Computed tomographic features of Legionella pneumophila pneumonia in 38 cases

Legionnaires Disease in Solid Organ Transplant Recipients: A Decade-Long Nationwide Study in France

BACKGROUND

Legionnaires disease (LD) is a rare, life-threatening opportunistic bacterial infection that poses a significant risk to patients with impaired cell-mediated immunity such as solid organ transplant recipients. However, the epidemiologic features, clinical presentation, and outcomes of LD in this population are poorly described.

RESEARCH QUESTION

What are the clinical manifestations, radiologic presentation, risk factors for severity, treatment, and outcome of LD in solid organ transplant recipients?

STUDY DESIGN AND METHODS

In this 10-year multicenter retrospective cohort study in France, where LD notification is mandatory, patients were identified by hospital discharge databases. Diagnosis of LD relied on positive culture findings from any respiratory sample, positive urinary antigen test (UAT) results, positive specific serologic findings, or a combination thereof. Severe LD was defined as admission to the ICU.

RESULTS

One hundred one patients from 51 transplantation centers were eligible; 64 patients (63.4%) were kidney transplant recipients. Median time between transplantation and LD was 5.6 years (interquartile range, 1.5-12 years). UAT results were positive in 92% of patients (89/97). Among 31 patients with positive culture findings in respiratory samples, Legionella pneumophila serogroup 1 was identified in 90%. Chest CT imaging showed alveolar consolidation in 98% of patients (54 of 57), ground-glass opacity in 63% of patients (36 of 57), macronodules in 21% of patients (12 of 57), and cavitation in 8.8% of patients (5 of 57). Fifty-seven patients (56%) were hospitalized in the ICU. In multivariate analysis, severe LD was associated with negative UAT findings at presentation (P = .047), lymphopenia (P = .014), respiratory symptoms (P = .010), and pleural effusion (P = .039). The 30-day and 12-month mortality rates were 8% (8 of 101) and 20% (19 of 97), respectively. In multivariate analysis, diabetes mellitus was the only factor associated with 12-month mortality (hazard ratio, 3.2; 95% OR, 1.19-8.64; P = .022).

INTERPRETATION

LD is a late and severe complication occurring in solid organ transplant recipients that may present as pulmonary nodules on which diabetes impacts its long-term prognosis.

Community-Acquired Pneumonia: Postpandemic, Not Post-COVID-19

The coronavirus disease 2019 (COVID-19) pandemic upended our approach to imaging community-acquired pneumonia, and this will alter our diagnostic algorithms for years to come. In light of these changes, it is worthwhile to consider several postpandemic scenarios of community-acquired pneumonia: (1) patient with pneumonia and recent positive COVID-19 testing; (2) patient with air space opacities and history of prior COVID-19 pneumonia (weeks earlier); (3) multifocal pneumonia with negative or unknown COVID-19 status; and (4) lobar or sublobar pneumonia with negative or unknown COVID-19 status. In the setting of positive COVID-19 testing and typical radiologic findings, the diagnosis of COVID-19 pneumonia is generally secure. The diagnosis prompts vigilance for thromboembolic disease acutely and, in severely ill patients, for invasive fungal disease. Persistent or recurrent air space opacities following COVID-19 infection may more often represent organizing pneumonia than secondary infection. When COVID-19 status is unknown or negative, widespread airway-centric disease suggests infection with mycoplasma, Haemophilus influenzae, or several respiratory viruses. Necrotizing pneumonia favors infection with pneumococcus, Staphylococcus, Klebsiella, and anaerobes. Lobar or sublobar pneumonia will continue to suggest the diagnosis of pneumococcus or consideration of other pathogens in the setting of local outbreaks. A positive COVID-19 test accompanied by these imaging patterns may suggest coinfection with one of the above pathogens, or when the prevalence of COVID-19 is very low, a false positive COVID-19 test. Clinicians may still proceed with testing for COVID-19 when radiologic patterns are atypical for COVID-19, dependent on the patient's exposure history and the local epidemiology of the virus.

