Acute Hepatitis

Categorization and Differentiation of Liver Diseases

  • Liver conditions are definitively diagnosed using specific lab tests and differentiating signs and symptoms.
  • Acute hepatitis is categorized as a condition lasting less than 66 months, usually followed by resolution and the return of liver function tests to normal within that window.
  • Chronic hepatitis is defined as a condition persisting for greater than 66 months.
  • Identifying chronic conditions is critical because they confer an increased risk for both cirrhosis and hepatocellular carcinoma.

Acute Viral Hepatitis

  • Viral causes, specifically Hepatitis A, B, and C, are the most common causes of acute hepatitis.
  • Other infectious causes include Infectious Mononucleosis (EBV), CMV (Cytomegalovirus), and Herpes Simplex virus.
  • Bacterial and parasitic infections can also cause acute hepatitis.
  • Acute viral hepatitis involves four distinct phases:
    • Phase 1: Incubation: The virus multiplies and spreads; the patient is asymptomatic. The duration varies by the specific viral type.
    • Phase 2: Prodromal (Pre-icteric) Phase: The patient is symptomatic but generally not jaundiced. Symptoms include anorexia, malaise, nausea, vomiting, and right upper quadrant pain. Smokers may develop a new distaste for cigarettes. In some cases, urticaria (hives) and arthralgia (joint pain) occur, which are unique indicators for Hepatitis B. Liver function tests begin to elevate during this phase.
    • Phase 3: Icteric Phase: Occurs approximately 33 to 1010 days after the prodromal phase starts. Jaundice appears. Bilirubinuria (specifically hyperbilirubinuria) occurs and can be detected in the urine before blood bilirubin levels are significantly elevated.
    • Phase 4: Recovery: Jaundice usually begins to subside after 22 to 44 weeks, and the patient recovers unless the condition progresses to a chronic form.

Laboratory Findings in Acute Viral Hepatitis

  • Significant increases are seen in Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST). Typically, ALT increases more significantly than AST.
  • Example of enzyme ratio: A 5+5+ increase in ALT and a 3+3+ increase in AST suggests acute viral hepatitis.
  • Other liver enzymes (ALP, GGT) are typically mildly to moderately elevated.
  • Bilirubin in the urine often precedes clinical jaundice.
  • Hyperbilirubinemia is mixed, meaning both conjugated and unconjugated fractions may be elevated depending on individual severity.
  • Urine urobilinogen is positive.
  • Cholesterol and lipoprotein levels are variable based on the viral type, timing, and severity.
  • CBC (Complete Blood Count) findings typically include leukopenia with lymphocytosis, characteristic of a viral infection.

Hepatitis A Virus (HAV)

  • Transmission: Spread via the fecal-oral route, often through contaminated water or poor hygiene in food handling.
  • Clinical Presentation: Young children (under age 66) are often asymptomatic. Adults usually experience fairly severe symptoms, matching the classic viral hepatitis progression.
  • Prognosis: Hepatitis A usually resolves spontaneously; treatment is purely supportive.
  • Serology:
    • Initial testing for hepatitis often includes five specific markers to differentiate subtypes A, B, and C.
    • Positive HAV antibody requires follow-up for IgM and IgG.
    • Hepatitis A Virus IgM (HAV-IgM\text{HAV-IgM}): Indicates acute infection; elevates early alongside ALT.
    • Hepatitis A Virus IgG (HAV-IgG\text{HAV-IgG}): Indicates a recovered or past infection; remains elevated long-term.

Hepatitis B Virus (HBV)

  • Transmission: Transmitted parenterally through needles, blood, sexual intercourse, and other bodily fluids.
  • Chronic Progression: Approximately 5%5\% to 10%10\% of acute cases become chronic.
  • Differentiating Features: Unique symptoms include urticaria (hives) and arthralgia (joint pain).
  • Serological Markers and Interpretation:
    • HBsAg (Hepatitis B Surface Antigen): Positive in acute and chronic infections.
    • Anti-HBs (Hepatitis B Surface Antibody): Indicates immunity (through recovery or vaccination). Negative in acute and chronic stages.
    • IgM Anti-HBc (IgM Antibody to the Core): Positive in acute infection; one of the first immunoglobulins to appear.
    • IgG Anti-HBc (IgG Antibody to the Core): Negative in acute infection; positive in chronic infection or prior recovery.
    • Acute HBV Profile: Positive HBsAg, positive IgM Anti-HBc, negative Anti-HBs, negative IgG Anti-HBc.
    • Chronic HBV Profile: Positive HBsAg, positive IgG Anti-HBc, negative Anti-HBs, negative IgM Anti-HBc.
    • Prior Infection/Vaccination Profile: Negative HBsAg, positive core antibody (specifically IgG for prior infection), and variable Anti-HBs findings.

