Comparative radiographic features of community acquired Legionnaires' disease, pneumococcal pneumonia, mycoplasma pneumonia, and psittacosis

The features of the chest radiographs of 49 adults with legionnaires' disease were compared with those of 91 adults with pneumococcal pneumonia (31 of whom had bacteraemia or antigenaemia), 46 with mycoplasma pneumonia, and 10 with psittacosis pneumonia. No distinctive pattern was seen for any group. Homogeneous shadowing was more frequent in legionnaires' disease (40/49 cases) (p less than 0.005), bacteraemic pneumococcal pneumonia (25/31) (p less than 0.01) and non-bacteraemic pneumococcal pneumonia (42/60) (p less than 0.05) than in mycoplasma pneumonia (23/46). Multilobe disease at presentation was commoner in bacteraemic pneumococcal pneumonia (20/31) than in non-bacteraemic pneumococcal pneumonia (15/60) (p less than 0.001) or legionnaires' disease (19/49) (p less than 0.025). In bacteraemic pneumococcal pneumonia multilobe disease at presentation was associated with increased mortality. Pleural effusions and some degree of lung collapse were seen in all groups, although effusions were commoner in bacteraemic pneumococcal pneumonia. Cavitation was unusual. Lymphadenopathy occurred only in mycoplasma pneumonia (10/46). Radiographic deterioration was particularly a feature of legionnaires' disease (30/46) and bacteraemic pneumococcal pneumonia (14/27), and these groups also showed slow radiographic resolution in survivors. Radiographic resolution was fastest with mycoplasma pneumonia; psittacosis and non-bacteraemic pneumococcal pneumonia cleared at an intermediate rate. Residual intrapulmonary streaky opacities remained in over a quarter of survivors from legionnaires' disease (12/42) and bacteraemic pneumococcal pneumonia (5/19).

The radiologic manifestations of Legionnaire's disease. The Ohio Community-Based Pneumonia Incidence Study Group

STUDY OBJECTIVES

To study the serial radiographic manifestations of Legionnaire's disease from the initial presentation on admission to recovery using strict criteria for the diagnosis of infection.

MATERIALS AND METHODS

We prospectively studied the chest radiographs of patients hospitalized with a diagnosis of community-acquired pneumonia in Summit County, Ohio between November 1990 and November 1992. Forty-three patients fulfilled strict criteria for legionellosis. The diagnosis of infection was based on the criteria of "definite" diagnosis as defined by the Ohio Community-Based Pneumonia Incidence Study Group report. The criteria included the isolation of the microorganism, the presence of a significant antibody rise, or the presence of Legionella antigen in the urine.

RESULTS

Forty of 43 patients had admission radiographs interpreted as compatible with pneumonia. In spite of appropriate antimicrobial therapy, worsening of the infiltrates was found in more than half of the patients within the first week. Twenty-seven patients were observed to have pleural effusion during the course of hospitalization: 10 effusions were found on admission, another 14 developed during the first week, and 3 new effusions were discovered after the first week. Cavitation was found in only one patient. None of the patients had apical involvement.

CONCLUSION

This study confirms previous reports using less stringent etiologic diagnosis criteria that chest radiographic findings in Legionnaire's disease are not specific. Even with appropriate therapy, more than half of the patients will have worsening of the infiltrates during the first week. Pleural effusion is common among our patients, and it is frequently detected during the serial radiographic studies during the first week of hospitalization. Chest radiography in Legionnaire's disease is useful only for the monitoring of disease progression and not for diagnostic purposes. In addition, worsening of infiltrates and pleural effusion are seen in more than half of the patients in spite of appropriate therapy and clinical improvement.

