Jaundice Health Article

Hepatic causes of jaundice

Liver diseases of all kinds, whether temporary or life-long, threaten the organ's ability to keep up with bilirubin processing. Some of the more common causes of jaundice include infectious hepatitis (types A, B, C, D, and E, and various other viruses), alcoholic hepatitis, and cirrhosis (scarring of the liver, due to various diseases, to the degree that it can no longer function). Starvation, circulating infections, and certain medications (acetaminophen overdose, isoniazid, and others) can cause inefficiency in bilirubin disposal. Certain hereditary defects also affect how the liver processes bilirubin (such as Gilbert's syndrome and Crigler-Najjar syndrome), causing elevated levels of unconjugated bilirubin. Also, there are several inherited conditions in which the liver cannot excrete bilirubin after it is made soluble (such as Dubin-Johnson syndrome and Rotor syndrome), resulting in direct (or conjugated) bilirubin being the predominant form of the molecule. Unlike hemolytic causes of jaundice, which always involve unconjugated bilirubin, the hepatic sources of jaundice often represent mixed results.

Posthepatic causes of jaundice

Posthepatic forms of jaundice include those caused when soluble bilirubin does not reach the intestines after it has left the liver, resulting in elevated direct bilirubin levels. These disorders are called obstructive jaundices. The most common cause of obstructive jaundice is the presence of gallstones in the ducts of the biliary system. Other causes include diseases where the bile ducts have been destroyed, such as the autoimmune disease primary biliary sclerosis, lesions (whether benign or malignant), and trauma. Some drugs (such as anabolic and contraceptive steroids), and occasionally pressures caused by a normal pregnancy, cause the bile in the ducts to stop flowing. This process is called cholestasis.

Neonatal jaundice

Several conditions can cause jaundice in a newborn baby. Erythroblastosis fetalis is a disease of newborns marked by the presence of too many immature red blood cells (erythroblasts) in the baby's blood. When a baby and mother have different Rh factors (positive-RH baby and negative-Rh mother), antibodies from the mother may leak into the baby's circulation through the placental exchange and destroy blood cells. This reaction may produce severe hemolysis and jaundice in the newborn. Rh-factor incompatibility is the most common cause. These births are usually induced a week or two early to keep third-trimester hemolysis to a minimum.

Even in the absence of Rh-factor incompatibility, the newborn's bilirubin level may reach threatening levels. Normal newborn jaundice is the result of two conditions occurring at the same time: a prehepatic and a hepatic source of excess bilirubin. During development, the fetal-type hemoglobin is important to extract oxygen from the mother's blood. At birth, the infant extracts oxygen directly from the lungs and no longer needs the fetal hemoglobin. So, fetal hemoglobin is removed from the system and replaced with mature hemoglobin. The resulting hemoglobin overload overwhelms the immature system, and bilirubin levels may rise until the third day of life, and then decline by day five to day 10. During that time, the baby is jaundiced.

These forms of jaundice in the newborn may result in high levels of unconjugated bilirubin. If conjugated bilirubin is found, it is usually due to serious causes, such as obstruction of the biliary system or overwhelming infection.

Symptoms

Certain chemicals in bile may cause itching in jaundiced patients. Fatigue is a very common symptom in people with liver disease. In more severe illness, nausea may occur. Poor appetite and weight loss can be a problem for some patients, usually those with acute infection or advanced scarring of the liver (cirrhosis). Depending on the cause of jaundice, patients may or may not have pain over the liver (upper right quadrant). Liver pain is common if there are gallstones, and may also occur in acute hepatitis. Patients whose bile does not drain into the small intestine adequately will have clay-colored stools. The conjugated form of bilirubin may be excreted by the kidneys and result in dark urine. Long-standing jaundice may upset the balance of chemicals in the bile and cause stones to form in the gallbladder or in the ducts.

In newborns, the concern about jaundice is that insoluble or unconjugated bilirubin may get into the brain and do permanent damage to the central nervous system. This serious condition is called kernicterus. It becomes a concern as bilirubin levels approach 20 mg/dL. Newborns are more likely to have problems with jaundice if they are premature, Asian or Native American, or bruised significantly during the birth process. Jaundice is also more common if a newborn was born after an induced labor, has lost too much weight during the first few days of life, was born at high altitude, or was born to a diabetic mother.