Diseases and the Pancreas and Gallbladder Flashcards
What are the cells of the pancreas
Pancreatic acinar cell
Centroacinar cell
What is the basic structure of the pancrease
Pancreatic acinus stemming from intercalated ducts
What are the two components of the pancreas
Exocrine component
Endocrine component
Acute pancreatitis
Acute inflammation of the pancreas caused by aberrant release of pancreatic enzymes
Relatively common, increasing incidence
Causes of acute pancreatitis
Duct obstruction: gallstones, trauma, tumours.
Metabolic/toxic: alcohol, drugs (thiazides), hypercalcaemia, hyuperlipidaemia
Poor blood supply: shock, hypothermia
Infection/inflammation: viruses (mumps)
Autoimmune
Idiopathic
What proportion of alcoholics develop acute pancreatitis
5%
Pathogenesis of acute pancreatitis due to ductal obstruction
Gallstone stuck distal to where the common bile duct and pancreatic ducts join leads to:
reflux of bile up the pancreatic duct followed by damage to acini with release of proenzymes which then become activated
Pathogenesis of acute pancreatitis due to alcohol
Alcohol leads to spasm/oedema of sphincter of oddi and the formation of a protein rich pancreatic fluid which obstructs the pancreatic ducts
Pattern of injury in acute pancreatitis
Periductal: necrosis of acinar cells near ducts (usually secondary to obstruction)
Perilobular: necrosis at the edges of the lobules (usually due to poor blood supply)
Panlobular - develops from periductal and perilobular damage
Pattern of injury in acute pancreatitis
Activated enzymes –> acinar necrosis –> enzyme release, etc…
Ranges from stromal oedema, to haemorrhagic necrosis
E.g. lipases –> fat necrosis (calcium ions bind to free fatty acids forming soaps which are seen as yellow-white foci)
Complications of acute pancreatitis
Pancreatic: pseudocyst, abscess
Systemic: shock, hypoglycaemia, hypocalcaemia
Prognosis of acute pancreatitis
Overall mortality up to 50% for hemorrhagic pancreatitis
Chronic pancreatitis
Relapsing or persistent, associated with acute pancreatitis in half of cases
Relatively uncommon
Mortality from chronic pancreatitis
3% per year
Causes of chronic pancreatitis
Metabolic/toxic: alcohol (80%), haemochromatosis
Duct obstruction: gallstones, abnormal pancreatic duct anatomy, cystic fibrosis (mucoviscoidosis)
Tumours
Idiopathic: autoimmune
Pattern of injury for chronic pancreatitis
Pathogenesis of the same as for acute pancreatitis
Chrnoci inflammation with parenchymal finbrosis and loss of parenchyma
Duct strictures with calcified stones with secondary dilations
Complications of chronic pancreatitis
Malabsorption
Diabetes mellitus
Pseudocyts
Carcinoma of the pancreas
What is diagnostic of chronic pancreatitis
Abdominal radiograph with pancreatic calcifications
Pancreatic pseudocysts
Associated with acute and/ or chronic pancreatitis
Lined by fibrous tissue (no epithelial lining), contain fluid rich in pancreatic enzymes) or necrotic material
Connect with pancreatic ducts
May resolve, compress adjacent structures, become infected or perforate
Histology of pancreatic pseudocyst
The cyst lining is composed of granulation tissue & infiltrating cells without a discrete epithelial lining. A thickened fibrotic wall with prominent vascualrity is present
Autoimmune pancreatitis
Characterised by large numbers of IgG4 positive plasma cells.
May involve the pancreas, bile ducts and almost any other part of the body.
Often called “IgG4 Disease”.
Histology of autoimmune pancreatitis
IgG4 positive plasma cells
Tumours of the pancreas
Carcinomas: ductal (85%), acinar
Cystic neoplasma: serous cystadenoma, mucinous cystic neoplasm
Pancreatic neuroendocrine tumours (islet cell tumour)
Ductal pancreatic carcinoma
5% of cancer deaths
Increasingly common with age. 2M:F
5 year survival is 5%
Risk factors for pancreatic carcinoma
Smoking
BMI and dietary factors
Chronic pancreatitis
Diabetes
Ductal pancreatic carcinoma
Arise from dysplastic ductal lesions: pancreatic intraductal neoplasia (PanIN)
K-Ras mutations in 95% of cases
Ductal carcinoma of the pancreas macroscopic appearance
Gritty and grey
Invades adjacent structure
Tumours in the head present earlier
Ductal carcinoma of the pancreas microscopic appearance
Adenocarcinomas: mucin secreting glands set in desmoplastic strome
Sites of ductal carcinoma of pancreas
Head 60%
Body
Tail
Diffuse
How does a ductal carcinoma of the pancreas typically spread
Direct: bile ducts, duodenum
Lymphatic: lymph nodes
Blood: liver
Serosa: peritoneum
Complications of ductal carcinoma of the pancreas
Due to spread
Chronic pancreatitis
Venous thrombosis (migratory thrombophlebitis)
Histology of ductal adenocarcinoma of the pancreas
Findings diagnostic of ductal adenoCa. Perineural invasion is virtually diagnostic of invasive Ca provided the epithelial structures are gland forming.
Cystic tumours of the pancreas
Usually multilocular
Contain serious or mucin secreting epithelium (CF ovarian tumours)
Usually benign
Pancreatic endocrine neoplasms
Usually non-secretory
Contain neuroendocrine markers e.g. chromogranin
Behaviour difficult to predict,
May be associated with the Multiple Endocrine Neoplasia (MEN) 1 syndrome
Insulinomas
Derived from beta cells in the pancreas
The commonest type of secretory tumour
Histological pattern of insulinoma
Nested pattern
Gallbladder pathology
Gallstones
Inflammation
Cancer
Gallstones (i.e. cholelithiasis) prevalence
20% of adults in the West are affected
Risk factors for gallstones
Age and gender: increasing age, F>M
Ethnic and geographic: e.g. Native Americans
Hereditary: e.g. disorders of bile metabolism
Drugs e.g. oral contraceptive
Acquired disorders e.g. rapid weight loss
FAT, FOURTY, FEMALE
Types of gallstones
Cholesterol (more than 50% cholesterol), may be single, mostly radiolucent
Pigment (contain calcium salts of unconjugated bilirubin), multiple, mostly radio-opaque
Complications of gallstones
Bile duct obstruction
Acute and chronic cholecystitis
Gall bladder cancer
Pancreatitis
Acute cholecytitis
Acute inflammation of the gallbladder
90% associated with gallstones
Chronic cholecystitis
Chronic inflammation of the gallbladder
Fibrosis
Diverticula - Rokitansky-Aschoff sinuses
90% contain gallstones
Gallbladder cancer
Adenocarcinomas
90% are associated with gallstones
