From the Research
Chromoendoscopy is a valuable diagnostic tool for detecting and assessing gastrointestinal graft-versus-host disease (GVHD) in patients who have undergone hematopoietic stem cell transplantation, particularly when combined with targeted biopsies from abnormal areas highlighted by the dye, as it enhances visualization of subtle mucosal abnormalities that might be missed with standard white-light endoscopy 1.
Key Points
- Chromoendoscopy involves applying dyes such as indigo carmine or methylene blue to the gastrointestinal mucosa during endoscopy to enhance visualization of mucosal abnormalities.
- The procedure is particularly useful for detecting early or patchy GVHD involvement that might be overlooked with random biopsies.
- Targeted biopsies should be taken from abnormal areas highlighted by the dye to improve diagnostic yield compared to standard endoscopy.
- The technique is especially valuable in patients with suspected GVHD who have normal-appearing mucosa on conventional endoscopy but persistent symptoms.
- A study found that sigmoid biopsy for GVHD diagnosis is effective, safe, and less expensive compared to other endoscopic interventions 1.
Diagnostic Approach
- A typical protocol for chromoendoscopy in GVHD assessment includes spraying 0.2% indigo carmine or 0.1% methylene blue onto the mucosa using a catheter spray, followed by careful examination for characteristic features such as denudation, erythema, erosions, and altered vascular patterns.
- The procedure should be performed by an experienced endoscopist familiar with GVHD manifestations.
- The use of chromoendoscopy can help identify patients who require treatment for GVHD, and can also help identify patients who do not require treatment, thereby avoiding unnecessary immunosuppression 2.
Clinical Considerations
- The decision to treat for GVHD should be based on a combination of clinical, endoscopic, and histological findings, rather than relying solely on the diagnostic category of indeterminate for GVHD (iGVHD) 2.
- Clinicians should be aware of the potential for minimal crypt apoptosis in patients with iGVHD, and should use their clinical judgement when deciding whether to treat with increased immunosuppression.