AMEBIC LIVER ABSCESS

Hello friends. Today I want to discuss a liver condition that arises from a common disease amongst us, amebic dysentery. Many people know about dysentery caused by a microorganism called entamoeba histolytica, but some are not aware that this same organism can proceed to cause liver damage and even death.

By Wellcome Images CC-BY-4.0, CC BY 4.0, Wikimedia

Amebic liver abscess is a liver disease caused by Entamoeba histolytica that results in the collection of pus in the liver. This parasite normally enters the digestive system. Then, it penetrates the inner lining of the large intestine where it causes the passage of watery stool, bloody stool, fever, etc.

These parasites can further penetrate the blood vessels around the intestines, from where they are carried to the liver through a channel called portal circulation. In the liver, they rapidly multiply and start damaging the liver especially the right lobe of the liver. These lead to the accumulation and collection of pus in the liver, thereby forming the liver abscess.

Because of this ongoing liver damage, the patient will start having a fever and a painful swollen liver. The pain is usually experienced in the right upper part of the abdomen and is a dull and constant pain that does not come and go. There may also be the presence of cough, pain in the right shoulder, general feeling of unwell, and diarrhea may or may not be present.

By CDC, Public Domain, Wikimedia

In severe cases, a large collection of pus may rupture into the chest cavity or abdominal cavity. A rupture into the chest cavity may cause the pus to sip into the lungs through an abnormal tract called a fistula. This results in cough and chest pain and the patient start coughing up the pus as an odorless brown substance.

The abscess can also rupture into the heart covering and this is very fatal. Death from this disease is mostly from the rupture of the abscess into the lungs and heart spaces.

Why is it important for us to know about this?

Infection with Entamoeba histolytica ranks second worldwide among parasitic causes of death, following malaria.

Amebic liver abscess: Worldwide, approximately 40-50 million people are infected annually, with the majority of infections occurring in developing countries. The prevalence of infection is higher than 5-10% in endemic areas and sometimes as high as 55%. The highest prevalence is found in developing countries in the tropics, particularly in Mexico, India, Central and South America, and tropical areas of Asia and Africa.

HOW DOES ONE GET IN CONTACT WITH THIS PARASITE?
This disease is transmitted by eating food or drinking water contaminated by the feces of an infected person. So, it is more of a disease of hygiene. That's why it's commoner in developing countries especially in overcrowded places with poor hygiene, and even in confined persons. It can also be transmitted from person to person through contact.

By Fotokannan - Own work, CC BY-SA 3.0, Wikimedia

RISK FACTORS FOR AMEBIC LIVER ABSCESS
Those at risk for this disease are those with low immunity (immunocompromised). This can be from malnourishment, old age and use of certain drugs like steroids, chronic infections, chronic alcohol use, etc These persons lack the body's natural ability to fight infections and they are more predisposed to this disease. Those living in endemic areas are also at higher risk and those migrating from those areas can infect new persons.

The relevant investigations that are usually recommended for the patient include an abdominal ultrasound scan, a chest x-ray, full blood count, immunofluorescence for antibodies, or the stool can also be checked for the egg of the parasites. These investigations help to confirm the diagnosis and also in the proper management of the patient.

TREATMENT
When detected early, effective treatment is always achieved with the use of Antibiotics. Metronidazole or Tinidazole is usually very effective.

However, for a very large abscess or when medical treatment fails, an aspiration of the abscess can be done.

PREVENTION
This disease is mostly from poor hygiene, therefore it is very very preventable through adequate personal and environmental hygiene.

Food hygiene is very important here. All food items must be properly washed and also cooked to kill these parasites. Food handlers must also be regularly checked to avoid spreading this infection.

Hand washing is also a key preventive measure. This COVID-19 era has inculcated the habit of proper and regular hand washing in many persons and we should maintain that habit. Hand washing saves us from many of these diseases. I want to emphasize here that effective Hand washing is done with running water and soap. Washing hands with only water is not usually enough. There are also steps to proper hand washing which you may want to check out here.

By Davyimage - Own work, CC BY-SA 4.0, Wikimedia

Drinking water must be well purified according to standards. The regulatory bodies should do well to monitor the various water plants in our environment. I once saw one sachet water-producing plant that was located in a very unhygienic environment and they have been producing and distributing water for public consumption. Those should be properly checked.

The use of human feces as fertilizer has also been implicated here and should be well monitored.

Also, those traveling to the endemic areas should be extra careful with what they eat and drink. They should ensure adequate sanitation and protection.

In conclusion, the amebic liver abscess is common in developing countries and can be a cause of death in severe cases. Since it is transmitted through the feco-oral route and person-to-person contact, total prevention can be achieved by adhering to strict personal and environmental hygiene. Continuous awareness is also very important to put people in the know so that they can protect themselves.

Thanks so much for reading.

For references and further reading on this topic, please check the materials below:

Science Direct

National Institute of Health

The Lancet

Research Gate

Centre for Disease Control