Hepatobiliary MCQs

In patients aged less than 55 years with normal CBD on USS and normal LFT's the incidence of CBD stones is 5%.

Common bile duct stones In the West CBD stones typically originate in the gallbladder and migrate into the CBD. Primary CBD stones may develop de novo and underlying parasitic infections are a recognised precipitant. In those patients with normal CBD on USS and normal LFTs the incidence of CBD stones at the time of cholecystectomy is unlikely to exceed 5% and is the rationale for not performing OTC as a routine.

Common bile duct stones: Diagnosis USS: Not sensitive – why ? Intra-operative cholangiogram CT scan ERCP MRCP Endoscopic Ultrasound (EUS) Laparoscopic Ultrasound

Aetiology Most benign bile duct strictures are the result of iatrogenic injury during surgery. The commonest cause of malignant strictures is pancreatic cancer. Most of the benign biliary strictures following injury during cholecystectomy go unrecognized at the time of surgery (as many as 75% of cases). Presentation after more than 5 years may occur in 30% of cases; therefore, a history of recent or past cholecystectomy should be sought in all cases. Other causes of strictures include: Primary Sclerosing Cholangitis (strictures, beading, and irregularities of the intrahepatic and extrahepatic bile ducts). Abdominal radiotherapy HIV/ AIDS, liver transplantation, trauma

Treatment of biliary strictures Treat cholangitis (iv antibiotics & fluids) Biliary decompression, usually via ERCP. Non-resectable malignant strictures are best palliated with metallic stent insertion. Treatments for benign strictures include stents / endoscopic dilatation or surgical bypass e.g. hepatico-jejunostomy.

Management of acute pancreatitis – some rules Antibiotics have no role for non infected acute pancreatitis. ERCP should be performed early (<72hrs) in those with gallstone related biliary obstruction Sphincterotomy should generally be performed irrespective of whether stones are found, if the attack is severe and gallstones the aetiology. All patients with gallstone pancreatitis who are fit enough should undergo cholecystectomy once medically stable either during the index admission or within 2 weeks of it. Imaging of the bile duct should be performed pre or peri operatively. Patients with >30% necrosis and symptoms should undergo radiologically guided FNA and culture of the areas, this is to allow conservative management of non infected cases. Patients with infected necrosis should generally undergo surgical debridement and closed lavage systems.

Pancreatitis Pancreatitis is one of the most common serious complication of ERCP Transient rise in pancreatic amylase may be noted in up to 75% of patients undergoing the procedure. The incidence is approximately 3.5%. Reducing the risk of pancreatitis Administration of indomethacin Temporary pancreatic duct stents Wire guided cannulation Risk factors for post ERCP pancreatitis Normal bilirubin Young age Pancreatic duct injection Precut sphincterotomy Balloon dilatation of sphincter Sphincter of Oddi dysfunction

Other complications of ERCP Bleeding Occurs most often following sphincterotomy and is intra luminal Occurs in 1.3% of cases Severe haemorrhage has an incidence of less than 1 in 1000 Perforation Occur in 0.6% - 1% of cases Both malignancy and pre cut access increase the risk of perforation Cholangitis Occurs in 1% of cases Incidence may be reduced by use of antibiotics when an obstructed duct is not completely cleared

Pancreatic divisum Most common congenital anomaly of the pancreas (7% of population) Occurs as a result of a failure of the dorsal and ventral pancreatic buds to fuse antenatally Most cases are asymptomatic. Where symptoms do occur they may be the result of raised pancreatic pressures

Liver metastasis from colorectal cancer 70% of patients with metastatic colorectal cancer will have disease that is confined to the liver. Detection is usually made using CT scanning. Hypoattentuating on CT. Only 15% of patients will have disease that is surgically resectable.

Liver metastasis from colorectal cancer FOLFOX 4 chemotherapy regime is standard (oxaliplatin, fluorouracil and folinic acid). Given prior to liver resection. A regime lasting 3 months is usually favored Recurrence is seen in up to 60% of patients undergoing surgical resection of liver metastasis. Usually within the first 1-2 years.

Stents for resectable pancreatic CA Both benign and malignant biliary obstruction may be treated by placement of stents. These may be either plastic tubes or self expanding metallic stents. The use of routine preoperative biliary drainage in the setting of pancreatic cancer with biliary obstruction is controversial. Prospective studies have shown that complications related to preoperative biliary drainage using endoscopic placement of traditional plastic endoprostheses increase the overall morbidity compared to pancreaticoduodenectomy alone.

Abdominal Emergencies Pregnancy Cholecystectomy performed in the second trimester is the safest option and that which is associated with the lowest morbidity for mother and child. Appendicitis is the most common non obstetric cause of abdominal pain in pregnancy resulting in laparotomy and the foetal loss rate approaches 35%. Because of diagnostic uncertainty the perforation rate is 55% (hence the high rate of foetal loss). Biliary disease is also common in pregnancy and gallstones may form as a complication of biliary stasis (progesterone causes reduced gallbladder contraction). Acute cholecystitis – surgery in the second trimester is usually advised. Pancreatitis may occur in the pregnant women (1 in 1000). The two most common causes are gallstones and hypertriglyceridaemia.

Hydatid cysts Hydatid cysts are endemic in Mediterranean and Middle Eastern countries. They are caused by the tapeworm parasite Echinococcus granulosus. An outer fibrous capsule is formed containing multiple small daughter cysts. These cysts are allergens which precipitate a type 1 hypersensitivity reaction.

Hydatid cysts Up to 90% cysts occur in the liver and lungs Can be asymptomatic, or symptomatic if cysts > 5cm in diameter Morbidity caused by cyst bursting, infection and organ dysfunction (biliary, bronchial, renal and cerebrospinal fluid outflow obstruction) In biliary rupture there may be the classical triad of; biliary colic, jaundice, and urticaria

Hydatid cysts In fit patients with hydatid disease the best option is generally surgical excision. During the operation the operating field is draped with drapes impregnated with hypertonic saline to minimise the dangers associated with cyst spillage. Options range from peeling off the endocyst layer from the exocyst layer, with marsupialisation of the cyst cavity. Peripherally sited lesions may be considered for formal resection. Medical therapy with mebendazole may be used to provide peri-operative cover. There is no role for percutaneous treatment.

Pancreatic injury in splenectomy The tail of the pancreas lies adjacent to the hilum of the spleen and is thus vulnerable to injury. Injury to the pancreatic tail may cause a pancreatic fistula. Initial management is easier if a drain was placed at the time of surgery. In most cases distal pancreatic fistulae will heal with conservative management and nutritional support. The use of TPN to reduce pancreatic stimulation may be beneficial and considered at an early stage. Decompression of the pancreas with ERCP, sphincterotomy and stent insertion may be beneficial for very high output fistula.

Blood supply to bile duct 60% from gastroduodenal artery 40% from the hepatic artery The bile duct has an axial blood supply which is derived from the cystic and right hepatic arteries. Unlike the liver there is no contribution by the portal vein to the blood supply of the bile duct. Damage to the hepatic artery during a difficult cholecystectomy is a recognised cause of bile duct strictures.