Bedside chest radiography of novel influenza A (H7N9) virus infections and follow-up findings after short-time treatment

BACKGROUND

Influenza A (H7N9) virus infections were first observed in China in March 2013. This type virus can cause severe illness and deaths, the situation raises many urgent questions and global public health concerns. Our purpose was to investigate bedside chest radiography findings for patients with novel influenza A (H7N9) virus infections and the followup appearances after short-time treatment.

METHODS

Eight hospitalized patients infected with the novel influenza A (H7N9) virus were included in our study. All of the patients underwent bedside chest radiography after admission, and all had follow-up bedside chest radiography during their first ten days, using AXIOM Aristos MX and/or AMX-IV portable X-ray units. The exposure dose was generally 90 kV and 5 mAs, and was slightly adjusted according to the weight of the patients. The initial radiography data were evaluated for radiological patterns (ground glass opacity, consolidation, and reticulation), distribution type (focal, multifocal, and diffuse), lung zones involved, and appearance at follow-up while the patients underwent therapy.

RESULTS

All patients presented with bilateral multiple lung involvement. Two patients had bilateral diffuse lesions, three patients had unilateral diffuse lesions of the right lobe with multifocal lesions of the left lobe, and the remaining three had bilateral multifocal lung lesions. The lesions were present throughout bilateral lung zones in three patients, the whole right lung zone in three patients with additional involvement in the left middle and/or lower lung zone(s), both lower and middle lung zones in one patient, and the right middle and lower in combination with the left lower lung zones in one patient. The most common abnormal radiographic patterns were ground glass opacity (8/8), and consolidation (8/8). In three cases examined by CT we also found the pattern of reticulation in combination with CT images. Four patients had bilateral and four had unilateral pleural effusion. After a short period of treatment the pneumonia in one patient had significantly improved and three cases demonstrated disease progression. In four cases the severity of the pneumonia fluctuated.

CONCLUSIONS

In patients with influenza A (H7N9) virus infection, the distribution of the lung lesions are extensive, and the disease usually involves both lung zones. The most common imaging findings are a mixture of ground glass opacity and consolidation. Pleural effusion is common. Most cases have a poor short-time treatment response, and seem to have either rapid progressive radiographic deterioration or fluctuating radiographic changes. Chest radiography is helpful for evaluating patients with severe clinical symptoms and for follow-up evaluation.

Comparison of demographic, clinical, radiological characteristics and comorbidities in mechanically ventilated and nonventilated, adult patients admitted in ICU with confirmed diagnosis of influenza A (H1N1)

INTRODUCTION

Influenza A(H1N1) infection affected Indian population in 2009. Patients needed ICU admission and monitoring. Simple demographic, clinical and radiological variables are described in this article in mechanically ventilated and nonventilated patients.

OBJECTIVES

To describe and correlate demographic, clinical, radiographic characteristics and comorbidities in mechanically ventilated and nonventilated, adult patients admitted in ICU with confirmed diagnosis of Influenza A(H1N1) infection.

MATERIAL AND METHODS

Retrospective study of records of 100 RT-PCR confirmed patients with Influenza A (H1N1) infection from August 2009 to March 2010 was done. Each patient underwent an evaluation to determine demographic, clinical and radiographic features, comorbidities, mechanical ventilator required or not.

RESULTS

35 Patients required mechanical ventilation. 27 required IMV, 4 required NIMV while 4 patients initially were put on NIMV required IMV subsequently. 19 (40.42%) female patients required mechanical ventilator. Mean age of mechanically ventilated patients was 33 years, mean duration of illness was 7.9 days, mean duration of hospital stay was 6.8 days. 07 (20.00%) patients with pregnancy, 05 (14.29%) with DM, 05 (14.29%) with HT, 04/11.43%) with obesity required mechanical ventilator. 97.14% patients with fever, 88.54% with breathlessness, 11.43% with haemoptysis, 31.42% patients with throat pain required mechanical ventilator. However except Tachypnoea (p <0.01) no other symptom was statistically significant for mechanical ventilation 33(36.26%) patients with abnormal X ray,16 (80.00%) patients with right sided, 09(60.00%) patients with left sided and 40(71.43%) patients with bilateral disease required mechanical ventilator, right sided (p < 0.01) and bilateral (p <0.01) disease is statistically significant for requirement of mechanical ventilator. 33(47.14%) patients with lower zone involvement, 44 (67.70%) patients with middle zone and 23 (47.92%) patients with upper zone involvement required mechanical ventilator. Upper zone disease (p < 0.01) and middle zone disease (p < 0.01) is statistically significant for requirement of ventilator. 23 (47.92%) patients with right upper zone, 29 (42.64%) patients with right middle zone, 29 (46.77%) with left middle zone, 32 (42.67%) with right lower zone involvement required mechanical ventilator. RUZ (p < 0.01), RMZ (p < 0.01), LMZ (p < 0.001) and RLZ (p < 0.01) involvement had statistical significance for requirement of mechanical ventilator. 20 (33.89%) patients with patchy consolidation, 08 (36.36%) patients with reticulonodular and 05 (50.00%) patients with nodular pattern required mechanical ventilator however none of the pattern is statistically significant for mechanical ventilator. 08 (72.72%) patients with 6 zone involvement, 05 (50.00%) patients with single zone, 08 (40.00%)patients with 4 zone and 06 (33.33%) patients with 3 zone involvement required mechanical ventilator,however none was statistically significant for mechanical ventilator. All four patients requiring NIMV survived, while 28 died out of 31 on IMV.