Clinical and computed tomographic features of Legionella pneumonia with negative urine antigen test results

BACKGROUND

Legionella spp. can cause severe pneumonia and most Legionella pneumonia (LP) cases are diagnosed using the urine antigen test (UAT). However, diagnosis of LP with negative UAT results (LPNUAT) is challenging. We investigated the clinical and radiological features of LPNUAT.

METHODS

We retrospectively collected LP cases with positive UAT (LPPUAT) and cases of suspected LP with negative UAT that were examined by Legionella culture between July 2014 and March 2020. We investigated the clinical and CT findings for LP that showed negative UAT results and was diagnosed by culture and compared these findings with those for other pneumonias suspicious for LP with negative results in UAT and Legionella culture (OPSLP).

RESULTS

Eight LPNUAT, 20 LPPUAT, and 19 OPSLP cases were included in this study. There were no significant differences in the clinical and CT findings between LPPUAT and LPNUAT when examined by UAT. In LPNUAT, dyspnea, renal dysfunction, liver dysfunction, and bilateral lesions were more commonly observed and inflammatory changes and the number of affected lobes were significantly higher when examined by culture than when examined by UAT. Comparison to OPSLP, LPNUAT did not show such differences, but rather showed disturbances in consciousness, hyponatremia and rhabdomyolysis. Furthermore, lobar consolidation was observed more frequently and bronchial wall thickening and centrilobular nodules were observed less frequently in LPNUAT.

CONCLUSIONS

LP characteristics such as disturbance of consciousness, hyponatremia, rhabdomyolysis, lobar consolidation, and less bronchial wall thickening and centrilobular nodule contribute to the diagnosis of LP in patients with negative UAT results.

Evaluation of a novel urinary antigen test kit for diagnosing Legionella pneumonia

OBJECTIVES

The aim of this study was to evaluate the diagnostic utility of a novel test kit that could theoretically detect all serogroups of Legionella pneumophila for diagnosing Legionella pneumonia, in comparison with existing kits.

METHODS

This study was conducted in 16 hospitals in Japan from April 2016 to December 2018. Three urinary antigen test kits were used: the novel kit (LAC-116), BinaxNOW Legionella (Binax), and Q-line Kyokutou Legionella (Q-line). In addition, sputum culture and nucleic acid detection tests and serum antibody tests were performed where possible. The diagnostic accuracy and correlations of the novel kit with the two existing kits were analyzed.

RESULTS

In total, 56 patients were diagnosed with Legionella pneumonia. The sensitivities of LAC-116, Binax, and Q-line were 79%, 84%, and 71%, respectively. The overall match rate between LAC-116 and Binax was 96.8% and between LAC-116 and Q-line was 96.4%. One patient had L. pneumophila serogroup 2, and only LAC-116 showed a positive result, whereas Binax and Q-line did not.

CONCLUSIONS

The novel Legionella urinary antigen test kit was useful for diagnosing Legionella pneumonia. In addition, it could detect Legionella pneumonia caused by non-L. pneumophila serogroup 1.

Fatal Legionella pneumophila serogroup 1 pleural empyema: A case report

BACKGROUND

Legionella pneumophila (L. pneumophila) is a gram-negative intracellular bacillus composed of sixteen different serogroups. It is mostly known to cause pneumonia in individuals with known risk factors as immunocompromised status, tobacco use, chronic organ failure or age older than 50 years. Although parapneumonic pleural effusion is frequent in legionellosis, pleural empyema is very uncommon. In this study, we report a case of fatal pleural empyema caused by L. pneumophila serogroup 1 in an 81-year-old man with multiple risk factors.

