occurs as a result of Budd–Chiari syndrome, CHF, or constrictive pericarditis The liver is engorged, resulting in hepatomegaly and right upper quadrant tenderness in each of these entities Nonalcoholic fatty liver disease (NAFLD), usually associated with obesity and type diabetes, is the most common cause of liver disease in children and may lead to fibrosis and cirrhosis later in life If there is associated liver disease and ascites, NAFLD may cause abdominal discomfort and distension Finally, a diseased peritoneum from infectious, inflammatory, or malignant causes can also cause an intra-abdominal effusion A history of recent trauma and signs of shock point to intraperitoneal bleeding, usually due to a splenic or hepatic laceration An ileus secondary to both peritoneal inflammation and shock likely contributes to the abdominal distension Trauma in the recent past suggests chylous ascites Finally, a diffusely tender abdomen suggests infectious peritonitis, pancreatitis, or bile peritonitis Extreme hepatomegaly that develops acutely occurs secondary to inflammation, congestion due to increased central venous pressure or vascular obstruction, or trauma (see Chapter 91 Gastrointestinal Emergencies ) There will be marked right upper quadrant tenderness and general systemic toxicity Causes include hepatitis, CHF, constrictive pericarditis, and congenital enzyme deficiencies Neoplastic disease, especially the proliferative blood cell disorders (leukemia, lymphoma), commonly causes significant hepatomegaly and splenomegaly Extreme splenomegaly without marked hepatomegaly in the toxic-appearing child suggests intraparenchymal bleeding with an intact capsule, sickle cell sequestration crisis, or malaria (see Chapters 93 Hematologic Emergencies and 94 Infectious Disease Emergencies ) In the nontoxic child, portal hypertension, neoplastic disease, and chronic hemolysis should be suspected Neoplastic disease often results in a spleen with an irregular surface Chronic hemolysis secondary to sickle cell disease, β-thalassemia, and hereditary spherocytosis may also result in a very large spleen In the case of hemoglobin “SS” disease, but not hemoglobin “SC” disease or sickle-thalassemia, splenic enlargement is followed by splenic atrophy beyond years of age A peripheral blood smear generally identifies this group of causes of massive splenomegaly (see Chapter 93 Hematologic Emergencies ) Other causes of abdominal distension include cysts, masses, tumors, uterine enlargement, obstructive uropathy, bowel duplication, and inflammation Cystic lesions include ovarian cysts; mesenteric, omental, or peritoneal cysts; choledochal cysts; and polycystic kidneys These conditions generally present with a subacute history and physical examination The exception is torsion of the