CONCLUSIONS

Mechanical ventilation requirement was more in females, in presence of comorbidities like pregnancy, DM, HT, in presence of tachypnoea, in presence of bilateral disease and in presence of middle zone and right upper zone disease and with multiple zone disease. All patients with heart involvement required mechanical ventilator. If there is radiological finding of right upper zone involvement, then, there is more probability that these patients require mechanical ventilator for case management. Similarly, RMZ, LMZ and RLZ and cardiomegaly if shown in X-ray, the necessity of ventilator management is more.

A detailed epidemiological and clinical description of 6 human cases of avian-origin influenza A (H7N9) virus infection in Shanghai

BACKGROUND

The world's first reported patient infected with avian influenza H7N9 was treated at the Fifth People's Hospital of Shanghai. Shortly thereafter, several other cases emerged in the local area. Here, we describe the detailed epidemiological and clinical data of 6 cases of avian influenza H7N9.

METHODS AND FINDINGS

We analyzed the epidemiologic and clinical data from clustered patients infected with H7N9 in the Minhang District of Shanghai during a 2-week period. Of the 6 patients, 2 were from a single family. In addition, 3 patients had a history of contact with poultry; however, all 6 patients lived in the proximity of 2 food markets where the H7N9 virus was detected in chickens and pigeons. The main symptoms were fever, cough, and hemoptysis. At onset, a decreased lymphocyte count and elevated creatine kinase, lactate dehydrogenase, procalcitonin, and C-reactive protein levels were observed. As the disease progressed, most patients developed dyspnea and hypoxemia. Imaging studies revealed lung consolidation and multiple ground-glass opacities in the early stage, rapidly extending bilaterally. All patients were treated with oseltamivir tablets beginning on days 3-8 after onset. The main complications were as follows: acute respiratory distress syndrome (ARDS; 83.3%), secondary bacterial infection (66.7%), pleural effusion (50%), left ventricular failure (33.3%), neuropsychiatric symptoms (33.3%), and rhabdomyolysis (16.7%). Of the 6 patients, 4 died of ARDS, with 2 patients recovering from the infection.

CONCLUSIONS

An outbreak of H7N9 infection occurred in the Minhang District of Shanghai that easily progressed to acute respiratory distress syndrome. Two cases showed family aggregation, which led us to identify the H7N9 virus and indicated that human transmission may be involved in the spread of this infection.

Clinicoradiologic correlation in adult patients diagnosed with novel influenza A (H1N1)

BACKGROUND

Influenza A(H1N1) infection affected Indian population in 2009. Patients needed ICU admission and monitoring.

OBJECTIVES

To describe and correlate clinical and radiographic features of Influenza A(H1N1) infection in patients hospitalised in Intensive care unit.

MATERIAL AND METHODS

Retrospective study of records of 100 RT-PCR confirmed patients with Influenza A(H1N1) infection from August 2009 to March 2010 was done. Each patient underwent an evaluation to determine clinical and radiographic features.

