The liver is an important organ located in the upper right quadrant of the abdomen. Its functions include producing proteins that are important for blood clotting, processing fats, storing sugar for energy use, filtering the blood of waste products and metabolizing ingested medications. Hepatomegaly is the medical term that describes enlargement of the liver. In children, palpating the liver and finding its edge below the margin of the ribs can indicate hepatomegaly.
Viral hepatitis, or inflammation of the liver, is a common cause of hepatomegaly in children. According to the National Digestive Diseases Information Clearinghouse, the main viruses that cause hepatitis are the hepatitis viruses A, B, C, D and E; the Epstein-Barr virus, which causes infectious mononucleosis, or mono; adenovirus; and parvovirus. The main symptoms of viral hepatitis include enlargement of the liver, fever, fatigue, abdominal pain, vomiting and jaundice, or a yellowing of the skin and eyes. In children with acute viral hepatitis, the hepatomegaly eventually resolves and the liver returns to its normal size. Children with chronic hepatitis will continue to have enlargement of the liver until the disease becomes so severe that the liver atrophies and starts to shrink.
Hepatomegaly can be a sign of a metabolic disorder in a child. These are a group of conditions in which the body fails to produce a specific enzyme, leading to a wide variety of symptoms. For example, according to the website Genetics Home Reference, tyrosinemia is a condition in which the body fails to produce an enzyme that breaks down tyrosine, an important component of certain proteins. This breakdown process takes place in the liver. As a result of this failure, tyrosine builds up in the liver, causing liver enlargement, among other symptoms. Other metabolic disorders that can cause liver enlargement in children include defects in the processing of sugars. As the liver is the main organ involved in the storage of sugars for the body’s energy needs, any defect in the metabolism of these sugars can cause hepatomegaly. For example, glycogen storage diseases impair the liver’s ability to convert glycogen, the long-term storage form of sugar, into glucose, the main sugar used by the body. These defects cause enlargement of the liver and stunt growth in children.
Liver enlargement can be a sign of heart failure in children. According to the Merck Manuals, heart failure can result in a condition called congestive hepatomegaly. Children with heart failure lose the ability to pump blood efficiently from their hearts. This leads to a pooling or backup of blood in the main veins of the body, including the hepatic veins, which help drain blood out of the liver. The liver then becomes engorged with blood. The liver becomes enlarged and tender, and fluid can accumulate in the rest of the abdomen. By managing the heart failure, the liver can return to its normal size, but long-standing failure can lead to permanent liver damage.