Tension pneumothorax was also ruled out, as chest x-ray showed neither mediastinal shift nor tracheal deviation, and the patient had denied any trauma. Laboratory analyses did not indicate hyponatremia, and the patient’s hemoglobin and hematocrit were satisfactory. She was tachycardic on admission, but her blood pressure was stable. As the patient denied any use of vasodilators or diuretics, hypovolemia was ruled out.
Patients experiencing asthma exacerbation can present with acute SOB, which usually resolves following use of IV steroids, nebulizer therapy, and inhaler treatments. Despite being administered IV methylprednisolone and magnesium sulfate in the ED, the patient experienced PEA and respiratory distress and required intubation for airway protection.
The HIV test was nonreactive, and blood and urine cultures did not show any growth. Results of tests for
normal">Legionella urinary antigen and Streptococcus pneumoniae antigen were negative. Sputum culture showed normal flora. Immunovirology testing, however, was positive for both influenza A and B antigens.
Chest X-ray showed no acute pulmonary pathology, nor did chest CT show any central, interlobar, or segmental embolism or mediastinal lymphadenopathy. It was determined that the patient’s acute SOB might represent asthma exacerbation secondary to influenza viral infection. Her PEA was attributed to possible acute pericarditis secondary to concomitant influenza A and B viral infection.
DISCUSSION
Currently, the CDC recognizes three types of influenza virus: A, B, and C.14 Only influenza A viruses are further classified into subtypes, based on the presence of surface proteins called
normal">hemagglutinin (HA) or neuraminidase (NA) glycoproteins. Humans can be infected by influenza A subtypes H1N1 and H3N2.14 Influenza B viruses, found mostly in humans, are associated with significant morbidity and mortality.
Influenza A and B viruses are further classified into strains that change with each flu season—thus, the need to update vaccinations against influenza A and B each year. No vaccination exists against influenza C virus, which is known to cause only mild illness in humans.15
In patients with asthma (as in the case patient), chronic bronchitis, or emphysema, infection with the influenza virus can manifest with SOB, in addition to the more common symptoms of fever, sore throat, headache, rhinorrhea, chills, muscle aches, and general discomfort.16 Patients with coronary artery disease, congestive heart failure (CHF), and/or a history of smoking may experience more severe symptoms and increased risk for influenza-associated mortality than do other patients.17,18
Rare cardiac complications of influenza infections are myocarditis and benign acute pericarditis; myocarditis can progress to CHF and death.19,20 A case of acute myopericarditis was reported by Proby et al21 in a patient with acute influenza A infection who developed pericardial effusions, myositis, tamponade, and pleurisy. That patient recovered after pericardiocentesis and administration of inotropic drugs.
In the literature, a few cases of acute pericarditis have been reported in association with administration of the influenza vaccination.22,23
In the case patient, the diagnosis of influenza A and B was made following testing of nasal and nasopharyngeal swabs with an immunochromatographic assay that uses highly sensitive monoclonal antibodies to detect influenza A and B nucleoprotein antigens.24,25
According to reports in the literature, two-thirds of cases of acute pericarditis are caused by infection, most commonly viral infection (including influenza virus, adenovirus, enterovirus, cytomegalovirus, hepatitis B virus, and herpes simplex virus).26,27 Other etiologies for acute pericarditis are autoimmune (accounting for less than 10% of cases) and neoplastic conditions (5% to 7% of cases).26
PATIENT OUTCOME
Consultation with an infectious disease specialist was obtained. The patient was placed under droplet isolation precautions and was started on a nebulizer, IV steroid treatments, and oseltamivir 75 mg by mouth every 12 hours. She was transferred to a medical floor, where she completed a five-day course of oseltamivir.
As a result of timely intervention, the patient was discharged in stable condition on a therapeutic regimen that included albuterol, fluticasone, and salmeterol inhalation, in addition to tapered-dose steroids. She was advised to follow up with her primary care provider and at the pulmonary clinic.
CONCLUSION
To our knowledge, this is the first reported case of acute pericarditis in a patient with concomitant acute infections with influenza A and B. According to conclusions reached in recent literature, further research is needed to explain the pathophysiology of influenza viral infections, associated cardiovascular morbidity and mortality, and the degree to which these can be prevented by influenza vaccination.1,28 Also to be pursued through research is a better understanding of the morbidity and mortality associated with influenza viruses, especially in children and in adults affected by asthma, cardiac disease, and/or obesity.
REFERENCES
1. Finelli L, Chaves SS. Influenza and acute myocardial infarction. J Infect Dis. 2011;203(12):