Makindo Medical Notes

Related Subjects: |Acute Kidney Injury (AKI) / Acute Renal Failure |Chronic liver disease |Cirrhosis |Alkaline phosphatase (ALP) |Liver Function Tests |Ascites Assessment and Management |Budd-Chiari syndrome |Autoimmune Hepatitis |Primary Biliary Cirrhosis |Primary Sclerosing Cholangitis |Wilson disease | |Hereditary Haemochromatosis |Alpha-1 Antitrypsin (AAT) deficiency |Non alcoholic steatohepatitis (NASH) |Spontaneous Bacterial Peritonitis |Alcoholism and Alcoholic Liver Disease

About

• Hepatorenal Syndrome (HRS): A form of acute renal failure occurring in patients with advanced liver disease and ascites. It is a serious complication often associated with cirrhosis, alcoholic hepatitis, or fulminant liver failure.
• There are two types of HRS (Type 1 and Type 2), both of which share the same basic pathophysiology: intense renal vasoconstriction due to arterial underfilling and systemic vascular changes.

Aetiology

• Nitric Oxide (NO): Implicated in the pathophysiology of HRS. Excessive production of NO leads to splanchnic vasodilatation, which causes a reduction in systemic vascular resistance.
• Splanchnic Vasodilatation: The dilation of blood vessels in the splanchnic circulation reduces effective blood volume, triggering compensatory mechanisms that cause renal vasoconstriction.
• Renal Vasoconstriction: Leads to reduced renal perfusion, resulting in oliguria (low urine output) and acute kidney injury despite the absence of structural kidney damage.

Clinical Features

• Oliguria: Marked reduction in urine output.
• Hypotension: Low blood pressure, commonly seen in patients with advanced liver disease due to reduced systemic vascular resistance.
• Signs of Chronic Liver Disease: Patients usually present with jaundice, ascites, and hepatic encephalopathy, in addition to renal symptoms.

Comparing types

Investigations

• Rising Urea and Creatinine: Indicative of renal failure, with no significant structural damage to the kidneys.
• No Proteinuria: Absence of protein in the urine, which helps differentiate HRS from intrinsic renal diseases.
• Low Urinary Sodium: Urinary sodium concentration is typically < 10 mmol/L, reflecting reduced renal perfusion.
• Urine/Plasma Osmolarity: The urine-to-plasma osmolarity ratio is usually > 1.5, indicating concentrated urine despite low renal function.

Management

• Albumin Infusions: Used to expand plasma volume and improve renal perfusion.
• Terlipressin: A vasopressor that helps counteract the splanchnic vasodilatation and improves renal blood flow by constricting blood vessels.
• Haemodialysis: Not typically indicated, as it does not improve the underlying condition or prognosis of HRS.
• Liver Transplantation: The definitive treatment for HRS, offering the potential for renal function recovery in patients who survive to receive a transplant.
• Prognosis: Poor overall, particularly for Type 1 HRS, with high mortality rates without liver transplantation.

Type II Hepatorenal Syndrome (HRS)

• Type II HRS is less severe than Type I, with more gradual renal insufficiency.
• It is primarily characterized by diuretic-resistant ascites, and renal dysfunction progresses more slowly than in Type I.
• Type II patients may still experience significant morbidity and a poor prognosis without liver transplantation.