Gallstones & Biliary Colic Flashcards
What is cholelithiasis?
cholelithiasis refers to the formation of hard stones in the gallbladder (gallstones)
this typically takes years to occur
How common is cholelithiasis?
Are all of these cases symptomatic?
it is very common and affects 10-15% of the general population in the developed world
the vast majority of these cases are asymptomatic and only a small proportion present with complications of gallstones
Are gallstones themselves problematic?
No, gallstones themselves are not problematic in the vast majority of cases
But they can predispose to other problems with the biliary tree
What % of gallstones lead to further problems with the biliary tree?
What are the most common presentations?
Each year, 1 - 4% of gallstones will have an acute presentation of biliary disease
about 60% of these are biliary colic
and 40% are acute cholecystitis
How are gallstones generally classified?
they are classified as either cholesterol stones or pigment stones
in reality, they are usually mixed
In what parts of the world are pigment stones and cholesterol stones more common?
- cholesterol stones are more common in the developed world
- in Europe & the USA, 75% of gallstones are cholesterol stones
- pigment stones are more common in the developing world
What do cholesterol stones typically look like?
they are usually solitary and large
stones of about 70% or more of cholesterol are usually smaller and more numerous
the rest of the stone is made up of calcium compounds and protein
What are the 3 risk factors for cholesterol stones?
- female gender
- advancing age
- obesity
What do mixed stones tend to look like?
there are usually multiple stones and they are irregularly shaped
How can pigment stones be divided into 2 categories?
What is the difference in appearance / composition?
Brown stones:
- these tend to be softer
- they contain a mixture of pigment, cholesterol and calcium salts
Black stones:
- these are much harder and made of pure pigment
Why do women tend to have a higher incidence of gallstones than men?
- cholesterol secretion is a massive factor in gallstone formation - particularly the proportion of cholesterol secreted in relation to the concentration of bile salts
- women naturally secrete a higher proportion of cholesterol than men
How does incidence of gallstones change with age?
incidence increases with age
- at age 30 - 5% women and 2% of men have / have had gallstones
- at age 55 - 20% women and 10% of men have / have had gallstones
- at age 70 - 30% women and 20% of men have / have had gallstones
What are the racial differences in who develops gallstones?
- more common in Scandinavia
- more common in Native North and South American populations
What are the 6 main risk factors for developing gallstones?
-
weight
- obesity
- sudden weight loss
- family history
-
oestrogen
- female gender
- oral contraceptive pill
- diet (high fat, low fibre)
-
increasing age
- stones take time to form
- diabetes
What are the 4 Fs that are used to describe the typical patient with gallstones?
- fair
- fat
- female
- forty
What 3 factors are needed for the formation of cholesterol stones?
- high concentration of cholesterol in the gallbladder
- gallbladder stasis
- products that promote the crystallisation of cholesterol
- some lipoproteins found in bile will do this
When do cholesterol stones form?
What is there insufficient quantities of and what process can increase the formation of stones?
- cholesterol stones form when the concentration of micelles is not great enough to hold all the cholesterol within micelles
- formation of stones is increased during fasting
- particularly extended fasting (e.g. in IV nutrition)
- fasting increases the concentration of cholesterol in the gallbladder relative to other solutes
What type of bile pool do patients with cholesterol stones often have?
they generally have a smaller bile pool that circulates more often
What is the first stage in the formation of cholesterol stones?
cholesterol crystals initially form in bile that is supersaturated with cholesterol
this results in the production of “sludge”
What factors inhibit the formation of sludge?
- caffeine
- NSAIDs
- bile salts
What factors exacerbate the formation of sludge?
- mucin
- rapid weight loss
- pregnancy
- increased serum cholesterol
- large amounts of body fat
- female gender
- advancing age
- diabetes / high dietary fat
- reduced bile production or circulation
- e.g. in malabsorption (like Crohn’s) where so much bile is lost, it cannot be replaced quickly enough
What 2 drugs can exacerbate the formation of sludge?
