What is the appropriate treatment for an elderly female patient with abdominal pain, nausea, and bloody stools, suspected of having inflammatory colitis after consuming chicken wings, with no vomiting or diarrhea, and pending stool culture results?

Management of Suspected Infectious Colitis in an Elderly Patient with Bloody Stools

This elderly patient with inflammatory colitis, bloody stools, and abdominal pain following chicken wing consumption should receive immediate empiric antibiotic therapy with azithromycin 1000 mg as a single oral dose or ciprofloxacin 500 mg twice daily for 5-7 days while awaiting stool culture results, as the clinical presentation strongly suggests invasive bacterial enterocolitis requiring treatment. 1, 2

Immediate Empiric Antibiotic Therapy

Empiric antibiotics should NOT be withheld pending culture results in this clinical scenario. The combination of bloody stools, abdominal pain, and inflammatory colitis on imaging meets criteria for severe infectious colitis requiring immediate treatment. 1, 2

Preferred Antibiotic Regimens:

• Azithromycin 1000 mg as a single oral dose is the preferred first-line empiric treatment, covering the most likely pathogens (Shigella, Salmonella, Campylobacter). 2, 3

• Ciprofloxacin 500 mg orally twice daily for 5-7 days is an acceptable alternative if fluoroquinolone resistance is unlikely in your region. 1, 2, 4

• The decision to start empiric therapy is supported by the presence of bloody diarrhea and inflammatory colitis, which indicate invasive/inflammatory bacterial pathogens as the most likely cause. 1, 3

Critical Diagnostic Testing Required

Comprehensive stool studies must be sent immediately but should not delay antibiotic initiation:

• Stool culture for Campylobacter jejuni, Salmonella species, Shigella species, and E. coli O157:H7 are mandatory. 1, 2, 5

• Shiga toxin testing or STEC PCR is essential because the absence of fever with bloody diarrhea raises concern for STEC infection. 1, 3

• Clostridioides difficile toxin assay must be performed even without recent antibiotic exposure, as community-acquired cases are increasing in elderly patients. 2, 6

• Multiplex PCR panel can provide results within 24-48 hours for rapid pathogen identification and antibiotic de-escalation. 2, 5

STEC-Specific Warning

If STEC O157:H7 or other Shiga toxin-producing E. coli is suspected or confirmed, antibiotics must be immediately discontinued. 1

• Antibiotic therapy for STEC infections that produce Shiga toxin 2 significantly increases the risk of hemolytic uremic syndrome and should be avoided. 1

• Clinical clues suggesting STEC include: bloody diarrhea with minimal or no fever, recent consumption of undercooked meat or contaminated food, and severe abdominal cramping. 1, 3

• If STEC is confirmed, switch to supportive care only with aggressive hydration and close monitoring for complications. 1

Supportive Care Measures

Aggressive fluid resuscitation remains the cornerstone of treatment regardless of antibiotic use:

• Administer 2-4 liters of oral rehydration solution over 3-4 hours for moderate dehydration. 2

• Escalate to intravenous hydration if the patient develops severe dehydration, altered mental status, severe orthostatic hypotension, or cannot maintain oral intake. 2

• Antiemetics (ondansetron) can be used if nausea limits oral intake. 2

• Antimotility agents (loperamide) are contraindicated in this patient with inflammatory colitis and bloody stools, as they may worsen outcomes and increase risk of toxic megacolon. 2

Antibiotic Adjustment Based on Culture Results

De-escalate to pathogen-specific therapy within 24-48 hours once culture results return:

• For confirmed Campylobacter: Azithromycin 500 mg daily for 3 days or ciprofloxacin 500 mg twice daily for 5-7 days (if susceptible). 1, 2

• For confirmed Salmonella or Shigella: Ciprofloxacin 500 mg twice daily for 5-7 days or azithromycin 500 mg daily for 3 days. 1, 2

• For confirmed C. difficile: Oral vancomycin 125 mg four times daily for 10 days (first-line) or fidaxomicin 200 mg twice daily for 10 days. 2, 6

• For uncomplicated Salmonella gastroenteritis in immunocompetent patients: Consider discontinuing antibiotics as treatment may prolong fecal shedding without clinical benefit. 1, 7

Monitoring for Clinical Response

Clinical improvement should occur within 3-5 days of appropriate antibiotic therapy:

• Persistent fever beyond 72 hours on appropriate antibiotics suggests resistant organism, inadequate source control, or complications such as abscess or toxic megacolon. 2

• Worsening abdominal pain or distension may indicate toxic megacolon or perforation requiring urgent surgical consultation. 2

• Increasing blood in stool or development of new bloody diarrhea warrants close monitoring and reassessment. 2

Special Considerations for Elderly Patients

This elderly patient requires heightened vigilance due to age-related risk factors:

• Elderly patients with inflammatory colitis have higher rates of complications including perforation, toxic megacolon, and sepsis. 1

• Immunocompromised status, organ dysfunction, or septic shock in elderly patients mandates broad-spectrum empiric therapy started immediately. 1

• Consider underlying comorbidities (diabetes, renal insufficiency, immunosuppression) that may influence pathogen susceptibility and antibiotic selection. 1

Common Pitfalls to Avoid

• Do not delay antibiotics while awaiting culture results in a patient with bloody stools and inflammatory colitis—this represents severe disease requiring immediate treatment. 1, 2, 6

• Do not give antibiotics if STEC is confirmed—this increases hemolytic uremic syndrome risk. 1

• Do not repeat C. difficile testing within 7 days of initial testing, as diagnostic yield is only 2% and risks false-positives. 6, 5

• Do not perform "test of cure" after treatment completion, as >60% remain pathogen-positive despite clinical resolution. 6, 5

• Do not use antimotility agents in patients with bloody diarrhea or inflammatory colitis. 2