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Septic Pulmonary Embolism of Unknown Origin in Patients With Staphylococcus aureus Bacteremia
Abstract
Septic pulmonary embolism (SPE) results when fragments of thrombus containing bacteria or fungi travel to the pulmonary circulation and lodge in segmental and subsegmental pulmonary arteries. Almost invariably such embolization implies the presence of an endovascular infection (typically endocarditis, septic thrombophlebitis, or catheter-related infection) as the source of embolism. Here we report a case of Staphylococcus aureus bacteremia complicated with SPE in a patient who had no septic foci other than a soft tissue infection. We found 17 similar cases in the literature and reviewed their clinical presentation and outcomes. The most common presenting symptoms were fever (88%), chest pain (47%), dyspnea (29%), and cough (18%). Skin and soft tissue infections represented the most common suspected source of SPE. Methicillin-resistant S. aureus was isolated in most of the cases (71%). The USA300 strain carrying the Panton-Valentine leukocidin toxin gene was uniformly identified in all of the patients in whom genotyping of the isolate was available. Almost 90% of the patients reviewed had a full recovery with 4 to 8 weeks of intravenous antibiotic therapy. We conclude that SPE of unknown origin is an infrequently reported but serious complication of S. aureus bacteremia.
... Bizim olgumuzdaki gibi enfekte santral kateterler de bu nedenler içerisinde önemli bir yer tutmaktadır. Enfekte kataterden kaynaklanan periferal septik tromboflebit enfekte kanın kökenini oluşturmaktadır [2,5]. Radyoloji, SPE'nin hem ayırıcı tanısında hem de tanısında çok önemli bir role sahiptir.PA akciğer grafisinde periferik parankimal nodüller ile ince-orta kalınlıkta irregüler duvara sahip kavitasyonlar tipik olmakla beraber toraks BT, SPE tanısını koymada akciğer grafisinden üstündür. ...
... Son yıllarda, santral kateterin predispoze ettiği SPE'de metisiline dirençli Staphylococcus aureus etken patojen olarak dikkati çekmektedir. Bizim olgumuzda ise metisilin duyarlı Staphylococcus aureus+ Escherichia coli ajanları birlikte izole edilmiştir [3,5]. Sonuç olarak; SPE erken tanı ve etkin antibiyotik tedavisi gerektiren ağır bir tablodur. ...
Septic pulmonary embolism, is a phenomenon characterized with hematogenous spread of coagulated blood containing microorganisms from right heart to the lungs, and infarct and abscess formations in lungs. It is associated with some precipitating situations such as congenital heart disease, IV drug use, long-term catheter use. Septic pulmonary emboli has high morbidity and mortality. Early diagnosis and broad-spectrum antibiotics are the main factors determining the prognosis. From this point, here we offer a septic pulmonary emboli case. 60-year-old female patient, who was treated by nephrology clinic with hemodialysis because of chronic renal failure, was referred to our clinic due to new onset of dyspnea and low SpO2. It was seen that the patient had a central catheter. In physical examination of the respiratory system, fine crackles were heard at bilateral bases. Whereupon bilateral multifocal nodular densities were observed in the chest X-ray, thorax CT was performed. In thorax CT, multiple nodular densities, being more prominent in the upper lobes of both lungs and which were the largest of 12x20mm in size, were monitored. It was learned that patient had no history of any immunosuppressive therapy. Although those radiological lesions were resembling the metastatic lesions, the lack of described lesions in the 5 days prior chest X-ray turned away us from a possible metastasis. Than, it was learned that E.coli MSSA were found in the catheter tip culture received 2 days prior. With those existing findings, the patient was diagnosed with septic pulmonary embolism. Clinical improvement was provided with broad-spectrum antibiotics, held in accordance with the microbiological resistance profile. Significant decline in the lesions were observed in the thorax CT drawn on 20th day of treatment. We shared this phenomenon with original radiological presentation to remind septic emboli in clinical differential diagnosis.
Though USA300 community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) has emerged as a major public health concern in the United States, its relative virulence is unknown. We sought to evaluate if the USA300 strain of CO-MRSA causes more severe infections than other MRSA (ie, USA100, -500, -800, and others) strains.
An epidemiologic study was conducted from 2000 to 2007 to measure rates of severe infection. A matched case-control study was conducted from 2004 to 2006 to assess the relationship of strain type, syndrome, and severity of infection. Severe illness was defined as CO-MRSA infections with medical intensive care unit (MICU) admission or death within 1 week of admission. Controls were those with CO-MRSA infection without MICU admission.
We found an incidence of 75 cases per 100000 people of CO-MRSA infection in 2000, which increased to a rate of 396 per 100000 in 2007 (relative risk [RR], 5.3; 95% confidence interval [CI], 4.47-6.27). The incidence of severe infections increased from 5 cases per 100000 in 2000 to 17 per 100000 in 2007 (RR, 3.4; 95% CI; 1.67-6.43). USA300 strains were negatively associated with severe clinical courses or death as compared with other MRSA strain types. The highest risk of severe infection was found in those with pulmonary embolic infiltrates and bacteremia in the setting of USA300 infection (odds ratio, 31.41; 95% CI, 6.40-154.23).
