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.

Other than alcohol, causes include:

• genetic: cystic fibrosis, haemochromatosis
• ductal obstruction: tumours, stones, structural abnormalities including pancreas divisum and annular pancreas

Features

• epigastric pain
  • radiates to the back
  • typically worse 15 to 30 minutes following a meal
  • may be relieved by sitting forward
• steatorrhoea: symptoms of pancreatic insufficiency usually develop between 5 and 25 years after the onset of pain
• diabetes mellitus develops in the majority of patients. It typically occurs more than 20 years after symptom begin

Investigation

• abdominal x-ray shows pancreatic calcification in 30% of cases
• CT is more sensitive at detecting pancreatic calcification. Sensitivity is 80%, specificity is 85%
• functional tests: faecal elastase may be used to assess exocrine function if imaging inconclusive

Faecal elastase is a pancreatic enzyme secreted by the exocrine pancreas and remains stable during intestinal transit, making it a reliable marker of pancreatic exocrine function.

• Principle: Faecal elastase-1 concentration is measured in stool samples using an ELISA test. It reflects the amount of pancreatic enzyme output into the duodenum.
• Interpretation:
  • Normal: >200 µg/g stool – normal exocrine function
  • Mild to moderate insufficiency: 100–200 µg/g stool
  • Severe insufficiency: <100 µg/g stool – consistent with significant exocrine pancreatic insufficiency (EPI)
• Limitations:
  • False positives can occur in diarrhoea due to dilution effect.
  • Not useful for assessing endocrine function or acute pancreatitis.
• Guideline recommendations: NICE guidelines recommend faecal elastase testing in patients with suspected EPI secondary to chronic pancreatitis to guide pancreatic enzyme replacement therapy (PERT).