Gallstone

Gallstone
Classification and external resources
gallstones
ICD-10	K80.
ICD-9	574
OMIM	600803
DiseasesDB	2533
MedlinePlus	000273
eMedicine	emerg/97
MeSH	D042882

Gall bladder opened to show numerous gallstones. Their brownish to greenish color suggest they are cholesterol calculi.

In medicine, gallstones (choleliths) are crystalline bodies formed within the body by accretion or concretion of normal or abnormal bile components.

Gallstones can occur anywhere within the biliary tree, including the gallbladder and the common bile duct. Obstruction of the common bile duct is choledocholithiasis; obstruction of the biliary tree can cause jaundice; obstruction of the outlet of the pancreatic exocrine system can cause pancreatitis. Cholelithiasis is the presence of stones in the gallbladder or bile ducts: chole- means "bile", lithia means "stone", and -sis means "process".

Characteristics

Size

A gallstone's size can vary and may be as small as a sand grain or as large as a golf ball. The gallbladder may develop a single, often large stone or many smaller ones. They may occur in any part of the biliary system.

Content

Gallstones

Gallstones have different appearance, depending on their contents. On the basis of their contents, gallstones can be subdivided into the two following types:

• Cholesterol stones are usually green, but are sometimes white or yellow in color. They are made primarily of cholesterol, the proportion required for classification as a cholesterol stone being either 70% (Japanese classification system) or 80% (US system).^[1]
• Pigment stones are small, dark stones made of bilirubin and calcium salts that are found in bile. They contain less than 20% of cholesterol. Risk factors for pigment stones include hemolytic anemia (such as sickle cell anemia and hereditary spherocytosis), cirrhosis, and biliary tract infections.

The proportions of these different types of stone found varies between samples, and is thought to be affected by the age and ethnic or regional origin of the patients.^[2]

Mixed stones

All stones are of mixed content to some extent. Those classified as mixed, however, contain between 30% and 70% of cholesterol. In most cases the other majority constituent is calcium salts such as calcium carbonate, palmitate phosphate, and/or bilirubinate. Because of their calcium content, they can often be visualized radiographically.

Pseudoliths

Also known as "Fake stones," they are sludge-like gallbladder secretions that act like a stone.

Causes

Researchers believe that gallstones may be caused by a combination of factors, including inherited body chemistry, body weight, gallbladder motility (movement), and perhaps diet.

Pigment gallstones

Most commonly seen in the developing world. People with erythropoietic protoporphyria (EPP) are at increased risk to develop gallstones.^[3]

Conditions causing hemolytic anemia can cause pigment gallstones.^[4]

Risk factors for pigmented stones:

 1. Chronic hemolytic syndromes
 2. Biliary infection
    i.	Microbial beta-glucuronidases deconjugate the bilirubin in the biliary tract 
 3. Gastrointestinal disorders

Cholesterol gallstones

Cholesterol gallstones develop when bile contains too much cholesterol and not enough bile salts. Besides a high concentration of cholesterol, two other factors seem to be important in causing gallstones. The first is how often and how well the gallbladder contracts; incomplete and infrequent emptying of the gallbladder may cause the bile to become overconcentrated and contribute to gallstone formation. The second factor is the presence of proteins in the liver and bile that either promote or inhibit cholesterol crystallization into gallstones.

In addition, increased levels of the hormone estrogen as a result of pregnancy, hormone therapy, or the use of combined (estrogen-containing) forms of hormonal contraception, may increase cholesterol levels in bile and also decrease gallbladder movement, resulting in gallstone formation.

No clear relationship has been proven between diet and gallstone formation; however, low-fiber, high-cholesterol diets and diets high in starchy foods have been suggested as contributing to gallstone formation. Other nutritional factors that may increase risk of gallstones include rapid weight loss, constipation, eating fewer meals per day, eating less fish, and low intakes of the nutrients folate, magnesium, calcium, and vitamin C.^[5] On the other hand, wine and whole grain bread may decrease the risk of gallstones.^[6]

The common mnemonic for gallstone risk factors refer to the "four Fs": fat (i.e., overweight), forty (an age near or above 40), female, and fertile (pre-menopausal);^[7] a fifth F, fair is sometimes added to indicate that the condition is more prevalent in Caucasians. The absence of these risk factors does not, however, preclude the formation of gallstones.

