Patient A is a transfusion dependant 24-year-old woman who was treated for myelodysplastic syndrome with a matched unrelated peripheral blood stem cell transplantation in December 2008 complicated by post transplant lymphoproliferative disorder and graft versus host disease. She recently received a stem cell boost and courses of corticosteroids, rituximab, and tacrolimus in the two months prior to infection with influenza.
The patient presented on October 24th, 2009 with fever of 38.5°C, coryza, myalgias, productive cough with clear sputum, and loose stool. She had course breath sounds bilaterally, heart rate was 120 beats per minute, and she was tachypnic with an oxygen saturation of 89%. Chest radiography demonstrated a right-sided infiltrate and complete blood count showed slight lymphopenia. The patient was treated with oxygen, empiric oseltamivir 75mg twice daily, and piperacillin/tazobactam. Rapid test for influenza A was positive and all bacterial cultures negative. The patient required oxygen for approximately 8 days, and chest CT performed on day 6 showed bilateral patchy infiltrates. The patient was treated for 30 days continuously with oseltamivir and remained symptomatic, but respiratory symptoms began to improve after day 21. All repeat nasopharyngeal washes and a bronchioalveolar lavage remained positive for influenza A by viral culture until 44 days after initial diagnosis ().
Patient B is a 49-year-old male who underwent matched unrelated donor peripheral blood stem cell transplantation in March 2009 to treat recurrence of diffuse large B-cell lymphoma. The patient was recently treated for cytomegalovirus reactivation and graft versus host disease, and medications included sirolimus and prednisone. On October 22, 2009, this patient presented with mild upper respiratory symptoms. He was afebrile and breathing comfortably. Chest radiography showed no evidence of disease and complete blood count revealed lymphopenia. The respiratory virus culture was positive for influenza A at 24 hours and the patient was subsequently treated with 75mg oseltamivir twice daily.
After 14 days of oseltamivir therapy the patient was admitted with worsening fatigue, cough, sinus pressure, and significant lower extremity edema. Radiographs and chest CT demonstrated extensive bilateral patchy infiltrates. Cultures from both a nasal wash and bronchoscopy were positive solely for influenza A. Oseltamivir therapy was continued and levofloxacin was added empirically.
After 24 days of continuous oseltamivir therapy he developed respiratory distress and was admitted to the ICU for treatment with noninvasive positive pressure ventilation. A second bronchoscopy was performed that revealed positive influenza cultures. Further empiric antibiotics were added and 10 days of peramivir IV was administered. Thirty one days after diagnosis the patient’s severe symptoms had stabilized, but the patient remained symptomatic and nasopharyngeal wash samples remained positive for influenza A on day 32 and day 40. The patient then received 10 days of inhaled zanamivir therapy and by day 46 a negative nasopharyngeal wash was obtained with overall improvement of symptoms ().