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Hepatology

By Dr. Jim Ferguson

I used to like liver and onions; at least until I worked at an inner city hospital during my internal medicine training.  I’ve seen some bad livers in my day, and I can no longer stomach this traditional English dish.  That being said, the English eat some strange things and aren’t noted for culinary gifts.

The liver is a large internal organ which lies under the right lower rib cage.  It is involved in a host of metabolic functions: the manufacture of proteins which hold water in our blood vessels limiting edema; the production of coagulation proteins that prevents abnormal bleeding as in hemophilia; the production of lipids and their carrier proteins which allow fats to circulate in our water-based blood stream; the liver also helps regulate blood sugar during fasting; and the liver aids in the removal of toxins and metabolizes (breaks down) medications.  Obviously, liver dysfunction can result in serious medical issues.

Liver disease can occur rapidly with viral infection or from poisoning, such as occurs with acetaminophen (Tylenol) overdose.  Additionally, there are increasing reports of liver damage from over-the-counter nutritional supplements and herbal preparations.

Liver disease is often silent until late in the course of the illness, perhaps because ninety percent of the liver must be destroyed before severe symptoms arise.  The liver has a marked ability to regenerate itself and repair damage.  This regeneration even allows healthy people to donate a part of their own liver to someone with liver failure.

Chronic liver disease is often discovered by abnormal liver function tests found on blood panels.  Any condition that irritates the liver cells or impairs the circulation of bile fluids within the liver can cause an excessive release of liver cell enzymes which are registered  in blood samples.  Enzymes are proteins that facilitate chemical reactions, and the human body is a chemical factory dependent on these chemical reactions.  There are measurable levels of enzymes in everyone’s blood stream.  Disease is suggested by elevated liver enzyme levels.

The word cirrhosis often confuses people.  This term simply means scarring of the liver. Cirrhosis does not suggest a cause for the scarring, and is not a synonym for alcohol abuse.  Unfortunately, there remains a social stigma with the term cirrhosis.  Lots of conditions can lead to a scarred liver including chronic viral infections as well as alcoholism.

Similarly, the term hepatitis is often misunderstood.  Hepatitis is a nonspecific term for inflammation of the liver.  The suffix -itis means inflammation of any area of the body.  When coupled with the Greek term for liver (hepar-) you get the nonspecific descriptive term, hepatitis.  Actually, you can combine -itis with other areas of the body yielding, for example, derma-itis (inflamed skin), arthron-itis (inflamed joints), etc.

When the American food and water supply was less secure, acute infectious hepatitis from the hepatitis A virus was much more common.  Now the greatest risk for this infection is foreign travel with exposure to unsafe food and water since the virus is shed in feces.  Fortunately, this virus rarely causes death and does not lead to chronic hepatitis or scarring.  Additionally, there is an effective vaccination for those at higher risk of hepatitis A.

Greater problems occur with type B and C hepatitis viruses which are spread through blood and body fluid contact.  These agents can cause acute liver inflammation, but can also lead to chronic infection and cause scarring of the liver.  There is an effective vaccination for hepatitis B virus, but unfortunately not one for hepatitis C.

There are more unusual alphabet viruses that can inflame the liver, designated as hepatitis D and E.  Even the herpes family of viruses (fever blister viruses, chicken pox and shingles viruses, and mononucleosis/cytomegalovirus agents) can cause liver inflammation.  Additionally, blocked bile ducts from gallstones or cancer lead to liver enzyme elevation.  In some cases of abnormal liver enzymes, doctors check for congenital metabolic conditions or lupus-like syndromes to explain the hepatitis.

There is no treatment for hepatitis A infection, and the treatment of chronic infection with hepatitis B and C viruses remains problematic.  A recent paper in the NEJM (New England Journal of Medicine) described exciting new therapy options for hepatitis C infection even in the viral subtype that has historically been very resistant to treatment.

There is another major cause of liver disease that is increasing because America is overweight.  Studies show that two-thirds of us are either overweight or obese.  The latter is a medical term for those whose BMI (body mass index) is 30 or greater (normal BMI is 20-25).  Morbid obesity refers to those at least 100 pounds over their ideal body weight or who have a BMI of 40 or greater.  The BMI better defines weight and body fat than just our scales.  You can calculate your body mass index:

BMI = weight in Kg / height in meters²  OR

BMI = weight in lbs / height in inches²

Obesity is important not only for its association with diabetes and vascular disease, but obesity also causes fatty deposits in the liver.  In fact, the medical condition NASH (non alcoholic steatohepatitis) has replaced chronic alcohol and viral infection as the most common cause of an inflamed or scarred (cirrhotic) liver.  NASH is defined as the accumulation of fat (steato-) in the liver producing inflammation (hepatitis) which can lead to cirrhosis.

Acute hepatitis occurs suddenly and acts like the “flu” and often causes jaundice (yellowing of the skin and eyes).  Chronic liver disease is more subtle with symptoms of fatigue or personality changes.  Often abnormalities of white blood cells and platelets occur as a result of alterred circulation in a scarred liver.

This essay may be too techy for some, and I admit the study of liver disease (hepatology) is not my passion.  But, there are some simple take home points: be careful in your dating and avoid the second slice of pie.

 

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