Final answer:
The first-line treatment of toxic megacolon is supportive care, which includes stopping any antibiotics, rehydration, and electrolyte replacement. If C. difficile is present, metronidazole or vancomycin are preferred. For other infections, treatment like fecal microbiota transplantation or specific antibiotics may be used.
Step-by-step explanation:
The first-line treatment of toxic megacolon involves rehydration and other supportive therapies. This includes stopping antibiotic use and providing supportive therapy with electrolyte replacement and fluids. Specific medication strategies depend on the underlying cause. If a Clostridium difficile (C. difficile) infection is confirmed, the preferred treatments are metronidazole or vancomycin, particularly metronidazole, unless the patient is under 10 years of age, pregnant, or allergic to it. Additionally, fecal microbiota transplantation has shown over a 90% success rate in resolving C. difficile infections and can be a subsequent line of treatment.
In cases where the underlying cause is protozoal, like in amoebiasis, the first line of treatment includes metronidazole or tinidazole, followed by other agents like diloxanide furoate, iodoquinol, or paromomycin to eliminate the remaining cysts. For bacterial infections like cholera, rehydration is crucial, and antibiotics such as azithromycin may be used as a first-line antibiotic treatment for severe cases.