Causes of Obstructive Jaundice
Jaundice is a yellowing of the skin, eyes and other tissues due to the circulation of excess bilirubin in the body. Obstructive jaundice, also known as "cholestasis," is caused by impaired bile flow. Common causes of this condition include liver disease, drug reactions, alcoholism, bile duct stones and cancer.
Physiology of Jaundice
Bilirubin is a breakdown product of heme, a protein found in red blood cells (RBCs), bone marrow, liver cells, and other tissues. Most circulating bilirubin comes from the catabolism of defunct or damaged RBCs. Bilirubin is not water-soluble, so it is bound to albumin for transport through the blood to the liver. There it is conjugated (made water-soluble) and then excreted into the bile. Bile is broken down in the intestine to stercobilinogens, which are excreted in the stool or re-absorbed and excreted again into the bile. A small portion passes into the urine as urobilinogen. Stercobilinogen and urobilinogen are pigments which give the stool and urine their colors. Any pathology along this pathway will result in a buildup of bilirubin in the blood and the symptoms of jaundice.
Obstructive Jaundice
Cholestasis, or obstructive jaundice, occurs when the flow of bile from the liver to the intestines is obstructed or impaired. This can occur inside the liver (intrahepatic) or outside of it (extrahepatic).
Intrahepatic Causes
Any condition that damages the liver cells can cause obstructive jaundice. The most common causes are hepatitis, alcoholism and drugs that are toxic to the liver. In these conditions, blood work will show increased liver enzymes, indicative of liver damage. In addition to jaundice, symptoms of intrahepatic obstruction include ascites (swelling of the belly due to reduced circulation through the liver) and enlarged spleen.
Extrahepatic Causes
The common duct carries bile from the liver to the intestines. Any blockage of the duct will cause obstructive jaundice. The most common causes are bile stones in the duct and pancreatic cancer. Bile stones, or gallstones, form in the gall bladder, which stores bile produced by the liver. If a stone lodges in the gallbladder duct, painful abdominal symptoms arise. Stones which pass through the gallbladder duct and obstruct the common bile duct can cause pancreatitis and obstructive jaundice in addition to abdominal pain. Pancreatic cancer causes obstructive jaundice when the tumor presses on the common bile duct. This is often the first noticeable symptom of pancreatic cancer.
Signs and Symptoms of Obstructive Jaundice
The most obvious sign of jaundice is the yellowing of the skin and eyes that gives the disease its name ("jaune" is the French word for yellow). In obstructive jaundice, bilirubin cannot pass to the intestines. The stool is pale, because stercobilinogen is not formed. Excess conjugated bilirubin spills over to the kidneys and is excreted as urobilinogen, which gives the urine a very dark color. All-over itching may result from the excess of bile salts forming in the body. Symptoms of the underlying disease or substance (in the case of alcoholism and drug toxicity) will be present. Long-term symptoms include a darkening of skin tone (the so-called "bar room tan"), inability to form blood clots (bile salts are necessary for the absorption of vitamin K, vital to the clotting process), and osteoporosis due to malabsorption of vitamin D and calcium.
Treatment
Treating the cause of obstructive jaundice will usually resolve the symptoms. In chronic or irreversible disorders, cholestyramine is given to bind bile salts and relieve the itching. Supplements of vitamins D, K, and calcium can be given to counteract malabsorption. In the case of extrahepatic obstruction, surgery may be necessary to remove the obstruction and resolve the symptoms.
Tags: obstructive jaundice, bile duct, , , cause obstructive jaundice, Obstructive Jaundice, yellowing skin eyes