Our findings suggest that USA300 infections are negatively associated with severe clinical courses, suggesting less virulence than other MRSA strains, except in the setting of pneumonia with septic pulmonary emboli.
Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are
intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss
the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections
(SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations
are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility
to vancomycin, and vancomycin treatment failures.
Radiographic and CT findings in 15 patients with clinically documented septic pulmonary emboli were compared retrospectively. In most cases, radiographic changes were nonspecific. In comparison, on CT a combination of specific signs could be identified in all patients. These included peripheral nodules with clearly identifiable feeding vessels associated with metastatic lung abscesses (10 [67%] of 15 cases), and subpleural, wedge-shaped densities with and without necrosis caused by septic infarcts (11 [73%] of 15 cases). Ancillary pleural, mediastinal, axillary, and pericardial abnormalities also were more easily identified with CT. We conclude that CT is complementary to other imaging techniques in the recognition of septic pulmonary emboli.
We report four adult patients who presented with septic pulmonary emboli and community-acquired methicillin-resistant Staphylococcus aureus bacteremia associated with deep tissue infections, such as pyomyositis, osteomyelitis, and prostatic abscess. The patients
lacked evidence of right-sided endocarditis or thrombophlebitis. This association, previously described in children, may also
be important in adults.
Three weeks following a toothache, a 56-year-old man developed cough, sputum, fever, and pleuritic chest pain. He had mild periodontal disease and his chest radiographs and chest computed tomographic (CT) scans showed multiple pulmonary nodules. The CT scan strongly suggested septic pulmonary embolism. Aspirated pus from one of the nodules yielded pure growth of Streptococcus intermedius. Lesions resolved with antimicrobial therapy. The usual predisposing factors for septic pulmonary embolism were absent, and, the isolation of S intermedius from the pus, the antecedent toothache, and periodontal disease all suggested the gingiva as the source. We hypothesize that periodontal infection led to bacteremia, seeding of the lungs, and multiple anaerobic pulmonary abscesses, akin to reported instances of infective endocarditis from dental foci without any prior dental procedures. To our knowledge, this presentation of septic pulmonary embolism is unprecedented.
Early detection of metastatic infection in patients with Gram-positive bacteremia is important as morbidity and mortality are higher in the presence of these foci, probably due to incomplete eradication of clinically silent foci during initial treatment. We performed a prospective study in 115 patients with Staphylococcus aureus or Streptococcus species bacteremia with at least 1 risk factor for the development of metastatic foci, such as community acquisition, treatment delay, persistently positive blood cultures for >48 hours, and persistent fever >72 hours after initiation of treatment. An intensive search for metastatic infectious foci was performed including ¹⁸F-fluorodeoxyglucose-positron emission tomography in combination with low-dose computed tomography scanning for optimizing anatomical correlation (FDG-PET/CT) and echocardiography in the first 2 weeks of admission. Metastatic infectious foci were detected in 84 of 115 (73%) patients. Endocarditis (22 cases), endovascular infections (19 cases), pulmonary abscesses (16 cases), and spondylodiscitis (11 cases) were diagnosed most frequently. The incidence of metastatic infection was similar in patients with Streptococcus species and patients with S. aureus bacteremia. Signs and symptoms guiding the attending physician in the diagnostic workup were present in only a minority of cases (41%). An unknown portal of entry, treatment delay >48 hours, and the presence of foreign body material were significant risk factors for developing metastatic foci. Mean C-reactive protein levels on admission were significantly higher in patients with metastatic infectious foci (74 vs. 160 mg/L). FDG-PET/CT was the first technique to localize metastatic infectious foci in 35 of 115 (30%) patients. As only a minority of foci were accompanied by guiding signs or symptoms, the number of foci revealed by symptom-guided CT, ultrasound, and magnetic resonance imaging remained low. Mortality tended to be lower in patients without complicated infection compared to those with metastatic foci (16% vs. 25%, respectively). Five of 31 patients (16%) without proven metastatic foci died. In retrospect, 3 of these 5 patients likely had metastatic foci that could not be diagnosed while alive. In patients with Gram-positive bacteremia and a high risk of developing complicated infection, a structured protocol including echocardiography and FDG-PET/CT aimed at detecting metastatic infectious foci can contribute to improved outcome.
Objective:
The purpose of this essay is to highlight the clinical features and imaging findings associated with different types of nonthrombotic pulmonary embolism.
Conclusion:
Nonthrombotic pulmonary embolism is an infrequent condition with various causes that can be life-threatening pathologic conditions. The entity presents a diagnostic challenge because of the low specificity of clinical symptoms and imaging signs. Awareness of the imaging features of nonthrombotic pulmonary embolism facilitates correct diagnosis and leads to appropriate patient care.