- oral contraceptive pill
-
clofibrate
- a fibrate drug that lowers plasma cholesterol by increasing cholesterol secretion in the bile
What 2 things can happen to sludge after it has formed?
- it can be reabsorbed
- it can go on to form cholesterol stones
- only in 15% of cases will it go on to form stones
How long does the process of cholesterol stone formation take?
When is a cholecystectomy usually performed?
- it takes around 8 years for a stone to form from the beginning of the initial process
- in symptomatic patients, a cholescystectomy is usually performed 12 years after the process of stone formation began
How is the process of pigment stone formation related to cholesterol stone formation?
Where do pigments in bile come from?
- the process of pigment stone formation is completely independent of that of cholesterol stones
- pigments in bile are from bilirubin breakdown
What are the 3 main causes that can lead to pigment stones?
- an increase in bilirubin load, as a result of haemolytic anaemia
- pigments become less water soluble once in the bile as a result of the action of glucuronidases
- cirrhosis - due to depletion of glucuronidase inhibitors at the site
What is thought to be the major cause of pigment stones, relating to the action of glucuronidases?
Where is this more common and what is associated with?
- most cases of pigment stones result from the subclinical bacterial colonisation of the gallbladder
- common in East Asia and associated with E. coli
What do the stones related to the action of glucuronidases look like?
What about the 2 other causes of pigment stones?
- stones associated with bacterial colonisation tend to be softer and brown and combined with calcium carbonate
- the other 2 types are smaller, blacker and harder and more commonly encountered in the West
Which gender is more commonly affected by pigment stones?
pigment stones affect both sexes equally
What % of cases of gallstones are symptomatic?
90% of cases are asymptomatic and discovered incidentally
When do gallstones cause vague upper abominal symptoms?
gallstones usually DO NOT cause flatulence, dyspepsia, fat intolerance or other vague upper abdominal symptoms
unless they are causing an acute flare-up of biliary colic or other acute manifestations
How can symptomatic gallstones present?
symptomatic gallstones can present as:
- biliary colic
- cholescystitis (infection in the biliary tree - emergency)
- pancreatitis
- other acute manifestations
What is biliary colic?
it describes an intermittent RUQ / epigastric pain that is associated with a blockage in the bile duct
it is often caused by a stone migrating down the duct
What does the term “colic” mean?
What structure is it associated with?
- “colic” means a wave of pain
- it is associated with a tubular structure surrounded by smooth muscle
- the wave nature is related to the fact that smooth muscle has its own “pace maker” that causes contractions at certain intervals
Why is the name “colic” misleading when describing the pain in biliary colic?
- a true colic increases and decreases in intensity gradually in a rhythmic fashion
- in biliarly colic, the pain is constant and crescendoes
What is the pain in biliary colic associated with?
What can be done to make it better?
- pain is sporadic and associated with eating - particularly fatty foods
- pain subsides with analgesia
- pain is usually reduced with modification of diet
When does the pain typically come on in biliary colic and how long does it last for?
Can it radiate?
- pain comes on after eating a large and/or fatty meal
- pain typically appears in the mid-evening and lasts until the early hours of the morning
- pain may radiate to the right shoulder tip
What other symptoms may present at the same time as biliary colic pain?
What does more severe pain suggest?
- nausea and vomiting can occur in severe attacks
- more severe prolonged pain suggests association with an underlying condition
- cholescystitis
- cholangitis
- gallstone-induced pancreatitis
Does biliary colic recur?
Can it go on to develop into something else?
What do LFTs show?
- biliary colic is a recurring condition
- over a 5-year period, 100% of patients will experience it again
- 20% of patients go on to develop something more serious - cholecystitis, obstructive jaundice or pancreatitis
- LFTs usually normal
How does location of gallstones influence the production of abnormal lab test results / symptoms?
- stones within the gallbladder or cystic duct that are causing biliary colic are unlikely to produce abnormal lab test results
- stones within the common bile duct are more likely to account for symptoms and abnormal lab test results
What might be raised on LFTs in cholecystitis?