Clinical aspects of Legionnaires' disease

Since the initial description of Legionnaires' disease 2 years ago, a clearer picture of its clinical manifestations has emerged as a result of investigations of further epidemics and studies of laboratory-confirmed sporadic cases. Although individual clinical features are not sufficiently distinctive to distinguish Legionnaires' disease from other types of acute pneumonia, a composite can provide a sufficiently characteristic clinical profile to indicate the likelihood of this diagnosis. Such a profile includes high fever (above 39.4 degrees C); recurrent chills; relative bradycardia; early gastrointestinal symptoms (particularly diarrhea); prominent myalgias; microscopic hematuria; liver function abnormalities; toxic encephalopathy; nonproductive cough; absence of bacterial pathogens on Gram stain and culture of transtracheal aspirate; progression from patchy bronchopneumonia to lobar and multilobar consolidation; and frequently prompt and sometimes dramatic response to treatment with erythromycin.

The chest radiograph in legionnaires' disease

The chest radiographs of 24 patients with documented Legionnaires' disease were evaluated. Twenty-two of the 24 patients had positive findings for the disease initially. There was unilateral involvement in 68% and the most common lung shadows were poorly marginated round opacities (46%), diffuse patchy (25%) and peripheral opacities (21%). At peak, 70% of patients had a lobar shadow. Pleural effusions were present in 39% of cases but could be explained by underlying congestive heart failure or renal failure in 7 of the 9. Although the findings are not specific, the radiologist should consider this diagnosis in a patient with compatible clinical history, a pneumonia of obscure etiology, and these radiographic manifestations.

Nosocomial Legionnaires' disease. Occurrence in recipients of bone marrow transplants

Nosocomial pneumonia caused by Legionella pneumophila serogroup 1 occurred in five patients after bone marrow transplantation for hematologic malignancies. Two patients died as a result of the infection despite treatment with erythromycin. Serologic screening revealed no other cases of Legionnaires' disease in 40 consecutive recipients of bone marrow transplants, giving a frequency of infection of 13 percent. These five cases represent 23 percent of the pneumonia occurring in this group of patients. Patients undergoing bone marrow transplantation are highly susceptible to infectious complications. Legionnaires' disease must now be added to the list of pathogens infecting this group of patients. Erythromycin is not generally a part of standard empiric antibiotic regimens in febrile neutropenic patients, but appears to be a reasonable addition when pneumonia does not respond to conventional, empiric treatment. Even with appropriate therapy, Legionnaires' disease remains a highly lethal infection in immunocompromised hosts.

Clinicoradiographic correlation with the extent of Legionnaire disease

Serial chest radiographs from 34 confirmed cases of legionnaire disease diagnosed between February 1979 and June 1981 were reviewed. Initial involvement was most often a peripheral patchy alveolar infiltrate (76%, 26/34) with progression to consolidative pneumonia in 70% (18/26) of these cases. Initial or eventual involvement of noncontiguous lobes (50%, 17/34) was common. Bilateral changes developed in 50% of cases and bilateral diffuse disease developed in 12%. Pleural effusions attributable to legionnaire disease occurred in 32% of the patients. Definite clearing took longer than 2 weeks in 50% of treated patients. The severity of radiographic abnormality correlated with the presence of Legionella pneumophila detectable in sputum by direct immunofluorescence (p less than 0.001). No correlation of radiographic severity to smoking, immunosuppression, advanced age, race, or underlying disease, nor to symptoms of abdominal pain, diarrhea, neurologic abnormalities or high fever, nor to laboratory data including hyponatremia, leukocytosis, or hematuria was found. A comparative review of the literature is provided.

Computed tomographic features of Legionella pneumophila pneumonia in 38 cases

PURPOSE

To characterize the imaging features of Legionella pneumophila pneumonia (LPP).

SUBJECTS AND METHODS

Imaging findings of computed tomography (CT) in 38 cases of microbiologically or serologically determined LPP were analyzed and compared with those of 35 cases of Streptococcus pneumoniae pneumonia.

