The Biliary System

Mr E. Leung

Content

• Surgical Anatomy

• Physiology

• Investigations for biliary tree

• Common Pathology

SURGICAL ANATOMY

Surgical Anatomy - Gallbladder

• Pear shaped

• 7 – 13 cm in length, Volume ~ 50ml

• Cystic duct 1 – 3cm– Spiral valves of Heister

• Fundus, body, neck and Hartmann’s pouch

Surgical Anatomy - Gallbladder

• Lies between quadrate lobe and right lobes

• Covered in peritoneum except the GB fossa

Surgical Anatomy - Gallbladder

• 1st + 2nd part of duodenum lies behind

• T-colon lies inferiorly

• Common Bile Duct (CBD) – 7cm long– 7mm wide – pressure of 7mmHg

Surgical Anatomy – Calots Triangle

Surgical Anatomy – Common Bile Duct

• CBD = CHD + cystic duct

– Supraduodenal part – • free edge of lesser sac• 2.5cm long

– Retroduodenal part

– Infraduodenal part

– Intraduodenal part

Surgical Anatomy – Major and minor papilla

• CBD enters duodenum posteromedially

• Joins pancreatic duct = Ampulla of Vater– (10cm from pylorus)

• Accessory pancreatic duct joins duodenum via minor papilla

Endoscopic view of Ampulla of Vater, also known as Major duodenal papilla

Surgical Anatomy – Sphincter of Oddi

• Circular muscle of duodenum wraps around the confluence of the pancreatic duct and CBD

• Forms a sphincter and prevents reflux of duodenal contents

Surgical Anatomy – nerve supply

• T7-9 sympathetic and parasympathetic vagus

• Afferent fibres (including pain) => coeliac plexus

=> greater splanchnic nerves => dorsal ganglia

• Preganglionic efferent fibres => coeliac plexus

=> postganglionic fibres run along the hepatic artery

• Vagus stimulation = GB to contract, Oddi to relax

PHYSIOLOGY

Physiology – Bile salts

• Bile = 97% water, 2% bile salts, 1% pigments

• Bile acids are synthesised in the liver from cholesterol

• Primary bile acids = chenodeoxycholic + cholic acid– Conjugated with Taurine + Glycine = water soluble bile salts

• Secondary bile salts = gut bacterial metabolism (deoxycholic and lithocholic acid)

Physiology – function of gallbladder + bile

• Concentrates and stores bile (upto 10x)

• Mucin secretion

• Bile + small globlets of fat = micelles

• Allows digestion by lipases

Physiology – The enterohepatic circulation

• Secretin and CCK, secreted by duodenum

• low pH or high fat content

• CCK => GB to contract and Oddi to relax

• Secretin => bile production and pancreatic juice release

CLINICAL INVESTIGATIONS

Investigations

• Largely radiological

• Blood tests: – inflammatory markers, GGT, LFTs, Clotting, Amylase

• Radiology:– AXR, USS, cholangiography (oral, iv or intraductal)– CT, MRCP, radionuclide scans (HIDA or PIPIDA)

Radiological investigations

• Plain AXR

• USS

Radiological investigations

• Cholangiography

• CT – better at assessing the pancreas

• MRCP – best resolution in assessing the biliary tree

• Tc-labelled scan – functional study

PATHOLOGY

Congenital abnormalities

• Atresia – type I, II and III or Gallbladder– 1 in 30,000

• Double or intra-hepatic gallbladder

• Phrygian cap

• Choledochal cysts

Acquired pathology – Gallstone disease

• Very common – The 4 “F”s– F:M = 3:1 West > East

1.Pure cholesterol stone – 5%

2.Mixed stone (70%) – Lecithin, cholesterol and salts

3.Pure pigment stones – 25%

• 90% of time is radiolucent

Causes of Gallstone formation

• Changes in bile composition, multifactorial– Supersaturation – Precipitation

1.Metabolic – e.g. diet, cirrhosis

2. Infective – e.g. reflux of bile

3.Biliary stagnation – e.g. pregnancy

Complications of gallstones

Complications of gallstones

• Biliary colic– Analgesia then cholecystectomy

• Cholecystitis• Mucoceole• Perforation

– Abx then cholecystectomy

• GS ileus– Surgery

Cholangitis Abx and ERCP, then

cholecystectomy

Pancreatitis

Other benign gallbladder conditions

• Strawberry GB – lipid/cholesterol infiltration to mucosa

• Adenomyomatosis - Mucosal diverticula

• Acalculus cholecystitis – 5%– Precipitated by illness, surgery or trauma

• Benign polyp

Symptoms of gallstone disease

Most gallstones are asymptomatic

Symptoms of gallstone disease

• Biliary colic– Intermittent colicky RUQ pain– Post-prandial vomiting– Right shoulder pain

• Cholecystitis– Constant sharp RUQ pain– Fever and vomiting (not post-prandial)

Symptoms of gallstone disease

• Cholangitis– Jaundiced (urine, faeces, itch)– Rigors – Colicky RUQ pain

• Pancreatitis– Continuous sharp pain alleviated by leaning forward– Other symptoms for complications of pancreatitis…

Differential diagnoses

• PUD / Gastritis / GORD

• Pancreatitis

• Liver pathology

• Cardiac

ANY QUESTIONS