Monday, December 24, 2012

Gallstones



Types of gallstones:
  • Cholesterol stones
  • Pigment (brown/black) stones and
  • Mixed stones



Pathogenesis

Cholesterol stone:

Cholesterol is synthesized in liver. Its solubility is determined by relative concentration of cholesterol, bile salts and lecithin. Altered levels of cholesterol, lecithin, and bile salts in bile reduces the micelle concentration in the bile leading to precipitation of insoluble cholesterol, hence the stone formation.
Factors altering the cholesterol to bile salt ratio are obesity, high-calorie diets and certain medications. These increase the secretion of cholesterol and supersaturate the bile, increasing the lithogenicity of bile.


Pigment stone:
Types- black and brown
Black stones
composed of insoluble bilirubin pigment polymer mixed with calcium phosphate and calcium bicarbonate. Black stones accompany hemolysis (hereditary spherocytosis or sickle cell disease)
Brown stones-
 composed of calcium bilirubinate, calcium palmitate, calcium stearate and cholesterol. It is rare in gall bladder and usually forms in bile duct and are related to bile stasis and infected bile. Deconjugation of bilirubin deglucuronide by bacterial beta- glucuronidase  causes insoluble unconjugated bilirubinate to precipitate leading to stone formation.
Brown stones are also associated: Foreign body within the bile duct (e.g. endoprosthesis) 
Parasites (like Clonorchis sinensis and Ascaris  lumbricoides)


Cholesterol stone
Pigment stone
Clinical presentation:
Patient may be asymptomatic or presents with features of its complications.

Effects and complications of gallstones
In the gall bladder
Biliary colic
Acute cholecystitis
Chronic cholecystitis
    Empyema of the gall bladder
    Mucocele
    Perforation
b. In the bile ducts
    Biliary obstruction
    Acute cholangitis
    Acute pancreatitis
c. In the intestine: Gallstone ileus ( intestinal obstruction)


Diagnosis:
Based on history, physical examination and confirmatory radiological studies such as transabdominal USG and radionucleide scans.

T/T
Asymptomatic gall stone: observation
If symptomatic or complication of gallstones: cholecystectomy
Prophylactic cholecystectomy is done in:
diabetic pt
those with congenital hemolytic anaemia
those who undergo bariatric surgery for morbid obesity


Acute Cholecystitis

Definition: acute inflammation of the gallbladder, usually caused by cystic duct obstruction by gallstones.

Presentation
Biliary colic: severe right upper quadrant pain associated with nausea and vomiting. Pain may radiate to the chest. Pain is usually severe and last for minutes or several hours. Frequently, pain starts during the night, waking the patient. Dyspeptic symptoms may coexist and be worse after the attack. 
Right upper quadrant (RUQ) tenderness on palpation that is exacerbated during inspiration: Murphy’s Sign.
 Low-grade fever and leukocytosis


Murphy’s sign
Investigations

1. USG: reveals presence or absence of gallstone and thickening of the gall bladder wall
2. Plain X-ray abdomen : 10% of gallstone are radiopaque
3. Blood: Leucocytosis
Moderately elevated liver function
4. Radioisotope scanning
Allows visualisation of biliary tree and gall bladder. GB is visualised within 30min of isotope injection. Non-visualization of GB is suggestive of Acute cholecystitis.


USG findings in Ac. Cholecystitis
Treatment
  • After the diagnosis of acute cholecystitis is made, IV fluids, antibiotics, and analgesia should be initiated. 
  • Antibiotics should cover gram-negative aerobes as well as anaerobes. 
  • Cholecystectomy is the definitive treatment for patients with acute cholecystitis. 
  • Early cholecystectomy performed within 2 to 3 days of presentation  (if patients fail initial medical therapy and require surgery during the initial admission)
  • If early cholecystectomy not indicated: Interval or delayed cholecystectomy that is performed 6 to 10 weeks after initial medical therapy. 


Cholecystectomy: open or laparoscopic



Complications

i. Empyema of the gall bladder
ii. Gangrene of the gallbladder
iii. Perforation and peritonitis
iv. Fistula formation and gallstone ileus (small bowel obstruction by a large gallstone


Chronic Cholecystitis

Defnition: ongoing chronic inflammation of the gallbladder usually caused by gallstones
Micro: chronic inflammation and Rokitansky-Aschoff sinuses
Late complication: calcification of the gallbladder ("porcelain gallbladder")
T/t: Cholecystectomy


Rokitansky-Aschoff sinuses
Porcelain gallbladder
Acalculous Cholecystitis
  • Inflammation of the gall bladder in the absence of the stones.
  • Seen particularly in patients recovering from major surgery, trauma and burns.
  • Clinical picture similar to calculous cholecystitis.

T/t: Cholecystectomy


Empyema of the gall bladder

Definition: Presence of pus in the gall bladder

Etiology

Sequel of acute cholecystitis
Infected mucoecele

c/f
Fever, toxicity
Pain and tenderness in Rt. Hypochondrium
The wall may become necrotic and perforate with the development of localised peritonitis


Investigation   

1. USG abdomen
2. Blood: leucocytosis

   Treatment
   Drainage and, later, cholecystectomy


Mucocele

A nontender, palpable gall bladder results from complete obstruction of the cystic duct with resbsorption of the intraluminal bile salts and secretion of uninfected mucus by the gall bladder epithelium 

Mucocele of gall bladder
Clinical presentations
  • Painless swelling in the right hypochondrium
  • O/E: Non tender, smooth, globular, palpable gall bladder
  • If infected, can cause empyema gall bladder


Investigation
USG abdomen

T/t: cholecystectomy

ShareThis

Google+ Badge