RESULTS

In cases with LPP, abnormal opacities were distributed in a single lobe in 5 cases, in multiple lobes unilaterally in 10 cases, and multifocally and bilaterally in 23 cases. All cases showed consolidation and/or ground glass opacity in lung fields. Sharply demarcated peribronchovascular foci of consolidation intermingled with ground glass opacity were noted in 24 cases (24 of 38, 63%), whereas imaging features were seen in only 3 cases (3 of 35, 9%) of Streptococcus pneumoniae pneumonia. These CT patterns have nothing to do with clinical features such as age, sex, severity of disease, and time between onset of disease and CT examination.

CONCLUSIONS

Imaging features of LPP on CT include bilateral and unilateral single and multifocal consolidation and ground opacity. Sharply demarcated peribronchovascular foci of consolidation intermingled with ground glass opacity seem to be one of the most frequent CT appearances of LPP.

The chest radiograph in Legionnaires' disease. Further observations

Chest radiographs of 70 patients with Legionnaires' disease were evaluated and compared to the authors' previous series of 24 patients as well as others in the literature. A larger number of patients in the more recent survey had pleural effusion, and there were 3 with cavitation whereas none was seen previously. Analysis of the radiograph showing the most marked changes in survivors versus patients who died showed no consistent pattern, indicating that the radiograph cannot be used as a prognostic indicator. On long-term follow-up (mean, 104.2 days), the radiograph remained abnormal for many months and demonstrated a variety of slowly resolving or permanent abnormalities.

Radiographic features of Legionnaires' disease

Serial chest radiographs of 35 patients with confirmed Legionnaires' disease were evaluated. A unilateral, unilobar alveolar infiltrate was, in general, the initial radiographic finding. Progression to consolidation or to new areas of involvement was typical. Every lobe was involved, but lower lobe involvement was most common. Pleural effusion was often present. Cavitation was not seen. Radiographic progression for several days following institution of therapy, and despite clinical response, was noted. In patients who survived, radiographic improvement of abnormalities was usually apparent within two weeks of therapy. Aradiographic spectrum exists and, although many features are typical, no single feature is pathognomonic.

Nosocomial and community-acquired Legionella pneumonia: clinical comparative analysis

Previous reports have suggested that nosocomial and community Legionella pneumonia cases are similar. However, community and hospital characteristics, such as aquatic environment, antibiotic pressure (usage) and populations, are quite different, leading to the suspicion that Legionella infection may differ in the two settings. Univariate and multivariate analyses were performed to compare demographic data, risk factors, clinical, radiological and outcome data between 125 nosocomial and 33 community-acquired cases of Legionella pneumophila infection. Patients in the nosocomially acquired Legionella pneumonia (NALP) group were older than those in the community-acquired Legionella pneumonia (CALP) group. Univariate analysis showed that smoking habit, cough, thoracic pain, and extrapulmonary manifestations were more prevalent in the CALP group, whilst chronic lung disease and cancer were more prevalent in the NALP group. Moreover, patients in the NALP group were more likely to have received oxygen and corticosteroid therapy and also to have altered creatinine values than patients in the CALP group, whilst more patients in the latter group had altered alanine amino-transferase values. However, multivariate analysis failed to confirm most of these differences. Smoking habit and blood creatinine levels were the only variables remaining significant. In conclusion, demographic, clinical, laboratory, radiological and outcome data in nosocomial and community-acquired Legionella pneumonia are quite similar.

Sporadic Legionnaires' disease: clinical observations on 87 nosocomial and community-acquired cases

