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Liver: Function, Failure & Disease

abdomen, liver
Credit: Sebastian Kaulitzki | Shutterstock

The liver is an abdominal glandular organ in the digestive system. It is located in the upper-right area of the abdomen, under the diaphragm. The liver is a vital organ that supports nearly every other organ to some capacity. You cannot live without a healthy liver.

The liver is the body’s second-largest organ (skin is the largest organ), weighing about 3 pounds (1.4 kilograms). It has four lobes and is a very soft, pinkish brown organ. It contains several bile ducts.

Function

The liver performs many functions necessary for digestion, metabolization, detoxification and maintenance of the immune system. It produces bile, a chemical substance that breaks down fats and makes them more easily digestible. The liver also produces multiple important elements of plasma. In addition to producing important substances, the liver stores some vital nutrients, including vitamins (especially A, D, E, K, and B-12) and iron. It also stores simple sugar glucose and converts it to usable glucose if your blood sugar levels fall.

One of the best-known roles of the liver is as a detoxification system. It removes toxic substances from blood, such as alcohol and drugs. It also breaks down hemoglobin, insulin and excessive hormones to keep hormone levels in balance.

The liver is vital for healthy metabolic function. It metabolizes carbohydrates, lipids and proteins into useful substances, such as glucose, cholesterol, phospholipids and lipoproteins that are used in various cells throughout the body. The liver breaks down the unusable parts of proteins and converts them into ammonia, and eventually urea.

The liver also destroys old blood cells and captures and digests bacteria, fungi, parasites and other unwanted contaminants. This function supports the immune system.

Liver Disease

There are several types of diseases that can affect the liver. The Mayo Clinic lists the following diseases:

  • Acute liver failure
  • Alcoholic hepatitis
  • Alpha-1-antitrypsin deficiency
  • Autoimmune hepatitis
  • Bile duct obstruction
  • Chronic liver failure
  • Cirrhosis (when the liver gets scar tissue because of an illness)
  • Enlarged liver
  • Gilbert's syndrome
  • Hemochromatosis
  • Hepatitis A
  • Hepatitis B
  • Hepatitis C
  • Hepatitis D
  • Hepatitis E
  • Liver adenoma
  • Liver cancer
  • Liver cyst
  • Liver hemangioma
  • Liver nodule (focal nodular hyperplasia)
  • Nonalcoholic fatty liver disease
  • Parasitic infection
  • Portal vein thrombosis
  • Primary biliary cirrhosis
  • Toxic hepatitis
  • Wilson's disease

While some liver diseases are genetic, others are caused by viruses or toxins, such as drugs, poisons and excessive alcohol. Some risk factors include drug or heavy alcohol consumption, having a blood transfusion before 1992, high levels of triglycerides in the blood, diabetes, obesity and being exposed to other people’s blood and bodily fluids. This can happen from shared drug needles, unsanitary tattoo or body piercing needles, and unprotected sex.

The most common symptom of liver disease is jaundice — yellowish skin and eyes. Other symptoms include abdominal pain and swelling, persistent itchy skin, dark urine, pale stools, bloody or black stools, exhaustion, nausea and loss of appetite.

Fatty liver

Nonalcoholic fatty liver disease is extra fat in the liver that is not caused by excessive alcohol. If more than 5 percent to 10 percent of the liver’s weight is composed of fat, then you have fatty liver. Fatty liver disease can lead to swelling and cirrhosis, and it increases the chance of liver failure or liver cancer. People who are overweight, have experienced rapid weight loss, or who have diabetes, high cholesterol, or high triglycerides are at risk for fatty liver.

Some people may get fatty liver even if they don’t have any risk factors. Up to 25 percent of the U.S. population suffers from fatty liver disease. There are no medical treatments for fatty liver disease, though avoiding alcohol, eating a healthy diet, and exercising can help prevent or reverse fatty liver disease in its early stages.

Enlarged liver

An enlarged liver (or hepatomegaly) isn’t a disease itself, but a sign of an underlying serious problem, such as liver disease, cancer or congestive heart failure. There may be no symptoms of an enlarged liver, though if they are they are the same as the symptoms for liver disease. Normally, the liver cannot be felt unless you take a deep breath, but if it is enlarged, your doctor may be able to feel it. The doctor may then do scans, MRIs, or ultrasounds of the abdomen to determine if you have an enlarged liver. Treatment will involve addressing the underlying problem.

Liver pain

Liver pain is felt in the upper right area of the abdomen, just below the ribs. Usually, it is a dull, vague pain though it can sometimes be quite severe and may cause a backache. Sometimes people perceive it as pain in the right shoulder. It is often confused with general abdominal pain, back pain or kidney pain. It can be hard to pinpoint the exact location or cause of such pains, so it is important to see a doctor. Doctors may do blood tests, ultrasounds or biopsies to determine the cause of pain.

Liver pain can be the result of a variety of causes, most commonly a form of liver disease. Liver pain can also be caused by gallstones, disturbances or obstructions in the bile duct, irritable bowel syndrome, pneumonia, gastritis (abdomen inflammation) or ascites (fluid buildup in the abdomen).

Liver failure

Liver failure is an urgent, life-threatening medical condition. It means that the liver has lost or is losing all of its function. Early symptoms of liver failure are fairly general, making it difficult to know that the liver is failing. Early symptoms include diarrhea, nausea, loss of appetite and fatigue. But as the condition worsens, symptoms become more serious. You may become confused, extremely sleepy or disoriented. You may even fall into a coma.

Chronic liver failure is the most common type of liver failure. It is the result of malnutrition, disease and cirrhosis, and it can develop slowly over years. Acute liver failure is more rare, and it can come on suddenly. Acute liver failure is usually the result of poisoning or a drug overdose. Sometimes, liver failure can be treated without surgery, but in other cases a liver transplant is the only option for patients with liver failure.

Liver transplant

Donated livers can come from cadavers or living donors. In the case of living donors, the donor donates part of his or her liver to another person. The liver can regrow itself, so both people should end up with healthy, functional livers. According to the NIH, the most common reason adults get liver transplants is cirrhosis, though transplants can also be done for patients with various liver diseases or early stage liver cancer.

A liver transplant is a very serious surgery that may take up to 12 hours. There are several risks involved with liver transplants, including:

  • Bile duct complications, including leaks or shrinking
  • Bleeding
  • Blood clots
  • Failure of donated liver
  • Infection
  • Memory and thinking problems
  • Rejection of donated liver

If you have a liver transplant, you can expect to stay in the hospital for at least a week after the surgery, to get regular checkups for at least three months, and to take anti-rejection and other medications for the rest of your life. It will take six months to a year to feel fully healed from the surgery.

Liver transplant success depends on the individual case. Transplants from cadavers have a 72 percent success rate, meaning that 72 percent of liver transplant recipients lived for at least five years after the surgery. Transplants from living donors had a slightly higher success rate, at 78 percent, according to the Mayo Clinic.

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