Hepatitis in general is an inflammation of the liver which can either be self-limiting or proceeds to fibrosis or scarring, liver cirrhosis or malignancy.
As far as the etiology is concerned, Hepatitis viruses are known to be the commonest causes of hepatitis. But certain other primary infections, alcohol, medication and autoimmune diseases can contribute to the condition.
There are 5 main types of hepatitis viruses, identified as A, B, C, D and E. These viruses have a significant potential of leading to outbreaks and spreading an epidemic. In fact, types B and C have a high risk of causing the chronic type of this liver disease, which is the commonest cause, so far identified with the development of liver cirrhosis and cancer, later in life.
Even though all these viruses can give rise to Hepatitis in general, each condition caused by each type of virus will differ in the aspects of pathology, clinical features and treatment. Through this article we are going to discuss them separately, focusing more on A, B, C and D types of hepatitis and how they can be distinguished from one another, mainly for the purposes of diagnosis and treatment.
Hepatitis A viral infection is transmitted from one person to another, faeco-orally, which is by consuming food and water contaminated with faeces containing this particular virus (HAV). Moreover, certain unprotected sexual practices are also known to increase the spread HAV in general. A higher incidence can be seen in developing countries mainly with poor hygiene and sanitation measures. However, the World Health Organization has taken many measures in order to reduce this rate of affected individuals, by introducing various protocols and vaccines, efficacious mainly in controlling the transmission of the virus.
The incubation period of hepatitis A is around 2–4 weeks.
Patients will present with fever, malaise, loss of appetite, loose stools, nausea, abdominal discomfort, dark-colour urine and jaundice.
Infections caused this way are usually mild to moderate in severity, where most affected individuals will reach a full recovery and acquire a lifelong immunity for further HAV infections. Rarely, HAV infections can become severe, particularly in patients who are immune-compromised and result in a life threatening condition. It’s important to know that infections caused by hepatitis A aren’t easy to be distinguished clinically from other types of acute viral hepatitis. However, an accurate diagnosis is usually made by doing an antibody test which will show HAV-specific Immunoglobulin G (IgM) antibodies in the blood.
Furthermore, a reverse transcriptase polymerase chain reaction (RT-PCR) can be used to detect the hepatitis A virus RNA, but it requires advanced laboratory techniques. While there is no specific treatment for hepatitis A, the infection will gradually resolve on its own. Patients should be supplied with fluids to prevent episodes of dehydration. People should be made aware of safe water supply, food safety, improved sanitation and proper hand washing techniques in order to prevent themselves from this infection.
Caused by Hepatitis B virus which is mainly transmitted through infected blood, blood products, semen, body fluids, from infected mothers to infants at the time of birth or from an infected family member to an infant during the early childhood. Invasive medical procedures and blood transfusions are the main routes of introducing infected blood and body fluids to individuals at risk.
Most affected individuals wont show any symptoms during the acute infection, whereas some may be present with signs of Jaundice, dark urine, lethargy, fatigue, nausea, vomiting and abdominal pain.
A rare entity of patients with acute hepatitis might end up with acute liver failure or death if proper treatments aren’t administered on time.
In the case of some people, the hepatitis B virus can also lead to a chronic liver infection that can later develop into cirrhosis of the liver or liver cancer.
Even though there are no specific treatments for acute hepatitis B, a proper management should be carried out to provide an adequate nutritional balance and fluid replacement. Oral antiviral drugs can be used regarding patients with chronic hepatitis B infection which could reduce the progression of cirrhosis, incidence of liver cancer and improve the quality of life. Vaccines against Hepatitis B virus are currently available to prevent related infections.
This virus is usually transmitted through the exposure to blood and blood products contaminated with Hepatitis C virus. Similar to Hepatitis B virus, this can take place by blood and blood products transfusions, contaminated injections during invasive medical procedures rarely through unprotected sexual intercourse. A higher risk can be present in intravenous drug users and so far there hasn’t been any vaccine introduced against HCV.
Patients usually present with fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, joint pain and signs of jaundice. Screening for anti-HCV antibodies with a serological test is helpful in identifying patients who have been infected previously with this infection where as a chronic infection could only be diagnosed by a nucleic acid test for HCV ribonucleic acid (RNA).
Antiviral medicines are used in most affected patients which is known to be effective in 90% of persons with hepatitis C infection.
The most special feature of this infection is, it only occurs in patients who have already been infected by Hepatitis B Virus, which is known as Super infection. In fact, this combined dual infection of HDV and HBV can give rise to a more serious disease with a high rate of morbidity. Even though, no effective antiviral treatment has been introduced to treat hepatitis D, so far (except for Pegylated interferon alpha which is not widely been used), a Hepatitis B vaccine is available with a protection against Hepatitis D virus.
How to differentiate these 4 types?
Spread of the disease- Hepatitis A virus characteristically spreads through the ingestion of contaminated food and water whereas Hepatitis B, C and D usually take place due to parenteral contact with contaminated body fluids like blood (blood and blood product transfusions, invasive medical procedures). Furthermore, Hepatitis B can get transmitted from an infected mother to baby at birth due to possible mixing of blood and also by unprotected sexual intercourse.
Natural history- Hepatitis A virus usually results in an acute inflammation of the liver (hepatitis) which will resolve on its own whereas Hepatitis B virus (HBV) can either be acute (short-term illness) or chronic (ongoing illness) and Hepatitis C virus (HCV) only has a chronic natural history. Hepatitis D will usually infect people, who have already got infected by Hepatitis B virus-Super infection.
Signs and symptoms- So, as far as the signs and symptoms are considered, acute hepatitis will give rise to jaundice, fever, nausea, vomiting, abdominal pain and fatigue where chronic hepatitis will present asymptomatic until it leads to cirrhosis of the liver, fibrosed and less functional after several years, which may be too late.
Complications- Hepatitis A infection rarely results in chronic liver diseases compared to hepatitis B and C and unfortunately ends up in debilitating symptoms and fulminant hepatitis or acute liver failure) which are often life threatening.