To add information about sporadic Legionnaires' disease, 87 cases of L. pneumophila pneumonia were reviewed. Twenty cases were nosocomial infections and 67 cases were community-acquired. Most cases (64%) occurred between July and October. The mean age of patients was 51.4 years and males outnumbered females 2.5:1.0. Thirty-one percent of patients were receiving corticosteroid, immunosuppressive, or antineoplastic chemotherapy when illness began. Immunosuppression at onset of illness was more common in nosocomial infections (90%) than in community-acquired infections (14%). Seventy percent of patients had underlying diseases. Malignancies, renal failure, and transplantation were the most common conditions underlying nosocomial infections. Chronic lung disease and malignancies were the most common diseases underlying community-acquired infections. The case-fatality rate in nosocomial infection (70%) was greater than that in community-acquired disease (22%). Clinical, laboratory, and radiologic features of the cases were examined. Illness ranged from mild to severe. Extrapulmonary findings of encephalopathy and renal failure were more common in fatal than in non-fatal cases. Indirect immunofluorescent and microagglutination antibody responses plateaued by the fourth week of illness. Twenty-nine patients died. The case-fatality rate of patients receiving erythromycin (6%) was less than that of patients receiving penicillin (36%), ampicillin (28%), cephalosporin (32%), or aminoglycosides (41%). Despite erythromycin therapy, the case fatality rate for nosocomial L. pneumophilia pneumonia was unacceptably high (25%).

An outbreak of Legionnaires' disease in Sweden: report of sixty-eight cases

From August 27 to September 21, 1979, 58 patients fell ill with Legionnaires' disease (LD) in the town Västerås, Sweden. All patients had been staying in the town some time during 2 weeks preceding their illness, as had 10 LD patients who fell ill from mid-June to mid-August the same year. Clinically, high fever, headache, dizziness and gastrointestinal symptoms were dominating. Respiratory symptoms were moderate, radiologically verified pneumonia was seen in 59 of 64 patients examined. One patient died. The diagnosis was verified by serology, using the IFL method, in all cases. Legionella pneumophila serogroup 1 was isolated from a closed lung biopsy from 3 patients. Isolates of identical strains were made from the cooling tower on the roof of an indoor shopping centre in Västerås, visited by 57 of the patients during the incubation period.

Isolation of Legionella pneumophila by centrifugation of shell vial cell cultures from multiple liver and lung abscesses

A 7-year-old girl was admitted to the hospital with acute lymphoblastic leukemia and was treated with allogenic cord blood transplantation. At day 30 after graft, she developed a fever and multiple nodular lesions disseminated in the liver and lungs. All bacterial cultures attempted on liver and lung biopsy specimens and blood remained sterile on standard axenic media. However, inoculation of liver and lung biopsy specimens on eukaryotic cell monolayers by the centrifugation-shell vial technique (M. Marrero and D. Raoult, Am. J. Trop. Med. Hyg. 40:197-199, 1989) led to the recovery of a strain of Legionella pneumophila serogroup 1, identified by 16S rRNA gene amplification and sequencing and serotyping. Our findings demonstrate that the centrifugation-cell culture method, which has previously been useful for the isolation of other strictly or facultatively intracellular bacteria, can also serve as a method for the recovery of L. pneumophila from clinical material.

Bacterial pneumonia in immunocompromised patients

Immunocompromised patients develop infections resulting from a wide range of organisms. The most commonly encountered type of infection is bacterial in origin. Many of the infections are community-acquired pneumonias in which most of the infections are caused by organisms that typically produce disease in the healthy person. Hospital-acquired pneumonias are particularly serious, being caused by the highly virulent gram-negative bacilli and Staphylococcus aureus. Immunocompromised patients frequently have indwelling intravascular catheters. These catheters may become infected and seed the lung with septic emboli, producing a hematogenous pneumonia. Underlying conditions and therapy increase the risk for aspiration in the immunocompromised patient. These aspirations can result in the development of an aspiration pneumonia and lung abscess formation. The majority of pneumonias resulting from Legionella and Nocardia occur in immunocompromised patients.

Hot spring bath and Legionella pneumonia: an association confirmed by genomic identification

A 59-year-old man developed pneumonia 9 days after bathing in a hot spring spa. Bilateral shadows on his chest radiograph rapidly progressed after admission. He was successfully treated with erythromycin and rifampicin. Legionella pneumophila serogroup 6 was recovered from an intratrachial specimen and a significant elevation was observed in a paired indirect fluorescent antibody to Legionella. Persistent slight fever and chest rentogenographic shadows resolved after administering low-dose prednisolone to treat organizing pneumonia shown by transbronchial lung biopsy. The same serotype of Legionella was recovered from the water of the hot spring spa where the man had bathed. When the extracted DNA of these two strains showed identical restriction fragments by pulsed-field gel electrophoresis, we had direct evidence that hot spring spas can be a source of Legionella pneumonia.

