HBV is an infectious virus that invades the liver and consequently causes inflammation of the predominant cells forming said liver, the hepatocytes.
This infection could be acute or chronic.
Routes of infection:
A person could be infected through contact with infected body fluids as saliva, blood, semen and vaginal secretions.
We deduct from the later that risk factors for the acquisition of HBV would include:
Intravenous drug use | Tattoos/acupuncture needles |
Needlestick injury | Infected unscreened blood products |
Intercourse | Vertical transmission from an infected mother to newborn at birth |
Sharing a razor/toothbrush | Sharing medical equipment (glucometer) |
A person infected with HBV would experience vague and non-specific manifestations as:
Headache, myalgia (muscle pain), arthralgia (joint pain), nausea, anorexia, vomiting, diarrhea, abdominal discomfort, dark urine, pale stool, jaundice and tender liver.
Diagnosis of HBV usually starts by carrying out liver function tests.
The liver function tests typically include alanine transaminase (ALT) and aspartate transaminase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), serum bilirubin, prothrombin time (PT), the international normalized ratio (INR), total protein and albumin. These tests pinpoint the source of liver damage, thus in viral hepatitis we'd find ALT and AST (ALT predominantly) far more elevated than ALP.
Consequently, other serological tests will be carried out to diagnose HBV by searching for HBV antigens, antibodies and measuring the viral load using PCR technique.
Once the diagnosis has been confirmed, management will differ according to the period of infection. If it has lasted for less than 6 months, then it'll be considered as an acute infection. While if it has persisted for more than 6 months, then it'll be considered as a chronic infection.
Management in case of acute HBV infection:
Full spontaneous recovery occurs in more than 95% of adults by the means of supportive measures as bed rest, a nutritious diet and fluid intake; in addition to monitoring for acute liver failure. While antiviral therapy is considered in patients with severe liver injury with coagulopathy (INR >1.5) or in patients with a protracted course with symptoms persisting for more than 4 weeks.
Management in case of chronic HBV infection:
Spontaneous clearance after 6 months is uncommon, hence the use of antiviral drugs and drugs that would augment the host immune responses. On the other hand, liver transplantation could also be a mean of therapy in chronic HBV in advanced stages.
Complications of chronic HBV include cirrhosis, liver failure and/or hepatocellular carcinoma (HCC) in up to 40% of patients.
On that account, prevention is of utmost importance.
Prevention from HBV is achieved through vaccination. It's the most effective mean of preventing HBV infection as it offers >95% protection in normal individuals; typically given in a three-dose series. It's also highly effective if given as postexposure immunoprophylaxis to prevent perinatal transmission.
Unfortunately, vaccination is ineffective in those already infected by HBV, nevertheless intramuscular injection of specific hepatitis B antibody can minimize the infection provided being administered within 48 hours to 1 week after exposure.
References:
Lala V, Zubair M, Minter DA. Liver Function Tests. [Updated 2023 Jul 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
Wright, Teresa L. M.D.. Introduction to Chronic Hepatitis B Infection. American Journal of Gastroenterology 101():p S1-S6, January 2006.
Colin W. Shepard, Edgar P. Simard, Lyn Finelli, Anthony E. Fiore, Beth P. Bell, Hepatitis B Virus Infection: Epidemiology and Vaccination, Epidemiologic Reviews, Volume 28, Issue 1, August 2006, Pages 112–125, https://doi.org/10.1093/epirev/mxj009.
Davidson's Principles and Practice of Medicine textbook. Assessed and Endorsed by the MedReport Medical Review Board