RESULTS

Mean age of the patients was 33.43 years (+/- 12.152) with maximum patients between 18-40 years, with 53% males and 43% females. Cough (96%), Fever (95%), breathlessness (83%), throat pain (34%), crepitations (69%), Tachypnoea (59%)were the prominent symptoms and signs. 61% (n = 63) had comorbid condition like pregnancy (n = 13,20.63%), Diabetes Mellitus (DM) (n = 12,19.05%), HT (n = 11,17.60%), Obesity (n = 10, 15.87%) and Rheumatic Valvular Heart Disease (RVHD) (n = 6,09.52%). Chest X ray was abnormal in 91% patients and normal in 09% pts. Bilateral findings were seen in 61.53% cases. Most common zones affected were lower zones (77.46%), then middle zones (71.42%), followed by upper zones (42.7%). Most common patterns were consolidation (64.83%), reticulonodular (24.17%) and nodular (10.98%). 27.47% had two, 21.97% had four, 19.78% had three,12.08% had six, 7.69% had five and 10.98% had single zone involvement. Fever, cough and tachypnoea were present in all 100% pts with nodular pattern while crepitations were observed in 79.66% cases of consolidation. Patchy consolidation was seen in comorbidities like pregnancy (n = 10) and obesity (n = 06), while reticulonodular pattern was observed in hypertensive patients (n = 06). Maximum number of deaths were between 21 and 30 years of age (60.71%). Total number of deaths were 28 with 60.71% (n = 17) deaths between 21 and 30 years of age. Deaths were more in presence of comorbidities like Pregnancy (n = 5, 17.85%), Hypertension (n = 4,14.28%), Diabetes (n = 3 10.21%) and RVHD (n = 3,10.71%), in presence of RLZ involvement (92.85%), RMZ (89.28%), LMZ (85.21%) and RUZ involvement (71.42%), with consolidation pattern (57.14%) followed by reticulonodular pattern (21.42%) and in presence of six zone involvement (36.37%) followed by four zone (35%) and then by three(33%) and two (32%) zone involvement. Mean duration of hospital stay was 9.1 days. 23% patients stayed for less than 5 days, 41% stayed between 9 and 14 days while only 7% required to stay for more than 15 days. 37% pts showed normal Xray at the time of discharge or death. 38% patients showed persistence of radiological lesion at discharge or death.

CONCLUSIONS

Young to middle age patients were commonly affected. Common comorbidities were Pregnancy, Diabetes, Hypertension, and Obesity and patients had fever, cough, breathlessness, tachypnoea, crepitations as common clinical features. Radiologically it was multizonal, bilateral disease with predominant lower zone involvement and common patterns were consolidation followed by reticulonodular and nodular. Patchy consolidation was more common in pregnancy and obesity while reticulonodular pattern was more in hypertensive patients. Fever, cough and tachypnoea were present in all 100% pts with nodular pattern. Crepitations were common in pts with consolidation. Clinical recovery preceded radiological recovery. Young to middle aged individuals died more. Deaths were more in presence of comorbidities like Pregnancy, HT, DM and RVHD, also with RLZ, RMZ, LMZ involvement and with consolidation pattern and with six zone involvement.

Clinical and radiological characteristics of 2009 H1N1 influenza associated pneumonia in young male adults

PURPOSE

Pneumonia was an important cause of death in 2009 H1N1 influenza pandemic (pH1N1). Clinical characteristics of pH1N1 have been described well, but discriminative characteristics suggesting pH1N1 infection in pneumonia patients are not evident today. We evaluated differences between clinical and radiologic characteristics for those associated and not associated with pH1N1 influenza during the pandemic period.

MATERIALS AND METHODS

We reviewed all patients with pneumonia who visited the Armed Forces Capital Hospital between July 2009 and February 2010. During this period, all pneumonia patients were tested for pH1N1 by reverse transcription-polymerase chain reaction (RT-PCR) using nasopharyngeal specimens.

RESULTS

In total, 98 patients with pneumonia were enrolled. Their median age was 20 years and all patients were males. Forty-nine (50%) of patients had pH1N1 infection and the others (50%) had negative results in pH1N1 RT-PCR. Patients with pH1N1 infection complained of dyspnea more commonly (83.3% vs. 29.0%; p<0.001), had higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores [5 (range, 0-12) vs. 3 (range, 0-11); p<0.01], fewer days of prehospital illness [2 (range, 0-10) vs. 4 (range, 0-14); p=0.001], and a higher chance of bilateral infiltrates on chest X-ray (CXR) (67.3% vs. 14.3%; p<0.001) and ground-glass opacity (GGO) lesions on computed tomography (CT; 48.9% vs. 22.0%; p<0.001) than patients without pH1N1 infection.

CONCLUSION

Dyspnea, bilateral infiltrates on CXR, and GGO on CT were dominant features in pH1N1-associated pneumonia. Understanding these characteristics can help selection of patients who require prompt antiviral therapy.

