Pale stool is a common symptom accompanying diseases of the liver and biliary tract. To understand the issue, it is necessary to know what gives stool its normal brownish color. Brownish coloration of stool is caused by presence of bile substances, especially the decay products of bile pigment bilirubin excreted into the intestine. For this reason, pale stool is usually free of bile (acholic).
Causes of abnormally pale stool include either disorders of bile production or its excretion into the intestine.
Acute stage of infectious hepatitis may be associated with disruption of bile formation and this leads to temporary light colored stool.
Pale stool occurs when a gallstone blocks the bile duct and bile can not flow into the intestine. In addition, there is biliary colic with abdominal pain in upper right abdominal quadrant and vomiting.
Inflammation of the biliary tract
Infectious inflammation of the biliary tract (cholangitis) manifests with fever, chills and abdominal pain in the right upper abdominal quadrant. Abnormal flow of bile may result in jaundice and pale stool. Pale stool can be also found in chronic autoimmune inflammation of biliary tract known as primary sclerosing cholangitis.
Abnormal flow of bile can be caused by tumors whose growth obstructs bile duct. We can mention for example gallbladder cancer, biliary tract cancer, liver cancer and pancreatic cancer. Main symptom and source of patient’s complaints is however painless jaundice.
The finding of pale stool always point to suspicion of liver and biliary tract disorders. Comprehensive stool examination is necessary. In addition to medical history and physical exam we should take blood samples to evaluate liver tests and bilirubin level. Imaging methods are also important, mainly abdominal ultrasound. ERCP is much more invasive method that can display biliary tract and solve some obstruction causes.