Hepatic, Pancreatic, & Biliary Systems Flashcards

Hepatic, Pancreatic & Biliary Systems

  • Objectives:
    • Recognize anatomical features and functions of the gallbladder and understand associated conditions.
    • Understand the pancreas anatomy and physiology.
    • Differentiate between abnormal function of endocrine and exocrine function.
    • Understand acute and chronic pancreatitis.
    • Understand hepatic structure and functions that associate with hepatic conditions.
    • Know details related to acute and chronic hepatic pathology and the body-wide implications.

Biliary System: Gallbladder & Bile Physiology

  • Bile:
    • Formed by the liver.
    • Yellow to green fluid.
    • Approximately 500ml (up to 1L) produced per day.
    • Stored in the gallbladder (50-100ml).
    • Composition:
      • 70% salts.
      • 10% cholesterol.
      • 2-3% bilirubin.
      • 5% phospholipids/lecithin.
      • 5% enzymes, and other components.
    • Gallbladder contraction stimulated by cholecystokinin from the small intestine.
      • Also stimulates pancreatic enzymes (exocrine function).
      • Slows gastric emptying.
      • Induces satiety (hypothalamus).
  • Functions of Bile:
    • Emulsify fat in the small intestine.
    • Aids digestion of fat-soluble vitamins.
    • Alkaline to neutralize acidic chyme.
    • Excrete bilirubin & cholesterol.
    • Bactericidal (kills microorganisms).

Biliary System Pathology: Gallstone Disease (Cholelithiasis)

  • Epidemiology:
    • 25 million adults affected (10-15% of adult population).
    • Causes 1.8 million ER visits per year.
    • Increased prevalence with age; women > men.
    • Higher prevalence in American Indian and Hispanic populations compared to Asian, Black, and White populations.
    • Genetics play a role.
    • American Indian: 67% of women, 30% of men (all ages).
    • Pregnancy: 5-10% prevalence.
    • Gastric bypass/rapid weight loss: up to 50% in the first 6 months (40% symptomatic).

Gallstone Disease (Cholelithiasis)

  • Symptoms:
    • Referred pain in the upper right quadrant (migrating), sternum radiating to the back, often postprandial.
    • Includes flatulence, belching, epigastric discomfort.
  • Diagnosis:
    • Imaging: Ultrasound (US), MRI, CT scans.
  • Medical Management:
    • Antibiotics.
    • Dyslipidemics (long term).
    • Surgery/Laparoscopy/Endoscopy.
    • ERCP (Endoscopic Retrograde Cholangiopancreatography).
  • Clinical Complications from ERCP:
    • Pancreatitis (20% chance).
    • Infection.
    • 50-60% chance of recurrence without cholecystectomy.
  • Mortality:
    • 1950: 5,000 deaths/year.
    • 2000: ~1,000 deaths/year.
    • Altered role of PT (Prothrombin Time).

Pancreas Physiology

  • Two functions: Endocrine & Exocrine.
  • Anatomy:
    • Common Bile Duct
    • Ampulla of Vater (major papilla)
    • Gallbladder
    • Accessory Duct
    • Accessory papilla
    • Pancreas Divisum
    • Small Intestine

Pancreas Endocrine Function

  • Islets of Langerhans (10-20% of pancreatic cells).
  • Cell types:
    • α cells
    • β cells
  • Hormones secreted:
    • Amylin
    • Ghrelin
    • Pancreatic Polypeptide
    • Somatostatin (Growth Hormone Inhibiting Hormone).

Pancreas Exocrine Function

  • Acinar cells (80-90%):
    • Produce Zymogen/Pro-enzymes:
      • Proteases (for protein digestion).
      • Lipases (for fat digestion).
      • Amylases (for carbohydrate digestion).
  • Ductal cells:
    • Secrete bicarbonate-rich fluid to neutralize stomach acid.

