Pancreatic nutritional disease

Pancreatic exocrine insufficiency occurs when the amounts of enzyme secreted into the duodenum in response to a meal are not sufficient to maintain normal digestive processes.

Aetiology:

• Insufficient pancreatic capacity for synthesis
• Reduced stimulation of pancreas (anatomical or physiological)
• Impaired delivery of enzymes to the duodenum due to obstruction of the pancreatic duct

Clinical findings:

• Generally quite late in the course of the inciting disease, because findings do not manifest until duodenal enzyme levels are down to 5-10% of their normal levels
• Fat maldigestion and malabsorption, which leads to steatorrhoea and weight loss
  • Presence of steatorrhoea is the foundation of diagnosis - loose, oily, foul-smelling, difficult to flush stool

Diagnosis

• Imaging of pancreas for suggestive features
• Direct assessment of pancreatic function - direct measurement of secretions via duodenal sampling - fairly limited role for these in practice due to cost and difficulty
  • Secretin-CCK stimulation test
  • Lundh test
• Indirect tests
  • 3-day faecal fat test - gold standard for diagnosing and quantifying steatorrhoea
    • Steatorrhoea is present if more than 7% of ingested fat is excreted (in patients over 6 months of age)
  • Steatocrit - proportion of fat in a single stool
  • Microscopic examination of stools for fat droplets
  • Faecal chymotrypsin and elastase-1
    • Elastase-1 is recommended by UTD as the most commonly-performed test - sensitivity for mild, moderate and severe insufficiency of 63, 100 and 100 percent respectively; and specificity 93%
    • Faecal elastase-1 <200mcg/g is abnormal
    • Dilute diarrhoea from other causes can artificially lower the elastase-1 level
  • Breath tests - limited use of these in Australia
  • Serum trypsinogen - fairly good reflection of pancreatic function and reflects pancreatic acinar cell mass - cut-off of <20ng/mL is reasonably sensitive. Not sensitive for mild disease, or if levels are 21-30. Non-specific. Also cheap according to UTD.

Indications for workup:

• Classified as PEI possible on table above. Often get imaging (CT) then a 3-day stool test and FE-1 test and serum trypsinogen.
• Classified as unlikely: imaging then a non-invasive test

Therapy

• Either Creon or Panzytrat
• Creon is a porcine pancreatic enzyme extract (contains lipase, amylase and protease)
  • Half-life only 20 minutes - take the Creon with your first bite, and may need another dose if having a long meal
• Panzytrat is also porcine, just slightly different make-up of enzymes
• Dosing - 25,000 to 40,000 units with each meal. Can be titrated up to a maximum of 80,000 units per meal (more than that is very expensive and shouldn't be needed - something else is going wrong if you need that much).
  • If reported inadequate response to therapy, check compliance via measurement of faecal chymotrypsin? In the compliant patient, double or triple doses, and check for other causes of malnutrition. Consider trying concurrent PPI. Consider coeliac disease, bacterial overgrowth, blind loop syndrome, giardiasis.
• Give a 6-week trial of treatment, if starting Creon

Enzyme replacement and pancreatitis

• No evidence to support this during initial stages of acute pancreatitis
• Pancreatic exocrine function can take up to four years to return to normal, but most are better by 12 months
• Recommend nutritional assessment for all patients recovering from acute pancreatitis, especially if severe, or if patient is already malnourished
• Managing exocrine insufficiency in chronic pancreatitis
  • Goals
    • Control symptoms
    • Improve nutrition
    • Treat complications
  • Evidence is actually lacking that Creon can prevent weight loss/pain/steatorrhoea/QoL in this cohort

Other indications for creon:

• SOMETIMES after gastric resection
• Always after pancreatic head resection, often after mid-pancreatic resection, generally not after pancreatic tail resection
• Often helpful with palliative pancreatic cancer patients