Mod 3 Lecture 2 FULL DX of Hepatobiliary System

Conditions Affecting the Gastrointestinal System and Pharmacotherapy

Intellectual Property Notice

  • Course Title: NURS 282/432 – Pathophysiology & Pharmacology II

  • References:

    • Lehne’s 11th edition, Chapter 83, Page 981

    • Huether & McCance, Chapter 38, Pages 896-906

    • Chapter 37 Anatomy 1

Learning Objectives

  • Liver Anatomy and Physiology (A&P)

  • Cirrhosis

  • Hepatitis

  • Prevention and Treatment Strategies

  • Gallbladder Anatomy and Physiology

  • Cholelithiasis (Gallstones)

  • Bile Acids

  • Pancreas Anatomy and Physiology

  • Pancreatitis

  • Pancreatic Enzyme Deficiency

  • Pancrealipase

Liver Anatomy and Physiology

Hepatobiliary System

  • Ducts: Common hepatic duct, right and left hepatic ducts

Case Study: Martin (46-year-old male)

Medical History

  • Chronic Conditions: Chronic alcoholism, IV drug use

  • Medical Interventions: Appendectomy with blood transfusions 30 years ago

  • Current Symptoms:

    • Abdominal swelling

    • Confusion and unintentional weight gain (15 lbs in 4 weeks)

Symptoms Described by Family

  • Behavioral Changes: Confusion, unfamiliarity with his wife

  • Alcohol Consumption: Approximately 6-pack of beer per day

  • Infidelity: Involvement with other women

Physical Examination (PE)

  • Abdomen: Distended, firm, slightly tender

  • Signs:

    • Prominent veins around umbilicus

    • Hepatosplenomegaly

  • Skin: Slightly jaundiced

Laboratory Test Results at Admission

  • Increased Leukocytes: 15,000 per microliter

  • Elevated Ammonia: 250 ug/dL

  • Bilirubin: 2.4 mg/dL

  • Liver Enzymes:

    • AST: 107 IU/L

    • ALT: 86 IU/L

    • Alkaline Phosphatase: 224 IU/L

  • Hepatitis Markers:

    • HBsAg (+),

    • HBsAb (-),

    • HBcAb (+),

    • HCV RNA (-)

  • Albumin: 2.7 g/dL (Normal: 3.5-5 g/dL)

  • Prothrombin Time: 16s (Normal: 10-13s)

Clinical Questions

  1. Sudden Progression of Cirrhosis: Discuss lab implications.

  2. Contributing Risk Factors: Identify factors related to Martin's condition.

  3. Pathophysiology of Weight Gain: Explain mechanisms involved.

  4. Hepatic Encephalopathy Diagnosis: Identify lab tests and expected medication administration.

Liver Anatomy & Key Functions

Locations

  • Position: Upper right quadrant of the abdomen, under diaphragm

Structure

  • Capsule: Large fibrous capsule organized by falciform ligament into right and left lobes

Ducts

  • Duct System: Right & left hepatic ducts lead to common hepatic duct for bile drainage

Functional Unit

  • Hepatocytes: Liver cells organized into lobules, capable of regeneration

Blood Supply to Liver

  • Hepatic Artery: Carries oxygenated blood (~400-500 mL/min, 25% total blood flow)

  • Hepatic Portal Vein: Drains deoxygenated blood from intestines (~1,000-1,500 mL/min, 75% total blood flow)

  • Hepatic Vein: Drains blood into inferior vena cava

Bile Production and Function

Production

  • Source: Produced by hepatocytes (700-1200 ml/day)

    • Contents: Water, bile salts, bilirubin, cholesterol, electrolytes (HCO3)

Functions

  • Digestion: Emulsification of fats, fat-soluble vitamins absorption

Enterohepatic Circulation of Bile Salts

  • Formation: Bile salts from cholesterol facilitate fat digestion

  • Lipid-lowering Agents: Mention cholesterol absorption inhibitors and bile-acid sequestrants such as Ezetimibe, colesevelam

Gallstones (Cholelithiasis)