CASE SUMMARY

An 81-year-old man presented to the emergency with a 3 wk dyspnea, fever and left chest pain. His previous medical conditions were chronic lymphocytic leukemia, diabetes mellitus, chronic kidney failure, hypertension and hyperlipidemia, without tobacco use. Chest X-ray and comouted tomography-scan confirmed a large left pleural effusion, which puncture showed a citrine exudate with negative standard bacterial cultures. Despite intravenous cefotaxime antibiotherapy, patient’s worsening condition after 10 d led to thoracocentesis and evacuation of 2 liters of pus. The patient progressively developed severe hypoxemia and multiorgan failure occurred. The patient was treated by antibiotherapy with cefepime and amikacin and with adequate symptomatic shock treatment, but died of uncontrolled sepsis. The next day, cultures of the surgical pleural liquid samples yielded L. pneumophila serogroup 1, consistent with the diagnosis of pleural legionellosis.

CONCLUSION

L. pneumophila should be considered in patients with multiple risk factors and undiagnosed pleural empyema unresponsive to conventional antibiotherapy.

Relationship Between Clinical Features and Computed Tomographic Findings in Hospitalized Adult Patients With Community-Acquired Pneumonia

Background

Data on the relationship between the clinical and microbiological features of community-acquired pneumonia (CAP) and its computed tomography (CT) findings are limited. The aim of the present study was to investigate the clinic-microbiological features of patients with CAP presenting with ground-glass opacity (GGO) and centrilobular nodules or tree-in-bud pattern on CT images.

Methods

Patients with CAP who underwent a CT scan at presentation were retrospectively classified using CT findings into consolidation, GGO and bronchiolitis groups. These 3 groups were compared in terms of clinical parameters and microbiological data.

Results

A total of 40 patients (2.4%) were allocated to the bronchiolitis group and 46 (2.8%) to the GGO group. The most common pathogen in the bronchiolitis group was Mycoplasma pneumoniae, which was significantly more frequently isolated in this group. The bronchiolitis group was characterized by a higher percentage of cough, a lower percentage of chest pain and lower blood levels of inflammatory markers. Common pathogens in the GGO group were not significantly different from those in the other 2 groups. Unlike that observed in the consolidation group, complicated parapneumonic effusion or empyema was not observed in the bronchiolitis or GGO group. Outcome variables were similar in the 3 groups.

Conclusions

The bronchiolitis group was characterized by a higher frequency of M. pneumoniae and a less severe form of CAP. The GGO and consolidation groups was similar with respect to causative microorganisms and the clinical features of CAP. No patient in the bronchiolitis or GGO group exhibited complicated parapneumonic effusion or empyema.

Study of the radiologic features of Legionnaires' disease with mediastinal adenopathy: Legionella or lymphoma?

An index case of Legionnaires's disease with mediastinal adenopathy prompted us to review our recent experience with Legionnaires' disease to determine the incidence of mediastinal adenopathy of this finding in Legionnaires' disease. We reviewed the radiographic findings of 90 hospitalized adults with Legionnaires' disease from 2015 to 2017. Excluded were 11 patients with mediastinal adenopathy due to non-Legionnaires' disease causes, e.g., lymphoma. Thirty-seven of the remaining patients had both chest films and chest computed tomography (CT) scans. Of the 37 Legionnaires' disease cases, 13/37 (35%) had mediastinal adenopathy and 8/27 (24%) also had unilateral hilar adenopathy. These chest CT findings were not seen on chest films. Chest CT scans are needed to detect mediastinal adenopathy in Legionnaires' disease. Mediastinal adenopathy may be due to Legionnaires' disease or a malignancy. Some findings in Legionnaires' disease are also present in mediastinal adenopathy due to lymphomas, e.g., highly elevated erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), and ferritin. Hospitalized adults with Legionnaires' disease and mediastinal adenopathy should have serial chest CT scans to monitor resolution of the mediastinal adenopathy. In hospitalized adults with otherwise unexplained persistent mediastinal adenopathy, they should be considered as being due to another etiology, e.g., lymphoma, until proven otherwise.

