Cardiac Tamponade as a Severe Complication in a Patient With Dengue

Dengue, an arboviral disease transmitted by the Aedes aegypti mosquito, is a tropical disease prevalent in Brazil, with an increase in severe cases among older adults, especially those with cardiac comorbidities, such as aortic stenosis. Rare complications, such as pericardial effusion with cardiac tamponade, may result from systemic inflammation and plasma leakage, leading to fluid accumulation in serous cavities. A 75-year-old Caucasian male sought care for fever for five days, in addition to myalgia and asthenia, evolving over the last two days with reduced urinary output, progressive dyspnea, and later paroxysmal nocturnal dyspnea. Despite diuretic therapy, he evolved with persistence of symptoms and thrombocytopenia (98,000/mm³), and was then referred to a reference center for treatment of severe dengue. In the emergency department, he was admitted with dyspnea at rest, oxygen saturation of 87% on room air, requiring noninvasive ventilation and supportive measures. Point-of-care ultrasonography (POCUS) revealed diffuse bilateral B-lines and significant pericardial effusion, with inferior vena cava dilation and reduced variability. Laboratory tests showed Hb 14.1 g/dL, leukocytes 8,600/mm³, platelets 98,000/mm³, and positive dengue serology (reactive IgM and IgG). Urgent echocardiography identified a large pericardial effusion (20 mm) with diastolic restriction in the transverse view of the mid-pericardial space, as well as moderate aortic stenosis. Due to hemodynamic worsening, surgical pericardial drainage was indicated, with removal of 460 mL of yellow, citrine-appearing fluid. Analysis of the pericardial fluid showed cellularity of 136/mm³, with 84% macrophages and absence of neoplastic cells; culture was negative. The patient was transferred to the intensive care unit (ICU) after pericardial drainage and showed progressive clinical and laboratory improvement with supportive measures, being discharged after 7 days. The case highlights dengue as a cause of cardiovascular dysfunction, including the rare pericardial effusion with cardiac tamponade. Patients with pre-existing cardiac alterations such as aortic stenosis have increased risk of progressing to more severe cases. The combined approach using imaging diagnosis and pericardial drainage was effective, reinforcing the importance of early intervention when indicated.