Clinical characteristics and outcomes in hospitalized patients with respiratory viral co-infection during the 2009 H1N1 influenza pandemic

Background

The clinical consequences of co-infection with two or more respiratory viruses are poorly understood. We sought to determine if co-infection with pandemic 2009–2010 influenza A H1N1 (pH1N1) and another respiratory virus was associated with worse clinical outcomes.

Methods

A retrospective cohort study was performed of all hospitalized patients with a positive respiratory viral panel (RVP) for two or more viruses within 72 hours of admission at our institution from October 2009 to December 2009. We compared patients infected with one respiratory virus to those with respiratory viral co-infection.

Results

We identified 617 inpatients with a positive RVP sample with a single virus and 49 inpatients with a positive RVP sample for two viruses (i.e. co-infection). Co-infected patients were significantly younger, more often had fever/chills, tachypnea, and they more often demonstrated interstitial opacities suggestive of viral pneumonia on the presenting chest radiograph (OR 7.5, 95% CI 3.4–16.5). The likelihood of death, length of stay, and requirement for intensive care unit level of care were similar in both groups, but patients with any respiratory virus co-infection were more likely to experience complications, particularly treatment for a secondary bacterial pneumonia (OR 6.8, 95% CI 3.3–14.2). Patients co-infected with pH1N1 and another respiratory virus were more likely to present with chest radiograph changes suggestive of a viral pneumonia, compared to mono-infection with pH1N1 (OR 16.9, 95% CI 4.5–62.7). By logistic regression using mono-infection with non-PH1N1 viruses as the reference group, co-infection with pH1N1 was the strongest independent predictor of treatment for a secondary bacterial pneumonia (OR 17.8, 95% CI 6.7–47.1).

Conclusion

Patients with viral co-infection, particularly with pH1N1, were more likely to have chest radiograph features compatible with a viral pneumonia and complications during their hospital course, particularly treatment for secondary bacterial pneumonia. Despite this, co-infection was not associated with ICU admission.

Analysis of the clinical characteristics and treatment of two patients with avian influenza virus (H7N9)

Avian influenza is one of the most dangerous contagions in poultry worldwide, and avian influenza A viruses are the major pathogens responsible. Outbreaks of H7N9, a strain of the avian influenza A virus H7 subtype, have increasingly been reported in several countries since 2007. This spring, H7N9 broke out in China and has thus far caused 24 cases of infection and 7 deaths. Recently, we treated two patients with H7N9 infection. The infection was characterized by respiratory symptoms, fever, rapid progression, and significant hypoxemia. Laboratory tests showed a low level or decrease in leukocytes, a drop in blood platelets, and an increase in myocardial enzymes and aspartate aminotransferase. Oseltamivir, anti-infective drugs, and immunoglobulin were administered. Supplemental oxygen or non-invasive mechanical ventilation helped to relieve symptoms. This report provides information on the clinical characteristics and treatment of two Chinese patients with H7N9.

Hamman-Rich syndrome revisited: how to avoid misdiagnosis

Please cite this paper as: Fujita et al. (2012) Hamman‐Rich syndrome revisited: How to avoid misdiagnosis. Influenza and Other Respiratory Viruses. DOI: 10.1111/j.1750‐2659.2012.00353.x.

Severe hypothalamopituitary dysfunction accompanied by influenza-associated encephalopathy: report of two pediatric cases

Severe influenza infection may lead to neurological damage, such as encephalopathy. This may, in turn, cause acquired hypothalamopituitary dysfunction, which can result in severe morbidity and even death. We herein report two pediatric patients who developed influenza-associated hypopituitarism and were subsequently diagnosed with encephalopathy. They were diagnosed with acute necrotizing encephalopathy and postresuscitation encephalopathy, respectively. Both showed evidence of endocrine dysfunction, and hormone replacement therapy of adrenal, thyroid, and antidiuretic hormones are resulting in continued cardiac activity and resulted in prolonged survival. Screening for endocrine function is important in patients with severe central nervous system dysfunction.

Prolonged period of acute bronchitis with late progression to acute respiratory distress syndrome as possible result of influenza A (H1N1) virus infection

Young adults with underlying medical conditions who are infected with the H1N1 virus are at risk of quickly progressing from mild upper airways infection to severe ARDS within 4 to 5 days after the onset of the illness. Here, we report the case of a 46-year-old morbidly obese and diabetic woman infected with the H1N1 virus who developed acute bronchitis that lasted for 4 weeks and then progressed to ARDS. We discuss the month-long persistence of the H1N1 viral bronchitis and its late progression to ARDS which may reflect prolonged viral activity. Such a prolonged, rather than quick, course of deterioration can cause clinicians to misdiagnose the etiology of the ARDS and may cause the patient to receive a prolonged treatment with steroids to treat bronchitis symptoms. These steroids may cause increased viral replication and promote parenchymal involvement and the development of ARDS.

