Aetiology

• Idiopathic
• Obstruction
  • Choledocolithiasis
  • Ampullary or pancreatic tumours
• Pancreatic structural anomalies
• Toxins
  • Alcohol
  • Drugs - salicylates, azathioprine, cimetidine
• Trauma
  • Accidental
  • Iatrogenic
• Metabolic abnormalities
• Infection
• Vascular anomalies

Diagnosis

• Serum amylase has low sensitivity and specificity
• 20% cases of pancreatitis have normal serum amylase (particularly alcoholic aetiology)
• Serum lipase more sensitive

Pictures provided by Vikram Kate, Jawaharial Institute of Postgraduate Medical Education and Research, Pondicherry, India

Causes of hyperamylasaemia

• Perforated peptic ulcer
• Cholecystitis
• Generalised peritonitis
• Intestinal obstruction
• Mesenteric infarction
• Ruptured AAA
• Ruptured ectopic pregnancy

Prognostic factors

• 80% of patients have mild pancreatitis with good recovery
• Mild disease accounts for less than 5% of the mortality form pancreatitis
• Mortality from pancreatitis due to:
  • Early multiple organ failure
  • Late infected pancreatic necrosis
  • Haemorrhage
  • Associated co-morbidity
• Aim of prognostic scores is to identify patients with severe pancreatitis
• Need to have high sensitivity and specificity
• Ideally should be applicable on admission

Ranson's criteria

• On admission 
  • Age > 55 yrs
  • WCC > 16,000
  • LDH > 600 U/l
  • AST >120 U/l
  • Glucose > 10 mmol/l
• Within 48 hours
  • Haematocrit fall >10%
  • Urea rise >0.9 mmol/l
  • Calcium < 2 mmol
  • pO₂  < 60 mmHg
  • Base deficit > 4
  • Fluid sequestration > 6L
• Can not be applied fully for 48 hours
• Also poor predictor later in the disease
• 'Single snapshot in a whole feature length film'

APACHE II score

• Multivariate scoring system
• Measure objective parameter - vital signs and biochemical analysis
• Account for premorbid state and age
• Can be used throughout course of illness

Contrast-enhanced CT scoring system

Early treatment

• Aims of treatment are to :
  • To halt progression of local disease
  • Prevent remote organ failure
• Requires full supportive therapy – often on ITU or HDU
• Urinary catheter, CVP line and possibly arterial line
• Regular assessment of U+Es, Ca, blood sugar, LFTs
• Patients require:
  • Fluid resuscitation with both colloid and crystalloid
  • Correction of hypoxia with an increased inspired oxygen or ventilation
  • Adequate analgesia - opiate or epidural
• Increasing evidence that antibiotic prophylaxis useful in severe pancreatitis

Nutritional support

• Pancreatitis is associated with a catabolic state
• The benefit of pancreatic 'rest' by limiting oral intake is unproven
• Evidence that early enteral nutrition is safe
• Nasojejunal feeding limits pancreatic secretion
• Preferable to oral or nasogastric feeding

Complications of acute pancreatitis

Local

• Necrosis +/- infection
• Pancreatic fluid collections
• Colonic necrosis
• Gastrointestinal haemorrhage
• Splenic rupture

Systemic

• Hypovolaemia and shock
• Coagulopathy
• Respiratory failure
• Renal Failure
• Hyperglycaemia
• Hypocalcaemia

Pseudocysts

• Fibrous walled peri-pancreatic fluid collection
• Present for more than 1 month
• No epithelial lining. Fluid has high amylase content
• Acute fluid collections are not pseudocysts
• 35% patients with pancreatitis develop peri-pancreatic fluid collections
• More than 50% resolve spontaneously over a 3 month period
• Complication rate increases after 6 weeks
• Diagnosis may be suggested by persistent elevation of serum amylase
• Planned intervention at 6 weeks

Classification of pseudocysts

• Type 1 - normal duct anatomy. No fistula between duct and cyst
• Type 2 - abnormal duct anatomy - No fistula
• Type 3 - abnormal duct anatomy and fistula

Investigation of pseudocysts

• Ultrasound will allow assessment of changes in the size of the cyst
• Endoscopic ultrasound increasingly used
• CT to define relationship to adjacent organs

• ERCP to define duct anatomy

Treatment options

Percutaneous drainage

• Ultrasound or CT guided
• 80% successful in type 1 cyst
• Less successful if fistula to duct present
• Occasionally associated with pancreatic abscess or fistula

Endoscopic drainage + insertion of pigtail catheter

• Transpapillary or transmural

Surgical drainage

• Cystogastrotomy
• Roux Loop Cystojejunostomy
• Allows adequate internal drainage
• Biopsy cyst wall to exclude cystadenocarcinoma
• Mortality similar to percutaneous drainage ( 5%)
• Lower recurrence rate ( approximately 5 vs. 20%)

Timing of intervention in pancreatitis

• All patients should undergo ultrasound within 24 hours of admission
• If confirms gallstones and severe pancreatitis consider ERCP within 48 hrs
• RCT confirm reduction in morbidity and mortality with early duct clearance
• If patient fails to settle during first week of admission
• Contrast enhanced CT to assess pancreatic necrosis
• If suspicion of infection - CT guided aspiration
• Consider pancreatic necrosectomy if
  • Clinical deterioration
  • Bacteriological proof on infection
• Operative mortality >40%

Picture provided by Jean-Pierre Arsenault, University of Montreal, Coventry.

Bibliography

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