January is Love Your Liver Awareness Month.
January is often a time that people take stock after the Christmas period but this year it is even more important as the numbers at risk have also increased during the Covid-19 pandemic. Many people have increased their alcohol consumption and gained weight during lockdown – the two biggest risk factors for developing liver disease.
WHAT IS THE LIVER? WHAT IS ITS FUNCTION?
The liver has multiple functions. It makes many of the chemicals required by the body to function normally, it breaks down and detoxifies substances in the body, and it also acts as a storage unit.
Hepatocytes (hepar=liver + cyte=cell) are responsible for making many of the proteins (protein synthesis) in the body that are required for many functions, including blood clotting factors, and albumin, required to maintain fluid within the circulation system. The liver is also responsible for manufacturing cholesterol and triglycerides. Carbohydrates are also produced in the liver and the organ is responsible for turning glucose into glycogen that can be stored both in the liver and in the muscle cells. The liver also makes bile that helps with food digestion.
The liver plays an important role in detoxifying the body by converting ammonia, a byproduct of metabolism in the body, into urea that is excreted in the urine by the kidneys. The liver also breaks down medications and drugs, including alcohol, and is responsible for breaking down insulin and other hormones in the body.
The liver is also stores vitamins and chemicals that the body requires as building blocks. These includes:
- vitamin B12,
- folic acid,
- iron required to make red blood cells,
- vitamin A for vision,
- vitamin D for calcium absorption, and
- vitamin K to help the blood to clot properly.
IS THE LIVER A GLAND OR AN ORGAN?
The liver is one of the vital organs of the body, responsible for hundreds of chemical actions that the body needs to survive. It is also a gland because it secretes chemicals that are used by other parts of the body. For these reasons the liver is both an organ and a gland; in fact, it is the largest internal organ in the body.
WHAT ARE THE SYMPTOMS AND SIGNS OF LIVER DISEASE?
The liver is a large organ and a significant amount of liver tissue needs to be damaged before a person experiences symptoms of disease. Symptoms also may depend upon the type of liver disease.
- The inflammation of hepatitis may be associated with pain in the right upper quadrant of the abdomen, nausea and vomiting. This may also be seen in people with gallstones.
- People may have jaundice (have a yellow-orange hue to their skin) because the liver cannot metabolize bilirubin (the normal breakdown product of old red blood cells).
- There may be a tendency to bleed excessively or bruise easily because the liver is unable to manufacture blood clotting factors in adequate amounts.
- Fatigue, weakness, weight loss, and shortness of breath because of muscle wasting; due to the inability of the liver to manufacture proteins.
- Because the liver is involved in the metabolism of sex hormones, gynecomastia (enlarged breast tissue in men) and impotence may occur.
- In end-stage liver disease, ascites (fluid accumulation in the abdominal cavity), and leg swelling may occur because of inadequate production of albumin by the liver.
- There also may be difficulty in metabolizing ammonia causing its levels in the blood to rise, resulting in confusion due to encephalopathy (encephala=brain + pathy=dysfunction).
WHAT DOES THE LIVER LOOK LIKE? WHERE IS IT LOCATED IN THE BODY?
The liver is divided into two lobes and has a rich blood supply obtained from two sources:
- The portal vein delivers blood from the gastrointestinal tract (stomach, intestine, colon) and spleen, and
- The hepatic artery supplies blood from the heart.
The biliary tree describes a system of tubes that collect bile, used to help digest food, and drains it into the gallbladder or the intestine. Intrahepatic ducts are located inside the liver (intra=inside + hepar=liver) while extrahepatic ducts are located outside the liver.
LIVER DISEASE CAUSES (FATTY LIVER, CIRRHOSIS, HEPATITIS, AND INFECTIONS)
Many diseases may affect the liver directly or as a consequence of an illness or disease that begins in another organ.
Fatty liver disease
- Fatty liver disease, caused by accumulation of cholesterol and triglycerides within the liver is not associated with alcohol abuse. Fatty liver disease is also referred to as nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH).
- Cirrhosis of the liver describes a condition of scarring in the liver that is not reversible and may lead to liver failure.
- Alcohol abuse causes cirrhosis of the liver and is the most common cause of liver disease in North America.
Hepatitis is an infection of the liver that causes liver inflammation.
- Hepatitis A is often spread by poor sanitary habits including poor handwashing and may be transmitted by food handlers. It tends to be self-limited.
- Hepatitis B and hepatitis C are spread by contact with infected body fluids.
- Hepatitis D is spread in conjunction with hepatitis B and needs the B virus for it to survive in the body and cause liver damage.
- Hepatitis E is a food or water borne infection.
- There are vaccinations available to prevent hepatitis A and hepatitis B.
Infections may affect the liver, including:
- Epstein Barr virus that causes infectious mononucleosis
- Rocky Mountain spotted fever
Liver disease causes (medications, toxins, genetics, cancer, and others)
Medications or drug induced liver inflammation
Liver inflammation is a relatively common side effect of medications. Some commonly prescribed medications include the following:
- acetaminophen over the counter (Tylenol, Panadol) but also in prescription pain medications (hydrocodone/acetaminophen (Lortab, Vicodin, Norco)
- Statins (medications used to control elevated blood cholesterol levels)
- Antibiotics (amoxiciilin-clavulinic acid [Augmentin, Augmentin XR], nitrofurantoin [Macrodantin, Furadantin, Macrobid], tetracycline, isoniazid)
- methotrexate (Trexall, Rheumatrex)
- disulfiram (Antabusel)
- Herbal remedies, for example, kava kava, mahuang, comfrey
- Poisonous mushrooms may damage the liver and cause liver failure.
- Alcohol in large doses can be toxic for the liver and damages the liver over time.
- Aflatoxins produced by certain fungi are toxic to the liver
- Industrial chemicals may be toxins that affect the liver, such as arsenic and carbon tetrachloride
Genetic disorders can affect the liver, examples include the following:
- Hemochromatosis with abnormal iron storage
- Wilson’s Disease with abnormal copper storage
- Gilbert’s Disease with abnormal bilirubin metabolism
- Primary liver cancers arise directly from cells within the liver.
- Metastatic liver disease describes cancer that arises from another organ and invades the liver
Abnormalities of bile flow from the liver
Abnormalities of bile flow from the liver may lead to liver inflammation, for example:
Decrease in blood flow draining from the liver
Decrease in blood flow draining out of the liver may cause the liver to become congested and inflamed, two examples include:
- Congestive heart failure (CHF) is a condition in which the heart is not strong enough to pump all of the blood it receives, and that blood can back up into the liver.
- Budd Chiari syndrome is a disease in which blood clots form in the hepatic veins, preventing blood from leaving the liver.
CAN LIVER DISEASE BE PREVENTED?
- Moderate alcohol consumption to decrease the risk of the most common cause of liver disease in North America.
- The risk of contracting hepatitis B and hepatitis C can be decreased by minimizing exposure to body fluids.
- As mentioned previously, vaccinations are available for hepatitis A and B.
- Maintain a healthy weight and eat a balanced diet to decrease the risk of developing fatty liver disease.