Hiding in plain sight: H1N1 influenza presenting with respiratory failure and normal chest radiography

Sepsis and respiratory failure are uncommon complications of infection with H1N1 influenza. In the majority of cases of H1N1-associated sepsis and respiratory failure found in the literature, evidence of pneumonia or the acute respiratory distress syndrome was seen on chest radiography. This case report describes the clinical characteristics of a patient who presented with septic shock and multi-system organ failure due to H1N1 influenza, but had normal chest radiography. Beyond describing a unique presentation of H1N1-related sepsis, this report highlights the need for clinicians to maintain a high index of suspicion for infection with H1N1 influenza in patients with sepsis and respiratory distress.

Clinical, laboratory, and radiologic characteristics of confirmed avian influenza (H5N1)

This was a cross sectional study to determine the clinical, laboratory and radiologic characteristics of confirmed avian influenza (AI) (H5N1) infection among children and adults. This study was conducted at Sulianti Saroso Infectious Diseases Hospital (SS-IDH), Jakarta among subjects confirmed to have AI infection hospitalized during September 2005 to August 2010. The proportion of confirmed AI patients was 33 out of 321 suspected and probable cases (10.2%). Of 26 subjects analyzed (7 subjects was excluded due to loss of or incomplete medical records), the median ages were 7 years and 25 years in children and adults, respectively (range 1 - 39 years). Prominent clinical features were respiratory symptoms [productive cough (13/13 children; 12/13 adults), dyspnea (12/13 children; 13/13 adults)], and fever (12/13 children; 12/13 adults). Leukopenia was found in 9 subjects in each group. Four children and 7 adults had lymphopenia, while thrombocytopenia was found in 7 children and 10 adults. Two children had an increased ALT, while most adults had an increased AST (10/13) and/or ALT (8/13). Bilateral infiltrates found in most subjects on chest x-ray who had clinical deterioration. Of the 3 children who survived out of 13 children with AI, they all had less severe clinical features and no central nervous system involvement, lymphopenia, thrombocytopenia, or increased creatinine level. None of the adults survived.

Critical influenza (H1N1) pneumonia: imaging manifestations and histopathological findings

BACKGROUND

The global outbreak of influenza A (H1N1) has led to the Ministry of Health of China listing it as one of the A-class infectious diseases. Pneumonia is the most serious complication of influenza A, commonly causing death. Populations are ordinarily susceptible to influenza A. This study aimed to investigate the imaging manifestation features of critical influenza A (H1N1) pneumonia and to improve its diagnostic techniques.

METHODS

A total of seven death cases from critical influenza A (H1N1) pneumonia were retrospectively analyzed on their imaging manifestations and autopsy data. Pulmonary CT scanning was performed for five cases, with one receiving additional chest X-ray and chest CT scanning, and chest postero-anterior position X-ray examination was performed for other two. Autopsy was performed for five cases and postmortem examinations were performed for other two cases.

RESULTS

The seven cases of influenza A showed critical manifestations in 4 - 7 days after symptoms onset, with two having basic diseases of diabetes and one being pregnant. Extensive blurry high-density shadows of bilateral lungs were found in three cases, which were most obvious in middle and inferior parts of lungs. Pulmonary CT scanning revealed bilateral flaky parenchymal shadows in peripheral, dorsal and fundus segments of the middle-inferior parts of lungs, with one case of complicated pneumothorax, atelectasis and pleural effusion and another case of thin-walled cavity and dilated bronchi shadows in the superior parts of lungs.

CONCLUSIONS

Diagnostic imaging is an important assessing tool for critical influenza A (H1N1) pneumonia. The imaging manifestations are characteristic instead of being specific. The definitive diagnosis can be made in combination with clinical examinations and laboratory tests.

H1N1 pneumonia: our experience in 50 patients with a severe clinical course of novel swine-origin influenza A (H1N1) virus (S-OIV)

PURPOSE

The authors reviewed chest radiographs (CXR) and thin-section computed tomography (CT) findings of pulmonary complications in a selected population of 50 consecutive patients with severe novel swine-origin influenza A (H1N1) virus (S-OIV) pneumonia who were seen at the Subintensive Respiratory Unit (UTSIR) and at the Intensive Care Unit (ICU) at Monaldi Hospital, Naples, Italy.

