Study Notes on Hepatobiliary and Pancreatic Disorders

DISORDERS OF HEPATOBILIARY & PANCREAS FUNCTION

UNIT OBJECTIVES

  • Functions of the liver: Relate the functions of the liver to the manifestations of liver failure.
  • Liver Cirrhosis: Diagram the development of liver cirrhosis, including common manifestations seen with this disorder.
  • Hepatitis Comparison: Compare and contrast Hepatitis A, B, C, D, and E from each other.
  • Portal Hypertension Consequences: Outline the consequences of portal hypertension on the body, including ascites, esophageal varices, and splenomegaly.
  • Cholelithiasis: Explain the development of cholelithiasis and its consequences.
  • Laboratory Report Analysis: Viewing a laboratory report, explain the values which indicate damage to the hepatobiliary system.
  • Pancreatitis Implications: Infer the consequences of pancreatitis or pancreatic cancer from normal exocrine pancreatic function.

FUNCTIONS OF THE LIVER

  • Production of Bile Salts: Essential for fat digestion and absorption.
  • Elimination of Bilirubin: Byproduct of red blood cell breakdown, crucial for maintaining normal jaundice levels.
  • Metabolism of Steroid Hormones: Alters steroid hormones and regulates their availability in the body.
  • Carbohydrate Metabolism: Controls blood sugar levels through glycogen storage and glucose metabolism.
  • Drug Metabolism: Modifies drugs for excretion; influences drug efficacy.
  • Fat Metabolism: Breaks down fats for energy storage and use; involved in cholesterol production.
  • Protein Metabolism: Synthesis of amino acids and enzymes; influences nitrogen balance.

HEPATOBILIARY FUNCTION TESTS

  • Alanine Aminotransferase (ALT):
      - Found predominantly in the liver.
      - More specific for liver inflammation.
  • Aspartate Aminotransferase (AST):
      - Found in liver, heart, and muscles.
      - May be elevated in diseases affecting other organs.
  • Serum Protein Levels: Assessment of liver’s production capability.
  • Prothrombin Time:
      - Measures blood clotting ability, indicative of liver function.
      - Vitamin K-dependent factors (II, VII, IX, and X).
  • Serum Bilirubin: Levels indicate liver’s ability to eliminate bilirubin.
  • Glutamyltransferase (GGT):
      - Indicator of hepatobiliary disease.
      - Helpful in diagnosing alcohol abuse.
  • Alkaline Phosphatase: Reflects bile duct function; elevated levels indicate cholestasis.

VIRAL HEPATITIS

  • Classification: Hepatotropic Viruses, Autoimmune Mechanisms, Reactions to Drugs/Toxins, Secondary to other systemic disorders.
      - Important viruses include Epstein-Barr, Cytomegalovirus, Enteroviruses.
Etiology & Pathophysiology
  • Direct Cellular Injury: Caused by the pathogen and immune response during virus elimination.
  • Induction of Immune Responses:
      - Extent of necrosis and inflammation depends on the immune response effectiveness.
Clinical Manifestations
  • Prodrome: Abrupt or insidious onset with symptoms like malaise, myalgia, fatigue, anorexia, nausea, and vomiting.
  • Icterus:
      - Occurs 7 to 14 days after prodromal symptoms, characterized by tenderness, mild weight loss, and spider angiomas.
  • Recovery Phase: Return of appetite and disappearance of jaundice.

HEPATITIS A

  • Transmission: Fecal-oral route.
  • Etiology: Small unenveloped single-stranded RNA virus; replicates in the liver, excreted in bile, shed in stool.
  • Incubation Period: 14 – 28 days.
  • Clinical Manifestations: Abrupt onset of fever, malaise, nausea, anorexia, and abdominal pain lasting approximately 2 months.
  • Serologic Markers: Anti-HAV antibodies appear early in the disease.
  • Immunization: Available Hepatitis A Vaccine.

