Jaundice, also known as icterus, is a yellowing of the skin, whites of the eyes, and body fluids due to an increase in the amount of bilirubin in the blood. Bilirubin is a yellowish pigment and byproduct of the natural daily breakdown of red blood cells (RBCs). Red blood cells typically survive for about 120 days before the body breaks them down, forming bilirubin in the process. The blood transports bilirubin to the liver, where bilirubin is metabolized and excreted in the bile. Bile is a thick, yellow-green-brown fluid that is secreted into the upper small intestine (duodenum) to eliminate waste products (such as bilirubin and excess cholesterol) and to aid in the digestion of fats. Disruption of this normal metabolism and/or the overproduction of bilirubin may cause jaundice.
Jaundice is a clinical sign that reflects an accumulation of bilirubin in the blood. It can result from increased bilirubin production, inability of the liver to conjugate bilirubin or failure to excrete bilirubin into the biliary tree. Appropriate investigation of jaundice starts with a history of associated symptoms, and risk factors for liver disease.
Clinical examination should look for stigmata of chronic liver disease and signs of specific liver diseases. Initial blood tests should assess liver injury and synthetic function. A combination of urinalysis and the pattern of abnormal liver function tests can indicate whether the jaundice is likely to be hepatitic or cholestatic, and can guide further investigations. This review describes bilirubin metabolism, the causes of jaundice and the appropriate investigation of jaundice.
Biliary obstructioncirrhosishaemolytic anaemiahepatitishyperbilirubinaemiajaundiceliver injuryMRCP
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