Checkpoint Inhibitor Colitis With Superimposed Clostridioides difficile Infection

Area of Science:

• Oncology
• Immunology
• Gastroenterology

Background:

• Immune checkpoint inhibitors (ICI), such as anti-PD-1 antibody pembrolizumab, are crucial in cancer therapy.
• Immune-mediated diarrhea and colitis (IMDC) is a common gastrointestinal immune-related adverse event (irAE) associated with ICI use.
• Accurate diagnosis of IMDC often requires extensive workup, including stool studies, imaging, and colonoscopy.

Observation:

• A 76-year-old female with nonmetastatic non-small cell lung cancer developed IMDC after pembrolizumab treatment.
• Initial IMDC symptoms responded to steroid therapy.
• The patient later experienced worsening diarrhea, prompting further investigation.

Findings:

• The patient was diagnosed with checkpoint inhibitor colitis.
• Superimposed Clostridioides difficile infection was identified as the cause of worsening symptoms.
• The coexistence of IMDC and C. difficile infection was confirmed in this case.

Implications:

• This case underscores the potential for Clostridioides difficile infection to complicate immune-mediated colitis in patients receiving pembrolizumab.
• Understanding shared risk factors between IMDC and C. difficile infection is critical for effective patient management.
• Prompt recognition and appropriate treatment for superimposed C. difficile infection are essential for managing ICI-induced colitis.