Biliary tract diseases Flashcards
What are the biliary tract diseases?
Diverse spectrum of diseases affecting the biliary system (gallbladder, bile ducts and liver).
Basic anatomy: the common hepatic duct.
The right hepatic duct and left hepatic duct leave the liver and join together to become the common hepatic duct.
Basic anatomy: the cystic duct.
The cystic duct from the gallbladder joins the common hepatic duct halfway along.
Basic anatomy: the pancreatic duct.
The pancreatic duct from the pancreas joins with the common hepatic duct further along.
Basic anatomy: the ampulla of Vater.
When the common bile duct and the pancreatic duct join, they become the ampulla of Vater, which then opens into the duodenum.
Basic anatomy: sphincter of Oddi.
The sphincter of Oddi is a ring of muscle surrounding the ampulla of Vater that controls the flow of bile and pancreatic secretions into the duodenum.
Describe the 3 types of gallstones and their causes.
Stones form from supersaturation of bile, meaning they are either made of:
- Cholesterol - large, often solitary; obesity and fatty diets, age, female sex
- Pigment - small, friable, irregular, seen in haemolytic anaemia
- Mixed - faceted (calcium salts, pigment + cholesterol) - made of both of the above
What is biliary colic?
Gallbladder attack:
Intermittent right upper quadrant (RUQ) pain caused by gallstones irritating/blocking the bile ducts and temporarily obstructing drainage of the gallbladder.
It is the name given to the pain experienced from gallstones, it is not a condition itself!!
Explain the pathophysiology of biliary colic.
Gallstones lodged in bile ducts -> temporary severe abdominal pain.
After meal, gallbladder contracts.
Gallstone ejected into cystic duct -> lodged -> gallbladder contract against lodged stone -> severe abdominal pain.
Pain subsides when gallstone dislodged.
Give 4 causes of biliary colic.
- Gallstones
- Narrow bile duct
- Pancreatitis
- Duodenitis
- Oesophageal spasms
What can trigger biliary colic?
Eating a heavy meal especially one that is high in fat.
Why do fatty foods trigger biliary colic?
Fat entering the digestive system causes cholecystokinin (CCK) secretion from the duodenum.
CCK triggers contraction of the gallbladder, which leads to biliary colic.
Patients with gallstones and biliary colic are advised to avoid fatty foods to prevent CCK release and gallbladder contraction.
Exams may test this mechanism, so it is worth remembering!!
Give the 5 risk factors for biliary colic.
The 5Fs:
1. Fat (obesity)
2. Fertile (- more kids = increased risk of gallstones)
3. Forty (age >40)
4. Female
5. FHx
Describe the pain of biliary colic.
Any other symptoms may occur?
Sudden onset, severe but constant, crescendo characteristic.
Severe, colicky epigastric or RUQ pain - increases.
Can radiate to right shoulder/scapula (epigastrium/back).
Other symptom:
- Nausea and vomiting
What exactly is meant by ‘colicky’ pain?
Colicky pain is pain that ‘comes and goes’.
Differential diagnoses of biliary colic.
Think of other causes of RUQ pain:
1. Cholecystitis and cholangitis (often progressions from untreated gallstones anyway).
2. IBD.
3. Pancreatitis.
4. GORD.
5. Peptic Ulcers.
Diagnosis of biliary colic - the diagnostic test?
Abdominal Ultrasound - most useful for gallstone disease diagnosis:
1.Stones
2.Gallbladder wall thickness (inflammation)
3.Duct dilation (suggests distal blockage)
More investigations for biliary colic.
- FBC and CRP → look for inflammatory response suggesting cholecystitis
- LFTs: Raised ALP → ALP is associated with biliary pathology.
- Bilirubin and ALT usually normal.
- Amylase → Check for pancreatitis as it can also give RUQ.
These tests are more to rule out the cholecystitis and cholangitis than to confirm gallstones. They alone are unlikely to derange many tests. Ultrasound is the diagnostic test.