A07.1 Giardiasis [lambliasis]

Name of the Condition

• Giardiasis [lambliasis]

Summary

Giardiasis is an intestinal infection caused by the protozoan parasite Giardia lamblia (also known as Giardia intestinalis). It primarily affects the small intestine and is a common cause of diarrheal illness worldwide. The infection can range from asymptomatic to severe, with symptoms typically appearing 1–3 weeks after exposure.

Causes

Giardiasis is caused by ingesting the cyst form of Giardia lamblia, which is shed in the feces of infected individuals or animals. Transmission occurs through contaminated water (e.g., drinking or recreational), food, or direct contact with infected persons or surfaces. The parasite is highly resistant to standard water treatment methods, including chlorination.

Risk Factors

• Consumption of untreated or contaminated water (e.g., from lakes, rivers, or wells)
• Travel to regions with poor sanitation
• Close contact with infected individuals or animals (e.g., in daycare settings or households)
• Weakened immune system (e.g., due to illness or immunosuppressive therapy)
• Exposure to fecal-oral contamination (e.g., poor hygiene practices)

Symptoms

• Watery, foul-smelling diarrhea
• Abdominal cramps or bloating
• Excessive gas
• Nausea or vomiting
• Fatigue
• Weight loss (in chronic cases)
• Dehydration (in severe or prolonged infections)

Diagnosis

Diagnosis is confirmed by detecting Giardia cysts or trophozoites in stool samples. Microscopic examination, antigen detection tests, or molecular methods (e.g., PCR) may be used. Multiple stool samples are often required due to intermittent shedding of the parasite. Endoscopic procedures (e.g., duodenal aspirate) may be performed in chronic or severe cases.

Treatment Options

• Antiparasitic medications (e.g., metronidazole, tinidazole, nitazoxanide) to eliminate the parasite
• Supportive care, including oral rehydration solutions to manage dehydration
• Nutritional support for individuals with significant weight loss or malabsorption

Prognosis and Follow-Up

Most individuals recover fully with appropriate treatment within 1–2 weeks. Chronic infections may require extended therapy. Follow-up stool testing may be recommended to confirm eradication of the parasite, especially in immunocompromised patients or those with persistent symptoms.

Complications

• Chronic diarrhea or malabsorption leading to weight loss or nutritional deficiencies
• Dehydration (particularly in severe cases)
• Post-infectious irritable bowel syndrome (IBS) in some individuals
• Rarely, severe complications in immunocompromised patients (e.g., disseminated infection)

Lifestyle & Prevention

• Avoid consuming untreated water from natural sources (e.g., lakes, rivers)
• Practice good hand hygiene, especially after using the restroom or handling food
• Ensure proper sanitation and water treatment in communities or travel settings
• Avoid consuming raw or undercooked foods that may be contaminated
• Use caution when traveling to areas with poor sanitation or water quality

When to Seek Professional Help

Seek medical attention if you experience:

• Persistent diarrhea lasting more than a week
• Severe dehydration (e.g., dizziness, reduced urination, dry mouth)
• High fever or severe abdominal pain
• Unexplained weight loss or signs of malabsorption
• Symptoms that worsen or do not improve with home care

Tips for Medical Coders

• Use code A07.1 for giardiasis (lambliasis) when the condition is documented in the medical record.
• Ensure documentation supports the diagnosis, including clinical symptoms, diagnostic test results (e.g., stool analysis), or treatment for Giardia lamblia.
• Do not use this code for asymptomatic carriers unless clinically relevant or specified by the provider.
• Verify that the code aligns with the specific parasite identified (e.g., Giardia lamblia) to avoid misclassification.