Causes of Hepatomegaly

Abstract:

Hepatomegaly is  enlargement of the liver  detected during medical examination. Both palpation and percussion techniques are used during abdominal examination to assess the size of the liver. O

Hepatomegaly is enlargement of the liver detected during medical examination. Both palpation and percussion techniques are used during abdominal examination to assess the size of the liver. On percussion the normal liver span is 7 cm for women and 10.5 cm for men. Hepatomegally is diagnosed when the liver size is found to be 2 to 3 cm larger than the above mentioned values.
Enlargement of the liver can be an apparent enlargement or true enlargement which can be due to several disease conditions. The disease conditions can be classified as cirrhosis, inflammatory conditions, cysts, metabolic conditions, haematological conditions, tumors, venous congestion and biliary obstruction.

Diseases which can cause apparent enlargement of the liver are low lying diaphragm and Reidel’s lobe. The liver is situated just below the right hemidiaphragm. Chest pathologies such as pneumothorax, emphysema, chronic obstructive pulmonary disease etc. push the right hemidiaphragm down along with the liver. This is noted as hepatomegaly on abdominal examination. Reidel’s lobe is defined as downward tongue-like projection of the anterior edge of the right liver lobe to the right of the gallbladder. This condition is commonly seen in women and can be an accessory lobe or a normal variant, which may extend up to the right iliac fossa. On palpation and percussion this can also be detected as enlarged liver.
One of the commonest causes of hepatomegaly is early cirrhosis which is the final outcome of most of the liver pathologies. Some of the causes of cirrhosis are Hepatitis C, alcoholic liver disease, non alcoholic fatty liver disease, hepatitis B, autoimmune hepatitis, primary and secondary biliary cirrhosis, primary sclerosing cholangitis, haemochromatosis, Wilson’s disease,  Alpha-1 antitrypsin deficiency, Sarcoidosis, Type IV glycogen storage disease, Drug-induced liver disease etc.
Cysts which cause hepatomegaly are Hydatid cysts and cysts seen in patients with polysystic kidney disease. Hydatid cysts are caused by the larval stage of the tapeworm Echinococcus granulosus. The cysts can occur in many organs but the liver is commonly involved. These cysts increase in size at an average rate of approximately 1-1.5 cm/year. The disease manifests as hepatomegaly when these cysts enlarge up to a detectable size.
Metabolic diseases causing hepatomegaly are fatty liver, Amyloid and glycogen storage disease. Fatty liver can occur with (alcoholic fatty liver disease) or without (non-alcoholic fatty liver disease) alcohol consumption. It is caused by accumulation of triglycerides and other fats in the liver cells. The ultimate outcome of the disease can be liver inflammation and cell death. Its prevalence is increasing worldwide along with the increasing number of obese people.  Liver is a commonly affected organ in Amyloidosis and can rarely cause massive hepatomegaly. The next metabolic disease causing hepatomegaly is glycogen storage disease which is a disease characterized by defective metabolism of glycogen.

Haematological diseases causing hepatomegaly are leukaemia, lymphoma, myeloproliferative disorders, and thalassaemia. In leukaemia, extra-medullary infiltration by leukemic cells may cause hepatomegaly along with Lymphadenopathy and splenomegaly. In patients with thalassaemia hepatomegaly occurs due to engorgement of hepatic paranchymal and phagocytic cells with hemosiderin deposits.

Tumors causing hepatomegaly can be either primary or secondary. Liver is one of the commonest sites for secondary deposits, especially from malignancies from the gastro-intestinal tract. Venous congestion caused by heart failure, hepatic vein occlusion can also lead to enlargement of the liver. Biliary obstruction particularly caused by an extra-hepatic cause is also an important cause of hepatomegaly.

Since there are a lot of causes of hepatomegaly, careful history taking, examination and investigations plays a vital role in detecting the correct eatiology and planning the future management.