The Gallbladder - An Organ You Can Live Without

by Food and Drug Administration (FDA)

Even though she was about 15 pounds overweight, the woman indulged in her favorite fatty foods with gusto, consuming fried chicken, french fries, and topping it off with a hot fudge sundae. By 3 a.m., she regretted her actions, awakening with indigestion and a sharp, stabbing pain in the upper right quarter of her abdomen. The pain continued for hours, spreading to her shoulders, slowly ebbing away by the next afternoon.

Since the symptoms had abated and no one else in the family became ill, the woman forgot her experience — until a few weeks later. This time the seeming culprit was a pizza binge, another fatty meal. The unrelenting, severe abdominal pain returned. Finally, the woman went to her doctor, who immediately suspected a gallbladder problem.

Although this woman is a composite of several gallstone patients, her experiences are fairly typical. She was not one of the 10 percent of patients whose gallstones contain calcium, which makes them visible on a standard x-ray. So she was given a tablet containing a radiopaque dye the night before undergoing a special x-ray called an oral cholecystogram. The dye outlined her gallbladder and individual stones within it. Had the dye not shown up at all, it would have meant that her gallbladder was packed full with stones. An ultrasound scan confirmed the presence of stones.

The diagnosis: acute cholecystitis. The tube leading from her gallbladder to her small intestine was blocked by a cholesterol stone. Pressure was building in her gallbladder, alerting the immune system to send in the white blood cells and biochemicals of an inflammatory response.

Although she was in intense pain, the woman would soon be helped by recent developments that make treating a diseased gallbladder easier than ever.

The Gallbladder

The gallbladder is a small, muscular, pear-shaped sac nestled in a depression on the right underside of the liver. It holds about a quarter of a cup of a yellowish-green, pasty material called bile. Bile contains water, bile salts and acids, pigments, cholesterol, phospholipids (a type of fat molecule), and electrolytes (electrically charged fluids). Bile tastes bitter, and this is why the word "bile" has come to denote bitterness. Bile breaks up, or emulsifies, large globs of fat into smaller globs in the small intestine, a first step in fat digestion.

The gallbladder is a storage stop between the liver and the small intestine. It fills with viscous bile, thickening it, until a hormone released after eating signals the gallbladder to squirt out its colorful contents.

A healthy gallbladder keeps bile moving in several ways. The inner lining, called the mucosa, secretes hydrogen ions into the gallbladder contents. This maintains an acidic environment, necessary to keep calcium from precipitating (coming out of solution as solid particles). As food is digested, water and electrolytes pour into the area, continually diluting and washing out the bile. Finally, bile salts latch onto cholesterol molecules, keeping them in solution.

Stone Formation

Should any of these biological balances backfire, the sludge-like gallbladder contents can crystallize. A stone forms when a speck of calcium becomes coated with either cholesterol or the pigment bilirubin. Bilirubin comes from the blood's oxygen-carrying molecule, hemoglobin. The brownish-black color of pigment stones is due to bilirubin, much as a vibrantly-hued bruise appears as blood spreads beneath the skin.

While pigment stones are small, dark, and relatively rare, cholesterol stones are crystalline and waxy, can grow quite large, and may accumulate in the hundreds. Many stones are mixed, with pigment on the inside, wrapped in a cholesterol coat.

About half of people with gallbladder stones do not even know that they have them. Painless stones probably float freely in the gallbladder. Pain results when a stone is small enough to pass through and lodge in either the cystic duct leading from the gallbladder, or farther along in the common bile duct, which is shared by the gallbladder and the liver and leads to the small intestine. In fact, one large stone trapped in the gallbladder is not as likely to cause pain as are several small stones that can escape.

The type and severity of symptoms depend upon where stones lodge. A stone stuck in the lower common bile duct results in jaundice (yellowing of the skin and whites of the eyes, due to bilirubin accumulation) and may cause pancreatitis, because a conduit from the pancreas joins the common bile duct. The pancreas' digestive enzymes, which normally go to the small intestine, become trapped in this essential gland, destroying it.

A stone trapped in the neck of the gallbladder causes acute cholecystitis. A milder condition is chronic recurrent acute cholecystitis, characterized by intermittent pain of shorter duration and less intensity.

In the most severe scenario, pressure builds so much that the gallbladder bursts, sending bile into the abdominal cavity. Pus accumulates, bacteria move in, and the infected bile may lead to peritonitis, a severe infection of the abdominal cavity. But this is very rare because a gallbladder is usually removed before disease can progress this far.

Who Gets Gallstones?

Although gallstones are a very common medical problem, we know very little about why some people develop them and some do not. We do know that women are twice as likely to have gallbladder problems as men.

Women may owe their higher risk of gallbladder disease to hormones. The female hormone estrogen is known to increase the rate of lipid (fat) synthesis, use and excretion, while at the same time calming gallbladder movements that would mix up the contents. Pregnancy raises risk by altering the chemical composition of bile to favor stone formation and decreasing the contractability of the gallbladder. Birth control pills containing estrogen increase the cholesterol content of bile, and seem to heighten the risk of gallbladder disease in women under 29 who have taken them for less than 5 years.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.