Editing Gallstone disease

== '''Epidemiology''' ==

* 10-15% of Americans in lifetime
* 80% will be asymptomatic

== '''Risk factors''' ==

* Obesity
* Female
* 30-50yo
* Rapid weight loss (seen in 30% of patients after bariatric surgery, which can possibly be reduced by daily ursodeoxycholic acid)
* Pigment stones - haemoglobinopathies (sickle cell, hereditary spherocytosis, thalassaemia, CF, cirrhosis, Crohn's)

== '''Pathophysiology''' ==

=== Cholesterol stones ===

** Bile salts and lecithin render cholesterol soluble in bile by acting as detergents
** When cholesterol concentration exceeds the solubility capacity of bile, it nucleates into solid cholesterol monohydrate crystals
** Cholesterol precipitates into sludge, then stones as the precipitation progresses
** Main factors provoking cholesterol gallstone formation:
*** Supersaturation of secreted bile from the liver
**** Either cholesterol and lipids for cholesterol stones, or haemoglobin processing products for pigment stones
*** Concentration of bile in the GB
**** Absorption of water and sodium
*** GB dysmotility
**** Allows more time for solutes to precipitate in the GB
**** Prolonged fasting, TPN, after vagotomy, somatostatin analogues
*** Accelerated crystal enucleation
**** Process accelerated by pro-nucleating agents - glycoproteins and immunoglobulins

=== Pigment stones ===

** Complex mixtures of insoluble calcium salts of unconjugated bilirubin and inorganic calcium salts
** High levels of unconjugated or conjugated bilirubin can predispose
** Infection with certain organisms can favour stone formation - usually brown stones

=== Small's triangle of solubility: ===


== Types of gallstones ==

* Cholesterol (>70%)
** Mostly have calcium incorporated as well as cholesterol
**
* Pigment
** Black - haemolytic conditions and cirrhosis. Occur with concentration of bilirubin, and fond almost exclusively in the GB. Contain bilirubin, calcium and mucin glycoproteins.
** Brown - suggest disorder of biliary motility and associated bacterial infection - found in biliary tree
*** The brown colour comes from incorporation of cholesterol

== '''Natural history''' ==

* Become symptomatic when they obstruct a visceral structure
* Small stones (<5mm) linked to biliary pancreatitis
* Large stones (>3cm) linked to acute cholecystitis and GB adenocarcinoma
* 20-30% of patients with asymptomatic stones will develop symptoms within 20 years
* 1% of patients with asymptomatic stones develop complications of their stones before onset of symptoms

== '''Medical management of cholelithiasis''' ==

* High recurrence rates limit use to patients who cannot have a GA, have stones <1cm with minimal calcification, have mild disease only, have a patent cystic duct, and have good gallbladder mucosal concentration function
* Oral bile salt therapy (ursodeoxycholic acid)
** Can take several years to work, especially with large gallstones
** Dissolves gallstones by solubilising cholesterol from the surface
** A patent cystic duct is required for it to enter the gallbladder
** 10mg/kg/day in two to three divided doses, and up to 15mg/kg/day in patients with gallstones >2cm
** Abdominal USS every 6-12 months - but keep in mind that stones dissolve from the inside out, so they do not seem to get smaller until the outer shell disintegrates all at once
** Stones dissolve at about 1mm/month
** Overall success rate is about 30-50% for stones <2cm, but symptoms seem to reduce within a few weeks of starting treatment
** Recurrence 45% at five years
** Continue UDA for at least six months after USS demonstrates clearance of stones, and can be continued indefinitely in patients who are high risk for recurrent stones and cholecystectomy
* Contact dissolution
* Extracorporeal shock wave lithotripsy
** Recurrence rate 60% at five years - can be used in patients with single stones 0.5-2cm in size
** 30-50% get biliary colic
** Overall not useful
* Gallstone extraction
** Can be done after percutaneous cholecystostomy
** Dilate tract a few weeks after placement
** Use a basket to extract stones and irrigate

== '''Asymptomatic gallstones''' ==

* Cholecystectomy is not indicated except for certain specific populations
* Haemolytic anaemias
** Sickle cell disease - extremely high rate of pigment stone formation, and cholecystitis can precipitate a crisis - reasonable to operate
** Hereditary spherocystosis - once splenectomy is done, risk reverts to normal
* Spinal cord problems - non-op management unless symptomatic
* Higher risk of GB cancer - consider cholecystectomy
** Calcified gallbladder wall (porcelain GB)
** >2.5cm stones
** Long common channel of bile and pancreatic ducts
* Diabetes and asymptomatic cholelithiasis is a weak relative indication for cholecystectomy, as there is a higher rate of gangrene

