Medical Health Encyclopedia

Pigment Stones. Pigment stones are composed of calcium bilirubinate, or calcified bilirubin. Pigment stones can be black or brown.

• Black stones form in the gallbladder and are the more common type. In fact, they represent 20% of all gallstones in the US. They are more likely to develop in people with hemolytic anemia (a relatively rare anemia where red blood cells are destroyed) or cirrhosis (a scarred liver).
• Brown pigment stones are more common in Asian populations. They contain more cholesterol and calcium than black pigment stones and are more likely to occur in the bile ducts. Infection plays a role in the development of these stones. One report suggested that bacteria or other microorganisms may trigger oxidation--a damaging chemical process in the body--which, in this case, can cause changes that lead to pigment stone formation.

Choledocholithiasis

Gallstones can also be present in the common bile duct. This is called choledocholithiasis.

Click the icon to see an image of gallstone obstruction.

Secondary Common Bile Duct Stones. In most cases, common bile duct stones originally form in the gallbladder and pass into the common duct (called secondary stones). Choledocholithiasis occurs in about 10% of patients who have gallstones.

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Primary Common Bile Duct Stones. In less common cases, the stones form in the common duct itself (called primary stones). Primary common duct stones are usually of the brown pigment type and are more likely to cause infection than secondary common duct stones.

Gallbladder Diseases Without Stones

Gallbladder disease can occur without stones. This is called acalculous gallbladder disease.

Gallbladder disease can occur without stones, a condition called acalculous gallbladder disease. It can be acute (arising suddenly, often as a one-time occurrence) or chronic (persistent).

• Acute acalculous gallbladder disease usually occurs in patients who are very ill from other disorders. In such cases, inflammation occurs in the gallbladder, usually from a diminished blood supply or an impaired ability to contract and empty its bile (i.e. impaired motility).
• Chronic acalculous gallbladder disease (also called biliary dyskinesia) appears to be caused by muscle defects or other problems in the gallbladder that cause impaired motility.