This lecture discussed two of the main causes of diarrhea in the liver transplant recipient: C. difficile and cytomegalovirus (CMV). Clostridium difficile can present itself in the first few weeks post-transplant, and anytime thereafter. According to one report, its incidence is higher early post-transplant in patients that had a higher MELD score pre-transplant. This probably reflects the severity of their illness and the likelihood that they were given multiple antibiotics.
The assay to detect toxin has a good sensitivity, and sending 2 or 3 stool specimens for assay can add about 10% to the sensitivity. If suspicion remains high despite negative toxins and absent pseudomembranes on endoscopy, a PCR can be sent for confirmation; treatment can be started prior to the PCR result, which may take many days. Treatment for an initial infection is with Flagyl; the specifics of treatment for recurrence can be found by clicking on this New England Journal review article on C. difficile.
Cytomegalovirus presents itself after prophylaxis is removed. The highest risk for infection is found in the donor+/recipient- patient. It may present as a CMV syndrome, with fever, anorexia and malaise, leukopenia or thrombocytopenia…or as a specific CMV organ disease (colitis, hepatitis, pneumonitis).
Detecting antigenemia or antibody status is not always helpful, so ordering a viral load/PCR is your best bet. If a viral load is detected, treatment is indicated. If you are faced with organ-specific disease and CMV is not detected in the blood, you should still pursue a tissue biopsy to exclude the disease. Treatment is with either IV gancyclovir or oral valgancyclovir. Duration of treatment is at least 6 weeks.