07/07/2026
Cytomegalovirus
Cytomegalovirus (CMV) is one of the herpes viruses. It is thought that around 50% of people have been exposed to the CMV virus although it only usually causes disease in the immunocompromised, for example people with HIV or those on immunosuppressants following organ transplantation.
Pathophysiology
infected cells have a 'Owl's eye' appearance due to intranuclear inclusion bodies
Patterns of disease
CMV post renal-transplant
CMV is a key opportunistic infection after renal transplant, causing systemic illness and increasing the risk of acute rejection and graft loss.
highest risk group: Donor CMV-positive to recipient CMV-negative (D+/R-), especially with potent immunosuppression.
typical timing: Usually occurs 1-6 months post-transplant or after escalation of immunosuppression.
clinical features:
fever, malaise, leukopenia
tissue-invasive disease (GI colitis, retinitis, pneumonitis, nephritis mimicking rejection).
management:
prevent with valganciclovir prophylaxis or pre-emptive PCR monitoring
treat with valganciclovir or IV ganciclovir and reduce immunosuppression where possible.
Congenital CMV infection
features include growth retardation, pinpoint petechial 'blueberry muffin' skin lesions, microcephaly, sensorineural deafness, encephalitiis (seizures) and hepatosplenomegaly
CMV mononucleosis
infectious mononucelosis-like illness
may develop in immunocompetent individuals
CMV retinitis
common in HIV patients with a low CD4 count (< 50)
presents with visual impairment e.g. 'blurred vision'. Fundoscopy shows retinal haemorrhages and necrosis, often called 'pizza' retina
IV ganciclovir is the treatment of choice
Fundus photograph showing CMV retinitis. Credit: National Eye Institute, National Institutes of Health
CMV encephalopathy
seen in patients with HIV who have low CD4 counts
CMV pneumonitis
CMV colitis
