Toxic megacolon Micrograph of pseudomembranous colitis, a cause of toxic megacolon. H&E stain. Classification and external resources Specialty gastroenterology ICD-10 K59.3 ICD-9-CM 556.9 DiseasesDB 27702 MedlinePlus 000248 eMedicine med/1418 radio/702 MeSH D008532