GI Medicine Flashcards
(135 cards)
What are the causes of Pancreatitis?
*Remember the pneumonic
What are the most common causes?
- Gallstones (60%)
- Ethanol (i.e. alcohol – 30%)
- Trauma
- Steroids
- Mumps (other viruses include Coxsackie B)
- Autoimmune (e.g. polyarteritis nodosa), Ascaris infection
- Scorpion venom
- Hypertriglyceridaemia, Hyperchylomicronaemia, Hypercalcaemia, Hypothermia
- ERCP
-
Drugs (azathioprine, mesalazine*, didanosine, bendroflumethiazide, furosemide, pentamidine, steroids, sodium valproate)
- pancreatitis is 7 times more common in patients taking mesalazine than sulfasalazine
Breifly explain what pancreatitis is
Acute pancreatitis is caused by the destructive effect of premature activation of pancreatic enzymes which causes self-perpetuating pancreatic inflammation by enzyme-mediated AUTOdigestion.
.
Explain pathophysiology of gall stones pancreatitis
- Gallstone pancreatitis:
- Accumulation of enzyme-rich fluid WITHIN the pancreas due to
- OBSTRUCTION of the pancreatic duct by gallstones
- Intracellular Ca2+ increases and causes the early activation of
- trypsinogen
- In this situation, trypsinogen is cleaved (by cathepsin B) to trypsin, and trypsin degradation (by chymotrypsin C) is impaired and overwhelmed leading to a buildup of trypsin and thus increased enzymatic digestion of the pancreas and inflammation leading to extensive acinar damage
Explain pathophysiology of gall stones pancreatitis
- Alcohol-induced pancreatitis:
- Alcohol is shown to interfere with Ca2+ homeostasis in increased stimulation of enzyme secretion and obstruction of the duct due to contraction of the ampulla of Vater
Explain how pancreatitis can lead to oedema, inflammation and hypovolaemia
- The prematurely activate enzymes also cause leaky vessels by digesting vessel walls in the pancreas leading to the leakage of fluid into the tissues causing OEDEMA, INFLAMMATION and HYPOVOLAEMIA (as extracellular fluid is trapped in the gut, peritoneum and retroperitoneum)
- Destruction of blood vessels by enzymes causes haemorrhage Destruction of the adjacent islets of Langerhans can result in
- hyperglycaemia as beta cells will be destroyed resulting in less insulin
- Lipolytic enzymes cause fat necrosis, which can result, if extensive and involving the anterior abdominal wall, in skin discolouration (Grey Turner’s sign)
- The released fatty acids bind to Ca2+ ions, forming white precipitates in the necrotic fat
- If this is very severe, it can result in hypocalcaemia - presenting with tetany
List 4 clinical signs of acute pancreatitis
Clinical features:
- Severe epigastric pain that may radiate through to the back – sitting forward may relive the pain
- Anorexia, Nausea and Vomiting - common
- Examination may reveal guarding, tenderness, ileus and low-grade fever, tachycardia, hypotension
- Periumbilical discolouration (Cullen’s sign) and flank discolouration (Grey-Turner’s sign) – rare
- Other rare features:
- ischaemic (Purtscher) retinopathy - may cause temporary or permanent blindness
What investigations would you request for pancreatitis and what would you expect to see? (6)
Investigations:
- raised amylase:
- 3x normal limit
- seen in 75% of patients.
- Note: may be normal even in severe pancreatitis as levels fall after 3-5 days of acute event & other things can cause raised amylase e.g. upper GI perforation
- levels do not correlate with disease severity.
- Raised serum lipase - more sensitive and specific for pancreatitis than amylase
- Raised urinary amylase – maybe diagnostic as levels remain elevated over long time period
- CRP level for monitoring severity and prognosis
- ABG- for scoring and lactate
- Erect CXR:
- Essential to exclude gastroduodenal perforation - which also raises serum amylase
- May show gallstones or pancreatic calcification
- Abdominal ultrasound:
- Diagnoses gallstone pancreatitis
- Contrast enhanced CT:
- To identify extent of pancreatic necrosis
- MRI:
- Identifies degree of pancreatic damage
- Useful in differentiating fluid and solid inflammatory masses
What scoring systems are used for pancreatitis?
Scoring systems
- There are several scoring systems including the Ranson score, Glasgow score and APACHE II (Acute Physiology And Chronic Health Evaluation)
- They increase accuracy of prognosis
What factors indicate severe pancreaitis?
