Liver disease Hepatitis

Viral Hepatitis Overview

• Viral hepatitis is a viral infection of the liver
• Hepatitis viruses A, B, C, D, and E exist
• Hepatitis A, B, and C are most relevant to dentistry

Hepatitis A

• Caused by the hepatitis A virus
• Transmitted through the faeco-oral route (contaminated food/water)
• Common in areas with poor sanitation
• Symptoms typically last a few months
• No specific treatment, only symptom relief

Hepatitis B

• Caused by the hepatitis B virus
• Common worldwide infection
• Spreads through blood, from infected mothers to babies, unprotected sex, sharing needles, razors, or toothbrushes
• 5% develop chronic hepatitis B
• Some develop cirrhosis or liver cancer
• Can persist in children, causing significant liver damage
• 90% of infected babies develop chronic hepatitis
• Vaccination for all healthcare workers, added to child immunisation list since 2017
• High concentration in blood, serum, and wound exudates
• Moderate concentration in semen, vaginal fluid, saliva
• Low/undetectable concentration in urine, faeces, sweat, tears, breast milk
• Very infectious, can survive outside the human body for up to 7 days
• Not spread by hugging, kissing, or sharing eating utensils

Hepatitis B Pathogenesis

• Incubation period: 45 to 180 days (average 60 days)
• Virus enters hepatocytes via the bloodstream
• Immune response to viral antigens on hepatocyte surfaces is responsible for clinical syndrome
• 5% become chronic carriers, at higher risk of hepatocellular carcinoma
• Hepatitis B surface antibody likely provides life-long immunity

Hepatitis B Symptoms

• May be asymptomatic
• Symptoms (if present) appear 2-3 months post-exposure
• Symptoms can include: tiredness, fever, general aches, loss of appetite, nausea, diarrhea, stomach pain, and jaundice
• Acute Hepatitis B symptoms usually resolve within 1-3 months
• Chronic Hepatitis B can last for 6 months or longer

Hepatitis B Diagnosis

• Blood tests (serological tests) are used
• Hepatitis B antigens indicate infection
• Hepatitis B antibodies indicate recovery/immunity
• Virus can persist at low levels even after recovery
• Reactivation can occur, particularly if the immune system is compromised

Hepatitis B Treatment

• Emergency treatment following exposure: Hep B vaccination & immunoglobulin
• Acute Hepatitis B: Rest, analgesia, and symptom relief (e.g., metoclopramide for nausea)
• Chronic Hepatitis B: Peginterferon alfa-2a (stimulates immune system to attack virus) and antiviral medications (e.g., tenofovir, entecavir)

Hepatitis B Prevention

• Vaccination for those at increased risk of HBV infection (3 doses: month 0, 1, 6)
• Good immune response (50% after 1 dose, 95% after 3 doses) with lasting protection (>15 years) depending on initial antibody response
• Hepatitis B immunoglobulin (to protect exposed people) within 48 hours post-exposure
• Screening of blood donors, blood and body fluid precautions

Hepatitis C

• Single-stranded RNA virus
• Similar pathogenesis, symptoms, and transmission routes as hepatitis B
• Occupational transmission risk, including needlestick injury and blood splash to eye
• No vaccine exists
• Long-term complications can include cirrhosis, liver failure, and liver cancer
• Treated with direct-acting antiviral medications (e.g., ribavirin, simeprevir, sofosbuvir) for 8-12 weeks

Hepatitis D & E

• Hepatitis D: Delta virus; only infects those with Hepatitis B; chronic infections can lead to cirrhosis, and liver cancer; spread via bodily fluids, including IV drug users;. Vaccine available
• Hepatitis E: RNA virus; similar transmission to Hepatitis A (facaelo-oral); no vaccine

Hepatitis B Important Notes

• Hepatitis B carriers pose a definite mortality risk and should be treated as potential disease carriers
• Healthcare professionals should be immunized and adhere to universal precautions
• Always wear appropriate personal protective equipment (PPE) to prevent saliva from entering the eye.
• Always avoid needlestick injuries, and report them immediately to the correct authorities if they occur