Differential Diagnosis for Enteroinvasive E. coli Infection

Single Most Likely Diagnosis

• Enteroinvasive E. coli (EIEC) Infection: This is the most likely diagnosis given the presence of EIEC in the stool sample. EIEC infections are known to cause dysentery-like symptoms, including stomach pain and changes in stool, which align with the patient's symptoms. The positive McBurney's point suggests localized inflammation, possibly indicating an appendiceal involvement or a localized gastrointestinal infection.

Other Likely Diagnoses

• Acute Appendicitis: Although the presence of EIEC is a strong indicator of an infectious cause, the positive McBurney's sign (tenderness at McBurney's point) is a classic sign of appendicitis. It's possible that the EIEC infection could be complicating or mimicking appendicitis.
• Gastroenteritis due to Other Pathogens: Other bacterial pathogens (e.g., Salmonella, Shigella) could cause similar symptoms. However, the specific identification of EIEC makes this less likely but still a consideration, especially if the patient's symptoms do not fully resolve with treatment targeted at EIEC.

Do Not Miss Diagnoses

• Intussusception: Although more common in children, intussusception can occur in adults and is a medical emergency. It could present with abdominal pain and changes in bowel habits. The presence of a pathogen like EIEC could potentially contribute to the intussusception by causing an intestinal mass or serving as a lead point.
• Inflammatory Bowel Disease (IBD) Flare: Conditions like Crohn's disease or ulcerative colitis could present with similar symptoms and may be exacerbated by or initially mistaken for an infectious process like EIEC.
• Diverticulitis: Especially if the patient is older, diverticulitis could present with localized abdominal pain and changes in bowel habits. The presence of EIEC might complicate the diagnosis or represent a secondary infection.

Rare Diagnoses

• Yersiniosis: Yersinia enterocolitica can cause symptoms similar to those of EIEC, including abdominal pain and diarrhea, and can mimic appendicitis.
• Tuberculous Appendicitis: In endemic areas or in immunocompromised patients, tuberculosis affecting the appendix could present with chronic abdominal pain, weight loss, and changes in bowel habits, although this would be less likely given the acute presentation and the presence of EIEC.
• Eosinophilic Gastroenteritis: A rare condition characterized by eosinophilic infiltration of the gastrointestinal tract, which could present with abdominal pain and changes in bowel habits, although it would not typically be associated with a positive stool culture for EIEC.