Case report. A 60-year-old man was admitted to the hospital in 2003 due to fever (39ºC) and jaundice. His symptoms had started 12 days earlier with general malaise, myalgia, mild cough, and slightly sore throat. His general practitioner had treated him with clarithromycin (500 mg bid) and paracetamol. The physical examination revealed only the jaundice, the presence of some small cervical lymphadenopathies and a palpable hepatic margin 2 cm below the costal margin. The main findings from the complementary examinations (Table 1) were the presence of lymphocytosis in peripheral blood with abundant (> 10%) atypical forms (activated lymphocytes), and hyperbilirubinemia. The patient also presented marked dyslipidemia with serum triglyceride concentration > 1000 mg/dL and total cholesterol > 600 mg/dL, with increased LDL and VLDL fractions (Table 1). The abdominal ultrasound highlighted only liver hyperechogenicity. The additional investigations revealed the following: weakly positive antinuclear antibodies in serum (1/80); immunoglobulin-G (IgG), 1580 mg/dL; IgA, 314 mg/dL; and IgM, 411 mg/dL. The serological tests for human immunodeficiency virus, hepatitis B, and hepatitis C were negative. The tests for hepatitis A virus, herpes simplex virus, varicella-zoster virus, and cytomegalovirus revealed only a past infection (presence of positive IgG with negative IgM). The serum heterophile antibody test was negative; however, the IgM against the viral capsid antigen (VCA) of EBV was positive. The patient underwent only symptomatic treatment. In the following weeks, the patient developed successively IgG antibodies against VCA, followed by antibodies against EBV nuclear antigen (EBNA), with a progressive disappearance of IgM against VCA, thereby confirming the EBV primary infection. In parallel, the lymphocytosis progressively disappeared, the bilirubin and transaminase levels normalized, and the serum lipid concentrations decreased (Table 1). In the following 17 years, with no specific treatment, his serum triglyceride levels remained between 110 and 190 mg/dL, and the total cholesterol remained between 220 and 250 mg/dL.
Study population and design. The clinical records of adult (15-year old) patients with infectious mononucleosis who were admitted to the Department of Internal Medicine of the Santiago de Compostela (Spain) University Hospital between 1995 and 2018 were reviewed. The hospital is a reference center for an area of approximately 400,000 inhabitants. A definite diagnosis of infectious mononucleosis was considered when the usual clinical syndrome was accompanied by positive IgM antibodies against the viral capsid antigen of EBV and/or a positive heterophil antibody test (Lennon & Crotty, 2015). The main reasons for hospital admission were severe signs of systemic inflammatory response, difficulty with oral intake, and the presence of complications. A total of 401 patients met the diagnostic criteria; baseline (acute phase) serum triglyceride measurements (after 12 h of fasting) were not available for 41 cases. The case reported in this study was not included in the analysis. The study therefore included 360 patients (51.4% male patients; median age, 19 years; range, 15–87 years). Four patients had a previous history of dyslipidemia. For 160 patients, a second triglyceride measurement was available during the convalescence period (after a median of 30 days from the acute-phase determination; range, 14–177 days). A random subsample (n = 75) of the general adult population in the area , aged 18–30 years (median age, 23 years) was used for the comparison of serum triglyceride concentrations. The study was reviewed and approved by the Galician Ethics Committee.
Statistical analyses. The Mann-Whitney test was used to compare numerical data between groups. The Wilcoxon test was used to compare paired samples of numerical values. The Spearman’s rank test was used to assess the correlations, and the chi-squared test was used to compare proportions.