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Гастроэнтерология (анг,рус)

COMPOSITION AND RISK FACTORS FOR PIGMENT STONES

 

 

 

 

 

 

 

 

 

 

Mixed stones

n            Mixed stones account for the majority of stones.

n            Most of these are a mixture of cholesterol and calcium salts.

n            Because of their calcium content, they can often be visualized radiographically.

Size

n            A gallstone's size varies and may be as small as a sand grain or as large as a golf ball.

n            The gallbladder may develop a single, often large stone or many smaller ones.

n            They may occur in any part of the biliary system.

 

Biliary sludge

n            The term 'biliary sludge' describes bile which is in a gel form that contains numerous crystals or microspheroliths of calcium bilirubinate granules and cholesterol crystals as well as glycoproteins.

n             It is an essential precursor to the formation of gallstones in the majority of patients. Biliary sludge is frequently formed under normal conditions, but then either dissolves or is cleared by the gallbladder; only in about 15% of patients does it persist to form cholesterol stones.

n            Fasting, parenteral nutrition and pregnancy are also associated with sludge formation.

Risk factors

n            The common mnemonic for gallstone risk factors refer to the "four F's":

n            fat (i.e., overweight),

n            forty (an age near or above 40),

n            female, and

n            fertile (pre-menopausal);a fifth F, fair is sometimes added to indicate that the condition is more prevalent in Caucasians.

n            The absence of these risk factors does not, however, preclude the formation of gallstones.

 

Clinical features

 

 

 

                                                                                                

 

n            The majority of gallstones are asymptomatic and remain so. They start developing symptoms once the stones reach a certain size (>8mm). Only about 10% of those with gallstones develop clinical evidence of gallstone disease.

n            Symptomatic gallstones manifest either as biliary pain ('biliary colic') or as a consequence of cholecystitis.

n            If a gallstone becomes acutely impacted in the cystic duct, the patient will experience pain.

Biliary pain

n            The term 'biliary colic' is a misnomer because the pain does not rhythmically increase and decrease in intensity as in colic experienced in intestinal and renal disease.

n            Instead the pain is typically of sudden onset and is sustained for about 2 hours; its continuation for more than 6 hours suggests that a complication such as cholecystitis or pancreatitis has developed.

n            Pain is felt in the epigastrium (70% of patients) or right upper quadrant (20% of patients) and radiates to the interscapular region or the tip of the right scapula, but other sites include the left upper quadrant, the epigastrium and the lower chest;

n            The pain can be confused with intrathoracic disease, oesophagitis, myocardial infarction or dissecting aneurysm.

n            Combinations of fatty food intolerance, dyspepsia and flatulence not attributable to other causes have been referred to as 'gallstone dyspepsia'.

 

Investigations

n            A plain abdominal radiograph will demonstrate calcified gallstones in less than 20% of patients.

n            Ultrasonography is the method of choice to diagnose gallstones but oral cholecystography, MRI and CT can also be used.

 

CT showing gallstone within gallbladder (arrow).

 

 

 

 

 

 

 

 

 

 

Complications

 

 

 

 

 

 

 

                                                                                    

 

n            Occlusion of the cystic duct for any prolonged period of time results in acute cholecystitis.

n            Other complications include chronic cholecystitis, and a mucocoele of the gallbladder, in which there is slow distension of the gallbladder from continuous secretion of mucus.

n             If this material becomes infected, an empyema develops.

n            Calcium may be secreted into the lumen of the hydropic gallbladder, causing limy bile, and if calcium salts are precipitated in the gallbladder wall the radiological appearance of 'porcelain' gallbladder results.

n            Gallstones in the gallbladder (cholecystolithiasis) migrate to the common bile duct (choledocholithiasis) in approximately 15% of patients and cause biliary colic, but they may be asymptomatic.

n            Rarely, fistulae develop between the gallbladder and the duodenum, colon or stomach. Air will be seen in the biliary tree on plain abdominal radiographs..

n            If a stone larger than 2.5 cm in diameter has migrated into the gut it may impact either at the terminal ileum or occasionally in the duodenum or sigmoid colon. The resultant intestinal obstruction may be followed by 'gallstone ileus'.

n            Rarely, gallstones impacted in the cystic duct cause stricturing in the common hepatic duct (Mirizzi's syndrome), resulting in obstructive jaundice

n            Cancer of the gallbladder is uncommon, although it is recognised more frequently in an ageing population and in a 'porcelain' gallbladder.

n            In over 95% of patients with gallbladder cancer there are accompanying gallstones.

n            Cancer is usually diagnosed as an incidental histological finding following cholecystectomy for gallstone disease.

 

 

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