What is the treatment for Cytomegalovirus (CMV) colitis?

Treatment of CMV Colitis

Initiate intravenous ganciclovir 5 mg/kg every 12 hours for 3-5 days, then transition to oral valganciclovir 900 mg every 12 hours to complete a total 2-3 week course. 1, 2

Immediate Antiviral Therapy

• Begin IV ganciclovir immediately upon diagnosis or strong clinical suspicion of CMV colitis, even before histopathologic confirmation, as delays increase morbidity and mortality risk 3, 2
• The standard adult regimen is ganciclovir 5 mg/kg IV every 12 hours for 3-5 days as induction therapy 1, 2
• After the initial IV phase, switch to oral valganciclovir 900 mg every 12 hours for the remainder of treatment to complete a 2-3 week total course 1, 2, 4
• In pediatric patients or severely immunocompromised individuals (such as SCID), maintain parenteral ganciclovir for the full 14-21 day course rather than switching to oral therapy, as early transition may promote CMV reactivation 3

Diagnostic Confirmation

• Obtain flexible sigmoidoscopy or colonoscopy with multiple biopsies from ulcer bases and edges for histology and CMV-specific immunohistochemistry (IHC), which has 78-93% sensitivity 1, 2
• Send colonic tissue for CMV DNA PCR to improve diagnostic sensitivity, with a viral load >250 copies/mg tissue suggesting clinically significant infection 2
• Do not delay antiviral treatment while awaiting biopsy results if clinical suspicion is high 1, 3

Management of Immunosuppression in IBD Patients

• Do not abruptly discontinue immunosuppressive therapy in IBD patients with CMV colitis; instead, taper steroids gradually rather than stopping them suddenly 2
• Continue other immunosuppressive medications in general, though consider reduction in severely ill patients 3, 2
• Antiviral therapy should be initiated in steroid-refractory IBD patients with documented CMV colitis 2

Monitoring Requirements

• Check complete blood count at least twice weekly during ganciclovir therapy, as severe neutropenia occurs in approximately 11% of treated patients 2, 4
• Obtain weekly CMV viral load by PCR to assess treatment response and continue therapy until CMV is undetectable in blood 3, 2
• Monitor serum creatinine and electrolytes closely, particularly if alternative agents like foscarnet are required 3, 4

Alternative Agents for Resistance or Intolerance

• Use foscarnet 90 mg/kg IV every 12 hours (or 60 mg/kg every 8 hours) for 14-21 days when ganciclovir resistance is documented or suspected 3, 2
• High-dose valganciclovir (up to 1800 mg twice daily based on creatinine clearance) along with immunosuppression reduction may be effective for ganciclovir-resistant CMV colitis with UL97 and UL54 mutations 5
• Reserve cidofovir as a third-line agent due to substantial nephrotoxicity risk, only when both ganciclovir and foscarnet have failed or are contraindicated 3

Adjunctive Supportive Measures

• Add broad-spectrum antibiotics to the antiviral regimen, as bacterial translocation and secondary infection commonly complicate CMV colitis with bowel wall necrosis 3, 2
• Consider early infectious disease consultation for complex cases 2, 4
• In severely ill patients, admit to intensive care or step-down unit for close monitoring 3

Surgical Intervention Criteria

• Obtain early surgical consultation on admission for severely immunocompromised patients (such as SCID), given the extremely high mortality risk approaching or exceeding 70% 3
• Proceed urgently to subtotal or partial colectomy if the patient develops toxic megacolon, fulminant colitis, colonic perforation, or bowel ischemia despite antiviral therapy 3, 2
• Severe abdominal pain, continued systemic toxicity, or suspicion of perforation warrant immediate surgical review 1

Critical Pitfalls to Avoid

• Never delay ganciclovir initiation while awaiting stool cultures, histology, or other confirmatory tests in clinically suspected CMV colitis 1, 3
• Do not switch to oral valganciclovir prematurely in children or severely immunocompromised patients, as this increases reactivation risk 3
• Avoid abrupt discontinuation of corticosteroids in IBD patients with CMV colitis; taper gradually instead 2
• Do not overlook the need for twice-weekly CBC monitoring, as myelosuppression is common and may require dose adjustment 2, 4