Pancreas Pathology: Acute Pancreatitis

  • Cause: "Auto-digest".
  • Etiology:
    • Gallstones (40%).
    • Alcohol (toxin/dehydration) (30%):
      • Increases zymogen production, decreases ductal secretion leading to thick, viscous pancreatic secretion.
    • Physical Plug:
      • Trypsinogen is converted to ↑trypsin (protease).
      • Increases acinar secretion and pro-inflammatory response.
      • Neutrophils increase.
      • Increases zymogen production.
  • Epidemiology:
    • 80% mild, self-limiting.
    • Incidence: 4.9-35 per 100,000 US adults.
    • 275,000 ER/Hospitalizations per year.
    • M=W, Black > White, Hispanic, Asian, American Indian *accounting risk.
  • Clinical Presentation (Symptoms) - History:
    • Referred pain – back pain (relieved by heat), preferred positions & acute respiratory distress
  • Diagnosis:
    • Laboratory:
      • 3x Serum amylase, lipases
      • ↑WBC & ↑CRP/proinflammatory cytokines
      • ↑ Hct, BUN/Creatinine
    • Abdominal Imaging:
      • enlarged pancreas, gallstones, tumor/growth, etc
      • Ultrasound (endoscopic)
      • MRI or CT

Pancreas Pathology: Acute Pancreatitis - Clinical Complications

  • Early – Inflammatory (MOF)

  • Late – Infection/Necrosis

  • Systemic (Multiple Organ Failure – MOF):

    • Inflammation & Ischemia.
    • Acute kidney failure, liver failure, respiratory distress.
    • Hepatic – ascites, encephalopathy.
    • Cardiovascular – hypotension, coagulation.

  • Local:

    • Pancreas Necrosis.
    • Fibrosis.
    • Cyst, Obstruction  Chronic Pancreatitis.

  • ↑Mortality

  • Nutrient deficiency – macro/micro incl vitamins, minerals.

  • Interstitial edematous pancreatitis

  • Medical Management:

    • Late – Infection/Necrosis
      • Antibiotics
      • WOPN (walled-off pancreatic necrosis)
      • Surgical Treatment/Endoscopic Necrosectomy

Pancreas Pathology: Chronic Pancreatitis

  • Chronic, Persistent  Inflammation
  • Endocrine & Exocrine dysfunction
  • Inflammation
  • Fibrosis
  • ↓ exocrine – Acinar
  • ↓ endocrine – Islets of Langerhans
  • Prevalence:
    • 25-98 per 100K (US adults)
    • 5-8 new per 100K/yr
    • 25K ER/Hospitalizations/yr
    • M*>W, ↑ Age (4-6th decade)
    • Black* > White, Hisp, Asian, Other
    • *significant ↑alcohol, smoking
  • Cause:
    • 30% Idiopathic (esp W)
    • 30% Alcohol
    • Calcification
    • 13% Genetic
    • Auto-immune
    • 12% Obstructive
    • *Re-ccurent/Repeat Acute

Pancreas Pathology: Chronic Pancreatitis - Clinical Complications

  • Chronic, Persistent  Inflammation
  • Endocrine & Exocrine dysfunction
  • Pancreatic exocrine insufficiency
    • Steatorrhea immediate; often 10-15yrs
  • Pancreatogenic diabetes mellitus (Type 3C DM; ~5%)
    • insulin deficiency induced by damage to pancreas
    • e.g. cancer, cystic fibrosis, pancreatitis
  • Pancreatic cancer

Pancreas Pathology: Chronic Pancreatitis - Diagnosis

  • Clinical presentation (symptoms) – History
  • Laboratory
    • Serum amylase, lipases (slight elevation)
    • ↑WBC & ↑CRP/proinflammatory cytokines
    • Hormones – T3CDM
    • Pancreatic function test
    • Steatorrhea (“fatty feces”) /Malabsorption macro-/micro-nutrients
  • Abdominal Imaging
    • fibrosis, stricture, obstructions
    • Ultrasound (endoscopic)
    • MRI, CT

Pancreas Pathology: Chronic Pancreatitis - Medical Management

  • Chronic, Persistent  Inflammation
  • Endocrine & Exocrine dysfunction
  • Chronic abdominal pain
    • Surgical/nerve block, Anti-depressant (TCA/SSRI)/neuromodulators
  • Lifestyle Alterations eating
  • Pancreatic Enzyme Replacement Therapy
  • Smoking & Alcohol cessation
  • PA/Exercise
  • Surgical (endoscopic) reconstruction pancreatic ducts/strictures