Legionella pneumonia due to non-Legionella pneumophila serogroup 1: usefulness of the six-point scoring system

Background

Because of a limited number of reports, we aimed to investigate the clinical characteristics of patients with Legionella pneumonia due to non-Legionella pneumophila serogroup 1 and the diagnostic usefulness of the six-point scoring system for such patients compared with patients with pneumonia caused by L. pneumophila serogroup 1.

Methods

We retrospectively analysed patients diagnosed with Legionella pneumonia due to non-L. pneumophila serogroup 1 between March 2001 and June 2016. We examined the clinical characteristics, including symptoms, laboratory findings, radiologic findings, pneumonia severity, initial treatment and prognosis. We also calculated scores using the six-point scoring system in these patients. Furthermore, we compared the clinical characteristics and six-point scores between non-L. pneumophila serogroup 1 patients and L. pneumophila serogroup 1 patients among hospitalized community-acquired pneumonia patients enrolled prospectively between October 2010 and July 2016.

Results

Eleven patients had pneumonia due to non-L. pneumophila serogroup 1; their median age was 66 years and 8 patients (72.7%) were male. The most common pathogen was L. pneumophila serogroup 3 (6/11), followed by L. pneumophila serogroup 9 (3/11), L. pneumophila serogroup 6 (1/11) and L. longbeachae (1/11). Non-specific symptoms, such as fever and cough, were common. Six patients (54.5%) had liver enzyme elevation, but no patient developed hyponatraemia at <130 mEq/L. Nine patients (81.8%) showed lobar pneumonia and 7 patients (63.6%) manifested with consolidation and ground-glass opacity. Patients with mild to moderate severity comprised 10 (90.9%) by CURB-65 and 5 (45.5%) by the Pneumonia Severity Index. Of all patients, 4 were admitted to the intensive care unit and 3 died despite appropriate empiric therapy. The clinical characteristics were not significantly different between non-L. pneumophila serogroup 1 patients and L. pneumophila serogroup 1 patients (n = 23). At a cut-off value of ≥ 2 points, the sensitivity of the six-point scoring system was 54.5% (6/11) for non-L. pneumophila serogroup 1 patients and 95.7% (22/23) for L. pneumophila serogroup 1 patients.

Conclusions

Cases of non-L. pneumophila serogroup 1 pneumonia varied in severity from mild to severe and the clinical characteristics were often non-specific. The six-point scoring system was not useful in predicting such Legionella pneumonia cases.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0559-3) contains supplementary material, which is available to authorized users.

Diagnosis and treatment of community-acquired pneumonia in adults: 2016 clinical practice guidelines by the Chinese Thoracic Society, Chinese Medical Association

Community‐acquired pneumonia (CAP) in adults is an infectious disease with high morbidity in China and the rest of the world. With the changing pattern in the etiological profile of CAP and advances in medical techniques in diagnosis and treatment over time, Chinese Thoracic Society of Chinese Medical Association updated its CAP guideline in 2016 to address the standard management of CAP in Chinese adults. Extensive and comprehensive literature search was made to collect the data and evidence for experts to review and evaluate the level of evidence. Corresponding recommendations are provided appropriately based on the level of evidence. This updated guideline covers comprehensive topics on CAP, including aetiology, antimicrobial resistance profile, diagnosis, empirical and targeted treatments, adjunctive and supportive therapies, as well as prophylaxis. The recommendations may help clinicians manage CAP patients more effectively and efficiently. CAP in pediatric patients and immunocompromised adults is beyond the scope of this guideline. This guideline is only applicable for the immunocompetent CAP patients aged 18 years and older. The recommendations on selection of antimicrobial agents and the dosing regimens are not mandatory. The clinicians are recommended to prescribe and adjust antimicrobial therapies primarily based on their local etiological profile and results of susceptibility testing, with reference to this guideline.