Hepatitis C Virus (HCV)

  • Transmission: Transmitted parenterally through blood and bodily fluids.
  • Chronic Progression: High likelihood of becoming chronic, with approximately a 75%75\% chance of progression.
  • Serology: Uses Anti-HCV antibody test and HCV RNA test. These tests do not differentiate between acute and chronic stages.
  • Management: There is no vaccination for Hepatitis C. Antiviral medications are used to attempt to avoid a chronic course.

Chronic Hepatitis Overview

  • Causes include Hepatitis B and C, Nonalcoholic Steatohepatitis (NASH), alcoholic hepatitis, drug-induced liver disease, and autoimmune conditions.
  • Patients may not have a history of acute hepatitis; the initial indication is often an incidental finding of abnormal ALT and AST levels.
  • Symptoms are often mild, minimal, or vague, including malaise, anorexia, fatigue, low-grade fever, and nonspecific upper abdominal pain. Jaundice is rare in chronic phases.
  • Increased risk for cirrhosis and primary hepatocellular carcinoma.
  • Enzyme elevations (ALT and AST) are less notable than in acute conditions because fibrosis replaces hepatocytes. Values are often in the 200200 to 300300 range or even more mildly elevated.
  • Bilirubin is typically normal until the disease is very advanced.

Nonalcoholic Fatty Liver Disease (NAFLD) and NASH

  • NAFLD: Involves the accumulation of lipids in hepatocytes. Patients are usually asymptomatic, and liver function panels may be normal or show mild alterations in ALT and AST.
  • NASH (Nonalcoholic Steatohepatitis): A progression of NAFLD where lipid deposition leads to diffuse inflammation, cell damage, and eventually fibrosis.
  • Risk Factors: Metabolic syndrome, type 22 diabetes, insulin resistance, elevated triglycerides, low HDL, and being overweight or obese.
  • Differentiation from Alcohol-Related Disease: Attributed to nonalcoholic causes if alcohol intake is less than 2121 standard drinks per week for males or 1414 standard drinks per week for females.
  • Diagnosis: Often diagnosed based on risk factors and labs. To definitively differentiate NAFLD from NASH, a liver biopsy is required to identify signs of active inflammation.

Alcohol-Related Liver Disease

  • Hepatic Steatosis (Alcoholic Fatty Liver Disease): The precursor caused by alcohol. Often asymptomatic. GGT may be notably elevated even if ALT and AST are mild.
  • Alcoholic Hepatitis (Alcoholic Liver Disease): Inflammation arising from continued alcohol consumption. It typically takes about 1010 years of abuse to reach this stage.
  • Signs/Symptoms: More severe than other chronic types; includes fever, jaundice, fatigue, right upper quadrant pain, and tender hepatomegaly.
  • Laboratory Findings:
    • Increased WBC count (leukocytosis) indicates active inflammation, helping differentiate it from cirrhosis.
    • Anemia is common, often macrocytic due to impaired storage/packaging of B12 and folate in the liver.
    • AST is more notable than ALT. This is because ALT synthesis relies on Vitamin B6, which is also impaired in chronic alcoholic liver disease.
    • Slight increase in ALP; increased serum bilirubin.
    • Decreased serum albumin due to impaired synthesis and potential malabsorption.
    • Increased serum globulin due to inflammation.
    • Increased Prothrombin Time (PT) due to impaired synthesis of clotting factors and malabsorption of fat-soluble Vitamin K.
    • Significantly increased GGT.
  • Management: Immediate cessation of alcohol intake.

Autoimmune Hepatitis

  • Often associated with other autoimmune conditions (e.g., thyroid complaints, joint pain, digestive issues, acne, amenorrhea).
  • Symptoms are vague and mild but may fluctuate in severity.
  • Differentiating Lab Test: The anti-smooth muscle antibody (ASMA) test is typically positive.