Legionnaires' disease after heart transplantation

The cases of 8 heart transplant recipients with legionnaires' disease are reviewed. The diagnosis in each patient was made by fluorescent antibody stains or direct culture of the sputum, transtracheal aspirate, or fine needle aspirate of the lung. All patients were successfully treated with erythromycin alone or in combination with rifampin. Radiographic and clinical variations of legionnaires' disease as seen in the immunocompromised host are presented.

Chest CT findings and clinical features in mild Legionella pneumonia

OBJECTIVE

To evaluate mild Legionella pneumonia (LP) by chest CT, and clinical features.

PATIENTS

In June 2000, an outbreak of LP occurred in Japan. Eight patients with mild LP (seven men, one woman; mean age 55.9 years) had fevers of more than 38 degrees C, but respiratory symptoms were observed only in four. Chest CT was performed before starting an appropriate treatment.

MEASUREMENT

CT images were assessed by the distribution of ground-glass opacity (GGO), consolidation, and the existence of pleural effusion.

RESULTS

Chest CT findings: multiple segments were affected in all of the patients, (pleural effusion in three, peripheral lung consolidation in seven, and GGO in seven). GGO was located around the consolidation in six patients.

CONCLUSION

Mild LP may present as fever without respiratory symptoms. Chest CT findings of mild LP are bilateral, multiple affected segments and peripheral lung consolidation with GGO.

Rapidly expanding lung abscess caused by Legionella pneumophila in immunocompromised patients: a report of two cases

We describe two cases of lung abscess caused by Legionella pneumophila in immunocompromised patients. The first case had been treated initially with 60 mg prednisolone for ulcerative colitis, and L. pneumophila serogroup 1 was isolated from sputum samples after cavitation of the lung lesion. The second case was diagnosed as plasma cell lymphoma at post-mortem examination. L. pneumophila serogroup 5 was isolated from the contents of lung abscess, together with Enterococcus faecium and Prevotella intermedia in the post-mortem examination. Lung abscess caused by Legionella is unusual. Here, we discuss the difficulty of diagnosis of legionellosis in patients with unusual chest radiographic findings.

Legionnaires' disease and brain abscess

Neurologic symptoms are common in Legionnaires' disease, but the pathogenesis of these symptoms is not known. Brain scintigraphy or CT shows no abnormality that can account for the symptoms. We present the first evidence of cerebral abscess in a patient with serologically proven acute infection with Legionella.

Pneumonia caused by Pittsburgh pneumonia agent: radiologic manifestations

Using an objective scoring system, chest radiographs were reviewed in 23 cases of pneumonia due to the Pittsburgh pneumonia agent (PPA, Tatlockia micdadei, Legionella micdadei), including six cases of pneumonia with simultaneous isolation of PPA and L pneumophila (Legionnaires' disease). Infiltrates were typically segmental to lobar; nodular infiltrates were noted in three cases. Spread to additional lobes after presentation occurred in four of 17 PPA infections. Pneumonia caused by both PPA and L pneumophila was unusually severe, with involvement of all lobes occurring in four of six cases, compared with one of 17 cases of PPA infection (p less than 0.02). Radiographic severity did not correlate with underlying disease, immune status, or outcome. The majority of patients receiving erythromycin demonstrated objective radiologic improvement. In a patient population that included nonimmunosuppressed patients, nodule formation and rapid radiologic progression were not found to be characteristic of PPA pneumonia.