Thoracic Imaging Features of Legionnaire's Disease

Imaging examinations are often performed in patients with Legionnaires' disease. The literature to date has documented that the imaging findings in this disorder are relatively nonspecific, and it is therefore difficult to prospectively differentiate legionella pneumonia from other forms of pneumonia, and from other noninfectious thoracic processes. Through a review of clinical cases and the literature, our objective is for the reader to gain a better understanding of the spectrum of radiographic manifestations of Legionnaires' disease.

Early Radiographic and Tomographic Manifestations of Legionnaires' Disease

PURPOSE

Legionnaires' disease (LD) may occur sporadically or in the course of outbreaks, where the typical radiological manifestations of the disease may better be delineated. We took advantage of a rare community-based epidemic of LD (181 patients) that occurred in 2012 in Quebec City, Canada, to describe the radiographic features of LD and compare the its tomographic presentation with that of community-acquired pneumonia caused by common bacteria other than Legionella pneumophila.

METHODS

From the 181 individuals affected in the outbreak, we obtained the chest radiographs of 159 individuals (mean 63 ± 15 years of age) for detailed analysis; 33 patients had a computed tomography (CT) scan performed during the course of their illness. In a case-control study, we compared the CT scans of patients with LD with those of patients who had received a diagnosis of community-acquired pneumonia caused by a pathogen other than Legionella and confirmed by chest CT scan.

RESULTS

Overall, LD most often presented as an airspace consolidation involving 1 of the lower lobes. Pleural effusion and mediastinal adenopathies were apparent only in a minority, whereas no pneumothorax or cavitation was noted. We did not find any significant difference in chest CT scan findings in patients with LD vs those with community-acquired pneumonia from other bacterial origin. No radiological finding was clearly associated with an increased risk of intensive care unit admission or mortality.

CONCLUSIONS

The early radiographic and tomographic manifestations of LD are nonspecific and similar to those found in community-acquired pneumonia from other bacterial origin.

Community-Acquired Pneumonia Caused by Mycoplasma pneumoniae: How Physical and Radiological Examination Contribute to Successful Diagnosis

Mycoplasma pneumoniae is one of the most common causes of community-acquired pneumonia (CAP), particularly in young adults. Vital signs are usually normal except for temperature. On physical examination, general appearance is normal compared with that of typical pneumonia such as pneumococcal pneumonia patients. Mycoplasma sometimes causes ear infections such as otitis media. It is important to distinguish between typical pneumonia and atypical pneumonia such as mycoplasma pneumonia because having the right diagnosis allows for the use of the correct antibiotic to treat CAP while preventing development of drug-resistant bacteria and also decreasing medical cost. The symptoms and diagnosis of mycoplasma pneumonia is multi-fold. Auscultation of patients can demonstrate trace late inspiratory crackles or normal alveolar sounds; however, bilateral polyphonic wheezes can sometimes be heard because of bronchiolitis. With regard to radiological findings, a chest radiogragh often shows bilateral reticulonodular or patchy consolidation in both lower lobes. Pleural effusion is rarely observed in adult cases. Immunocompetent patients tend to reveal more extensive shadowing compared with immunocompromised patients. As serological diagnostic methods are not able to offer 100% reliable diagnosis, integration of physical and radiological examination is crucial to accurately diagnose mycoplasma pneumonia. Herein, I review the typical findings from physical examination and imaging patterns of patients with mycoplasma pneumonia.

Clinical Application of High-Resolution Computed Tomographic Imaging Features of Community-Acquired Pneumonia

Background

This article discusses the value of high-resolution computed tomography (HRCT) in the diagnosis and treatment of pulmonary infections. Lung infection caused by pathogens is an important cause of death. Traditional methods to treat lung infection involved empirical antibiotic therapy. Thin-slice CT scanning is widely used in the clinical setting, and HRCT scan can very clearly show alveolar and bronchiolar involvement of infection.

Material/Methods

In total, 178 patients with community-acquired pneumonia (CAP) were enrolled. All the patients underwent CT scan, qualified sputum, and blood samples for culture or immunological biochemical tests. CT imaging features, pathogenic bacteria, and treatment results were used for statistical analysis.