MATERIALS AND METHODS

CXR and CT findings of 50 patients who fulfilled the World Health Organisation (WHO) criteria for S-OIV infection were reviewed by four radiologists. The final study group of 50 patients was divided into two subgroups on the basis of clinical course: group 1 consisted of 42 patients requiring noninvasive mechanical ventilation and admitted to the UTSIR; group 2 consisted of eight patients who required ICU admission and extracorporeal membrane oxygenation or advanced mechanical ventilation from October 2009 to December 2009. All patients underwent CXR and thin-section multidetector CT (MDCT) scan; the initial and follow-up radiographs and CT scans were evaluated for the presentation and follow-up pattern (consolidation, ground-glass opacities, nodules, reticulation), distribution and extent of abnormality.

RESULTS

All patients had radiological signs of pulmonary involvement. Ground-glass opacity and consolidation, which was mainly peripheral, was the most frequent finding. In three patients, we report for the first time in viral pneumonia the reversed halo sign. Lesion extent was related to aggressiveness of the illness. More often, both lungs were involved (82%). Thoracic comorbidity was present in 18% of patients; 22% of patients was obese, and in this group, the clinical course was more aggressive than in the others with the same lesion extent at imaging. Furthermore, superinfection led to worsening of the clinical conditions.

CONCLUSIONS

The most common CXR and CT findings in patients with S-OIV infection were unilateral or bilateral ground-glass opacities with or without associated focal or multifocal areas of consolidation. On MDCT, ground-glass opacities and areas of consolidation had a predominant peribronchovascular and subpleural distribution, resembling organising pneumonia; they progressed to bilateral extensive airspace disease in severely ill patients.

Early recognition of the 2009 pandemic influenza A (H1N1) pneumonia by chest ultrasound

INTRODUCTION

The clinical picture of the pandemic influenza A (H1N1)v ranges from a self-limiting afebrile infection to a rapidly progressive pneumonia. Prompt diagnosis and well-timed treatment are recommended. Chest radiography (CRx) often fails to detect the early interstitial stage. The aim of this study was to evaluate the role of bedside chest ultrasonography (US) in the early management of the 2009 influenza A (H1N1)v infection.

METHODS

98 patients who arrived in the Emergency Department complaining of influenza-like symptoms were enrolled in the study. Patients not displaying symptoms of acute respiratory distress were discharged without further investigations. Among patients with clinical suggestion of a community-acquired pneumonia, cases encountering other diagnoses or comorbidities were excluded from the study. Clinical history, laboratory tests, CRx, and computed tomography (CT) scan, if indicated, contributed to define the diagnosis of pneumonia in the remaining patients. Chest US was performed by an emergency physician, looking for presence of interstitial syndrome, alveolar consolidation, pleural line abnormalities, and pleural effusion, in 34 patients with a final diagnosis of pneumonia, in 16 having normal initial CRx, and in 33 without pneumonia, as controls.

RESULTS

Chest US was carried out without discomfort in all subjects, requiring a relatively short time (9 minutes; range, 7 to 13 minutes). An abnormal US pattern was detected in 32 of 34 patients with pneumonia (94.1%). A prevalent US pattern of interstitial syndrome was depicted in 15 of 16 patients with normal initial CRx, of whom 10 (62.5%) had a final diagnosis of viral (H1N1) pneumonia. Patients with pneumonia and abnormal initial CRx, of whom only four had a final diagnosis of viral (H1N1) pneumonia (22.2%; P<0.05), mainly displayed an US pattern of alveolar consolidation. Finally, a positive US pattern of interstitial syndrome was found in five of 33 controls (15.1%). False negatives were found in two (5.9%) of 34 cases, and false positives, in five (15.1%) of 33 cases, with sensitivity of 94.1%, specificity of 84.8%, positive predictive value of 86.5%, and negative predictive value of 93.3%.

CONCLUSIONS

Bedside chest US represents an effective tool for diagnosing pneumonia in the Emergency Department. It can accurately provide early-stage detection of patients with (H1N1)v pneumonia having an initial normal CRx. Its routine integration into their clinical management is proposed.

Chest computed tomography findings in severe influenza pneumonia occurring in neutropenic cancer patients

OBJECTIVE

To describe the chest computed tomography findings for severe influenza H1N1 infection in a series of hospitalized neutropenic cancer patients.

