Unveiling the link between obesity and gallstones: risks, treatment, and prevention strategies.

Gallstones:

Gallstones refer to the formation of stones in any part of the gallbladder, intrahepatic or extrahepatic bile ducts. The types and compositions of gallstones vary greatly. Clinical manifestations also depend on whether there is concurrent infection or bile duct obstruction, as well as the location and degree of obstruction. Gallstone formation is related to factors such as increased cholesterol concentration in bile, impaired gallbladder emptying, and infection.

The chemical components of gallstones include organic substances such as cholesterol, bilirubin, fatty acids, bile acids, phospholipids, and glycoproteins; anions such as carbonates and phosphates; and metallic elements such as calcium, magnesium, copper, and iron. Based on the amount of components, gallstones are mainly divided into two types: cholesterol stones and pigment stones, the latter being further divided into black and brown stones. Cholesterol stones and black pigment stones mostly occur in the gallbladder, while brown pigment stones mostly occur in the bile ducts. Women, obesity, estrogen therapy, and ileal resection are risk factors for cholesterol gallstones; biliary tract infections and increased age are risk factors for brown pigment gallstones; and hemolysis, cirrhosis, and increased age are risk factors for black pigment gallstones. Obese patients have a significantly higher risk of developing gallstones than non-obese individuals. Clinically, 30% of obese patients are found to have gallstones during surgery, compared to only 5% of non-obese individuals. Treatment methods for gallstones include:

I. Dietary therapy: For obese patients and those with high blood lipids, fat intake should be appropriately restricted.

II. Drug therapy:
1. Symptomatic treatment: During an attack of biliary colic, 0.6 mg of nitroglycerin or 5-100 mg of isosorbide dinitrate (Isordil) can be administered sublingually, along with antispasmodics such as atropine or scopolamine intramuscularly. If the pain is not relieved, 50-100 mg of pethidine can be administered intramuscularly.

2. Litholytic Therapy
This treatment is primarily used for cholesterol gallstones. Litholytic drugs can be administered orally or via bile duct infusion.

(1) Oral Administration
Oral administration is suitable for cholesterol gallstones smaller than 15 mm in diameter. The gallstones must be radiolucent, and gallbladder function must be good. Currently, chenodeoxycholic acid and ursodeoxycholic acid are used clinically for oral dissolution. Both drugs dissolve cholesterol gallstones within the gallbladder. Chenodeoxycholic acid and ursodeoxycholic acid work by reducing intrahepatic cholesterol secretion and increasing bile acid levels in the bile.

Chenodeoxycholic acid: The usual dose is 750 mg daily, divided into several oral doses, adjusted until diarrhea occurs, then maintained at 250 mg daily. It is now less commonly used. Its main side effects include diarrhea and temporary elevation of transaminase levels.

Usodeoxycholic acid: The usual dose is 8–13 mg daily, divided into several oral doses. Ursodeoxycholic acid is the 7-β-hydroxy epimer of chenodeoxycholic acid and has a strong choleretic effect. It can contract the gallbladder, relax the sphincter, promote bile secretion and excretion, inhibit cholesterol absorption, and promote the formation of cholesterol-lecithin liquid crystals on the surface of gallstones, thus promoting stone dissolution. It also enhances the activity of hepatic peroxidase, improving the liver's detoxification and antitoxic functions. Besides oral litholysis, it can also be used as an adjunct therapy after ultrasonic lithotripsy. Adverse reactions are rare. Furthermore, it can help prevent gallstones in obese patients.

The typical treatment course is 6–9 months. The stone dissolution rate with single-drug use is 20%–40%, while the rate can be increased to 50% with two drugs combined. The recurrence rate is 13%–45% after 2 years of discontinuation and 75% after 5 years.

In addition, many traditional Chinese medicines are currently used clinically, such as Xiaoyan Lidan tablets, Jindan tablets, Daning, Danle, and Danshitong. The main effects of traditional Chinese medicine in dissolving gallstones are: ① increasing bile secretion and flow, flushing out stones; ② promoting gallbladder contraction; ③ relaxing the sphincter of Oddi; ④ antibacterial and anti-inflammatory effects, and improving symptoms.

(2) Direct Infusion Administration: Direct infusion administration involves injecting litholytic drugs into the gallbladder and common bile duct via percutaneous transhepatic gallbladder puncture catheterization, cholecystostomy tubes, T-shaped drainage tubes, and nasobiliary tubes.

The commonly used drug is methyl tert-butyl ether. After use, most cholesterol stones begin to dissolve 5 days after infusion. Litholytic agents can cause bile duct mucosal ulceration and submucosal hemorrhage, which usually recovers after 4 weeks. It can also flow into the duodenum and cause damage.