Yellow eyes in jaundice are not really the whites of the eyes
About 80 percent of newborns turn slightly yellow in their first week, yet jaundice in adults is rare and usually signals trouble with blood breakdown, the liver or the bile ducts. The first place it shows is the eye, though doctors now say the old term scleral icterus is wrong: the pigment settles in the conjunctiva on top.
Jaundice, or icterus, is a yellow or occasionally greenish tint to skin and eyes caused by excess bilirubin, a pigment made when haem from red blood cells is broken down. Normal blood levels sit below 1.0 milligram per decilitre; beyond about 2 to 3, the colour appears. Itching, pale stools and dark urine are the classic companions, because bilirubin irritates the skin and fails to reach the gut. The word comes from the French jaunisse, yellow disease.
The conjunctiva, the thin membrane covering the white of the eye, is rich in elastin, which binds bilirubin eagerly. That makes it an early warning sign, visible once levels reach roughly 3 milligrams per decilitre. On darker skin, the yellow is harder to see on the body and is better checked on the eyes, palms, soles and inside the mouth. In growing children, high bilirubin can even stain developing teeth yellow or green, something never seen when liver disease begins in adulthood.
Doctors sort causes by where the problem lies. Before the liver, too many red cells may be destroyed, as in glucose-6-phosphate dehydrogenase deficiency or infections such as malaria. In the liver itself, cells may be damaged by viruses, drugs or autoimmune disease; Gilbert's syndrome, found in about 5 percent of people, causes a mild harmless version. After the liver, bile ducts can be blocked, most often by gallstones, but also by cancer, pancreatitis or liver flukes. Fasting, big bruises and thyroid problems can also nudge levels up.
Not every yellow person has jaundice. Eating large amounts of carotene-rich food causes carotenemia, and the antibiotic rifampin can tint skin too. Treatment follows the cause: surgery for a blocked duct, otherwise medical care such as treating infection or stopping an offending drug. For newborns with high readings, phototherapy or exchange transfusion may be used depending on age and prematurity, and itching can be eased with measures including ursodeoxycholic acid or naltrexone.
Source: Jaundice