== '''Biliary colic (symptomatic gallstones)''' ==

* Classically described as steady epigastric/RUQ pain lasting longer than 30 minutes, onset over about 5-10 minutes, lasting up to 6 hours
** Visceral type pain
** Can radiate to back
** Can be a/w n/v
** 50% of patients will report post-prandial pain
** Pain longer than 24 hours is acute cholecystitis
** Tenderness is likely to be an element of cholecystitis, as true biliary colic isn't associated with inflammation and therefore shouldn't produce tenderness
* Caused by temporary blockage of the cystic duct
* Differential diagnosis
** Hepatic mets
** Pyogenic liver abscess
** Amoebic liver abscess
** RHF
*** Pulsatile liver
*** Signs of RHF
*** Generally deranged LFTs
** Hepatic adenoma/FNH
** HCC
** Hydatid cyst
** Budd-Chiari syndrome
* Once stones are symptomatic, they are much higher risk for causing complications, so should have a cholecystectomy
** 1-3% per year risk for mild symptoms
** 7% per year for severe or recurrent symptoms

== '''Acute cholecystitis''' ==

* [[Acute calculous cholecystitis]]
* Acalculous cholecystitis 

== '''Chronic cholecystitis''' ==

* Recurrent biliary colic or acute cholecystitis causing inflammation and scarring of the neck of the GB and cystic duct
* Lies along a continuum with biliary colic

== '''GB polyps''' ==

* See separate section

== '''GB wall calcifications''' ==

* Selective mucosal calcification
** 6% risk of malignancy compared with 1% of matched cohort
** Higher rate of malignancy than diffuse calcifications
* Diffuse intramural calcification (porcelain gallbladder)
** Diffuse band of calcium infiltrating the muscular layer of GB wall
** Chronic inflammation - 95% have gallstones
** Small a/w cancer - maybe 1%

== '''Choledocholithiasis''' ==

* CBD stones
* Pathophysiology
** Can either arise de novo in CBD or pass down from GB
** GB stones are cholesterol, CBD stones are brown pigment stones
** Retained stones are secondary stones found in CBD within 2 years of cholecystectomy
* Presentation
** Often silent
** Dark urine, jaundice, pale stool
** Generally painful when caused by stones - acute
* Diagnosis
** CBD > 8mm
** Obstructive LFTs
** MRCP (se>90%, sp>99%)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
* Management:
** CBDE or ERCP
** >50% of those managed by just ERCP will have recurrent symptoms of biliary tract disease
** Risk factors for failed ERCP:
*** Stones >2.5cm
*** Altered gastric or duodenal anatomy
*** Impacted stones
*** Intra-hepatic stones
*** Multiple stones
** Prefer ERCP for rapid source control if there is evidence of cholangitis, suspected malignancy, or the CBD is <3mm

== '''Gallstone ileus''' ==

* Secondary to bilioenteric fistula - most frequently GB to duodenum or small bowel. Cholecystocolic fistulae are rare.
** Differentiate from Bouveret syndrome, in which the stone erodes into stomach and impacts at pylorus
* Impaction usually occurs in TI or ICV, and in most cases requires a stone >2.5cm
* Although it only causes 3% of SBO, more common in elderly females with virgin abdomen
* Clinical presentation
** Typical SBO
** Can see the 'tumbling stone' phenomenon, where pain changes location in the days leading up to presentation
* Radiographic
** Rigler's triad
*** SBO
*** Pneumobilia
*** Aberrant stone in GIT
** Need CT to clinch diagnosis, and see other stones within GIT
* Management
** Operation required - laparotomy - can't evaluate bowel properly with laparoscopy
*** Manually palpate for stones
*** Enterotomy 5-30cm proximal to stone location in antimesenteric bowel (healthier bowel) and squish stone out. Close enterotomy transversely.
*** Whether to fix the fistula is controversial.
**** Only 10% or so will have recurrent symptoms, and only 10% of these will need an operation, so total risk of needing another operation is about 1%
**** Single-stage cholecystectomy and closure of cholecystoenteric fistula has morbidity up to 60%, compared with 25% for just enterolithotomy
**** Probably overall it's best to leave the biliary system alone at initial operation.
**** Consider single-stage procedure in patients with favourable anatomy and physiology
** Delayed operation to fix fistula is unwarranted in asymptomatic patients

== '''Gallstone pancreatitis''' ==

* See separate topic under 'pancreatitis'
[[Category:Biliary]]
[[Category:Intern education]]