Cirrhosis

  • Etiologies: Alcohol (most common but being caught by NASH), chronic Hepatitis B/C, and prolonged cholestasis.
  • Pathology: Significant scar tissue and fibrosis of the liver.
  • Signs/Symptoms: Weakness, anorexia, malaise, weight loss. Peripheral neuropathies (from B12 deficiency) and glossitis are common in alcoholic patients.
  • Portal Hypertension Sequelae: Ascites (fluid in the abdomen), esophageal varices, and kidney damage.
  • Malabsorption: Due to bile production issues, fat-soluble vitamin absorption is impaired. Lack of Vitamin K exacerbates clotting issues and GI bleeds.
  • Hormonal Imbalance: The liver fails to process hormones, leading to gynecomastia in males and hirsutism in females. Muscle breakdown and hair loss may also occur.
  • Physical Exam: The liver feels palpable and quite firm, rather than just enlarged.
  • Laboratory Findings in Cirrhosis:
    • Enzymes (ALT/AST) show minimal increases because there are fewer viable hepatocytes to produce them.
    • AST is slightly higher than ALT.
    • Urine bilirubin increased; serum albumin significantly decreased; serum cholesterol decreased.
    • WBC count is typically normal (helps differentiate from active alcoholic hepatitis).
    • Anemia (often macrocytic) and thrombocytopenia are common.
  • Diagnosis and Prognosis: Definitive diagnosis via liver biopsy. Prognosis is generally poor.

Liver Cancer (Carcinoma)

Primary Hepatocellular Carcinoma (HCC)
  • Often a consequence of cirrhosis or chronic hepatitis.
  • Symptoms: Frequently asymptomatic early. Later symptoms include upper abdominal pain, weight loss, a palpable right upper quadrant mass, and fever.
  • Laboratory Findings:
    • Alpha-fetoprotein (AFP) is significantly elevated.
    • Bilirubin typically remains normal until very late stages (80−90%80-90\% of liver destroyed).
    • Liver enzymes (ALT, AST, ALP) are highly variable.
  • Management: High-risk AFP levels warrant imaging (Ultrasound, MRI, or contrast-enhanced CT).
Metastatic Carcinoma
  • Common primary sites that metastasize to the liver include the GI tract, breast, lung, and pancreas.
  • Symptoms: "Red flag" symptoms like weight loss, anorexia, fever, and hepatomegaly.
  • Laboratory Findings: Elevations in ALP, GGT, and LDH are common. ALT and AST findings are variable. Bilirubin is usually normal until late stages.

Primary Biliary Cholangitis (PBC) and Cholestasis

  • Primary Biliary Cholangitis: Inflammation of small bile ducts within the liver, leading to prolonged cholestasis, cirrhosis, and potential liver failure.
  • Symptoms of Cholestasis: Itching (pruritus due to bile salt dissociation), mild jaundice, steatorrhea (fatty stool), and pale stools.
  • Types of Cholestasis:
    • Intrahepatic: Occurs within the liver (less common).
    • Extrahepatic: Most common; caused by stones (cholelithiasis), head of pancreas cancer, common bile duct strictures, or pancreatitis.
  • Cholecystitis: Inflammation often caused by cholelithiasis-induced blockage.
    • Physical Exam: Right upper quadrant pain referring to the right shoulder; Murphy’s inspiratory sign (tenderness to palpation in the RUQ). Guarding and fever/leukocytosis with neutrophils are common.
    • Cholestasis/Cholecystitis Lab Findings:
      • Significantly increased ALP and GGT (elevations "hold hands").
      • Serum cholesterol: Acute (300−400 mg/dL300-400\,mg/dL); Chronic (700−800 mg/dL700-800\,mg/dL).
      • Bilirubin: Jaundice occurs when levels exceed 2.5 mg/dL2.5\,mg/dL. Extrahepatic blocks cause significant increases in conjugated (direct) bilirubin.
      • AST and ALT are very minimally increased.
    • Management: Refer for abdominal ultrasound. Supplementation of fat-soluble nutrients may be attempted but is limited by the lack of bile flow.