Liver Disease: Diagnostic Evaluation
Guest: Dr. David Koch – Gastroenterology-Hepatology
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I am Dr. Linda Austin. I am interviewing Dr. David Koch who is Assistant Professor of Medicine and a specialist in liver disease here at the Digestive Disease Center. Dr. Koch, I am sure you become involved in the evaluation of many patients who are referred in by their general practitioners, their internists, for evaluation of liver disease. When you start to do a diagnostic evaluation, what are the first studies that you order?
Dr. David Koch: In general, patients that are referred for liver disease, often times it is for abnormal liver tests. Frequently that is elevation of liver enzymes, which are AST and ALT, which suggest that there may ongoing inflammation or hepatitis. But, depending on the nature of the abnormal liver test, it will guide us into how we evaluate the underlying problem.
Dr. Linda Austin: Many people may not understand what liver enzymes are, what they do and why they are elevated when they have liver disease. What are those enzymes and why do they go up when there is inflammation of the liver?
Dr. David Koch: The liver enzymes are AST and ALT. They are located in the hepatocytes, which are the main liver cells. In general, they are elevated with an increased turnover or death of the liver cells which may be the result of inflammation. When the levels are elevated, it just suggests that there is ongoing inflammation and increased turnover of liver cells in the liver itself. It does not determine what the cause of that is.
Dr. Linda Austin: So, in other words, it is a marker for liver disease because the cells are dying? Are they dying, then, and spilling out, or releasing, those liver enzymes that normally would be packaged within the cells?
Dr. David Koch: Exactly.
Dr. Linda Austin: So, then, you begin with blood work and the blood work that you would order, to start with, would include, what? What are you looking for?
Dr. David Koch: It depends, again, on the pattern of the liver test. AST and ALT are only two components of the hepatic panel. If, in general, it is the predominance of the abnormality, or these enzymes, then we look for disorders that would potentially cause inflammation of the liver and, hence, their elevation. Those things include viral hepatitis, autoimmune hepatitis and a history for drugs. Often times, an elevation of these enzymes may be a result of drugs that are being taken, either prescribed or over-the-counter.
Dr. Linda Austin: How about viral hepatitis? What would lead you to suspect viral hepatitis as a cause of liver disease?
Dr. David Koch: There are risk factors for viral hepatitis. Those risk factors include things like a history of IV drug use, nasal cocaine, which is a bit controversial as far as potential for transmitting viral hepatitis. But, tattoo placement, blood transfusion and/or promiscuous sexual activity, those things may suggest viral hepatitis. But, often times, up to 10 or 20 percent of cases, we do not have a classic risk factor. So, based, again, on the pattern of the liver test, with it predominantly being elevation of AST and ALT, we will check them for the presence of viral hepatitis in the blood.
Dr. Linda Austin: I understand that viral hepatitis can be very common in hospital workers. Is that correct?
Dr. David Koch: Well, hepatitis C could be transmitted to hospital workers by needle stick. It is a fairly uncommon cause of transmission. Hepatitis B, in general, is probably less likely to be transmitted because healthcare workers are required to be vaccinated against hepatitis B before they are allowed to work in the hospital. That includes medical students enrolled in medical school, nursing staff, physicians, and support staff that could be at risk or in contact with needles or blood products. So, unless they were not to mount an immune response to the vaccine, they should be protected against hepatitis B transmission.
Dr. Linda Austin: How about alcoholic cirrhosis, or alcoholic hepatitis? What are the markers for that?
Dr. David Koch: Actually, there really are very few markers for alcoholic liver disease or alcoholism in general. There are some suggestive patterns on the liver panel that would suggest a potential for alcohol use, specifically, the ratio of the enzyme levels, the AST and ALT enzymes that I mentioned earlier. But, in general, we have very few bio markers or markers that we can check in the blood to determine if the patient is actively consuming alcohol. Additionally, history for the amount of alcohol use, or abuse, is often a poor marker for the amount of alcohol a patient is consuming. So, to actually determine how much alcohol one is consuming or whether it is the cause of liver disease, sometimes, can be difficult.
Dr. Linda Austin: Can you evaluate the liver for tumors, whether benign or malignant, through blood work?
Dr. David Koch: Blood work is actually a poor way to try to evaluate for liver tumors. There is a marker, alpha fetoprotein (AFP), which, if elevated, might suggest there to be hepatocellular carcinoma or a primary cancer in the liver. But, it does not need to be elevated for hepatocellular carcinoma to be present and even if elevated, hepatocellular carcinoma may not be there. The better way to evaluate for tumors, or masses, in the liver would be radiographically, either with CT scan or MRI.
Dr. Linda Austin: Now, let’s imagine that comes back positive, that it looks as if there is some sort of tumor in the liver. Are you, then, the person who would follow a patient for that, or do you refer them at that point on to the oncologist?
Dr. David Koch: Actually, in general, the patients with hepatocellular carcinoma are evaluated and managed by the hepatologists and liver transplant surgeons. Depending on the size or number of tumors, and if the patient were an acceptable candidate, the treatment of choice, actually, would be transplantation. There are other options that we use to treat hepatocellular carcinoma, but those decisions generally are made by the hepatologists in coordination with the liver transplant surgeons as well as the interventional radiologists who have several different modalities to treat hepatocellular carcinoma.
Dr. Linda Austin: Just to clarify, hepatocellular carcinoma is a cancer that starts in the liver, not one that has spread to the liver, as happens with so many different kinds of cancer?
Dr. David Koch: Correct. It is a primary liver tumor, or malignancy, that occurs in the liver. It has not been the result of spread, or metastasis, to the liver.
Dr. Linda Austin: Dr. Koch, thank you very much.
Dr. David Koch: Thank you.
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