- raised bilirubin
- raised ALP
- raised ALT
- these may all be slightly raised in the presence of cholecystitis, even without current duct obstruction
What does it suggest if ALP and bilirubin are raised higher than ALT?
What if ALT is raised higher than ALP and bilirubin?
- if ALP and bilirubin are raised higher than ALT, this shows an obstructive pattern of LFTs
this tends to signify biliary duct problems
- if ALT is raised higher than ALP and bilirubin, this usually indicates intra-hepatic pathology
How might gallstones be seen on plain AXR?
What else might be seen?
Is this used diagnostically?
- gallstones can only be seen on AXR if they are calcified (10-15% cases)
- may show gas in the gallbladder as a result of gas-producing organisms
- may show fistulation of the large bowel
- AXR is not used diagnostically, but gallstones may be seen incidentally
What is the gold standard diagnostic test for gallstones?
ultrasound
this is 95% effective at detecting gallstones, but it is operator dependent
What can gallstones be confused for on ultrasound?
How can you tell them apart?
gallstones can sometimes be confused for polyps on USS and vice versa
you can tell the difference as gallstones will cast a “shadow” underneath them on USS, but polyps will not
How can cholecystitis be detected on USS?
What does a “halo effect” around the gallbladder indicate?
- cholecystitis is detectable as a thickening of the gallbladder wall to more than 4mm
- a “halo effect” around the gallbladder shows oedema surrounding the gallbladder
this can indicate acute viral hepatitis, hypoalbuminaemia or portal hypertension
What abnormality in the bile ducts may be seen on USS?
ductal dilatation caused by blockage of the bile duct may also be visible
What is oral cholecystography?
What do the results mean?
- the patient takes a dose of an oral dye that is absorbed and concentrated by the liver and then secreted in the bile
- this enables the gallbladder to be seen on radiograph
- if you cannot see the gallbladder, there could be a blockage in the cystic duct or recent cholecystitis
What is the drawback of oral cholecystography?
What is the false negative rate of this test?
- even when the test works correctly, some stones are too small to see
- false negatives occur 5% of the time
- used in conjunction with USS, the false negative rate is reduced to 2%
When might ERCP be used for investigating gallstones?
- used when the history is very suggestive of gallstones, but no stones are seen on USS or cholecystography
- a sample of bile is often taken and examined histologically for cholesterol crystals and debris
Why might serum and urinary amylase be measured in gallstone disease?
- a stone passing through the very last part of the common bile duct can get lodged and cause pancreatitis
- serum amylase returns to normal levels if conditions return to normal
- urinary amylase can remain elevated for up to 5 days
What is Courvoisier’s sign?
How do gallstones typically affect the size / appearance of the gallbladder?
Courvoisier’s sign involves a palpable gallbladder
the law states that a palpable gallbladder in the presence of painless jaundice is unlikely to be gallstones
gallstones typically result in a fibrotic shrunken gallbladder, which will not usually distend, and thus will not usually be palpable
What is gallbladder distension usually a sign of?
gallbladder distension is usually a sign of acute pathology
e.g. pancreatic malignancy / obstruction of the pancreas
What are the differential diagnoses of gallstones?
- GORD
- peptic ulcers
- irritable bowel syndrome
- pancreatitis
- tumour
- stomach
- pancreas
- large bowel
What are the 5 main complications of gallstones?
- acute and chronic cholecystitis
- acute cholangitis
- pancreatitis
- fistulation
- increased risk of adenocarcinoma of the wall of the gallbladder
How can fistulation result from gallstones?
What is gallstone ileus?
gallstones may perforate the gallbladder and form a fistula, often to the colon or small intestine
a gallstone passing into the small intestine may cause a blockage in the ileum - this is gallstone ileus
What is choledocholithiasis?
What is it commonly accompanied by?
