From the Guidelines
Elevated gamma-glutamyl transferase (GGT) is primarily caused by liver disease, particularly cholestatic liver disease, as indicated by concomitantly elevated alkaline phosphatase (ALP) levels, as seen in conditions such as primary biliary cholangitis, primary sclerosing cholangitis, and intrahepatic or extrahepatic bile duct obstruction 1. The causes of elevated GGT can be multifaceted, including:
- Liver conditions like hepatitis, cirrhosis, and fatty liver disease
- Bile duct obstruction, which can be due to choledocholithiasis, malignant obstruction, or biliary strictures
- Certain medications that can induce cholestasis, such as phenytoin and carbamazepine
- Other conditions like pancreatic disease, heart failure, and kidney disease GGT is an enzyme found in the liver, bile ducts, and other tissues, and its elevation typically indicates that these organs are under stress or damaged. Key points to consider when evaluating elevated GGT levels include:
- The presence of other elevated liver function tests, such as ALP, which can help confirm the liver as the source of elevated GGT
- The patient's clinical history and medications, which can provide clues to the underlying cause of elevated GGT
- The potential need for imaging of the biliary tree to determine the etiology of extrahepatic or intrahepatic cholestasis, as suggested by the American College of Radiology 1.
From the Research
Causes of Elevated GGT
Elevated gamma-glutamyltransferase (GGT) levels can be caused by various factors, including:
- Liver dysfunction and alcohol abuse 2, 3
- Obstructive liver disease 3
- High alcohol consumption 3
- Use of enzyme-inducing drugs 3
- Nonalcoholic fatty liver disease (NAFLD) 4, 5, 6
- Increased risk of mortality, incident type 2 diabetes, cardiovascular events, chronic kidney disease, and cancer 2
- Fatty liver change, with high triglyceride (TG) levels being an independent predictor of fatty changes in individuals with frequently elevated GGT levels 4
Associated Risk Factors
The following risk factors are associated with elevated GGT levels:
- Body mass index (BMI) 4
- Hemoglobin 4
- Alanine aminotransferase (ALT) 4, 5, 6
- Albumin 4
- Triglyceride (TG) levels 4, 6
- Fasting blood sugar 4
- High-density lipoprotein levels 4, 6
- Platelet counts 4
Treatment and Management
Treatment and management of elevated GGT levels may involve:
- Ursodeoxycholic acid (UDCA) therapy, which can improve liver function tests and reduce the risk of atherosclerosis, steatosis, and liver fibrosis in patients with NAFLD 5, 6
- Vitamin E therapy, which can be used in combination with UDCA to treat nonalcoholic steatohepatitis (NASH) 5
- Lifestyle modification, including diet and exercise, to achieve weight loss and improve liver function 6