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cholelithiasis

cholelithiasis (gallstones)

see also:

  • 10-20% of adults in Western cultures have gallstones, this may or may not be the cause of the clinical presentation!
  • cholesterol stones are not confined to patients who are Fat, Female, Fertile and Forty, but prevalence generally starts to rise after puberty and men also get these stones, albeit at a rate half that of women.
  • rapid weight loss or major illness or trauma are also important factors!
  • CT may fail to detect gallstones because many stones are isodense with bile

introduction

  • gallstones are stones which form insidiously within the gallbladder, and most remain asymptomatic but if they obstruct the cystic duct may cause biliary colic or if this obstruction lasts more than a few hours, it may lead to cholecystitis
  • the stones may pass into the common bile duct (CBD) or form within the CBD and this is termed choledocholithiasis, these tend to become impacted distally at the ampulla of Vater and may lead to biliary colic and the life threatening conditions, ascending cholangitis and pancreatitis.
  • the finding of gallstones within the gall bladder does NOT of itself mean that they are the cause of the patient's symptoms, as many are asymptomatic and may lead to misdiagnosis.
  • once they become symptomatic, it is usually an indication for cholecystectomy, preferably, electively.
  • elderly patients are more likely to progress from asymptomatic gallstones to serious complications of gallstones and cholangitis.
  • chronic gallbladder inflammation may lead to cancer of the gallbladder
    • hence patients with porcelain gallbladder (calcification of gallbladder wall seen on X-ray) are usually referred for cholecystectomy
  • patients may develop cholecystitis without the presence of gallstones - “acalculous cholecystitis”
    • these patients are generally very unwell hospitalised patients such as post-op or ICU patients, but it may occur in outpatients
    • high morbidity and mortality rates

types of gallstones

cholesterol stones

  • in Western cultures, 80% are cholesterol stones - that is cholesterol is their main component
  • the main factors that determine whether cholesterol gallstones will form are:
    • the amount of cholesterol secreted by liver cells, relative to lecithin and bile salts, and
    • the degree of concentration and extent of stasis of bile in the gallbladder
  • risk factors for formation of cholesterol stones:
    • traditional clinical mnemonic: “Fat, Female, Fertile, and Forty” indicates the main risk factors, HOWEVER, it should not be forgotten that men still get gallstones, it is just that women are about twice as likely to have them.
      • metabolic syndrome of truncal obesity, insulin resistance, type II diabetes mellitus, hypertension, and hyperlipidemia is associated with increased hepatic cholesterol secretion and is a major risk factor for the development of cholesterol gallstones.
    • pregnancy
      • more common in women who have experienced multiple pregnancies
      • a major contributing factor is thought to be the high progesterone levels of pregnancy.
      • progesterone reduces gallbladder contractility, leading to prolonged retention and greater concentration of bile in the gallbladder
      • a common time for clinical presentation of biliary disease is in the puerperium!
    • gallbladder stasis
      • progesterone (see above)
      • high spinal cord injuries
      • prolonged fasting with total parenteral nutrition,
      • rapid weight loss associated with severe caloric and fat restriction (eg. diet, gastric bypass surgery).
      • burns, ICU care, and major trauma.
    • drugs
      • oestrogens administered for contraception or for treatment of prostate cancer increase the risk of cholesterol gallstones by increasing biliary cholesterol secretion
      • clofibrate and other fibrate hypolipidemic drugs increase hepatic elimination of cholesterol via biliary secretion
    • genetics contribute 25% of risk
      • at least a dozen genes may contribute to the risk
      • prevalence of gallstones is highest in:
        • fair-skinned people of Northern European descent
        • Hispanic populations, Native Americans, and Pima Indians
    • reduced bile salts:
      • Crohn's disease, ileal resection, or other diseases of the ileum decrease bile salt reabsorption and increase the risk of gallstone formation.
  • prevention
    • short-term prophylaxis with ursodeoxycholic acid should be considered for patients at acute risk of developing cholesterol stones such as those likely to undergo rapid weight loss from aggressive dieting or bariatric surgery
    • specific foods in the diet otherwise does not appear to have a significant impact

calcium, bilirubin, and pigment gallstones

  • black pigment stones
    • represent 10-20% of gallstones in Western cultures
    • they are mainly due to increased heme turnover such as chronic haemolysis or cirrhosis
    • African Americans with sickle cell disease
  • brown pigment gallstones
    • are unusual in Western cultures but are fairly common in some parts of Southeast Asia, possibly related to liver fluke infestation
    • these stones tend to form in the CBD as a result of bacterial action on lecithin forming fatty acids

mixed stones

  • in chronic inflammation, over time, cholesterol stones may accumulate a substantial proportion of calcium bilirubinate and other calcium salts, producing mixed gallstones.
  • large stones may develop a surface rim of calcium resembling an eggshell that may be visible on plain x-ray films
cholelithiasis.txt · Last modified: 2013/12/27 06:21 by gary1