HEPATITIS B

  • Transmission: Through inoculation with infected blood or serum; can spread through oral or sexual contact.
  • Etiology: Double-stranded DNA virus; may lead to either acute or chronic hepatitis, cirrhosis, or a carrier state. Participates in the development of Hepatitis D.
  • Clinical Manifestations: Fatigue, decreased appetite, nausea/vomiting, abdominal pain, joint pain, clay-colored stools, dark urine. More serious health concern compared to Hepatitis A.
  • Serologic Markers: HBsAg, HBcAg, HBeAg; HBsAg is primarily measured.
  • Immunization: Available Hepatitis B Vaccine.

HEPATITIS C

  • Transmission: Inoculation with infected blood.
  • Etiology: Single-stranded RNA virus; incubation period ranges from 2 to 26 weeks.
  • Clinical Manifestations: Mostly asymptomatic, jaundice is uncommon.
  • Serologic Markers: Utilizes both antibody and viral tests for detection.
  • Immunization: No vaccine available.

HEPATITIS D

  • Transmission: Requires concurrent infection with Hepatitis B (presence of HBsAg); spread through inoculated blood or serum.
  • Etiology: Co-primary infection with acute Hepatitis B or superinfection on chronic hepatitis.
  • Serologic Markers: Anti-HDV.
  • Immunization: No vaccine available; primary prevention through Hepatitis B prevention.

HEPATITIS E

  • Transmission: Fecal-oral route.
  • Etiology: Unenveloped single-stranded RNA virus.
  • Clinical Manifestations: Similar to Hepatitis A; more severe in pregnant women.
  • Immunization: No immunization available.

INTRAHEPATIC BILIARY DISORDERS

PRIMARY BILIARY CIRRHOSIS
  • Description: Chronic liver disease characterized by autoimmune destruction of intralobar bile ducts causing cholestasis.
  • Clinical Manifestations: Insidious onset, progressive scarring and destruction of liver tissue, enlarged liver taking on a green hue, early symptoms of unexplained pruritus, weight loss, and fatigue; jaundice appears late.
  • Diagnosis & Treatment: Diagnosis requires 2 out of 3 signs/symptoms; treatment is symptomatic, with liver transplant for advanced disease.
SECONDARY BILIARY CIRRHOSIS
  • Causes: Prolonged obstruction of the extrabiliary tree; most commonly due to cholelithiasis.
  • Other Causes: Malignant neoplasms or surgical strictures.
  • Treatment: Aimed at relieving the obstruction.

NONALCOHOLIC FATTY LIVER DISEASE (NAFLD)

  • Description: Metabolic dysfunction affecting the liver; includes:
      - Simple Steatosis: Fatty infiltration of the liver.
      - Nonalcoholic Steatohepatitis: Steatosis with inflammation and hepatocyte necrosis; 10 - 25% may progress to cirrhosis.
  • Risk Factors: Include obesity, Type II diabetes and metabolic syndrome, hyperlipidemia, rapid weight loss, parental nutrition, and jejunoileal bypass.
  • Pathophysiology: Involves lipid accumulation in hepatocytes, formation of free radicals, inflammation, and fibrosis.
  • Clinical Manifestations: Typically asymptomatic, may show fatigue, discomfort in the right upper quadrant (RUQ), and mild/moderate elevation in AST and ALT levels.
  • Diagnosis: US, CT, MRI, biopsy.
  • Treatment: Dietary modification, promotion of exercise/weight loss, management of comorbidities, avoidance of alcohol.

CIRRHOSIS

  • Description: Transformation of normal liver architecture into nodules encircled by fibrosis, resulting in lost function of liver tissue; represents a balance of regenerative activity and constrictive scarring.
  • Clinical Manifestations: Include weight loss, weakness, anorexia, diarrhea, hepatomegaly, jaundice, portal hypertension, splenomegaly, portosystemic shunts, esophageal varices, hemorrhoids, caput medusae, bleeding, encephalopathy.

