What is the best treatment approach for a patient with acute abdominal pain, potentially related to a history of diarrhea or immunocompromised status?

Treatment of Acute Abdominal Pain in Immunocompromised Patients with Diarrhea

In immunocompromised patients presenting with acute abdominal pain and diarrhea, immediately obtain a contrast-enhanced CT scan and initiate broad-spectrum antibiotics (piperacillin-tazobactam or carbapenem) while pursuing early surgical consultation, as clinical signs are unreliable and mortality is high if surgical disease is missed. 1, 2

Immediate Diagnostic Workup

Obtain contrast-enhanced CT scan immediately as the first-line imaging study, as it is the most reliable diagnostic test for detecting intra-abdominal pathology in immunocompromised patients. 1, 2

• Plain radiographs and ultrasound are insufficiently sensitive and specific in this population and should not delay CT imaging. 1
• Clinical examination findings (fever, peritoneal signs, leukocytosis) are frequently absent or unreliable even with severe disease—the degree of immunocompromise directly correlates with decreased reliability of physical findings. 1
• Laboratory tests do not accurately reflect disease severity in immunocompromised patients. 1

Test for Clostridioides difficile and its toxin immediately in all cases of diarrhea with or without acute abdomen. 1

• Additional microbiologic testing should be performed only if clinically indicated (e.g., HIV-specific pathogens like abdominal tuberculosis or Mycobacterium avium complex in HIV patients). 1

Initial Medical Management

Hospitalize immediately and start broad-spectrum antibiotics covering enteric gram-negatives, gram-positives, and anaerobes. 2

• First-line monotherapy: piperacillin-tazobactam or carbapenem (imipenem-cilastatin). 1, 2
• This follows IDSA guidelines for fever with neutropenia and is appropriate for neutropenic enterocolitis, the most common cause of acute abdominal pain in neutropenic cancer patients. 1
• Bowel rest is mandatory alongside antibiotic therapy. 1

Add antifungal therapy (amphotericin) if no clinical improvement occurs after 48-72 hours of antibacterial therapy, as fungemia is common in non-responders. 2

Surgical Consultation and Indications

Obtain early surgical consultation immediately, even while pursuing medical management, due to the high mortality rate (up to 29.5%) associated with neutropenic enterocolitis and other surgical emergencies in immunocompromised patients. 1, 2

Absolute Surgical Indications:

• Bowel perforation 1, 2
• Intestinal ischemia 1, 2
• Persistent gastrointestinal bleeding 2
• Clinical deterioration despite aggressive medical management 2
• Signs of toxic megacolon or fulminant colitis 1

Condition-Specific Surgical Approach:

Neutropenic enterocolitis/typhlitis: Conservative management with antibiotics and bowel rest achieves resolution in up to 86% of cases. 1

• Surgery reserved only for perforation or ischemia, as mortality with emergency surgery during active chemotherapy reaches 57-81%. 1
• If surgery required, use damage control approach in severely sick patients with physiological derangement. 1

Cytomegalovirus colitis: Treat with antiviral therapy, broad-spectrum antibiotics, and bowel rest. 1

• Surgery only for toxic megacolon, fulminant colitis, perforation, or ischemia. 1

Severe C. difficile colitis progressing to systemic toxicity: Early surgical consultation with consideration for total colectomy in fulminant cases. 1

• Diverting loop ileostomy with colonic antibiotic lavage is an effective alternative to subtotal colectomy. 1

Monitoring Requirements

Serial abdominal examinations are mandatory with multidisciplinary team involvement including gastroenterology. 2

• CT findings of bowel wall thickening >10 mm predict 60% mortality risk versus 4.2% if <10 mm in neutropenic enterocolitis. 1
• High-risk ultrasound signs include fluid-filled bowel, ascites, free fluid between loops, and hyperechoic septa (representing necrotic mucosa). 1

Pain Management Considerations

Avoid NSAIDs (ketorolac) in immunocompromised patients with acute abdominal pain and diarrhea. 3

• NSAIDs are contraindicated in patients with inflammatory bowel disease as they may exacerbate the condition. 3
• They can obscure diagnosis and clinical course in acute abdominal conditions. 4

Use opioids (morphine) cautiously if pain control is necessary. 4

• Morphine diminishes propulsive peristaltic waves and may prolong obstruction. 4
• May obscure diagnosis or clinical course in acute abdominal conditions. 4

Critical Pitfalls to Avoid

Never delay CT imaging based on normal physical examination or laboratory findings—this is the most critical error, as clinical signs are unreliable in immunocompromised patients. 1, 2

Never use antidiarrheal agents in suspected neutropenic enterocolitis or infectious colitis, as they may aggravate ileus and worsen outcomes. 2, 5

Never delay surgical consultation even when pursuing medical management—high mortality demands early involvement. 2

Never miss C. difficile testing—it must be excluded in all cases of severe abdominal pain with diarrhea in immunocompromised patients. 1, 2

Never use antimotility agents in the presence of fever, bloody stools, or inflammatory diarrhea due to toxic megacolon risk. 6