Influenza A pneumonia presenting as progressive focal infiltrates in a stem cell transplant recipient

Imaging appearance of swine-origin influenza A (novel 2009 H1N1) pneumonia in an immunocompromised patient. Radiol Case Rep. 2010;5:361. [PMID: 27307850 PMCID: PMC4898215 DOI: 10.2484/rcr.v5i1.361]

The Centers for Disease Control (CDC) predicted a resurgence of Swine-origin Influenza A (novel 2009 H1N1) pneumonia, hospitalizations and deaths during the 2009-2010 flu season. Immunocompromised patients are at higher risk to contract it and may present (atypically) with greater morbidity and mortality. We report the first radiographic description of CDC-confirmed swine-origin influenza A (novel 2009 H1N1) in a 32-year-old immunocompromised man. At presentation, chest radiographs demonstrated bilateral, ill-defined nodular airspace opacities. Chest CT showed upper-lobe-predominant, patchy ground-glass opacities with areas of consolidation and a thick-walled cavity.

Community-acquired infections and their association with myeloid malignancies

INTRODUCTION

Antigenic stimulation is a proposed aetiologic mechanism for many haematological malignancies. Limited evidence suggests that community-acquired infections may increase the risk of acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS). However, associations with other myeloid malignancies including chronic myeloid leukaemia (CML) and myeloproliferative neoplasms (MPNs) are unknown.

MATERIALS AND METHODS

Using the Surveillance, Epidemiology and End Result (SEER)-Medicare database, fourteen community-acquired infections were compared between myeloid malignancy patients [AML (n=8489), CML (n=3626) diagnosed 1992-2005; MDS (n=3072) and MPNs (n=2001) diagnosed 2001-2005; and controls (200,000 for AML/CML and 97,681 for MDS/MPN]. Odds ratios (ORs) and 95% confidence intervals were adjusted for gender, age and year of selection excluding infections diagnosed in the 13-month period prior to selection to reduce reverse causality.

RESULTS

Risk of AML and MDS respectively, were significantly associated with respiratory tract infections, bronchitis (ORs 1.20 [95% CI: 1.14-1.26], 1.25 [95% CI: 1.16-1.36]), influenza (ORs 1.16 [95% CI: 1.07-1.25], 1.29 [95% CI: 1.16-1.44]), pharyngitis (ORs 1.13 [95% CI: 1.06-1.21], 1.22 [95% CI: 1.11-1.35]), pneumonia (ORs 1.28 [95% CI: 1.21-1.36], 1.52 [95% CI: 1.40-1.66]), sinusitis (ORs 1.23 [95% CI: 1.16-1.30], 1.25 [95% CI: 1.15-1.36]) as was cystitis (ORs 1.13 [95% CI: 1.07-1.18], 1.26 [95% CI: 1.17-1.36]). Cellulitis (OR 1.51 [95% CI: 1.39-1.64]), herpes zoster (OR 1.31 [95% CI: 1.14-1.50]) and gastroenteritis (OR 1.38 [95% CI: 1.17-1.64]) were more common in MDS patients than controls. For CML, associations were limited to bronchitis (OR 1.21 [95% CI: 1.12-1.31]), pneumonia (OR 1.49 [95% CI: 1.37-1.62]), sinusitis (OR 1.19 [95% CI: 1.09-1.29]) and cellulitis (OR 1.43 [95% CI: 1.32-1.55]) following Bonferroni correction. Only cellulitis (OR 1.34 [95% CI: 1.21-1.49]) remained significant in MPN patients. Many infections remained elevated when more than 6 years of preceding claims data were excluded.

DISCUSSION

Common community-acquired infections may be important in the malignant transformation of the myeloid lineage. Differences in the aetiology of classic MPNs and other myeloid malignancies require further exploration.