PORTAL HYPERTENSION

  • Definition: Increased resistance in the portal venous system with sustained portal vein pressure.
  • Etiology:
      - Prehepatic: Obstruction of the portal vein before it enters the liver (thrombosis or cancer/lymph node compression).
      - Intrahepatic: Obstruction within the liver (commonly due to cirrhosis).
      - Posthepatic: Obstruction of blood flow through the hepatic veins beyond the liver (thrombosis, veno-occlusive disease, severe right-sided heart failure).

LIVER FAILURE

  • Disorders of synthesis and storage functions: Affects glucose, proteins, lipoproteins, cholesterol, and bile salts leading to hypoglycemic events, hypoalbuminemia, edema/ascites, and decreased coagulation factors.
      - Consequences in this domain include: Bleeding, fatty stools, drug interactions, hyperbilirubinemia, encephalopathy, increased aldosterone levels, increased androgens/estrogens, jaundice, edema/ascites, gynecomastia and testicular atrophy in men, and menstrual irregularities in women.

CHOLELITHIASIS

  • Definition: Presence of gallstones in the gallbladder due to precipitation of bile, mainly cholesterol and bilirubin.
  • Etiology: Abnormalities in bile composition, increased cholesterol, and stasis of bile.
  • Risk Factors: Include female gender, obesity, genetic predisposition, Type II diabetes, multipara, oral contraceptive use, and rapid weight loss.

CHOLECYSTITIS

Acute Cholecystitis
  • Description: Diffuse inflammation of the gallbladder due to obstruction of gallbladder outlet.
  • Clinical Manifestations: Sharp RUQ pain, mild fever, nausea/vomiting, Murphy’s Sign (pain on deep inspiration during right subcostal palpation), elevated WBC, mildly elevated AST, ALT, and bilirubin.
Chronic Cholecystitis
  • Description: Results from repeated episodes of acute cholecystitis or chronic irritation by gallstones.

ACUTE PANCREATITIS

  • Definition: Inflammatory process due to inappropriately activated pancreatic enzymes autodigesting the pancreas.
  • Severity: Damage can range from mild to necrotizing hemorrhagic pancreatitis.
  • Etiology: Causes include biliary tract obstruction, gallstones, pancreatic duct obstruction, and alcohol abuse.
  • Clinical Manifestations: Abdominal pain in the epigastric/periumbilical region, fever, tachycardia, hypotension, abdominal tenderness, nausea/vomiting, and elevated WBC, lipase, and amylase; possible elevated AST, ALT, and bilirubin.
  • Diagnosis: Must have 2 out of 3 criteria: abdominal pain characteristic of acute pancreatitis, serum amylase/lipase 3 times the upper normal limit, and radiologic imaging consistent with pancreatitis.

CHRONIC PANCREATITIS

  • Definition: Progressive destruction of the exocrine pancreas by fibrosis; in later stages, endocrine pancreas may be destroyed.
  • Etiology: Similar to that of acute pancreatitis, including biliary tract obstruction, gallstones, pancreatic duct obstruction, alcohol abuse, and neoplasms.
  • Clinical Manifestations: Similar to acute but less severe; abdominal pain (epigastric/periumbilical), fever, tachycardia, hypotension, abdominal tenderness, nausea/vomiting, anorexia; elevated WBC, lipase, amylase (may not be extremely elevated).

PANCREATIC CANCER

  • Overview: Early-stage pancreatic cancer usually presents no symptoms and spreads quickly.
  • Etiology: Cause is unknown.
  • Risk Factors: Include age, smoking, alcohol use, obesity, diabetes, male gender, chronic pancreatitis, and genetic factors.
  • Clinical Manifestations: Dull epigastric and back pain exacerbated while lying supine, jaundice, fatigue, anorexia, nausea/vomiting, pruritus.
  • Diagnosis: Health history and physical examination (H&P), elevated bilirubin, US/CT imaging.
  • Treatment Options: Surgical intervention, radiation therapy, chemotherapy, and pain control.

QUESTIONS?

  • This section is left for any additional inquiries regarding the topics covered in the study notes.