Cytomegalovirus mononucleosis is a viral infection caused by a virus from the Herpesviridae family. It primarily affects immunocompetent patients and is similar in presentation to mononucleosis caused by the Epstein-Barr virus.
Cytomegalovirus mononucleosis presentation is indistinguishable from mononucleosis caused by Epstein-Barr virus (EBV) apart from several details discussed later. Mononucleosis manifests chiefly in young children and adolescents who had no prior immunocompromising diseases .
Presentation in this disease roughly consists of a triad of fatigue, fever, and lymphadenopathy. Fatigue, although a subjective symptom, is very well documented in the literature  . Fever up to 40.9°C can last for more than a week. Lymphadenopathy in CMV mononucleosis does not only affect cervical lymph nodes, but also involves mesenteric nodes. Patients present with abdominal pain due to these enlarged nodes along with hepatomegaly and splenomegaly. Swelling of the eyelids follows cervical lymphadenopathy with a disturbance of blood flow in the facial area .
To differentiate the mononucleosis caused by CMV from that caused by EBV, physicians must primarily seek immunologic evidence. Although, some features of presentation can help to distinguish the two conditions. CMV is thought to provoke larger mesenteric lymphadenopathy and swelling of the eyelids. Likewise, a skin rash commonly develops due to a reaction of complement fixing antibodies (for which CMV is responsible) to antibiotics . The rash can be macular, papular, maculopapular or similar to the rubella rash . To confirm a rash caused by CMV, a use of antibiotics has to be documented and possible prior causative agents excluded from history .
Cytomegalovirus mononucleosis can be diagnosed by detecting IgM or IgG antibodies to CMV. Reagents for immunoglobulin precipitation tend to be expensive and an algorithm of immunological testing was proposed by Tsaparas et al . It is based on exclusion and suggests that:
Other tests for providing evidence is pp65 phosphoprotein antigen detection and polymerase chain reaction (PCR) in qualitative or quantitative modality. Pp65 method is proposed to be very accurate, efficient, and overall a cost-effective test .
Blood analyses comprises of a complete blood count with findings of leukopenia (that is more common in CMV infection) or lymphocytosis. Also, atypical lymphocytes or virocytes are sought as they are pathognomic for mononucleosis  . Thrombocytopenia is not a common finding in a mononucleosis patient but is seen more frequently in CMV rather than EBV infection  .
Ultrasonography is useful in monitoring abdominal organ enlargement, specifically spleen, liver, and mesenteric lymph nodes .
In CMV mononucleosis aspartate and alanine transaminases are elevated and should be monitored for a possible liver damage .