Bilirubin forms from the breakdown of red blood cells. High levels of bilirubin in the blood, or hyperbilirubinemia, also called jaundice, can occur in newborns and adults. Bilirubin can be unconjugated, which means it hasn't passed through the liver yet and is in a lip-soluble form. When bilirubin passes through the liver, it becomes conjugated, or made into water soluble form to be excreted through the kidneys. Both unconjugated and conjugated bilirubin can raise overall bilirubin levels.
Causes
Jaundice in the newborn can be physiologic, normally short-lived and self-limiting, or pathologic, resulting from disease or abnormalities of the blood. Over half of all babies become jaundiced within the first week after birth, the Merck Manual states. Premature babies develop jaundice more frequently than full-term infants. In adults, jaundice is a symptom of dysfunction of the liver, gallbladder or bile ducts. Some medications can also raise bilirubin levels, including antibiotics, birth control pills, steroids and barbiturates, RnCeus.com explains.
Symptoms
Symptoms of hyperbilirubinemia in infants include yellowing of the skin and whites of the eyes, or sclera. If not treated, seizures, coma and increased muscle tone, called hypertonia, develop. In adults, hyperbilirubinemia can causes severe itching and yellowing of the eyes and skin. Urine turns dark, while stools turn clay-colored in people with elevated bilirubin levels. Bilirubin levels greater than 3 mg/dL normally cause visible jaundice, RnCeus.com states.
Treatment
In infants, phototherapy under fluorescent or natural light usually provides adequate treatment for jaundice. Light breaks the bilirubin down into water-soluble forms more quickly so it can be more quickly eliminated by the liver and kidney. More severe cases of jaundice in infants, as evidenced by signs of kernicterus or bilirubin over 20 mg/dl at 24 to 48 hours of age, require exchange blood transfusion, Merck states. In adults, diagnosis and treatment of the underlying cause helps reduce hyperbilirubinemia. Cholestyramine may help decrease severe itching.
Diagnosis
Abdominal ultrasonography helps determine the cause of jaundice in adults. Blood testing for conjugated and unconjugated levels also helps determine the cause, as certain diseases are associated with only one type of jaundice or the other. Checking blood cultures in infants for infection and doing genetic testing if no obvious cause appears helps determine the diagnosis. CT scans and magnetic resonance imaging may also help establish a cause.
Prognosis
The most serious complication of jaundice in newborns, kernicterus, occurs when unconjugated bilirubin accumulates in the brain. Kernicterus can cause irreversible brain damage, hearing loss and cerebral palsy. In adults, jaundice is always pathologic, the Merck Manual stresses, and the cause always needs evaluation and treatment.
