B67.5 Echinococcus multilocularis infection of liver

Name of the Condition

• Echinococcus multilocularis infection of liver

Summary

Echinococcus multilocularis infection of the liver is a parasitic condition characterized by the formation of cysts in the liver caused by the tapeworm Echinococcus multilocularis. This zoonotic infection results from ingesting parasite eggs, which develop into cysts in the liver. The disease may be asymptomatic or cause symptoms depending on cyst size, location, and complications. It is part of alveolar echinococcosis, a less common but more aggressive form of echinococcosis compared to cystic echinococcosis.

Causes

The infection is caused by ingesting eggs of Echinococcus multilocularis, which are shed in the feces of infected definitive hosts (typically foxes or other canids). These eggs contaminate soil, water, or food. Upon ingestion, the eggs hatch in the human intestine, releasing larvae that migrate to the liver and develop into cysts. The cysts grow slowly over years, potentially causing tissue damage or complications.

Risk Factors

• Living in or traveling to regions where the parasite is endemic (e.g., parts of North America, Europe, or Asia).
• Close contact with foxes or other definitive hosts, especially in rural or sylvatic settings.
• Ingesting food or water contaminated with parasite eggs.
• Occupational exposure, such as trapping or wildlife handling.
• Lack of access to clean water or sanitation in endemic areas.

Symptoms

Symptoms may be absent in early stages. As cysts grow, they can cause abdominal pain, hepatomegaly (enlarged liver), jaundice, or signs of liver dysfunction. Advanced cases may present with weight loss, fatigue, or complications like biliary obstruction.

Diagnosis

Diagnosis involves imaging (e.g., ultrasound, CT, or MRI) to detect liver cysts, serologic tests for antibodies, and sometimes biopsy to confirm the presence of Echinococcus multilocularis larvae. Clinical correlation with exposure history is essential.

Treatment Options

Treatment may include antiparasitic medications (e.g., albendazole) to slow cyst growth, surgical resection of cysts when feasible, or liver transplantation in severe cases. Long-term therapy is often required to prevent recurrence.

Prognosis and Follow-Up

Prognosis depends on early diagnosis and treatment. Untreated, the infection can be fatal due to liver destruction. Regular follow-up with imaging and serologic monitoring is necessary to assess treatment response and detect recurrence.

Complications

Complications include liver failure, biliary obstruction, cyst rupture (leading to anaphylaxis or dissemination), and secondary bacterial infections. Metastasis to other organs is rare but possible.

Lifestyle & Prevention

• Avoid contact with wild canids (e.g., foxes) or their feces.
• Wash hands thoroughly after outdoor activities or handling soil.
• Consume only properly washed or cooked food and safe water in endemic areas.
• Deworm pets (e.g., dogs) regularly to reduce environmental contamination.

When to Seek Professional Help

Seek medical attention if you experience persistent abdominal pain, unexplained weight loss, jaundice, or have a history of exposure in endemic regions. Early evaluation is critical for effective management.

Tips for Medical Coders

Code B67.5 is specific to Echinococcus multilocularis infection of the liver. Documentation should specify the parasite species and organ involvement. Ensure clinical correlation with imaging or serologic findings to support the diagnosis.