A04.3 Enterohemorrhagic Escherichia coli infection

Name of the Condition

• Enterohemorrhagic Escherichia coli infection

Summary

Enterohemorrhagic Escherichia coli (EHEC) infection is a bacterial infection affecting the intestines, often causing diarrhea and other gastrointestinal symptoms. It is typically associated with contaminated food, water, or environmental exposure, and may lead to severe complications such as hemolytic uremic syndrome (HUS).

Causes

EHEC infection is caused by the ingestion of food or water contaminated with enterohemorrhagic strains of Escherichia coli bacteria, most notably O157:H7. These bacteria produce Shiga toxins that damage the intestinal lining and can cause systemic effects.

Risk Factors

• Exposure to contaminated food (e.g., undercooked ground beef, raw vegetables) or water.
• Poor sanitation and hygiene practices.
• Contact with infected animals or their environments (e.g., farms, petting zoos).
• Travel to regions with high rates of bacterial infections.
• Weakened immune system.

Symptoms

• Watery or bloody diarrhea.
• Severe abdominal cramps.
• Nausea and vomiting.
• Low-grade fever (less common).
• Fatigue.
• Dehydration.

Diagnosis

Diagnosis involves stool sample analysis to identify EHEC bacteria and detect Shiga toxins. Clinical evaluation of symptoms and exposure history may guide testing. Laboratory methods such as culture or molecular testing can confirm the presence of specific bacterial strains.

Treatment Options

• Rehydration therapy to address fluid and electrolyte loss.
• Antibiotics are generally avoided as they may increase the risk of HUS.
• Monitoring for signs of HUS, which may require specialized care.

Prognosis and Follow-Up

Most EHEC infections resolve within a week with supportive care. However, HUS can develop, particularly in children or the elderly, requiring hospitalization and potential dialysis. Follow-up may include monitoring kidney function and hydration status.

Complications

• Hemolytic uremic syndrome (HUS), characterized by kidney failure, anemia, and low platelet count.
• Seizures or neurological issues in severe cases.
• Dehydration and electrolyte imbalances.

Lifestyle & Prevention

• Cook meat thoroughly, especially ground beef.
• Avoid unpasteurized dairy products and juices.
• Wash hands after handling raw meat or animals.
• Avoid cross-contamination in food preparation.
• Drink safe, treated water when traveling.

When to Seek Professional Help

Seek immediate medical attention if you experience:

• Bloody diarrhea.
• Severe abdominal pain.
• Signs of dehydration (e.g., dizziness, reduced urination).
• Confusion or neurological symptoms.
• Fever over 101°F (38.3°C).

Tips for Medical Coders

Document the presence of EHEC infection and any associated complications (e.g., HUS) clearly. Ensure clinical notes support the diagnosis, including stool test results or toxin detection. Code A04.3 is specific to enterohemorrhagic E. coli infection; avoid using this code for other E. coli strains.