When you eat some real fatty foods, like say some delicious samosa, kachori, they make their way to through the stomach and into the small intestine. At this point, they are not really samosa or kachori anymore and became half-digested food chyme (semiliquid partially digested food passing from the stomach to intestine ). But since they are high in fat, they are still a little more difficult to absorb, and that is where your gallbladder comes in work. This high-fat food stimulates the gallbladder to squeeze out some bile into the small intestine. The bile emulsifies the fat, or basically mixes the fat up, and makes it easier to absorb.
ANATOMY OF GALLBLADDER
Now let us see the anatomy of the gallbladder. The gallbladder is a 7-10 cm long, pear-shaped structure situated at the inferior part of the liver.
Gallbladder is divided into
- FUNDUS – It is round blind part of the gallbladder extending 1-2 cm from the liver margin. it contain maximum amount of smooth muscle in the gallbladder.
- BODY – Body is storage area of the gallbladder containing most of the elastic tissue in the gallbladder.
- NECK – Neck is the part of gallbladder which joins body to the cystic duct. Hartmann’s pouch is mucosal outpouching present in the neck region.
CRYPTS OF LUSCHKA– Mucosal lining of the gallbladder is formed by single layer of simple columnar epithelium. Indentations present in the mucosal lining is called crypts of Luschka.
CANTLE’S LINE -It is vertical plane running from the gallbladder fossa anteriorly to the inferior vena cava posteriorly. It divides liver into right and left lobes.
CALOT’S TRIANGLE – Calot’s triangle is area bounded by cystic duct laterally, common hepatic duct medially and inferior edge of liver superiorly.
FUNCTIONS OF GALLBLADDER
Does gallbladder makes bile?
NO! gallbladder does not make bile . However it store, concentrate and secrete bile.
- RESERVOIR OF BILE- In fasting state approximately 80% of bile secreted by liver stored in the gallbladder.
- CONCENTRATION OF BILE – Gallbladder actively absorbs water, sodium, chloride and bicarbonates. The gallbladder can concentrate bile 5 to 10 times.
- SECRETION – Gallbladder mucosa secretes mucus and hydrogen ion into the bile.
EMPTYING OF GALLBLADDER
This is pretty much clear now that gallbladder’s job is to store and concentrate bile. Gallbladder stores bile until fat, proteins or acid comes to contact the of the duodenum which causes the secretion of cholecystokinin, resulting into contraction of gallbladder and relaxation of the sphincter of Oddi.
HOW GALLSTONES FORM?
The primary event in the formation of gallstone is supersaturation of bile with cholesterol. This is followed by cholesterol crystal nucleation. Nucleation is the most critical step in gallstone formation.
FACTORS ASSOCIATED WITH GALLSTONE FORMATION
A) Increase Cholesterol Secretion
- High Calorie Diet
- Non-HDL hyperlipidemia
- Medicines like OCP
B) Diminished enterohepatic circulation
- terminal ileum resection
- conditions causing increased bowel transit time
- vagotomy or bariatric surgery
- gastric or duodenal surgery
- drugs – cholestyramine, deoxycholate
C) Impaired gallbladder functioning
- prolonged fasting
- total parental nutrition
TYPES OF GALLSTONES
A) PURE CHOLESTEROL STONES – generally seen as a single large stone with smooth surface. these stones are seen in less than 10% cases.
B) MIXED STONES – these are most common stones seen after cholecystectomy. mixed stones contains about 70% cholesterol by weight.
C) PIGMENT STONES – contains less than 20% cholesterol by weight.
a) BLACK PIGMENT STONES- seen in conditions like hemolytic disorders eg- sickle cell anaemia. With extravascular hemolysis macrophages in our body destroys red blood cells more than normal and unconjugated bilirubin production is ramped up, which is conjugated by the liver and sent to the gallbladder.
In this situation where there is a lot of hemolysis and unconjugated bilirubin production, this eventually leads to more conjugated bilirubin in the gallbladder.
when there is more conjugated bilirubin in the bile, there is also more unconjugated bilirubin produced by nonenzymatic degradation, to the point where it can now bind calcium instead of the bile salts, and precipitate out to form black pigmented stones
b) BROWN PIGMENT STONES – If the gallstone is brown pigmented type, it is often a sign of gallbladder or biliary tract infection. these stones usually found outside gallbladder into the bile ducts.These brown gallstones are also made of the calcium salts of unconjugated bilirubin, what is different here, is how the unconjugated bilirubin forms.
what happens is that a bacteria that causes gallbladder infection, like E coli., cause hydrolysis of both conjugated bilirubin and phospholipids, that again combine with calcium ions, which then precipitates out to form brown pigment stones.
these stones are also formed when the biliary obstruction is present eg – stricture, stents, parasitic infections likeAscitris lumbricoides and clonorchis sinesis etc.
SYMPTOMS OF GALLSTONE
most of the gallstones are asymptomatic and found incidentally in radiological investigations done for other conditions.
PAIN- patient with symptomatic gallstone present with right upper abdominal pain which usually dull aching type and radiates to right upper back and shoulder. pain starts usually after taking meal especially fatty meals. the pain of biliary colic usually lasts for few hours. pain develops because of obstruction of the cystic duct by gallstone leads to distension of the gallbladder wall.
other symptoms are – nausea , vomiting, anorexia , dyspepsia , belching etc.
does jaundice occurs in gallstone?
jaundice does not occurs in simple gallstone, until it obstructs common bile duct.
diagnosis of cholelithiasis or gallstones is based on
history of symptoms, physical examination and demonstration of gallstones by radiological imaging.
ultrasonography mostly detects gallstones by presence of acoustic shadow.
Only 10% gallstones are seen in plain abdominal radiographs having characteristic Mercedes Benz sign or sea-gull sign.
DIFFERENTIAL DIAGNOSIS OF CHOLELITHIASIS
- Acute pancreatitis
- Gastro Esophageal Reflux Disorder
- Peptic ulcer disease
- liver diseases
- acute appendicitis
- right sided renal stone
- right sided lower lobe pneumonia
- epigastric hernia
- myocardial infarction
treatment of symptomatic gallstone is cholecystectomy.
cholecystectomy is the removal of gallstones along with the gallbladder.
this operation is done by either laparoscopic or open surgical method by the surgeon.
laparoscopic cholecystectomy is the preferred method now a days.
complications of gallstones
- acute cholecystitis
- chronic cholecystitis
- empyema of gallbladder
- acute pancreatitis
- gallstone ileus, etc
disclaimer: information provided here is purely for the knowledge purpose and it should not be used as a substitute for medical advice.