The gallbladder is a pear-shaped organ located in the upper right side of the abdomen under the liver, and is part of the digestive system. The gallbladder stores a fluid composed mostly of water, bile salts, lecithin and cholesterol, called bile. Cholesterol makes up about 5% of bile. If the liver secretes too much cholesterol into the bile, the cholesterol may start to form gallstones. The process is very slow and most often painless. However, in time, these gallstones can block the flow of bile, which can result in inflammation and serious infection called gallbladder disease.
Gallstones affect about 10% of adults over 40 years old. They occur in nearly 25% of women by age 60 and up to 50% by age 75. Women have a higher risk of developing gallbladder disease because the female hormone, estrogen, stimulates the liver to remove more cholesterol from blood and divert it into bile. About 20% of men have gallstones, and gallstone disease is relatively rare in children.
When gallstones do occur in children, they are more likely to be pigment stones. Girls do not seem to be more at risk than boys. Conditions that put children at higher risk include:
- Spinal injury
- History of abdominal surgery
- Sickle-cell anemia
- Impaired immune system
- Receiving nutrition through a vein (intravenous).
Because gallstones are related to diet, particularly fat intake, Hispanics and Northern Europeans have a higher risk for gallstones. Native North and South Americans are especially prone to developing gallstones.
Obesity is a significant risk factor for gallstones because the liver over-produces cholesterol. Rapid weight loss or cycling (dieting and then putting the weight back on) further increases cholesterol production in the liver. The risk for gallstones is highest in:
- People who lose more than 24% of their body weight
- People who lose more than 3.3 pounds a week
- People on very low-fat, low calorie diets.
Men are also at increased risk for developing gallstones when their weight fluctuates. The risk increases proportionately with dramatic weight changes as well as with frequent weight cycling.
Although gallstones are formed from supersaturation of cholesterol in the bile, high total cholesterol levels themselves are not necessarily associated with gallstones. Gallstone formation is associated with low levels of “good” HDL cholesterol and high triglyceride levels. High levels of triglycerides may impair the emptying actions of the gallbladder.
About three-quarters of the gallstones found in the US population are formed from cholesterol. However, the other 25% are known as pigment gallstones. They are composed of calcium bilirubinate, or calcified bilirubin, the substance formed by the breakdown of hemoglobin in the blood. These black stones often form in the gallbladders of people with hemolytic anemia or cirrhosis.
Most people who develop symptomatic gallbladder disease have biliary pain in the mid-upper or right-upper section of the abdomen and it often radiates to the right shoulder blade. The pain is caused by obstruction of the bile-carrying duct, called the cystic duct, which leads from the gallbladder to the small intestines. This pain is often referred to as “colic” and is usually severe, steady and lasts from 25 minutes to 6 hours. Large or fatty meals can cause the pain, but it usually occurs several hours after eating, often at night.
Acute gallbladder inflammation (acute cholecystitis) is a more serious problem than biliary colic. Acute cholecystitis is usually caused by gallstones, but, in some cases, can occur without stones. Anyone who experiences an attack of acute cholecystitis should seek medical attention because it can progress to gangrene or perforation of the gallbladder, if untreated.
Chronic Cholecystitis occurs because of the prolonged presence of gallstones and low-grade inflammation. Scarring causes the gallbladder to become stiff and thick. Complaints of gas nausea and abdominal discomfort after meals are common.
Gallbladder disease can occur without stones, a condition called acalculous gallbladder disease. Acute acalculous gallbladder disease usually occurs in patients who are very ill from other disorders. Inflammation occurs in the gallbladder and usually results from reduced blood supply or an inability of the gallbladder to properly contract and empty the bile. Chronic acalculous gallbladder disease appears to be caused by muscle defects or other problems in the gallbladder, which interfere with the natural movements required to empty the sac.
The doctor will try to rule out other reasons for abdominal pain prior to making a diagnosis of gallbladder disease. A physical exam and blood tests are routinely done. Several diagnostic tools are also used to diagnose the presence of gallstone include:
- Abdominal ultrasound – can identify larger gallstones thickened gallbladder walls, and problems with ducts.
- Oral cholecystogram (OCG) – special kind of X-ray used to determine if the gall bladder is contracting correctly, and if there are gallstones.
- Computerized tomography (CAT) and MRI – to detect stones.
- Edoscopic Retrograde Cholangiopancreatography (ERCP) – may be used to confirm a diagnosis.
Treatment for gallbladder conditions varies depending on the specific condition, the severity of the symptoms, the presence of complications, and the individual’s medical history. Gallbladder conditions that are causing pain or biliary colic are treated with pain medications, and surgery may be recommended to have the gallbladder removed.