Acute pancreatitis

Pathogenesis:

• Autodigestion of the pancreas by proteolytic enzymes released in the pancreas (rather than in the interstitial lumen) may also be involved

Active enzymes could digest cell membranes, leading to:

• Proteolysis
• Pancreatic/peripancreatic oedema
• Vascular damage
• Pancreatic necrosis

• Mildest and most common form (oedematous pancreatitis – 75%):
• Interstitial oedema
• Inflammatory exudate
• Some fat necrosis

• Most severe form:
• Extensive pancreatic and peripancreatic necrosis
• Haemorrhage

Causes of acute pancreatitis:

• Gallstones
• Alcohol
• Infection (e.g. mumps, coxsackie B)
• Pancreatic tumours
• Drugs (e.g. azathioprine, oestrogens, corticosteroids)
• Post-ERCP
• Hyperlipidaemia
• Trauma
• Scorpion bite

Clinical features:

• Epigastric pain radiating to the back (between the scapulae)
• Pain varies from mild discomfort to excruciating pain
• Nausea
• Vomiting

On examination:

• Tenderness, guarding and rigidity of the abdomen
• Body wall ecchymoses can occur:
• Umbilical (Cullen’s sign)
• In the flanks (Grey Turner’s sign)

Investigations

Serum amylase:

• If the serum amylase is 5x greater than normal, acute pancreatitis is very likely

Ultrasound:

• Used to detect gallstones in the biliary tree
• Shows pancreatic swelling, necrosis and the presence or absence of peripancreatic fluid collections

Contrast-enhanced dynamic CT scanning:

• Is the most valuable technique as it detects:
• Swelling of the pancreas
• Pancreatic necrosis
• Peripancreatic fluid collections
• Diffuse inflammatory changes in the retroperitoneum

If there is any doubt in diagnosis, an exploratory laparotomy must be performed in all but the mildest cases to exclude a potentially fatal, but treatable, non-pancreatic lesion.

Factors during the first 48 hours indicating a poor prognosis:

• Age >55 years
• WBC >15
• Blood glucose >10
• Urea >16
• Albumin <30
• Aminotransferase >200
• Calcium <2
• LDH >600
• P_aO₂ <8kPa

Treatment:

In all cases:

• NBM
• Nasogastric suction (to reduce vomiting and abdominal distension)
• IV Fluids
• Electrolyte replacement
• Opiate analgesia (other than morphine)

In severe cases:

• Parenteral nutrition
• ITU (if shocked and/or in respiratory failure)

Complications:

• Acute fluid collection
• Pancreatic necrosis
• Pseudocysts
• Pancreatic abscesses
• Pancreatic ascites (indicates a poor prognosis)

Prognosis:

• Mortality varies from 1% (mild cases) to 50% (severe cases)
• With multiple complications and the presence of all the bad prognostic signs, the mortality is nearer 100%