Viral pneumonias in immunocompromised adult hosts

Viral infections have always been considered pediatric diseases. However, viral pneumonia has become an important cause of morbidity and mortality in immuncompromised adults. Improved diagnostic techniques, such as the introduction of highly sensitive nucleic acid amplification tests, have not only allowed us to discover new viruses but also to determine the etiology of viral pneumonia in immunocompromised adult hosts. Unfortunately, only a few antiviral agents are available. Thus, early diagnosis and treatment are crucial to patient outcome. In this article, we review the most common viruses that have been implicated as etiologic agents of viral pneumonia in immunocompromised adults. We discuss the epidemiologic characteristics and clinical presentation of these viral infections and the most appropriate diagnostic approaches and therapies when available.

Successful treatment of influenza A virus by oseltamivir in bone marrow transplant recipients

INFVA is an important cause of pulmonary infections in patients receiving BMT, and is associated with considerable morbidity and mortality for a readily preventable and treatable infection. Few studies have addressed the impact of the new neuraminidase inhibitors in the prognosis of influenza after BMT. The aim of this study is to assess the impact of oseltamivir on the control of INFVA infection in BMT recipients. INFVA was screened in NPA and/or bronchoalveolar lavage using IF in all BMT recipients having respiratory symptoms. Three URTI and one associated upper and LRTI were diagnosed in three BMT recipients out of six patients admitted to the BMT unit, during eight-wk period (March and April 2008). All patients having INFVA respiratory infection were treated by oral oseltamivir 60 mg/day, begun more than 48 h after symptom onset. Respiratory symptoms disappeared within a mean of 60 h (48-96 h) of treatment. However, viral tests had remained positive for 8-39 days. Outside the initial associated URTI and LRTI, no further viral pneumonia occurred. No patient died of INFVA. Oseltamivir was well tolerated outside vomiting during the first three days of treatment in one patient. Oseltamivir appears to play an important role in the outcome of INFVA infection as well in URTI as in severe LRTI in patients receiving BMT.

Serological response to influenza vaccine after hematopoetic stem cell transplantation

Vaccination is the best strategy to prevent influenza infection that is a potential cause of morbidity and mortality in immunosuppressed patients. Here, we evaluated the factors that may affect serological response to influenza vaccine in patients who have undergone hematopoetic stem cell transplantation (HSCT). Sixty-one HSCT recipients were included in the study during the 2007-2008 influenza season. Serum samples prior to vaccination and 6-10 weeks after vaccination were collected. Samples were assayed for antibodies to influenza virus A/H1N1, A/H3N2, and B strains by hemagglutination-inhibition assay. The patients were followed in terms of clinical symptoms up to the next influenza season and for adverse effects within a month after vaccination. Overall, pre-vaccine seroprotection rate against all vaccine antigens (A/H1N1, A/H3N2, and B antigens) was 45.1%, post-vaccine seroprotection rate 91% and seroconversion rate was 28.3%. Seroconversion rates were found to be low against B in patients who were vaccinated in the late influenza season (p = 0.018; respectively). Five patients (10.9%) had no immune response against H1N1. Adverse events were reported in 19.6% (n = 9/46) of the patients. In conclusion, the patients should be vaccinated as early as possible in the influenza season, before they are exposed to the virus.

Failure of Zanamivir Therapy for Pneumonia in a Bone-Marrow Transplant Recipient Infected by a Zanamivir-Sensitive Influenza a (H1N1) Virus

Influenza A viruses are responsible for significant morbidity and mortality after bone marrow transplantation. Here we report failure of inhaled zanamivir treatment in a bone-marrow transplant recipient with pneumonia caused by an influenza A (H1N1) virus, although the influenza viruses isolated from bronchoalveolar lavages before and after treatment were clearly found to be sensitive to zanamivir using cell-based and enzymatic assays. Subsequent oral treatment with oseltamivir allowed complete recovery. Poor bioavailability of zanamivir in the peripheral lungs might have been limiting treatment efficacy in such an immunocompromised patient.