Wrire in detail about Cholelithiasis. Its incidence, pathogenesis, clinical features and complications.
Definition: Cholelithiasis is a crystalline concretion formed with in gall bladder due to accumulation of bile componenets.
- North America : 10-20%
- Latin America: 20-40%
- Asian countries:3-4%
- Cholesterol stones - 80%
- Pigment stones – 20%
Pathogenesis: The excretion of excess cholesterol can occur in two ways;
- Free cholesterol
- Dissolved in bile (as it is water insoluble).
Whenever there is rise in the level of cholesterol or fall in level of bile or there is decreased motility of gall bladder there will be formation of Cholesterol stones . When there is excess hemolysis there will be formation of Pigment stones. Normal ratio of cholesterol and bile acids is 25:1 which doesnot allow formation of stone. But when it drops down to 13:1 called as critical ratio the bile becomes super-saturated and leads to formation of cholesterol stones.
Following mechanisms lead to Cholesterol stone formation:
- Supersaturation of the bile with cholesterol
- Nucleus formation by precipitates of calcium salts and microrganisms like Ecoli or Proteus
- Hypomotility of the gallbladder
- Mucus hypersecretion
Pigment Stones are formed due to:
- Decreased solubility of Unconjugated bilirubin in bile.(Unconjugated bilirubin rises in Hemolytic diseases)
 Factors increasing the biliary cholesterol:
- High fat diet
- Oral Contraceptive pills
- Rapid Weight loss
- Diabetes mellitus
- Drug like Clofibrate
 Factors decreasing bile acid
- Primary biliary cirrhosis (decreased secretion)
- Resection of stomach,Ileum (decrease enterohepatic circulation)
- Ileal disease ( Crohn’s disease)
- Fecal fistula
 Hypomotility of gall bladder
- Prolonged Parenteral nutrition
- Prolonged Fasting
- Truncal Vagotomy ( Denervation of Biliary tree)
- Drugs like Octreotide
- Cystic fibrosis ( impaired bile flow)
 Factors leading to formation of Pigment stones:
- Hemolytic diseases like Sickle cell anemia , Thalassemia
- Helminthic infection : Clonorchis sinensis , Ascaris Lumbricoides
Morphology of the stones
- Cholesterol stone : Pale yellow or Gray white( Due to Calcium carbonate,bilirubin,phosphate) Ovoid, Firm, Multiple, Faceted. Only 20% are radiopaque.
- Pigment stone: Two types Balck & Brown.Mainly contain unconjugated bilirubin.
- Black: Sterile bladder,small, large number, crumble easily, radiopaque (50-75%)
- Brown:Infected ducts, large, few in number, soft, greasy & soapy, radiolucent.
- Asymptomatic: 70-80%
- Symptomatic : Excruciating pain –constant or colicky. The pain radiates to right upper quadrant
- Murphy's sign positive
- Diagnosis is mostly by Ultrasonography as majority of gall stones are Radiolucent (90%).
- Gall Bladder: Acute & Chronic cholecystitis, Mucocele, Empyema, Perforation, Fistula, Carcinoma
- Common Bile Duct: CBD stone, Cholangitis
- Pancreas: Acute & Chronic Pancreatitis
- Small Intestine : Gall Stone Ileus.
AUTHOR: Ridham Khanderia References:
- Robbins and Cotran: Pathologic Basis of Disease. 8th Edition
- Chap 18-Liver and Biliary tract by James M.Crawford & Chen Liu. Elsevier- 2011.Page Num : 883-884
- Concise Textbook of Surgery by Arif Naseem . Pusle Publication , 2008. Chap 30- The Gall Bladder and Bile Duct. Page Num : 360-362.