Overview of Jaundice
Jaundice is basically a condition or a sign associated with various diseases that causes release of large amount of bilirubin in blood. The surplus bilirubin causes skin, sclera and mucosal membranes in mouth to turn yellow. Bilirubin is a waste product of red blood cell breakdown that remains in blood after removal of heme (made up of Fe2+ cofactor and porphyrin ring) from hemoglobin which is then catabolized to produce bilirubin. Excessive bilirubin leaks out in surrounding tissues, saturating them with this yellow substance. Freely circulating bilirubin is called unconjugated bilirubin while once it is taken up by liver for processing it attaches with other chemicals and is called conjugated bilirubin. Jaundice is normally seen when the level of bilirubin in the blood exceeds 2.5-3 mg/dL.
Causes and Risk Factors of Jaundice
Jaundice occurs due to abnormal metabolism or excretion of bilirubin which can occur at various stages. The causes of jaundice are generally categorized as pre-hepatic (problem arising before bilirubin enters the liver), hepatic (problem arising within the liver), and post-hepatic (problem occurring after excretion of bilirubin from the liver). Pre-hepatic jaundice occurs due to excessive destruction of red blood cells from different diseases such as malaria, sickle cell anemia, thalassemia, pyruvate kinase deficiency and G6PD deficiency. These causes increase the level of non-conjugated bilirubin. Hepatic causes of jaundice increase level of conjugated bilirubin and arise form abnormalities of bilirubin metabolism or excretion. These causes include cirrhosis, chronic hepatitis, hepatotoxicity, drug-induced hepatitis, Gilbert’s syndrome and autoimmune disorders. Post-hepatic causes occur due to obstruction of bile ducts which carries bilirubin from liver. The obstruction may arise from gallstones, pancreatitis, strictures of bile ducts and pancreatic cancer.
Signs and Symptoms of Jaundice
The most notable signs of jaundice are yellow tinge in skin to varying degree, yellowing of sclera and mucosal membrane of mouth, itching on skin (pruritus), dark urine and pale colored stools. The additional symptoms may also be seen depending upon underlying disease such as abdominal pain, nausea and vomiting, rectal bleeding, diarrhea, fatigue, fever, weight loss, swelling of legs and abdomen. People with inherited conditions (such as anemia, thalassemia) are at high risk of getting jaundice due to hemolysis. People consuming alcohol heavily are at increased risk of getting alcoholic hepatitis, pancreatitis and cirrhosis and associated jaundice.