Results

In 77 patients with lobar consolidation, the rate of detection was 43.26% (77/178), and in 101 patients with lobular pneumonia it was 56.74% (101/178). In 51 patients, pathogenic bacteria were detected (28.65%, 51/178). Sixteen of 33 patients detected with bacteria had cavities (48.5%, 16/33) and 35 of 145 patients detected with bacteria had no cavities (24.1%, 35/145). The difference between the 2 groups was statistically significant (χ²=7.795, P=0.005). According to the pathogenic bacteria, 38 patients were cured (74.51%, 38/51), and according to the CT imaging features 81 patients were cured (71.05%, 81/114). No statistically significant difference was found between them (χ²=0.209, P=0.647).

Conclusions

Treatment effect of CAP based on HRCT findings is not inferior to treatment effect guided by microbial characterization.

A Fatal Case of Relapsing Pneumonia Caused by Legionella pneumophila in a Patient with Rheumatoid Arthritis After Two Injections of Adalimumab

We present a rare fatal case of relapsing pneumonia caused by Legionella pneumophila in a patient with rheumatoid arthritis after only two injections of adalimumab. A 78-year-old Japanese woman with a 14-year history of rheumatoid arthritis was prescribed adalimumab because her disease activity remained high. However, 8 days after her second injection of adalimumab, she was admitted to our hospital and diagnosed with pneumonia caused by L. pneumophila. Following intravenous antibiotic therapy, she recovered completely from pneumonia and was discharged on day 10, but pneumonia relapsed, resulting in death 79 days after the first episode of pneumonia. L. pneumophila can lead to recurrence of pneumonia that can ultimately prove fatal, similar to the present case. A review of the pertinent literature is also presented.

The reversed halo sign: update and differential diagnosis

The reversed halo sign is characterised by a central ground-glass opacity surrounded by denser air-space consolidation in the shape of a crescent or a ring. It was first described on high-resolution CT as being specific for cryptogenic organising pneumonia. Since then, the reversed halo sign has been reported in association with a wide range of pulmonary diseases, including invasive pulmonary fungal infections, paracoccidioidomycosis, pneumocystis pneumonia, tuberculosis, community-acquired pneumonia, lymphomatoid granulomatosis, Wegener granulomatosis, lipoid pneumonia and sarcoidosis. It is also seen in pulmonary neoplasms and infarction, and following radiation therapy and radiofrequency ablation of pulmonary malignancies. In this article, we present the spectrum of neoplastic and non-neoplastic diseases that may show the reversed halo sign and offer helpful clues for assisting in the differential diagnosis. By integrating the patient's clinical history with the presence of the reversed halo sign and other accompanying radiological findings, the radiologist should be able to narrow the differential diagnosis substantially, and may be able to provide a presumptive final diagnosis, which may obviate the need for biopsy in selected cases, especially in the immunosuppressed population.

[Four cases of respiratory infections caused by Legionella pneumophila serogroup 3]

Legionella pneumonia tends to be severe and is known to be fatal. Introduction of the urinary Legionella antigen test and changes in the Infectious Disease Law have led to increased numbers of reports, and milder cases are now occasionally seen. We experienced three cases demonstrating mild respiratory infections and one case demonstrating nosocomial pneumonia associated by Legionella pneumophila serogroup 3. Case 1 showed multiple ground-glass opacities on HRCT and productive cough. Cases 2 and 3 showed abnormal findings on chest X-ray, and chest CT findings in both cases suggested chronic respiratory infection. Case 4 experienced fever and hypoxia, and pulmonary edema was noted on X-ray. All of them four cases were diagnosed with respiratory infections isolated L. pneumophila serogroup 3 by culture results, and three of them cases were treated in the outpatient clinic. Thus, milder cases of Legionella pneumonia may be encountered during routine care, and tests for Legionella should be performed in such cases.

