Pancreatitis (Acute) Flashcards
What is acute pancreatitis?
Acute pancreatitis refers to inflammation of the pancreas.
How does acute and chronic pancreatitis differ?
It can be distinguished from chronic pancreatitis by its limited damage to the secretory function of the gland, with no gross structural damage developing. Repeated episodes of acute pancreatitis can eventually lead to chronic pancreatitis.
What are the risk factors for acute pancreatitis?
‘GET SMASHED’:
- Gallstones
- Ethanol (alcohol)
- Trauma
- Steroids
- Mumps
- Autoimmune disease, such as SLE
- Scorpion venom (a rare and unlikely cause in most countries)
- Hypercalcaemia
- Endoscopic retrograde cholangio-pancreatography (ERCP)
- Drugs (azathioprine, NSAIDs or diuretics)
Briefly describe the anatomy of the biliary tree
Briefly describe the pathophysiology of acute pancreatitis
Each cause risk factor will trigger a premature and exaggerated activation of the digestive enzymes within the pancreas. The resulting pancreatic inflammatory response causes an increase in vascular permeability and subsequent fluid shifts (often termed “third spacing”).
Enzymes are released from the pancreas into the systemic circulation, causing autodigestion of fats (resulting in a ‘fat necrosis’) and blood vessels (sometimes leading to haemorrhage in the retroperitoneal space). Fat necrosis can cause the release of free fatty acids, reacting with serum calcium to form chalky deposits in fatty tissue, resulting in hypocalcaemia.
Severe end-stage pancreatitis will eventually result in partial or complete necrosis of the pancreas.
What are the clinical features of acute pancreatitis?
Patients will classically present with a sudden onset of severe epigastric pain, which can radiate through to the back, with nausea and vomiting.
On examination, there is often epigastric tenderness, with or without guarding. In severe cases, there may be haemodynamically instability, due to the inflammatory response occurring.
Less common signs that are often described are Cullen’s sign and Grey Turner’s sign, representing retroperitoneal haemorrhage. Tetany may occur from hypocalcaemia (secondary to fat necrosis) and, in select cases, gallstone aetiology may also cause a concurrent obstructive jaundice.
What is Cullen’s Sign?
Cullen’s sign: bruising around the umbilicus.
Representing retroperitoneal haemorrhage.
Shown as A.
What is Grey Turner’s Sign?
Grey Turner’s sign: bruising in the flanks.
Representing retroperitoneal haemorrhage.
Shown as B.
What is shown in picture A and B?
A= Cullen’s Sign
B= Grey Turner’s Sign
What investigations should be ordered for acute pancreatitis?
Note: laboratory investigations
Routine blood tests, as per investigation of any acute abdomen, are required. Specifically for acute pancreatitis, it is important to consider:
- Serum amylase
- LFTs
- Serum lipase
Why investigate serum amylase?
Diagnostic of acute pancreatitis if 3x the upper limit of normal.
Amylase can also be marginally raised in pathologies such as bowel perforation, ectopic pregnancy or diabetic ketoacidosis.
Why investigate LFTs?
Assess for any concurrent cholestatic element to the clinical picture.
Patients with acute pancreatitis noted that an alanine transaminase (ALT) level >150U/L has a positive predictive value of 85% for gallstones as the underlying cause.
Why investigate serum lipase?
A raised serum lipase is more accurate for acute pancreatitis (as it remains elevated longer than amylase), yet it is not available or routinely performed in every hospital.
What investigations should be ordered for acute pancreatitis?
Note: imaging
An abdominal ultrasound scan may be requested if the underlying cause is unknown; it is typically used to identify any gallstones (as a potential underlying cause) and any evidence of duct dilatation.
Whilst not routinely performed for acute pancreatitis, an AXR can show a ‘sentinal loop sign’.
A contrast-enhanced CT scan may be required if the initial assessment and investigations prove inconclusive.
How does acute pancreatitis appear on AXR?
Presents as sentinel loop sign. This is a dilated proximal bowel loop adjacent to the pancreas, which occurs secondary to localised inflammation. A CXR should be undertaken to look for pleural effusion or signs of ARDS.