METHODS

We performed a retrospective systematic analysis of chest computed tomography scans for eight hospitalized patients with fever, neutropenia, and confirmed diagnoses of influenza H1N1. The clinical data had been prospectively collected.

RESULTS

Six of eight patients (75%) developed respiratory failure and required intensive care. Prolonged H1N1 shedding was observed in the three mechanically ventilated patients, and overall hospital mortality in our series was 25%. The most frequent computed tomography findings were ground-glass opacity (all patients), consolidation (7/8 cases), and airspace nodules (6/8 cases) that were frequently moderate or severe. Other parenchymal findings were not common. Five patients had features of pneumonia, two had computed tomography findings compatible with bronchitis and/or bronchiolitis, and one had tomographic signs of chronicity.

CONCLUSION

In this series of neutropenic patients with severe influenza H1N1 infection, chest computed tomography demonstrated mainly moderate or severe parenchymatous disease, but bronchiolitis was not a common feature. These findings associated with febrile neutropenia should elicit a diagnosis of severe viral infection.

Pneumonia induced by swine-origin influenza A (H1N1) infection: chest computed tomography findings in children

PURPOSE

The purpose of this study was to determine the features of chest computed tomography (CT) in children with swine-origin influenza A (H1N1) virus (S-OIV).

MATERIALS AND METHODS

The study population consisted of 16 children with laboratory-confirmed S-OIV infection (12 boys, 4 girls), with an age range of 5-10 years (mean 6.3 years). Pneumonia was suspected in these patients based on clinical features or confirmed by radiography. All subjects underwent CT for close evaluation of pneumonia, including characteristics, distribution, extent, and other findings such as pleural effusion, pneumothorax, and pneumomediastinum.

RESULTS

The predominant CT finding was consolidation plus ground-grass opacity (GGO) (11/16, 69%). The consolidation-dominant pattern was found in 10 of 16 (66%) patients, and 1 (6%) was GGO-dominant. One (6%) had only GGO. In all, 7 of the 16 patients had segmental or lobar consolidation. Abnormal opacities were primarily distributed in the central lung zone (8/16, 50%) and were multifocal (15/16, 94%). Four showed atelectasis (4/16, 25%). Pneumomediastinum was observed in 4 of 16 (25%). One patient had negative radiographic findings but was positive on CT.

CONCLUSION

Multifocal consolidation with central distribution is a common CT finding in children with S-OIV, but there are few GGO-dominant cases. Widespread consolidation (segmental or lobar) is also common.

Acute Respiratory Distress Syndrome as a presenting manifestation in young patients infected with H1N1 influenza virus

INTRODUCTION

The new strain of influenza A (H1N1) 2009, often referred to colloquially as "swine flu", which was first detected in April 2009, raised to a pandemic of which the impact was not completely predictable. As reported, numerous cases with severe respiratory failure were also seen among young previously healthy people.

PATIENTS

In the present study, we report eight cases of influenza A (H1N1) 2009 admitted to our medical intensive care with severe respiratory failure between November and December 2009 and in January 2011. All patients were older than 30 but younger than 50 years, had clinical and radiological evidence of an Acute Respiratory Distress Syndrome (ARDS) and needed invasive ventilatory support.

RESULTS

Six of the eight patients had no relevant underlying disease; one had a pre-existing idiopathic lung fibrosis and another had a chronic obstructive pulmonary disease (COPD), an abuse of alcohol and an adiposities grade 3. Four patients needed an extracorporeal membrane oxygenation (ECMO) due to severe respiratory failure with global respiratory insufficiency that could not be treated by conservative ventilatory support. The one patient with a pre-existing lung fibrosis died shortly after lung transplantation despite use of an extracorporeal membrane oxygenation. One other patient died due to a subarachnoidal bleeding under the anticoagulatory regime during ECMO therapy. The adipose COPD-patient died due to septic shock with multiple organ failure without possibility for ECMO support.

CONCLUSIONS

The clinical course of severe cases of influenza A (H1N1) 2009-infection is markedly different from the disease pattern seen during epidemics of seasonal influenza. Most of the patients admitted to our intensive care unit due to influenza A (H1N1) 2009 associated ARDS were previously healthy young people.