Composition

  • Cholesterol: Most common type; pigment stones from excess bilirubin

Pathophysiology

  • Form from cholesterol precipitation in bile due to delayed GB emptying

Symptoms

  • Biliary colic, RUQ pain post fatty meals, abdominal distension, jaundice

Primary Roles of the Liver

  • Storage: Blood, vitamins, glycogen

  • Synthesis: Clotting factors (prothrombin) and albumin

  • Detoxification: Removal of toxins, drugs, waste products

  • Metabolism: Carbohydrates, protein, and fat regulation

  • Bile Production: Essential for fat digestion

Common Labs in Hepatic Function

Liver Function Tests (LFTs)

  • AST & ALT: Indicators of liver cell injury

  • ALP: Indicates biliary obstruction

  • Bilirubin: Evaluates liver's metabolic function

  • Albumin: Measures protein synthesis ability

  • Prothrombin Time: Clotting cascade function indicator

  • Ammonia: Elevated due to inability to convert to urea in liver disease

Hepatitis Overview

  • Definition: Inflammation of the liver, treatable/manageable

Types and Causes

  • Viral: Hepatitis A, B, C, D, E

  • Non-Viral: Alcohol, toxins, medications, autoimmune disease

  • Chronic Hepatitis: Lasting over 6 months, primarily caused by B and C

Pathophysiology of Viral Hepatitis

  • Mechanism: Viral infection triggers immune response against hepatocytes leading to inflammation and damage.

Strains of Hepatitis Virus

Transmission and Vaccine Availability

  • HAV: Fecal-oral, vaccine available

  • HBV: Blood/body fluids, vaccine available

  • HCV: Blood, no vaccine; treatment improves prognosis

Severity and Complications

  • Risk of cirrhosis and liver cancer associated with chronic viral hepatitis.

Clinical Presentation of Hepatitis

Stages

  1. Preicteric: Fatigue, malaise, nausea, fever

  2. Icteric: Jaundice, dark urine, high bilirubin levels

  3. Posticteric/Recovery: Symptoms resolve, liver function improves

Diagnosis of Hepatitis

Hepatitis B Panel Tests

  1. HBsAg: Indicates current infection

  2. HBsAb: Indicates immunity; protection against reinfection

  3. HBcAb: Indicates previous infection

Pharmacotherapy for Prevention of Hep A & Hep B

Vaccination Strategies

  • Hep A: Vaccination for children and high-risk adults

  • Hep B: Vaccination for infants and individuals at risk, such as healthcare workers.

Treatment for Hepatitis C

  • Screening: Antibodies and RNA quantification for diagnosis and viral load assessment.

  • Antivirals: Used for treatment of Hepatitis C infections.

Overview of Cirrhosis

  • Definition: Irreversible scarring of the liver, interruption of function.

Causes

  • Alcohol abuse, gallstones, hepatitis, toxic exposure

Cirrhosis Pathogenesis and Complications

  • Portal Hypertension: Increased pressure leading to esophageal varices.

  • Liver Insufficiency: Impaired detoxification and protein synthesis, leading to toxins accumulation.

Ascites in Cirrhosis

  • Mechanism: Fluid accumulation in the peritoneal cavity due to portal hypertension and reduced albumin production.

Pharmacological Treatment for Cirrhosis

  • Medications: Diuretics, vitamin K, anti-emetics, and lactulose for ammonia reduction.

Overview of Pancreas A&P

Functions

  • Exocrine: Digestive enzyme secretion

  • Endocrine: Insulin and glucagon production

Pathophysiology of Acute Pancreatitis

Causes and Mechanism

  • Precipitating Factors: Alcohol, gallstones lead to enzyme activation inside the ducts, causing tissue autodigestion and inflammation.

Management of Pancreatitis

  • Monitoring: Vital signs, input/output; dietary management, hydration; pharmacological support.

Pancreatic Enzyme Deficiency

Treatment Overview

  • Pancrelipase (Creon): Used for digestion enhancement in patients with chronic pancreatitis and pancreatic cancer; consideration of side effects and dosage.

Question Reference

  • Trigger for Tissue Damage: Identify the role of backup of pancreatic enzymes in pancreatitis.