney (the renal circulation) narrow and constricted as a result of hormones and chemicals that affect blood pressure and fluid balance. In this case, the kidneys receive less blood and oxygen, which impairs their ability to filter waste and toxins.
Symptoms of Hepatorenal Syndrome
HRS usually develops gradually over weeks or months, but it can also occur suddenly in some cases. The symptoms of HRS are similar to those of liver failure and may include:
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Swelling of the abdomen (ascites) and legs (edema) due to fluid retention
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Yellowing of the skin and eyes (jaundice) due to the buildup of bilirubin, a waste product of red blood cells
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Confusion, drowsiness, and coma (hepatic encephalopathy) due to the buildup of ammonia and other toxins in the brain
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Bleeding from the nose, mouth, or rectum (variceal hemorrhage) due to the rupture of enlarged veins in the esophagus, stomach, or intestines
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Dark or bloody urine (hematuria) or no urine output (anuria) due to the reduced function of the kidneys
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Nausea, vomiting, and loss of appetite due to the impaired digestion and absorption of food
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Fatigue, weakness, and weight loss due to the loss of muscle mass and energy
Diagnosis of Hepatorenal Syndrome
HRS is diagnosed based on the following criteria:
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The presence of chronic or acute liver disease with portal hypertension
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The presence of AKI, defined as a rapid increase in serum creatinine (a marker of kidney function) by 50% or more, or a decrease in urine output to less than 500 ml per day
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The absence of other causes of AKI, such as infection, dehydration, medication, or obstruction of the urinary tract
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The lack of improvement in kidney function after stopping potentially nephrotoxic drugs (such as diuretics, antibiotics, or nonsteroidal anti-inflammatory drugs) and giving intravenous fluids for at least 48 hours
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The lack of response to treatment with albumin (a protein that helps maintain fluid balance) and vasoconstrictors (drugs that narrow the blood vessels and increase blood pressure)
HRS is classified into two types, depending on the severity and progression of the condition:
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HRS Type 1: This is the more severe and rapidly progressive form of HRS, characterized by a doubling of serum creatinine to more than 2.5 mg/dl or a 50% decrease in creatinine clearance (a measure of kidney function) within two weeks. HRS type 1 is associated with high mortality rates and requires dialysis or liver transplantation often.
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HRS type 2: This is a less severe and more chronic form of HRS characterized by a moderate and stable rise in serum creatinine to more than 1.5 mg/dl or a 50% reduction in creatinine clearance in more than two weeks. Medical treatment is often successful in treating type 2 HRS, which has a lower mortality rate.
Treatment of Hepatorenal Syndrome
The treatment of HRS depends on the type and severity of the condition, as well as the availability of resources and facilities. The main goals of treatment are to improve kidney function, reduce portal hypertension, and prevent complications. The treatment options include:
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Drugs such as albumin and vasoconstrictors (such as terlipressin, norepinephrine, or midodrine) can be used as medical therapy to increase blood flow and pressure to the kidneys. For type 2 HRS, medical therapy is more effective than for type 1 HRS, and it can also be used as a bridge to other treatments.
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Through the use of a stent (a metal mesh tube), the transjugular intrahepatic portosystemic shunt (TIPS) bypasses the portal vein and the liver vein (the vein that drains blood from the liver). As a bridge to liver transplantation or for type 2 HRS, TIPS reduces portal hypertension and improves blood flow to the kidneys, but it also increases the risk of hepatic encephalopathy and liver failure.
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In renal replacement therapy (RRT), artificial devices are used to perform the kidney's function, such as hemodialysis (filtering blood through a machine) or peritoneal dialysis (filtering blood through the abdomen lining). The main use of RRT is for type 1 HRS or as a bridge to liver transplantation, but it also has a number of limitations and complications, including infection, bleeding, and fluid overload.
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A liver transplant is the definitive treatment for HRS, since it replaces the diseased liver with a healthy one. In addition to reversing liver failure and kidney failure, liver transplantation has risks and challenges, including rejection, infection, and a shortage of donors.
Prevention of Hepatorenal Syndrome
HRS can be prevented by preventing or treating the underlying causes of liver disease, such as viral hepatitis, alcohol abuse, or autoimmune disorders. Other preventive measures include:
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Avoiding or limiting the use of drugs that can damage the liver or the kidneys, such as acetaminophen, NSAIDs, or antibiotics
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Maintaining a healthy weight and diet, and avoiding foods that can worsen liver disease, such as salt, fat, or sugar
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Getting regular check-ups and blood tests to monitor liver and kidney function, and following the doctor’s advice on medication, diet, and lifestyle
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Seeking medical attention promptly if symptoms of liver disease or kidney disease develop, such as jaundice, ascites, confusion, or dark urine
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Getting vaccinated against hepatitis A and B, and avoiding exposure to hepatitis C and other blood-borne infections
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Joining a support group or seeking counseling to cope with the emotional and social aspects of living with liver disease and kidney disease
A serious and potentially fatal complication of liver disease, hepatorenal syndrome requires immediate medical attention. Understanding the causes, symptoms, diagnosis, treatment, and prevention of HRS will help you protect your liver and kidneys, and improve your quality of life.
