Primary CMV infection takes place in childhood and early adolescence is asymptomatic. After the resolution of the primary infection CMV is latent in the mononuclear leukocytes. Reactivation in immunocompetent patients presents with mononucleosis like syndrome, but severe infection can occur in elderly and critically ill patients. Common complications of CMV infection in immunocompromised patients include CMV retinitis, CMV colitis, CMV encephalitis, CMV pneumonia and CMV myocarditis. CMV is associated with increased risk of graft versus host disease, myelosuppression, and invasive bacterial and fungal infections increasing morbidity and mortality of the patients.

Primary CMV infection which occurs in childhood and early adolescence is asymptomatic. After the resolution of the primary infection, CMV is latent in the mononuclear leukocytes. Reactivation of the virus can occur during states of stress and immunosuppression. Reactivation in immunocompetent patients presents with a mononucleosis like syndrome. If left untreated, severe infection can occur in elderly and critically ill patients. They present with clinical manifestations affecting the gastrointestinal tract and the central nervous system. Retinitis and pneumonitis are uncommon in immunocompetent patients when compared to immunocompromised patients. Reactivation of CMV infection in immunocompromised patients results in CMV end organ infection affecting multiple organs.^[1]

Common complications of CMV infection in immunocompromised patients include:^[1]

• CMV retinitis can result in blindness
• CMV colitis can progress to bowel perforation and fatal diverticular bleeding^[2]
• CMV encephalitis is a rapidly progressive condition leading to death
• CMV pneumonia
• CMV myocarditis
• CMV hepatitis
• Increased risk of secondary bacterial and fungal infections
• Increased risk of cardiovascular related mortality^[3]

Complications in critically ill immunocompetent patients include:

• Increased mortality rate
• Prolonged intensive care unit and hospital length of stay
• Prolonged mechanical ventilation
• Nosocomial infections
• Endothelial cell dysfunction can cause portal or femoropopliteal vascular thrombosis

Complications of CMV infection in organ transplant patients:^[4]

• Acute allograft rejection and failure
• Death

CMV disease is common in patients with solid organ transplantation causing significant morbidity and mortality. CMV is associated with increased risk of graft versus host disease, myelosuppression, and invasive bacterial and fungal infections increasing morbidity and mortality of the patients.^[5][6]