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.
How does acute pancreatitis present on contast enhanced CT scan?
Note: after 48 hours
If performed after 48hrs from initial presentation, it will often show areas of pancreatic oedema and swelling, or any non-enhancing areas suggestive of pancreatic necrosis.
What is shown on the contrast enhanced CT scan?
Pancreatitis on Axial CT Scan (A) Localised oedema around the pancreas (B) Extensive fluid collections around the pancreas.
Briefly describe the treatment for acute pancreatitis
There is no curative management for acute pancreatitis, so supportive measures are the mainstay of treatment. Treat any underlying cause as necessary (e.g. urgent ERCP and sphincterotomy for gallstones) where appropriate.
Supportive measures include:
- Intravenous fluid resuscitation and oxygen therapy as required
- Nasogastric tube if the patient is vomiting profusely
- Catheterisation to accurately monitor urine output and start a fluid balance chart (due to the potential for rapid third space losses)
- Opioid analgesia
Where are patients with acute pancreatitis supposed to be managed?
Current UK guidelines state that all patients with severe acute pancreatitis should be managed in a high dependency unit or intensive therapy unit (although this is often impractical).
When is antibiotic therapy needed for acute pancreatitis?
A broad-spectrum antibiotic, such as imipenem, should be considered for prophylaxis against infection in cases of confirmed pancreatic necrosis.
If there is an underlying cause causing acute pancreatitis, when should this be addressed?
Treating the underlying cause should be addressed, once the patient has been stabilised.
For those caused by gallstones, early laparoscopic cholecystectomy is advised, whilst those secondary to alcohol excess should ensure they have access to the appropriate services made.
What are the systemic complications of acute pancreatitis?
The systemic complications of acute pancreatitis tend to occur within days of the initial onset:
- Disseminated Intravascular Coagulation (DIC)
- Acute Respiratory Distress Syndrome (ARDS)
- Hypocalcaemia
- Hyperglycaemia
Why is hypoglycaemia a complication of acute pancreatitis?
Fat necrosis from released lipases, results in the release of free fatty acids, which react with serum calcium to form chalky deposits in fatty tissue.
Why is hyperglycaemia a complication of acute pancreatitis?
Secondary to destruction of islets of Langerhans and subsequent disturbances to insulin metabolism.