- age > 55 years
- hypocalcaemia
- hyperglycaemia
- hypoxia
- neutrophilia
- elevated LDH and AST
- Note that the actual amylase level is not of prognostic value.
List 3 differential diagnoses for hyperamylasaemia aside from pancreatitis
List 3 different diagnoses for similar pain to pancreatitis
Differential diagnosis:
Differential causes of hyperamylasaemia
- Acute pancreatitis
- Pancreatic pseudocyst
- Mesenteric infarct
- Perforated viscus
- Acute cholecystitis
- Diabetic ketoacidosis
Differentials of similar pain:
- Small bowel perforation/obstruction.
- Ruptured or dissecting aortic aneurysm.
- Atypical myocardial infarction.
What is the management of acute pancreatitis?
Management:
- IV fluids:
- Patients need prompt and adequate fluid resuscitation
- Third space fluid losses can be huge so may require several litres stat
- Nutrition– feed with enteral nutrition via ng tube if nutritional support is needed or person is vomiting
- Analgesia - e.g. IM pethidine +/- iv benzodiazepine
- Morphine is relatively contra-indicated because of possible spastic effect on the sphincter of oddi
- Urinary catheter if unwell
- Thromboprophylaxis - All patients with pancreatitis should have thromboprophylaxis unless clearly contraindicated (check renal function, platelets and clotting prior to dosing heparin)
- Prophylactic antibiotic therapy – only if established infected pancreatic necrosis in the hope of averting the progression to infection.
- Beta-lactams e.g. Iv imipenem or iv co-amoxiclav
- Surgery
- Patients with acute pancreatitis due to gallstones should undergo early cholecystectomy.
- Patients with obstructed biliary system due to stones should undergo early ERCP (within 72 hours)
- Patients who fail to settle with necrosis and have worsening organ dysfunction may require debridement, fine needle aspiration is still used by some.
- Patients with infected necrosis should undergo either radiological drainage or surgical necrosectomy. The choice of procedure depends upon local expertise.
List 3 early complications of pancreatitis
Complications:
Early
- Shock
- Acute kidney injury
- Acute respiratory distress syndrome
- DIC
- Sepsis
- Hypocalcaemia
- Hyperglycaemia
- Pancreatic necrosis
List 3 late complications of pancreatitis
Late
- Pancreatic necrosis
- Pancreatic pseudocyst
- Pancreatic fluid in lesser sac
- Presents > 6 weeks later
- Abdominal mass may be present
- May need internal (via stomach) or external drainage
- Abscess
- Thrombosis
- Commonly in splenic/gastroduodenal arteries
- Fistulae
What are pancreatic psuedocysts?
- Occur in 25% cases
- Located in or near the pancreas and lack a wall of granulation or fibrous tissue
- May resolve or develop into pseudocysts or abscesses
- Since most resolve aspiration and drainage is best avoided as it may precipitate infection
Pseudocysts
- In acute pancreatitis result from organisation of peripancreatic fluid collection. They may or may not communicate with the ductal system.
- The collection is walled by fibrous or granulation tissue and typically occurs 4 weeks or more after an attack of acute pancreatitis
- Most are retrogastric
- 75% are associated with persistent mild elevation of amylase
- Investigation is with CT, ERCP and MRI or endoscopic USS
- Symptomatic cases may be observed for 12 weeks as up to 50% resolve
- Treatment is either with endoscopic or surgical cystogastrostomy or aspiration
How would you manage pancreatic necrosis?
Pancreatic necrosis
- Pancreatic necrosis may involve both the pancreatic parenchyma and surrounding fat
- Complications are directly linked to extent of parenchymal necrosis and extent of necrosis overall
- Early necrosectomy is associated with a high mortality rate (and should be avoided unless compelling indications for surgery exist)
- Sterile necrosis should be managed conservatively (at least initially)
- Some centres will perform fine-needle aspiration sampling of necrotic tissue if infection is suspected. False negatives may occur and the extent of sepsis and organ dysfunction may be a better guide to surgery
How would you manage a pancreatic abscess?
Pancreatic abscess
- Intraabdominal collection of pus associated with pancreas but in the absence of necrosis
- Typically occur as a result of infected pseudocyst
- Transgastric drainage is one method of treatment, endoscopic drainage is an alternative
What are the causes of chronic pancreatitis?
