Wednesday, August 20, 2008

The ABCs of Hepatitis


Hepatitis refers to an inflammation of the liver. There are many causes of which viruses are but one category. Hepatitis A, B and C are infections of the liver by 3 different viruses.

All 3 forms of hepatitis are infectious.

Hepatitis A is acquired through consumption of fecally contaminated water or food, particularly shellfish. It can also be transmitted through oral-anal sex with a recently infected individual. The likelihood of an individual having had an infection by the Hepatitis A virus increases with age. In Singapore, by the age of 50 years, about 90% would have been exposed to the virus.

Hepatitis B and C, on the other hand, are acquired as a result of sexual intercourse with another infected person or contact with the blood of an infected person. Hepatitis B is more infectious than Hepatitis C. Sexual promiscuity and having multiple sexual partners are known high risk factors in the acquisition of both infections. Blood contact most commonly occurs during acupuncture, tattooing or piercings performed contaminated needles. Sharing of needles by drug addicts or those experimenting with “mainlining lifestyle drugs” is another mode of infection. In less developed medical services, contaminated blood products and even improperly sterilized surgical/dental equipment may serve as sources of infection. Sharing of razors, toothpicks, toothbrushes, nail clippers, combs with an infected person can also potentially transmit the viruses.

About 4% of Singaporeans are infected with Hepatitis B. They are said to be Hepatitis B carriers. Carriage rates varies between countries, e.g. China 43%, Taiwan 20%, Philippines 17%, Australia 1%, Japan 3%. Singapore has a Hepatitis C carriage rate of about 0.4 % – 1.7%.

Another very important mode of Hepatitis B transmission is from an infected mother to her children at the time of birth. This mode of transmission can be largely prevented by timely treatment of the newborn at birth. Transmission while the baby is still in the womb has also been documented but this is probably rare. All pregnant mothers should therefore be screened for Hepatitis B so that the appropriate precautions may be taken at birth to protect the newborn.

Hepatitis C transmission during birth can also occur but is much less common than Hepatitis B.

Because of similarities in transmission methods Hepatitis B and C, a single individual can often be infected by more than one virus. Lastly, HIV is also transmitted in much the same scenarios (sexual intercourse, blood contamination and contact) and therefore should be screened if Hepatitis B or C is diagnosed.

Symptoms of Hepatitis

Nausea, loss of appetite, jaundice (yellowing of the eyes and skin), abdominal discomfort and the passage of tea coloured urine are the most common symptoms of Hepatitis A, B and C. Infection can however often occurs without any symptoms and infected individuals can feel and look perfectly normal. This explains why many individuals do not realize they have been previously infected until tests are performed, either during general health, blood donation or insurance related screenings or when pregnant. Each type of infection has a different incubation period. This means that symptoms may only be apparent only several weeks to even a few months after the point of contact with an infected individual.

Dr Cheong Wei Kuen
MBBS (Singapore), MRCP (UK), M Med (Int Med), FAMS (Gastroenterology)
Consultant Physician & Gastroenterologist
Mount Elizabeth Medical Centre
WK Cheong Gastrointestinal & Liver Specialists Pte Ltd