Chapter 4: How Doctors Diagnose Liver Disease and What Treatment Can Achieve
Liver disease can have many causes, and identifying the underlying condition is essential for choosing the right treatment. A person with metabolic fatty liver disease may need a different approach from someone with chronic viral hepatitis, alcohol-associated liver disease, autoimmune hepatitis, or bile duct obstruction.
The diagnostic process combines medical history, physical examination, laboratory tests, and, when appropriate, imaging or specialized investigations. Symptoms involving the feet or ankles may contribute to the assessment, but they are only one part of the overall picture.
Medical history and physical examination
A clinician may ask when symptoms began, whether they are getting worse, and whether the patient has noticed jaundice, abdominal swelling, itching, unusual bruising, changes in urine or stool color, or unexplained weight changes.
Medical history can provide important clues. Questions may cover alcohol consumption, diabetes, obesity, high cholesterol, viral hepatitis risks, family history, previous liver problems, and medication or supplement use.
Patients should describe all medicines and supplements they take, including products purchased without a prescription. Some medicines can cause liver injury in particular circumstances, and herbal supplements can also be associated with liver damage. However, patients should not stop essential prescribed treatment without medical advice.
During the examination, the clinician may look for jaundice, abdominal fluid accumulation, swelling in the legs, muscle loss, bruising, and other signs of chronic illness. The examination may also help identify alternative explanations for the symptoms.
No single physical sign can reliably establish the type or severity of liver disease. Further testing is often needed.
Understanding liver blood tests
Blood tests commonly play an important role in evaluating suspected liver disease, but the results require careful interpretation.
Alanine aminotransferase, or ALT, and aspartate aminotransferase, or AST, are enzymes that may rise when liver cells are injured. These enzymes can be elevated in many conditions, and AST can also come from tissues outside the liver.
Alkaline phosphatase and gamma-glutamyl transferase may help clinicians investigate problems involving bile flow or other conditions affecting the liver and biliary system. Bilirubin testing can identify abnormalities in the processing or elimination of bilirubin.
Albumin and prothrombin time or international normalized ratio, known as INR, may help assess aspects of the liver's ability to produce proteins. Platelet counts can provide additional clues, including in some people with advanced fibrosis or portal hypertension.
Importantly, normal liver enzyme results do not always exclude significant chronic liver disease. Conversely, elevated enzymes do not automatically mean that a person has cirrhosis.
Doctors interpret the results alongside the medical history, examination, and other tests.
Imaging and assessment of liver scarring
Ultrasound is frequently used to examine the liver and surrounding structures. It can help identify certain changes in liver appearance, fluid accumulation, bile duct abnormalities, and other findings.
Other imaging methods, including computed tomography and magnetic resonance imaging, may be used when more detailed information is needed.
Elastography is a technique that estimates liver stiffness and can help assess the likelihood of fibrosis. It is useful in selected patients because fibrosis may progress without producing obvious symptoms.