- stones pass out of the cystic duct and into the bile duct
- this causes obstructive jaundice
- this is commonly accompanied by cholangitis (bacterial infection of the gallbladder)
What is the treatment for asymptomatic gallstones?
asymptomatic gallstones are usually not treated
What treatments are given for the management of biliary colic?
-
IV morphine
- 5 - 10mg / 4 hours
-
anti-emetic
- e.g. domperidone, metoclopramide, cyclizine
What procedure is sometimes offered to patients with severe biliary colic?
How is this procedure performed?
elective cholecystectomy
- this is accompanied by cholangiography (imaging of the bile ducts using X-ray)
- performed under general anaesthetic after 4 hours of fasting
What prophylactic treatments are given following elective cholecystectomy?
- DVT prophylaxis is given if the patient is over 40
- prophylactic antibiotics are also usually given if the patient is over 40
this is a single dose of a second generation cephalosporin (e.g. cefuroxime)
this may be continued for 24-48 hours after the operation in the presence of sepsis
What is involved in an open cholecystectomy?
Why must a catheter be placed in the bile duct?
- there is a 10% chance that the patient will have a gallstone in the bile duct at the time of operation
- a catheter is inserted into the bile duct and dye squirted into it to outline the biliary tree
- if there is a stone present, it is removed
- after this, the gallbladder is removed
Why do some surgeons leave a drain in place of the gallbladder for a few days following open cholecystectomy?
Why is this not usually done?
- some people have small ducts that take bile directly to the gallbladder, and these may leak
- the drain is a cause of post-operative pain
- the evidence to suggest it improves the outcome from bile leak is limited
What is involved in laparoscopic cholecystectomy?
- camera inserted in the umbilicus and 3 other incisions are made for the instruments
- once the gallbladder is removed, it is important to check for leaks
- gallbladder is usually removed via the umbilicus
- peritoneal cavity is then washed out and cleaned up
What is involved in the post-operative care following open cholecystectomy?
- pain relief and nil-by-mouth for up to 48 hours following procedure
- IV fluids are required for 2 days as a result of the nil-by-mouth
- low dose heparin to reduce risk of thrombosis
- older patients may need physiotherapy and/or early mobilisation to avoid atelectasis (collapse of the lung)
What is the difference in the recovery following laparoscopic cholecystectomy?
- patients have considerably less pain and ileus than open surgery
- most are mobile sooner and there is less need for physio
What can happen to the Sphincter of Oddi as a complication of cholecystectomy?
sphincter of Oddi dysfunction can be a cause of post-operative pain
it is often due to trauma sustained during the operation
What is post-cholecystectomy syndrome?
What does it mean about the surgery and what is actually causing pain?
- biliary type pain that occurs months or years after cholecystectomy
- patients describe the pain as being identical to that for which the operation was carried out
- it means that the cholecystectomy was not needed as the gallbladder / stones was not the cause of pain
- pain is caused by functional colonic disease, where there is spasm at the hepatic flexure (hepatic flexure syndrome)
Why might a sphincterotomy be required following cholecystectomy?
- there may be hypertension of the sphincter of Oddi (it does not relax)
- this can be confirmed by imaging of the bile duct showing dilated bile ducts when the pain is present and lack of retained stone
- it is treated by sphincterotomy
What is cholestasis?
a condition affecting the liver in which bile cannot flow from the liver to the duodenum
What are intrinsic causes of bile duct obstruction?
- gallstones in the common bile duct
- cholangitis
- carcinoma of the bile duct
- carcinoma of the gallbladder
- benign post-traumatic stricture
- sclerosing cholangitis
- haemobilia
What are extrinsic causes of biliary duct obstruction?
- carcinoma of the pancreas
- carcinoma of the ampulla of Vater
- metastatic carcinoma
- lymphoma
- acute and chronic pancreatitis
- pancreatic cysts
- congenital causes
- biliary atresia
- choledochal cyst
- congenital intrahepatic biliary dilatation (Caroli’s disease)
