Repeated dengue shock syndrome and 'dengue myocarditis' responding dramatically to a single dose of methyl prednisolone

Myocarditis in a traveler returning from the Dominican Republic: an unusual presentation of dengue fever

Myocarditis is an uncommon manifestation of dengue fever. We describe a case of a 69-year-old Hispanic male who presented to an emergency room in New York City 3 days after returning from a trip to the Dominican Republic complaining of a 1-day history of chest pain and fever. His first electrocardiogram showed a new left bundle branch block, and initial cardiac enzymes included troponin of 5 ng/dL, creatine kinase-MB of 9 ng/mL, and myoglobin of 234 ng/mL. Dengue fever antibodies were found to be elevated: immunoglobulin M (IgM) titer was 2.48 (reference range < 0.9), and immunoglobulin G (IgG) titer was 4.26 (reference range < 0.9). The patient was diagnosed with myocarditis caused by dengue fever. He improved after 1 week with conservative management in a telemetry unit and was discharged home.

Aging and Environmental Enrichment Exacerbate Inflammatory Response on Antibody-Enhanced Dengue Disease in Immunocompetent Murine Model

We previously demonstrated in young mice that in comparison with animals raised in an impoverished environment (IE), animals from an enriched environment (EE) show more severe dengue disease, associated with an increased expansion of memory T target cells. Because active older adults show less functional decline in T-cell adaptive immunity, we hypothesized that aged mice from EE would show higher mortality and T-lymphocyte expansion than mice from IE. To test this hypothesis, we administered serial i.p. injections of anti-DENV2 hyperimmune serum, followed 24 h later by DENV3 (genotype III)-infected brain homogenate. Control mice received equal volumes of serum but received uninfected brain homogenate. The presence of virus or viral antigens was indirectly detected by real-time quantitative RT-PCR and immunohistochemistry. Compared to infected IE animals, EE mice, independent of age, showed higher mortality and more intense clinical signs. Compared to young mice, the higher mortality of aged mice was associated with a higher degree of T lymphocytic hyperplasia in the spleen and infiltration in kidneys, liver, and lungs, but less viral antigen immunolabeling. We propose that a higher expansion of T cells and serotype cross-reactive antibodies are associated with disease severity in aged mice.