Gallstones are solid round stones precipitated in the gall bladder that can be due to one of one of 2 types:
- Precipitation of cholesterol (Cholesterol stones) in bile, usually yellow cholesterol stones (also the most common stone) seen in 90% of gallstones.
- Precipitation of Bilirubin (bilirubin stones) in bile are black bilirubin pigmented stones, less common. These are usually seen in disease with increased red blood cell (RBC) turn over.
Stones develops due to super saturation of cholesterol or Bilirubin, causing precipitation. Some of the risk factors and reasons for increase gallstone formation include:
- Decreased phospholipids or bile acids (which are needed to increase solubility of cholesterol)
- Stasis affecting bile flow also increase gall stone formation.
Symptoms and Clinical Presentation of Gall Stones (Cholesterol and BR)
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- Gallstones are frequently asymptomatic in at least 80% of patients. Unless the stone in gallbladder grow large enough to get pushed and block the cystic duct causing a back pressure which can cause epigastric or right upper quadrant (RUQ) pain. This pain is usually transient and vague called biliary colic.
- Upper right quadrant pain is the most common symptom if any and usually the gallbladder is not palpable. Fibrosis of the gallbladder make it less distensible in general.
- Elevation of Alkaline phosphatase (ALKP) in common is gallstone in the common bile duct. The ALKP is made from bile duct epithelium and hepatic bile canalicular membrane.
- Jaundice can also be present if common hepatic or common bile duct blockage, preventing it transition to the duodenum.
Complications depending on where the stone is lodged
- Block Cystic Duct: (most common location for blockage)
- Acute and Chronic Cholecystitis – Gall Bladder inflammation which will give colic pain at RUQ (right upper quadrant) due to cystic duct blockage cause back pressure and secondary possibly secondary bacterial infection.
- Common Bile Duct Block: Choledocholithiasis (stone in common bile duct/past the join region)
- Obstruction at common bile duct hence no downward flow to wash down bacteria casuing ascending cholangitis. This is when there is blockage at common bile duct obstruct by gallstone and the bacteria eventually climb up from duodenum
- Jaundice more pronounced, elevated ALP, increase serum CBR (conjugated bilirubin), Cholesterol, fatty stool can be present.
- iliocaecal valve: cholecystoduodenal fistulas
- Gallstone ileus: when a gallstone passes into the small bowel and usually impacts at the iliocaecal valve.(can go in the jejunum, duodenum, ileum but can’t pass the iliocecal vale and hence lodged at the ileum. E.g. in long standing cholelithiasis.
- Pancreatic Duct: Pancreatitis if obstruction of the pancreatic duct occured from gallstone.
- Gall Bladder Cancer especially together with chronic cholecystitis, porcelain gall bladder is usually seen.
Etiology/Association/Risk Factors:
(1) Cholesterol Stones: These stones are usually Yellow, 90%, most common in West – 90% are radioluscent)
- Risk factor include age (40%), Increase Fenofibrate use (increase liver dump cholesterol)
- Estrogen (increase HMGCoA reductase activity), LDL receptor, oral contraceptives (OCP): estrogen recycled by liver to cholesterol, hence increased Estrogen increased bile cholesterol.
- Cystic Fibrosis that affect the secretions of pancreas
- Crohns diseases (because occurs in ileum, hence interfere with bile salt uptake recycling. The recycled bile salt will usually increase solubility of cholesterol in bile so they don’t precipitate as stoness) – patient if on TPN also decrease CCK secretion from food hence a decrease in contractile activity of gall bladder.
- Distal ileum resection
- Cirrhosis: decrease bile salt production.
(2) Bilirubin Stones: These stones are black in color, usually radio-opaque) – common in Asians
- Extravascular hemolysis (hence increase unconjugated / conjugaed bilirubin proportion in bile) giving black stones
- Biliary tract infection: E.coli infection present with brown stones precipitate due to bacteria unconjugating it, appearing as yellow stones. They can be dark if conjugated bilirubin. Ascaris Lumbricoides, Fluke worm-parasites can both infect the biliary tract.
Diagnosis of Gallstone
- Diagnosis of gallstone is made with ultrasound and complications
- Complications can be diagnosed with CT scan though not more accurate.
- The most accurate diagnostic test for gallstone is Cholescintigraphy (HIDA scan)
Complication of Gallstone
- Biliary colic, acute/chronic cholecystitis, choledocholethiasis, pancreatitis, gallstone ileus, ascending cholangitis are all complications of gallstone.
Treatment and Management of Gallstone
- Asymptomatic gallstones are left alone.
- Symptomatic gallstone are remove with cholecystectomy (surgically) before they get inflammed causing acute cholecystitis.
- Medical dissolution of gallstones as alternative in patients that are poor candidate or refuse to remove the gallbaldder are as follows: Small, cholesterol-rich stones without evidence of calcification and low concentrations of bilirubin salts are the best candidates for bile acid therapy.
- Hydrophilic bile acids, such as chenodeoxycholic acid and ursodeoxycholic acid (UDCA), have been used in the treatment of cholesterol gallstones.
- Currently, only ursodeoxycholic acid is widely used due to chenodeoxycholic acid associated with a many adverse side effects.
- These bile acids work by reducing biliary cholesterol secretion, increasing biliary bile acid concentrations, and as a result, reducing the cholesterol precipitation.
- Ursodeoxycholic acid has also been shown to inhibit biliary secretion of cholesterol, reduce intestinal absorption of cholesterol, increase hepatic bile secretion, and improve gallbladder emptying.
- UDCA (ursodeoxycholic acid) bile acids can also improve gallbladder muscle contractility, reduce gallbladder wall inflammation
- All pure cholesterol stones would be expected to dissolve in bile that is unsaturated with cholesterol. However, most gallstones have a mixed composition, containing significant amounts of calcium salts, affect the efficacy of medical therapy. Occasionally, rim calcification develops, inhibiting further stone dissolution.
- This approach is only useful in cholesterol predominant stones provided they meet the following criteria as a general rule