B67.7 Echinococcus multilocularis infection, unspecified

Name of the Condition

• Echinococcus multilocularis infection, unspecified

Summary

Echinococcus multilocularis infection is a parasitic condition caused by the tapeworm Echinococcus multilocularis. It typically involves the formation of alveolar cysts, most commonly in the liver, though other organs may be affected. This zoonotic disease is transmitted from animals to humans and can range from asymptomatic to severe, depending on cyst location and extent. 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 can contaminate soil, water, or food. Upon ingestion, the eggs hatch in the human intestine, releasing larvae that migrate to organs 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 hunting or wildlife handling.
• Lack of access to clean water or sanitation in endemic areas.

Symptoms

Symptoms depend on cyst location and size but may include abdominal pain, jaundice, weight loss, or hepatomegaly if the liver is affected. Other organs may present with localized symptoms, such as respiratory issues if the lungs are involved. Some cases remain asymptomatic until complications arise.

Diagnosis

Diagnosis involves a combination of imaging (e.g., ultrasound, CT, or MRI) to detect cysts, serological tests to detect antibodies, and sometimes biopsy to confirm the presence of Echinococcus multilocularis larvae. Clinical correlation with exposure history is also important.

Treatment Options

Treatment may include antiparasitic medications (e.g., albendazole) to control cyst growth, surgical intervention to remove cysts, or liver transplantation in severe cases. Management is often long-term and requires monitoring for recurrence.

Prognosis and Follow-Up

Prognosis varies; early diagnosis and treatment improve outcomes, but advanced disease can be life-threatening. Follow-up typically involves regular imaging and serological testing to monitor for recurrence or complications.

Complications

Complications may include cyst rupture, secondary infection, organ dysfunction (e.g., liver failure), or metastasis to other tissues. Severe cases can be fatal if left untreated.

Lifestyle & Prevention

• Avoid contact with wild animals, especially foxes, in endemic areas.
• Practice good hygiene, such as washing hands after outdoor activities.
• Ensure food and water are safe, especially when traveling to high-risk regions.
• Avoid consuming raw or undercooked meat from potentially infected animals.

When to Seek Professional Help

Seek medical attention if you experience persistent abdominal pain, unexplained weight loss, jaundice, or other symptoms consistent with organ involvement, especially after potential exposure to the parasite.

Tips for Medical Coders

Use code B67.7 for unspecified Echinococcus multilocularis infection. Document the site of infection if known, as this may impact coding specificity. Ensure clinical documentation supports the diagnosis and any associated complications for accurate coding.