Cytomegalovirus (CMV) disease is most often seen in the immunocompromised host, such as the patient post-transplant (not one with cirrhosis). Risk is greatest when the donor liver comes from a patient with CMV and the recipient is naive to CMV. Timing of infection is commonly in the 1-3 months following the discontinuation of prophylaxis.
Remember that CMV can arise as a “CMV syndrome” which consists of constitutional syptoms only (ie. fever, malaise, fatigue) or a CMV end-organ disease, like colitis, hepatitis, retinitis or pneumonitis.
There need not be a positive serologic PCR in order to have active end-organ involvement. The diagnostician must directly target the end-organ itself, and in the case of colitis, visualize and biopsy the colonic mucosa. The disease often involves the right side of the colon, so a sigmoidoscopy may be inadequate.