H1N1 influenza in an Irish population: patterns of chest radiograph abnormality in patients testing positive

The winter of 2010/2011 saw a second peak in the number of H1N1 cases detected in Ireland. The purpose of this study was to investigate the radiological characteristics of patients diagnosed during this period. A retrospective analysis of these cases was performed. Chest radiographs were classified as normal or abnormal. A total of 37 patients were included. Of these, 22 (59%) of chest radiographs were abnormal and 15 (41%) were normal. In the 7 paediatric patients, 4 (57%) had a perihilar distribution of disease, 2 (28%) had peripherally based disease with 1 (14%) having a mixed distribution. A series of radiographs was available for 9 patients, 6 of these showed a radiographic deterioration from the initial study. The majority of chest radiographs of patients with confirmed H1N1 infection will be abnormal. In children, disease is more likely to be perihilar in distribution. Chest radiography is an important initial investigation in patients with H1N1 infection and is useful to track progression of disease in the subset of patients requiring hospitalization for severe disease.

Severe influenza A (H1N1): the course of imaging findings

BACKGROUND

An outbreak of respiratory illness caused by a novel swine-origin influenza virus (influenza A/H1N1 2009) that began in Mexico was declared a global pandemic by the World Health Organization in June 2009. The pandemic affected many countries, including Israel.

OBJECTIVES

To compare the course of chest radiographic and computed tomography findings in patients who survived and those who died following admission to the intensive care unit (ICU) or intubation due to severe laboratory-confirmed swine-origin influenza A/H1N1 2009.

METHODS

We retrospectively reviewed the patient records (267 radiographs, 8 CTs) of 22 patients (10 males, 12 females) aged 3.5-66 years (median 34) with confirmed influenza A/ H1N1 2009, admitted to the ICU and/or intubated in five major Israeli medical centers during the period July-November 2009. We recorded demographic, clinical, and imaging findings--including pattern of opacification, extent, laterality, distribution, zone of findings, and presence/absence of nodular opacities--at initial radiography and during the course of disease, and compared the findings of survivors and non-survivors. Statistical significance was calculated using the Wilcoxon (continuous variables) and Fisher exact tests.

RESULTS

The most common findings on the initial chest radiography were airspace opacities, which were multifocal in 17 patients (77%) and bilateral in 16 (73%), and located in the lower or lower and middle lung zones in 19 patients (86%). Large airspace nodules with indistinct margins were seen in 8 patients (36%). Twelve patients survived, 10 died. Patients who died had multiple background illnesses and were significantly older than survivors (P = 0.006). Radiologic findings for the two groups were not significantly different.

CONCLUSION

Airspace opacities, often with nodular appearance, were the most common findings among patients with severe influenza A/H1N1 2009. The course of radiologic findings was similar in patients with severe influenza A/ H1N1 2009 who survived and those who died.

Distinguishing characteristics between pandemic 2009-2010 influenza A (H1N1) and other viruses in patients hospitalized with respiratory illness

Background

Differences in clinical presentation and outcomes among patients infected with pandemic 2009 influenza A H1N1 (pH1N1) compared to other respiratory viruses have not been fully elucidated.

Methodology/Principal Findings

A retrospective study was performed of all hospitalized patients at the peak of the pH1N1 season in whom a single respiratory virus was detected by a molecular assay targeting 18 viruses/subtypes (RVP, Luminex xTAG). Fifty-two percent (615/1192) of patients from October, 2009 to December, 2009 had a single respiratory virus (291 pH1N1; 207 rhinovirus; 45 RSV A/B; 37 parainfluenza; 27 adenovirus; 6 coronavirus; and 2 metapneumovirus). No seasonal influenza A or B was detected. Individuals with pH1N1, compared to other viruses, were more likely to present with fever (92% & 70%), cough (92% & 86%), sore throat (32% & 16%), nausea (31% & 8%), vomiting (39% & 30%), abdominal pain (14% & 7%), and a lower white blood count (8,500/L & 13,600/L, all p-values<0.05). In patients with cough and gastrointestinal complaints, the presence of subjective fever/chills independently raised the likelihood of pH1N1 (OR 10). Fifty-five percent (336/615) of our cohort received antibacterial agents, 63% (385/615) received oseltamivir, and 41% (252/615) received steroids. The mortality rate of our cohort was 1% (7/615) and was higher in individuals with pH1N1 compared to other viruses (2.1% & 0.3%, respectively; p = 0.04).

Conclusions/Significance

During the peak pandemic 2009–2010 influenza season in Rhode Island, nearly half of patients admitted with influenza-like symptoms had respiratory viruses other than influenza A. A high proportion of patients were treated with antibiotics and pH1N1 infection had higher mortality compared to other respiratory viruses.