Interestingly, a lack of melatonin could significantly contribute to gallbladder stones, as melatonin both inhibits cholesterol secretion from the gallbladder, enhances the conversion of cholesterol to bile, and is an antioxidant, capable of reducing oxidative stress to the gallbladder.^[8]

Symptoms

Gallstones usually remain asymptomatic initially. ^[9] They start developing symptoms once the stones reach a certain size (>8 mm).^[10] A main symptom of gallstones is commonly referred to as a gallstone "attack", also known as biliary colic, in which a person will experience intense pain in the upper abdominal region that steadily increases for approximately 30 minutes to several hours. A patient may also experience pain in the back, ordinarily between the shoulder blades, or pain under the right shoulder. In some cases, the pain develops in the lower region of the abdomen, nearer to the pelvis, but this is less common. Nausea and vomiting may occur. Patients characteristically exhibit a positive Murphy's sign, (the patient is instructed to breathe in while the gallbladder is deeply palpated). If the gallbladder is inflamed, the patient will abruptly stop inhaling due to the pain, resulting in a positive Murphy's sign.

These attacks are sharp and intensely painful, similar to that of a kidney stone attack. Often, attacks occur after a particularly fatty meal and almost always happen at night. Other symptoms include abdominal bloating, intolerance of fatty foods, belching, gas and indigestion. If the above symptoms coincide with chills, low-grade fever, yellowing of the skin or eyes and/or clay-colored stool, a doctor should be consulted immediately.^[11]

Some people who have gallstones are asymptomatic and do not feel any pain or discomfort. These gallstones are called "silent stones" and do not affect the gallbladder or other internal organs. They do not need treatment.^[11]

Treatment

Medical options

Cholesterol gallstones can sometimes be dissolved by oral ursodeoxycholic acid, but it may be required that the patient takes this medication for up to two years.^[12] Gallstones may recur however, once the drug is stopped. Obstruction of the common bile duct with gallstones can sometimes be relieved by endoscopic retrograde sphincterotomy (ERS) following endoscopic retrograde cholangiopancreatography (ERCP). Gallstones can be broken up using a procedure called lithotripsy (extracorporeal shock wave lithotripsy).^[12] which is a method of concentrating ultrasonic shock waves onto the stones to break them into tiny pieces. They are then passed safely in the feces. However, this form of treatment is only suitable when there are a small number of gallstones.

Surgical options

Cholecystectomy (gallbladder removal) has a 99% chance of eliminating the recurrence of cholelithiasis. Only symptomatic patients must be indicated to surgery. The lack of a gall bladder may have no negative consequences in many people. However, there is a significant portion of the population — between 5 and 40% — who develop a condition called postcholecystectomy syndrome^[13] which may cause gastrointestinal distress and persistent pain in the upper right abdomen. In addition, as many as 20% of patients develop chronic diarrhea.^[14]

There are two surgical options for cholecystectomy:

• Open cholecystectomy: This procedure is performed via an incision into the abdomen (laparotomy) below the right lower ribs. Recovery typically consists of 3–5 days of hospitalization, with a return to normal diet a week after release and normal activity several weeks after release.^[15]
• Laparoscopic cholecystectomy: This procedure, introduced in the 1980s,^[16] is performed via three to four small puncture holes for a camera and instruments. Post-operative care typically includes a same-day release or a one night hospital stay, followed by a few days of home rest and pain medication.^[15] Laparoscopic cholecystectomy patients can generally resume normal diet and light activity a week after release, with some decreased energy level and minor residual pain continuing for a month or two. Studies have shown that this procedure is as effective as the more invasive open cholecystectomy, provided the stones are accurately located by cholangiogram prior to the procedure so that they can all be removed.

Temporary Relief

Some patients have anecdotally reported that symptoms can be temporarily reduced by drinking several glasses of water when experiencing gallstone pain. This approach will not eliminate the gallstones or improve the patient's condition in the long term.

Value of animal gallstones

Gallstones are a valuable by-product of meat processing, fetching up to US$32–per–gram in their use as a purported antipyretic and antidote in the folk remedies of some cultures, particularly in China. The finest gallstones tend to be sourced from old dairy cows, which are called Niu-Huang (牛黄，yellow thing of oxen) in Chinese. Those obtained from dogs, called Gou-Bao (狗宝，treasure of dogs) in Chinese, are also used today. Much as in the manner of diamond mines, slaughterhouses carefully scrutinize offal department workers for gallstone theft.^[17]

References

External links

• Public domain NIH/NIDDK e-pub on gallstones
• MedlinePlus Encyclopedia Gallbladder removal
• 5-Minute Clinical Consult Cholelithiasis
• Gallstone information