Correlations between computed tomography findings and clinical manifestations of Streptococcus pneumoniae pneumonia

PURPOSE

The aim of this study was to characterize the imaging features and compare computed tomography (CT) findings with clinical features of patients with Streptococcus pneumoniae pneumonia.

MATERIALS AND METHODS

We retrospectively reviewed 75 patients (44 men, 31 women; mean age 67 years) diagnosed with S. pneumoniae pneumonia who underwent chest CT scanning at our institution between January 2007 and August 2008. Diagnoses were based on detection of the S. pneumoniae antigen in urine.

RESULTS

Chest CT scans revealed abnormalities in all patients. The predominant opacity patterns were an airspace pneumonia pattern (48%) and a bronchopneumonia pattern (48%), followed by an interstitial pneumonia pattern (4%). Consolidation was observed most frequently (84%) followed by ground glass opacity (82.7%), bronchial wall thickening (61.3%), and centrilobular nodules (49.3%). Airway dilatation (21.6%), pleural effusion (33.3%), lymphadenopathy (34.8%), and pulmonary emphysema (21.3%) were also observed. Pulmonary emphysema was significantly less frequent in patients with the bronchopneumonia pattern than in those without (p = 0.007). The clinical features and CT findings did not differ significantly.

CONCLUSION

CT image analysis showed that patients with S. pneumoniae pneumonia exhibited the bronchopneumonia and airspace pneumonia patterns with equal frequency. Bronchopneumonia pattern was less common in patients with preexisting emphysema.

Pneumonia in the immunocompetent patient

Pneumonia is an acute inflammation of the lower respiratory tract. Lower respiratory tract infection is a major cause of mortality worldwide. Pneumonia is most common at the extremes of life. Predisposing factors in children include an under-developed immune system together with other factors, such as malnutrition and over-crowding. In adults, tobacco smoking is the single most important preventable risk factor. The commonest infecting organisms in children are respiratory viruses and Streptoccocus pneumoniae. In adults, pneumonia can be broadly classified, on the basis of chest radiographic appearance, into lobar pneumonia, bronchopneumonia and pneumonia producing an interstitial pattern. Lobar pneumonia is most commonly associated with community acquired pneumonia, bronchopneumonia with hospital acquired infection and an interstitial pattern with the so called atypical pneumonias, which can be caused by viruses or organisms such as Mycoplasma pneumoniae. Most cases of pneumonia can be managed with chest radiographs as the only form of imaging, but CT can detect pneumonia not visible on the chest radiograph and may be of value, particularly in the hospital setting. Complications of pneumonia include pleural effusion, empyema and lung abscess. The chest radiograph may initially indicate an effusion but ultrasound is more sensitive, allows characterisation in some cases and can guide catheter placement for drainage. CT can also be used to characterise and estimate the extent of pleural disease. Most lung abscesses respond to medical therapy, with surgery and image guided catheter drainage serving as options for those cases who do not respond.

Comparison of clinical and radiological features of pneumocystis pneumonia between malignancy cases and acquired immunodeficiency syndrome cases: a multicenter study

BACKGROUND

The clinical features of pneumocystis pneumonia (PCP) differ according to the predisposing factors responsible for immunosuppression. Although PCP in patients with acquired immunodeficiency syndrome (AIDS) has been extensively described, its characteristics in non-AIDS patients, such as those with malignancies, are not thoroughly documented.

STUDY OBJECTIVE

To characterize and compare the clinical and imaging features of PCP in patients with malignancies with those in AIDS patients.

DESIGN

A multi-center retrospective study.

PATIENTS AND MEASUREMENTS

We evaluated the clinical and radiological features of PCP in 21 patients with malignancies and in 17 with AIDS. Clinical presentation, serum markers, oxygenation, CT findings, and outcome were examined.

