Cholelithiasis implies the presence of one or more concrements (gallstones) in the gallbladder.
In the USA, 20% of people over 65 years old have gallstones, and most of the disorders in the extrahepatic biliary tract are the result of cholelithiasis. Gallstones can be asymptomatic or cause biliary colic, but without dyspepsia. Other major complications of cholelithiasis include cholecystitis; obturation of the biliary tract (concrements in the bile duct), sometimes with infection (cholangitis); as well as biliary pancreatitis. Diagnosis is usually established using ultrasound. If cholelithiasis causes complications, it becomes necessary to perform cholecystectomy.
What Causes Cholelithiasis?
Risk factors for the formation of gallstones include female sex, obesity, age, ethnicity (for the US – American Indians), Western type of nutrition and heredity.
Gallstones and bile sludge are formed from various types of substances.
Cholesterol stones account for more than 85% of gallstones in Western countries. Three conditions are necessary for the formation of cholesteric gallstones.
- Bile is supersaturated with cholesterol. Typically, water-insoluble cholesterol becomes water-soluble when combined with bile salts and lecithin. In this case, mixed micelles are formed. The hyper saturation of bile with cholesterol can be a consequence of increased cholesterol secretion (for example, in diabetes), a decrease in the secretion of bile salts (for example, in malabsorption of fat) or a deficit of lecithin (for example, in genetic disorders that cause the form of progressive intrahepatic hereditary cholestasis).
- Excess cholesterol precipitates from the solution in the form of solid microcrystals. Precipitation is accelerated by mucin, fibronectin, su globulin or immunoglobulin. Apolipoproteins A-I and A-II can slow down the process.
- Microcrystals form complexes. The process of aggregation is facilitated by mucin, reduced gallbladder contractility (which is directly a result of excess cholesterol in the bile) and slowing down the passage of contents through the intestine, which facilitates the bacterial transformation of cholic acid to deoxycholic acid.
Symptoms Of Cholelithiasis
In 80% of cases, gallstones are asymptomatic; in the remaining 20% the symptomatology of the disease varies from biliary colic and signs of cholecystitis to severe and life-threatening cholangitis. Patients with diabetes are predisposed to especially severe manifestations of the disease. Stones can migrate to the vesicular duct without clinical manifestations. Nevertheless, with blockage of the cystic duct, pain usually occurs (biliary colic). Pain occurs in the right hypochondrium, but can often be localized or manifested in other parts of the abdomen, especially in patients with diabetes and the elderly. Pain can radiate into the back or arm. It begins suddenly, becoming more intense for 15 minutes to 1 hour, remaining constant for 1-6 hours, then after 30-90 minutes it gradually disappears, acquiring the character of dull pain. The pain is usually strong. Often there is nausea and vomiting, but neither fever nor chills occur. When palpation is determined moderate soreness in the right hypochondrium and epigastrium, but peritoneal symptoms are not caused, and laboratory indicators are within the norm. Between episodes of pain, the patient feels well.
Although pain like biliary colic can occur after taking heavy meals, fatty foods are not a specific provoking factor. Symptoms of dyspepsia, such as belching, bloating, vomiting and nausea, are not entirely associated with gallbladder diseases. These symptoms can be observed with cholelithiasis, peptic ulcer and with functional disorders of the gastrointestinal tract.
The severity and frequency of biliary colic weakly correlate with pathological changes in the gallbladder. Bile colic can develop in the absence of cholecystitis. However, if colic lasts more than 6 hours, there is vomiting or fever, there is a high probability of developing acute cholecystitis or pancreatitis.
Diagnosis Of Cholelithiasis
Suspicion for the presence of gallstones occurs in patients with biliary colic. Laboratory tests are usually not informative. Ultrasound of the abdominal cavity is the main method for diagnosing cholecystolithiasis, and the sensitivity and specificity of the method is 95%. You can also detect the presence of bile sludge. CT and MRI, as well as oral cholecystography (currently rarely used, but sufficiently informative) are alternative. Endoscopic ultrasound is especially informative in the diagnosis of gallstones less than 3 mm in size, if other methods give mixed results. The asymptomatic course of gallstones is often detected accidentally during studies performed on other indications (for example, 10-15% of calcified non-cholesterol stones are visualized on simple radiographs).