Legionnaires' disease in the renal transplant patient: clinical presentation and radiographic progression

The clinical presentation and radiographic progression of Legionnaires' disease is described in 10 renal transplant patients, the majority undergoing treatment for rejection. Presentation with pleuritic chest pain, fever, hypoxia, and hemoptysis was typical and in some cases led to confusion with pulmonary embolism. The radiographic appearance was that of rapidly progressive, dense, sublobar consolidation, occasionally showing patchy spread to other areas and usually accompanied by pleural effusion. Cavitation occurred in seven of 10 patients.

Tubulointerstitial nephritis associated with Legionnaires' disease

A 47-year-old man was admitted to our hospital for community-acquired pneumonia complicated with acute renal failure. Legionella pneumophila serogroup type 1 was grown in BCYE (buffered charcoal yeast extract) agar for sputum culture. Although his respiratory illness responded to intravenous erythromycin therapy, renal failure worsened and necessitated hemodialysis. Renal biopsy showed profound tubulointerstitial nephritis. After initiation of steroid therapy his renal function improved and he was discharged thereafter. These findings suggest that in Legionnaires' disease with acute renal failure, tubulointerstitial nephritis should also be considered and steroid therapy may be an effective modality for the renal complication.

Persistently positive culture results in a patient with community-acquired pneumonia due to Legionella pneumophila

We describe a patient with community-acquired pneumonia due to Legionella pneumophila serogroup 6. This patient was found to have bronchoalveolar carcinoma of the lung by means of cytologic testing in 1 of 2 bronchoalveolar lavage samples, but no lesions were visible on bronchoscopy. Despite intravenous administration of azithromycin to the patient, repeat culture and polymerase chain reaction showed persistence of Legionella; the isolates remained susceptible to azithromycin. The patient did not respond to 14 doses of daily intravenously administered azithromycin. The poor outcome may have been partially due to the suspected underlying lung malignancy, as shown by cytologic examination, and by a delay in seeking medical attention.

Radiographic appearance of nosocomial legionnaires' disease after erythromycin treatment

Radiographic features of 71 patients (48 men, 23 women) with nosocomial Legionella pneumophila pneumonia were assessed and compared with those of other nosocomial series of L pneumophila pneumonia. Sixteen patients were assessed retrospectively and 55 prospectively. Chest radiographs were assessed at the onset of the illness, 10 days later, and at 3 months. Erythromycin was given to 67 patients at the time of the diagnosis and to the remaining four at a later stage. Forty eight patients were over the age of 60. On the initial chest radiograph 53 of the 71 patients had unilateral shadowing (23 of them in the right lung); 35 had unilobar shadowing and the remaining 36 had more than one affected lobe. Pleural effusion was present in 24 cases and cavitation in 2. One patient had evidence of a pericardial effusion. At 10 days 21 patients had evidence of radiographic progression (14 ipsilateral), but 28 had improved. At 3 months 36 patients had an abnormal radiograph, 30 showing residual scarring, 15 loss of volume, six pleural shadows and two cavitation. Our series shows a lesser incidence of unilateral shadowing and pleural effusion than other nosocomial series and a lesser tendency to progression, but more patients had radiographic abnormalities at long term follow up.

Legionellosis in a lung transplant recipient obscured by cytomegalovirus infection and Clostridium difficile colitis

A 52-year-old-white male underwent double lung transplantation for severe emphysema due to alpha-1-antitrypsin deficiency and heavy tobacco use. Following a postoperative course complicated by renal insufficiency, pulmonary emboli, and Clostridium difficile colitis, he was discharged in stable condition. Two months later, he was admitted to a local hospital with a fever, abdominal pain, diarrhea, nausea, and dyspnea. Computerized tomography (CT) of the chest revealed bilateral pleural effusions. Sigmoidoscopy was grossly normal but biopsy demonstrated cytomegalovirus (CMV) colitis, and the patient was placed on intravenous ganciclovir. Over the next week, he became progressively hypoxemic and was transferred to the University of Pittsburgh Medical Center (post-transplant day 81) for further evaluation. His medications on transfer included: ganciclovir, prednisone, tacrolimus, dapsone, fluconazole, ondansetron, lansoprazole, digoxin, and coumadin.