Who are most affected and when does it typically present?
- Chronic pancreatitis is an inflammatory condition which can ultimately affect both the exocrine and endocrine functions of the pancreas.
- Around 80% of cases are due to alcohol excess with up to 20% of cases being unexplained.
- MALES affected more than females
- Median age of presentation is 51
- Smoking is a risk factor
Aetiology:
- alcohol
- genetic: cystic fibrosis, haemochromatosis
- ductal obstruction: tumours, stones, structural abnormalities including pancreas divisum and annular pancreas
- recurrent acute pancreatitis
What is the pathophsyiology of pancreatitis?
Pathophysiology:
- Obstruction or reduction in bicarbonate secretion, which produces an alkaline pH which in turn stabilises trypsinogen, leads to the activation of trypsinogen as pH rises making it more unstable and causing its activation into trypsin which leads to pancreatic tissue necrosis with eventual fibrosis
- Abnormalities of bicarbonate excretion can be the result of functional defects at the level of the cellular wall e.g. cystic fibrosis or mechanical as in trauma
- Increased intrapancreatic enzyme activity leads to the precipitation of proteins within the duct lumen in the form of plugs
- These plugs then become calcified resulting in ductal obstruction and further pancreatic damage
- Alcohol increases trypsinogen activation and also causes proteins to precipitate in the ductal structure of the pancreas leading to local pancreatic dilatation and fibrosis
- NOTE: the vast majority of people drinking excess alcohol DO NOT DEVELOP pancreatitis - this suggests that the disease process is a complex interaction of different mechanisms e.g. genes and environment
List 5 clinical features of chronic pancreatitis?
Clinical Features
- epigastric pain is typically worse 15 to 30 minutes following a meal
- exacerbated by alcohol, made better by sitting forward
- pain ‘bores’ to the back
- Nausea and vomiting
- Anorexia
- Diarrhoea
- steatorrhoea: symptoms of pancreatic insufficiency usually develop between 5 and 25 years after the onset of pain (exocrine dysfunction)
- weight loss
- diabetes mellitus develops in the majority of patients. It typically occurs more than 20 years after symptom begin (endocrine dysfunction)
List 4 differential diagnoses of chronic pancreatitis
Differentials:
- Acute pancreatitis
- Pancreatic malignancy
- Acute cholecystitis.
- Peptic ulcer disease.
- Acute hepatitis.
- Abdominal aortic aneurysm.
- Pyelonephritis.
What investigations would you request for chronic pancreatitis and what would you expect to see?
Investigations:
- Amylase and lipase usually normal as there may not be sufficient residual acinar cells to produce elevation
- Fasting blood glucose – check for DM
- abdominal x-ray shows pancreatic calcification and dilated pancreatic duct
- CT is more sensitive at detecting pancreatic calcification.
- MRCP – detects more subtle abnormalities
- EUS – endoscopic ultrasound can allow for direct visualisation of the pancreas
- faecal elastase may be used to assess exocrine function if imaging inconclusive
- Secretin stimulation test: a positive if 60%+ pancreatic exocrine function is damaged
- Biopsy rarely performed – too risky
What is the management of chronic pancreatitis?
Management
- Stop alcohol, stop smoking and high protein low carb diet
- pancreatic enzyme supplements e.g. Creon
- analgesia for Abdo. pain e.g. NSAIDS or paracetamol. Or coeliac plexus block
- Insulin – if diabetic
- Pancreatic duct stones - dislodge with ERCP or may require endoscopic shock-wave lithotripsy or laser lithotripsy.
- Surgical decompression of duct dilatation can be performed if this cannot be achieved by ERCP alone
- Local surgical resection of pancreatoduodenectomy has been used in some cases
List 3 complications of chronic pancreatitis
Complications:
- Malabsorption
- Diabetes
- Chronic pain
- Pancreatic pseudocyst
- These can rupture, bleed, or occlude nearby structures like the duodenum or CBD. If present for >6 weeks, spontaneous resolution is unlikely and they should be drained, either surgically or endoscopically into the stomach or duodenum.
- Ascites or pleural effusions if pancreatic duct is occluded
- Ascitic or pleural amylase will be elevated
- Pancreatic carcinoma
What is the prognosis of patients with chronic pancreatitis?
Prognosis:
- There is an increased mortality and morbidity
- Approximately 1/3 of patients will die within 10 years





