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Abstract

Introduction: The human bocavirus (HBoV) is an emerging parvovirus discovered in 2005. It has been identified in children in different parts of the world. Data suggest that HBoV may be an etiological agent responsible for respiratory tract diseases, especially in children and immunocompromised hosts. It can also cause gastrointestinal symptoms, such as diarrhea and vomiting. HBoV is not confined to the respiratory tract and its presence in respiratory secretions, serum and stool samples suggest that this virus may cause systemic illness, although it seems to be very rare. Currently, HBoV can be detected only by polymerase chain reactions (PCR). Another important feature of this agent is that no specific treatment is known. Case description: Male, 85 years old, pulmonologist physician, admitted to the Intensive Care Unit (ICU) of our hospital with a community-acquired pneumonia without clinical improvement after three days of outpatient treatment with clarithromycin. He was hospitalized for investigation and beggining of intravenous antibiotics. During his second day of hospitalization, he presented an acute atrial fibrillation with rapid ventricular response. During the episode, he was submitted to an echocardiogram (ECHO) that showed left ventricle ejection fraction (LVEF) of 0.50 with mild diffuse hypokinesis; the prior ECHO (4 months before the hospitalization) did not suggest any kind of contraction disfunction. He received amiodarone bolus followed by continuous infusion for 24 hours with adequate heart rate control. The patient evolved with acute respiratory failure after one day, and a new ECHO showed signs of severe systolic heart failure (LVEF .28) with diffuse hypokinesis, and sustained tachycardia; electrocardiogram showed atrial fibrillation again. He was submitted to a transesophageal ECHO followed by electric synchronized cardioversion, with reassignment of sinus rhythm. Antibiotic was scaled and clinical measures for acute heart failure were initiated. During the next 24 hours, ventricular function improved (LVEF .50), and the respiratory symptoms improved, as well. An oropharyngeal swab that was performed during the pneumonia investigation showed a positive polymerase chain reaction (PCR) for bocavirus. No other pathogen was isolated in blood cultures or secretions samples, despite comprehensive investigation. Computed tomography coronary ruled out ischemic event associated and myocardial necrosis markers were negative during all the stay. The patient showed great progress after this events, and was discharged from the ICU 8 days after admission. He left the hospital after finishing the pneumonia treatment, without any respiratory symptoms at all. Discussion: This case report shows the presence of HBoV in respiratory tract of a patient presenting with bronchopneumonia and acute left ventricular dysfunction. Considering the fact that no other etiological agents were identified, and myocardial infarction was ruled out, we can consider the possibility of bocavirus being associated with a myocarditis, causing these symptoms and clinical picture. The ultimate test to confirm that hypothesis, would be a myocardial biopsy, witch was not performed in this case. The bocavirus is a relatively new virus, with most reports focused on respiratory symptoms. Nevertheless, it has been shown the presence of HBoV DNA in heart and other tissues. The pathophysiology and the relationship between the presence of the virus and cardiac dysfunction have not been clearly elucidated, even though it is possible. Conclusion: The full spectrum of disease associated with HBoV remains to be elucidated and probably is not limited to respiratory infections, with other clinical implications. It remains to be seen if respiratory infection due to HBoV in a patient with acute cardiac failure can be a myocarditis caused by bocavirus, or it is just a mere coincidence.