Hepatic Alveolar Echinococcosis
Other Liver Diseases
Description
Alveolar Echinococcosis (AE) is a rare parasitic disease caused by a tiny tapeworm (Echinococcus multilocularis) that primarily affects the liver. People get infected by accidentally swallowing the parasite's eggs, either by eating contaminated raw fruits or vegetables, or less often by direct contact with an infected dog or fox. In the infected animals, also called definite hosts, the Echinococcus multilocularis adult stage, a 3-to 7-mm-long tapeworm, develops in the intestines and produces thousands of eggs that are released with the carnivore’s dirt into the external environment. This parasitic disease, which can be transmitted to humans from animals, is a zoonosis. The humans are also called indefinite host, because the parasite cannot develop further and cannot produce any eggs, which is why humans cannot infect others.
Although the disease progresses very slowly, it mimics a malignant tumor due to its local growth behavior and its capacity to metastasize to other organs such as lungs or far more exceptionally, the brain.
AE develops slowly over time, often taking 5–15 years before symptoms appear. Common symptoms include pain or discomfort in the abdomen, feeling full or swollen in the upper stomach, and yellowing of the skin (jaundice). In some cases, people might not feel sick at all, and the disease is found incidentally during tests for other conditions.
AE is most common in certain parts of Europe, Asia, and North America. People at higher risk include those who live in areas where foxes carry the parasite. Hunters, farmers, and people who handle wild animals may have a greater chance of exposure. Eating unwashed fruits or vegetables that may be contaminated with the parasite’s eggs also increases the risk.
Diagnosis
Doctors use imaging tests like ultrasound, computed tomography (CT) scans, or magnetic resonance imaging (MRI) to look for signs of AE in the liver. Blood tests to confirm the diagnosis by detecting specific antibodies made by the body in response to the parasite will also be performed. Even though the disease is mostly asymptomatic, doctors will perform a full physical examination.
Treatment usually depends on the extent of the disease. Surgical resection of the affected part of the liver should be evaluated since it is the only curative therapy available. The only available drugs albendazole or mebendazol slow down the parasite’s growth, but cannot cure the disease. They also have to be taken before and after surgery, in order to reduce the risk of disease recurrence, or life-long, if surgery cannot be performed. Very rarely the disease leads to the development of bile duct complications that sometimes require endoscopic interventions to palliate the symptoms or to avoid the need for surgery. In severe cases, liver transplantation may be considere
Management
Regular check-ups are essential during and after treatment for AE. After a complete resection, doctors monitor for any signs of the disease returning using imaging tests like ultrasound, CT scans, or MRIs. Blood tests are also done to check for parasite activity, treatment response or a re-infection. Patients treated with albendazol or mebendazol require liver function tests since these drugs sometime affect the liver. In rare cases the plasma drug concentrations have to be tested to guide the treatment. Because AE can come back many years after the curative treatment, long-term monitoring is critical.
Which Healthcare Professionals are Involved?
Treating AE often requires a team of specialists working together, including:
- Hepatologists: Doctors who specialize in liver diseases.
- Infectious Disease Specialists: Experts in treating parasitic infections.
- Parasitologists: Specialists who perform blood and tissue testing.
- Surgeons: Specialists who perform liver surgery.
- Radiologists: Doctors who analyze imaging tests to track the disease and are able to perform interventional radiology treatments
- Gastroenterologists: Doctors who perform interventional biliary endoscopy
- Primary Care Providers: They help coordinate care and ensure regular follow-up.
This team approach ensures that patients receive comprehensive care tailored to their specific needs.