A 26-year-old man comes to the office due to a week of fever, malaise, fatigue, and sore throat. The patient has no chronic medical conditions and takes no medications. He drinks 1 or 2 beers on the weekends but does not use tobacco or illicit drugs. The patient has had 3 male sexual partners over the past year and uses condoms inconsistently. Temperature is 38.3 C (101 F) , blood pressure is 120/76 mm Hg, pulse is 75/min, and respirations are 14/min. Physical examination shows pharyngeal erythema, mild splenomegaly, and a morbilliform rash. No enlarged lymph nodes are present. Laboratory results are as follows: Peripheral blood smear is shown in the exhibit below. Heterophile antibody testing is negative. Which of the following is the most likely diagnosis?

Question

A 26-year-old man comes to the office due to a week of fever, malaise, fatigue, and sore throat. The patient has no chronic medical conditions and takes no medications. He drinks 1 or 2 beers on the weekends but does not use tobacco or illicit drugs. The patient has had 3 male sexual partners over the past year and uses condoms inconsistently. Temperature is 38.3 C (101 F) , blood pressure is 120/76 mm Hg, pulse is 75/min, and respirations are 14/min. Physical examination shows pharyngeal erythema, mild splenomegaly, and a morbilliform rash. No enlarged lymph nodes are present. Laboratory results are as follows:

Peripheral blood smear is shown in the exhibit below. Heterophile antibody testing is negative. Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Cytomegalovirus (CMV) is a widely prevalent DNA virus of the herpes family that typically causes an asymptomatic initial infection. However, a minority (<10%) of patients develop a mononucleosis-like initial illness (closely resembling Epstein-Barr virus [EBV] mononucleosis) with several weeks of fever, malaise, fatigue, absolute lymphocytosis with >10% atypical lymphocytes (large basophilic cells with a vacuolated appearance), and mild elevations in aminotransferase levels. Compared with EBV, CMV mononucleosis usually causes much milder pharyngitis, lymphadenopathy, and splenomegaly (or these symptoms may be absent). atypical lymphocytes The diagnosis is generally suspected based on clinical symptoms, negative heterophile antibody testing (monospot), and positive CMV IgM serology. CMV mononucleosis resolves completely without treatment. However, patients are occasionally given antiviral medications (eg, valganciclovir) to speed resolution even though the data on this practice is weak. Men who have sexual encounters with men, such as this patient, have higher rates of CMV seroconversion than the general population and are at increased risk for infection with different CMV strains. (Choice A) Acute lymphoblastic leukemia usually causes lymphadenopathy and symptoms related to anemia (eg, fatigue), thrombocytopenia (eg, bruising), or neutropenia (eg, infection). Peripheral smear would show blasts, not atypical lymphocytes. blasts (Choice B) Acute toxoplasmosis is usually asymptomatic but may occasionally cause a mononucleosis-like illness. However, CMV is a far more common cause of non-EBV mononucleosis than toxoplasmosis. (Choice D) Disseminated gonococcal infections tend to present with tenosynovitis, dermatitis, and polyarthralgia or with purulent arthritis. (Choice E) Herpangina causes high fever, malaise, and throat pain. Examination of the throat typically shows hyperemic yellow or grayish-white papulovesicles. This patient has pharyngeal erythema, not papulovesicles. (Choice F) Streptococcal pharyngitis may present with pharyngitis, fever, and rash. Hepatitis, atypical lymphocytes, and absolute lymphocytosis are uncommon. Educational objective: Cytomegalovirus (CMV) mononucleosis is marked by persistent fever, malaise, and fatigue with absolute lymphocytosis on complete blood count and atypical lymphocytes on peripheral blood smear. Unlike Epstein-Barr virus, CMV usually causes mild pharyngitis, lymphadenopathy, and splenomegaly (or these symptoms may be absent). In patients with CMV, the heterophile antibody test is negative, and CMV IgM serology is positive.

A 26-Year-Old Man Comes to the Office Due to a Week