RESULTS

The patients with malignancies showed shorter durations of symptoms before PCP was diagnosed. The levels of serum markers and the oxygenation index did not differ. CT showed diffuse or widespread ground-glass opacity (GGO) in all of the patients evaluated. None of the AIDS patients demonstrated consolidation, whereas half of the patients with malignancy showed consolidation along with GGO. The extent of GGO scored on CT images was significantly greater in the AIDS patients. No correlation was observed between the CT findings and other clinical parameters. All of the AIDS patients recovered from PCP, whereas six patients with malignancies died within a month after the onset of PCP.

CONCLUSION

The characteristics of the CT images differed between the patient groups with different underlying disorders, although it remains to be determined whether CT findings are associated with other clinical features or are predictive of the outcome of PCP.

Atypical pneumonias: current clinical concepts focusing on Legionnaires' disease

PURPOSE OF REVIEW

This review provides clinicians with an overview of the clinical features of the atypical pneumonias. Atypical community-acquired pneumonia pathogens cause systemic infections with pneumonia. The key to the clinical diagnosis of atypical pneumonias depends on recognizing the characteristic pattern of extrapulmonary organ involvement different for each pathogen. As Legionella is likely to present as severe pneumonia and does not respond to beta-lactams, it is important to presumptively diagnose Legionnaires' disease clinically so that Legionella coverage is included in empiric therapy. This study reviews the clinical features and nonspecific laboratory markers of atypical pathogens, focusing on Legionnaires' disease.

RECENT FINDINGS

Case reports/outbreaks increase our understanding of Legionnaires' disease transmission. Both Mycoplasma pneumoniae and Chlamydophilia pneumoniae may cause asthma. Antimicrobial therapy of Chlamydophilia pneumoniae/Mycoplasma pneumoniae is important to decrease person-to-person spread and to decrease potential long-term sequelae.

SUMMARY

Atypical pulmonary pathogens cause systemic infections accompanied by a variety of characteristic extrapulmonary features. Clinically, it is possible to differentiate Legionnaires' disease from the other typical/atypical pneumonias. Rapid clinical diagnosis of atypical pathogens, particularly Legionnaires' disease, is important in selecting effective empiric therapy and prompting definitive laboratory testing.

Legionella community-acquired pneumonia (CAP) presenting with spontaneous bilateral pneumothoraces

Legionnaires' disease is a common cause of non-zoonotic atypical community-acquired pneumonia (CAP). Legionnaires' disease has varied manifestations but may be diagnosed clinically on the basis of its characteristic pattern of extra-organ involvement. In a patient with non-zoonotic CAP, the clinical and laboratory features in a patient with CAP pointing to the diagnosis of Legionnaires' disease include relative bradycardia, mental confusion/ encephalopathy, loose stools/diarrhea, abdominal pain, mild/transient increases in serum transaminases, decreased serum phosphorous, a highly elevated C-reactive protein (CRP), elevated creatinine phosphokinase (CPK), highly elevated serum ferritin levels, or microscopic hematuria. The radiologic manifestations of Legionnaires' disease are varied and no radiographic appearance is pathopneumonic. Patchy infiltrates in Legionnaires' disease are symmetrical and rapidly progressive even on appropriate anti-Legionella antimicrobial therapy. Spontaneous unilateral pneumothorax is a rare radiographic manifestation of Legionnaires' disease. We present a case of a young male who is presenting clinical finding was that of spontaneous bilateral pneumothoraces due to Legionella CAP. We believe this is the first reported case of Legionnaires' disease presenting as spontaneous bilateral pneumothoraces. Clinicians should be aware of the protean radiological manifestations of Legionnaires' disease. In patients presenting with CAP and unilateral or bilateral spontaneous pneumothorax, clinicians should have Legionnaires' disease in the differential diagnosis.

Mechanism of formation of the orange-colored sputum in pneumonia caused by Legionella pneumophila

It has been said that the color of sputum from patients with Legionella pneumophila pneumonia is orange. However, why the color is orange has not been clarified. First, orange-colored sputum obtained from a patient with L. pneumophila pneumonia is presented. Then, the formation of an orange-colored pigment in a culture medium (without charcoal) after the growth of L. pneumophila is demonstrated.