Pancreas: Functional Deficit

Pancreatic Insufficiency

Basics

  • Pancreatic Insufficiency Typically Refers to Loss of Exocrine Function with Preservation of Endocrine Function
    • However Loss of Endocrine Function is Also Possible
  • Effects:
    • Fat Malabsorption
    • Steatorrhea
    • Malabsorption of Fat-Soluble Vitamins

Causes

  • Chronic Pancreatitis (Most Common)
    • Once > 90% of Acinar Function Lost
  • Cystic Fibrosis (Second Most Common)
  • Duct Obstruction
  • Stomach or Bowel Resection – Loss of Stimulating Enzymes
  • Pancreas Resection – Loss of Glandular Tissue
  • Shwachman-Diamond Syndrome – Autosomal Recessive Mutations
    • Presentation: Bone Marrow Failure & Pancreatic Insufficiency

Diagnosis

  • Clinical Diagnosis
  • If Uncertain: Indirect Fecal Tests or Direct Secretin Stimulation Test
    • Fecal Elastase-1 (Most Sensitive & Specific Indirect Test)

Secretin Stimulation Test

  • Evaluates Pancreatic Exocrine Function
  • Normal Values of Pancreatic Fluid:
    • Total Volume: 2.0 cc/kg/hr
    • Bicarbonate Output: > 10 mmol/L in One Hour
    • Enzyme/Amylase Secretion: 6-18 U/kg
  • Abnormalities:
  Volume Bicarb Amylase
Chronic Pancreatitis Normal Decreased Normal
End-Stage Pancreatitis Decreased Decreased Decreased
Pancreatic Cancer Decreased Normal Normal
Malnutrition Normal Normal Decreased

Treatment

  • Pancreatic Enzyme Replacement
  • Diet (Low Fat & High Carb/Protein)

Diabetes

Pancreatic Diabetes

  • Diabetes Mellitus Induced by Pancreatic Exocrine Disease
    • Cause: Chronic Pancreatitis or Resection
  • Causes Impairment of Beta Cells & Alpha Cells
    • Decreased Secretion of Insulin, Glucagon & Pancreatic Polypeptide
    • Peripheral Sensitivity Increased; Liver Sensitivity Decreased
  • Glycemic Effects
    • Increased Risk of Hypoglycemia (Compared to Type 1 DM Given That Alpha Cells Are Also Affected)
    • DKA/Hyperglycemia Rare

Diabetes Mellitus (DM)

  • Type 1 – Pancreas Does Not Produce Insulin (Loss of Beta Cells)
  • Type 2 – Body Does Not Respond to Insulin (Insulin Resistance)
  • Type 3 – Unofficial Term with Varied Uses
    • Possibly Another Term for Alzheimer’s Disease – Insulin Resistance Within the Brain Was Found to Be a Feature of Alzheimer’s Disease
    • Possibly DM Due to Other Causes (Meds, Infection, etc) with Subclassification 3a-3h
      • Type 3c – Pancreatic Diabetes from Exocrine Disease – *See Above

Exogenous Insulin Administration (Munchausen’s Syndrome)

  • Presentation: Hypoglycemia with Low C-Peptide
    • If Hypoglycemia Due to Insulinoma or DM: C-Peptide Will be High
  • Patients Often Have a Medical Background (Nurse, etc.)