Gastrointestinal and hepatic complications of sickle cell disease.

Sickle cell disease (SCD) is an autosomal recessive abnormality of the beta-globin chain of hemoglobin (Hb), resulting in poorly deformable sickled cells that cause microvascular occlusion and hemolytic anemia. The spleen is almost always affected by SCD, with microinfarcts within the first 36 months of life resulting in splenic atrophy. Acute liver disorders causing right-sided abdominal pain include acute vaso-occlusive crisis, liver infarction, and acute hepatic crisis. Chronic liver disease might be due to hemosiderosis and hepatitis and possibly to SCD itself if small, clinically silent microvascular occlusions occur chronically. Black pigment gallstones caused by elevated bilirubin excretion are common. Their small size permits them to travel into the common bile duct but cause only low-grade obstruction, so hyperbilirubinemia rather than bile duct dilatation is typical. Whether cholecystectomy should be done in asymptomatic individuals is controversial. The most common laboratory abnormality is an elevation of unconjugated bilirubin level. Bilirubin and lactate dehydrogenase levels correlate with one another, suggesting that chronic hemolysis and ineffective erythropoiesis, rather than liver disease, are the sources of hyperbilirubinemia. Abdominal pain is very common in SCD and is usually due to sickling, which resolves with supportive care. Computed tomography scans might be ordered for severe or unremitting pain. The liver typically shows sickled erythrocytes and Kupffer cell enlargement acutely and hemosiderosis chronically. The safety of liver biopsies has been questioned, particularly during acute sickling crisis. Treatments include blood transfusions, exchange transfusions, iron-chelating agents, hydroxyurea, and allogeneic stem-cell transplantation.