Hepatomegaly is the condition of having an enlarged liver. It is a non-specific medical sign having many causes, which can broadly be broken down into infection, hepatic tumours, or metabolic disorder. Often, hepatomegaly will present as an abdominal mass. Depending on the cause, it may sometimes present along with jaundice. Signs and symptoms
The individual may experience many symptoms, including weight loss, poor appetite and lethargy (jaundice and bruising may also be present). Causes
Among the causes of hepatomegaly are the following:

Infective
Mechanism
The mechanism of hepatomegaly consists of vascular swelling, inflammation (due to the various causes that are infectious in origin) and deposition of (1) non-hepatic cells or (2) increased cell contents (such due to iron in hemochromatosis or hemosiderosis and fat in fatty liver disease). Diagnosis
Suspicion of hepatomegaly indicates a thorough medical history and physical examination, wherein the latter typically includes an increased liver span.On abdominal ultrasonography, the liver can be measured by the maximum dimension on a sagittal plane view through the midclavicular line, which is normally up to 18 cm in adults. It is also possible to measure the cranio-caudal dimension, which is normally up to 15 cm in adults. This can be measured together with the ventro-dorsal dimension (or depth), which is normally up to 13 cm. Also, the caudate lobe is enlarged in many diseases.
Folic acid had been found to alleviate the symptoms of megaloblastic anemia in the 1940s, not long after it was discovered, but the typical patient only made a full recovery—cessation of CNS and PNS symptoms as well as anemia—on B12 therapy. Five years earlier, folic acid deficiency was linked to birth defects in rats. Primidone was seen by some as too valuable to withhold based on the slight possibility of this rare side effect and by others as dangerous enough to be withheld unless phenobarbital or some other barbiturate failed to work for this and other reasons (i.e., reports of permanent psychosis). Available forms
Primidone is available as a 250 mg/5mL suspension, and in the form of 50 mg, 125 mg, and 250 mg tablets. It is also available in a chewable tablet formulation in Canada.It is marketed as several different brands including Mysoline (Canada, Ireland, Japan, the United Kingdom, and the United States), Prysoline (Israel, Rekah Pharmaceutical Products, Ltd.), Apo-Primidone, Liskantin (Germany, Desitin), Resimatil (Germany, Sanofi-Synthélabo GmbH), Mylepsinum (Germany, AWD.pharma GmbH & Co., KG)., and Sertan (Hungary, 250 mg  tablets, ICN Pharmaceuticals Inc.[1])

Other animals
Primidone has veterinary uses, including the prevention of aggressive behavior and cannibalism in gilt pigs, and treatment of nervous disorders in dogs and other animals. References
Further reading
"Toxicology and Carcinogenesis Studies of Primidone in F344/N Rats and B6C3F1 Mice (Feed Studies)" (PDF). Department of Health and Human Services National Toxicology Program. September 2000. Lay summary. {{cite web}}: Cite uses deprecated parameter |lay-url= (help)

External links
"Primidone". Drug Information Portal. U.S. National Library of Medicine.