Septic pulmonary embolism is an uncommon disease in which septic thrombi are mobilised from an infectious nidus and transported in the vascular system of the lungs. It is usually associated with tricuspid valve vegetation, septic thrombophlebitis or infected venous catheters. We report an immunocompetent young man who presented with fever and pleuritic chest pain. Chest roentgenography and CT showed multiple ill-defined nodules, with central cavitation and feeding vessels. He was found to have a clinically infectious source of methicillin-resistant staphylococcus aureus (MRSA) cultured from the peri-proctal abscess with the same bacteraemia. Pulmonary septic embolism from peri-proctal abscess was diagnosed by image study and bacterial culture correlation. All of the clinical presentations improved after the incision of the peri-proctal abscess and anti-MRSA antibiotics treatment.
CT pulmonary angiography (CTPA) has become the de facto clinical "gold standard" for the diagnosis of acute pulmonary embolism (PE) and has replaced catheter pulmonary angiography and ventilation-perfusion scintigraphy as the first-line imaging method. The factors underlying this algorithmic change are rooted in the high-sensitivity and specificity, cost-effectiveness, and 24-hour availability of CTPA. In addition, CTPA is superior to other imaging methods in its ability to diagnose and exclude, in a single examination, a variety of diseases that mimic the symptoms of PE. This article reviews the current role of CTPA in the diagnosis of acute PE as well as more recent developments, such as the use of CT parameters of right ventricular dysfunction for patient prognostication and the assessment of lung perfusion with CT.
Septic pulmonary embolism (SPE) is a critical disorder which requires fast diagnosis for treatment, while SPE continues to pose a diagnostic challenge in radiologic imaging. We describe detailed findings on breath-hold perfusion SPECT-CT fusion images in 2 patients with SPE. Regardless of absence or nonspecific morphologic abnormality in these patients, the fusion images showed multiple wedge-shaped segmental/subsegmental perfusion defects along specific pulmonary arteries, highly suggesting embolic event. Follow-up fusion images after treatment showed changes in lung perfusion defects and morphology. Assessment of lung morphology-perfusion correlation on reliable fusion images contributes to correct diagnosis of SPE and monitoring of treatment effect.
Daptomycin has demonstrated clinical efficacy in the treatment of methicillin-resistant Staphylococcus aureus-associated bacteremia and right-sided infective endocarditis. Although daptomycin is not approved for treatment of gram-positive pneumonia, clinical evidence suggests that it may be effective therapy for S. aureus-associated septic pulmonary emboli (SPE). We present our clinical experience with the use of daptomycin in combination with rifampin in four patients with SPE in the absence of infective endocarditis. Three of the patients had a history of injection drug use; two of these patients also had soft-tissue infections. All patients had clinical resolution of their infections. Daptomycin and rifampin appear to have a role in the treatment of methicillin-resistant S. aureus bacteremia with SPE in the absence of infective endocarditis and should be considered in patients that have failed therapy with vancomycin.
Recent reports have increasingly recognized methicillin-resistant Staphylococcus aureus (MRSA) as an important etiology of pyomyositis, an uncommon disease entity. Specific virulence factors such as the Panton-Valentine leukocidin protein have been identified that may play a role in the pathophysiology of pyomyositis, especially when community-acquired MRSA is implicated.
We review a case of disseminated pyomyositis and septic pulmonary emboli in an immunocompetent adult in whom a pvl+ USA300 clone was isolated.
The degree of dissemination in this patient suggests an emerging level of virulence for community-acquired MRSA that has not been reported previously.
The clinical history and management of severe disseminated pyomyositis, including diagnostic modalities, antimicrobial therapy, and surgical drainage, require an aggressive approach.
Septic pulmonary emboli are the result of infections that typically originate from an extrapulmonary source. Septic pulmonary embolus is a rare disorder that classically presents with fever, respiratory symptoms, and lung infiltrates.
Our objective is to share our experience of a rare diagnosis that was the result of a very common bacterium seen in the Emergency Department (ED).
We present a case of methicillin-resistant Staphylococcus aureus (MRSA) sepsis presenting as bilateral septic pulmonary emboli in a patient with undiagnosed acquired immunodeficiency syndrome. A 29-year-old Hispanic man presented to our ED with a history of abdominal pain and vomiting for 3 days and new onset of shortness of breath. The patient was seen 2 weeks prior for a simple abscess incision and drainage and was treated with trimethoprim/sulfamethoxazole. On the day of admission, a helical computed tomography scan of the chest was obtained, which revealed bilateral septic pulmonary emboli. The patient was admitted for intravenous antibiotic therapy and was subsequently found to have MRSA sepsis.
Septic pulmonary embolus is a rare finding that is most commonly seen in patients who are immunocompromised. The patient fully recovered after aggressive antibiotic therapy.
Conventional chest radiographs and computed tomographic (CT) scans of 70 inflammatory thoracic lesions in 63 patients were reviewed and scored for diagnostic features. Pathologic confirmation of the final diagnosis was available in 42% (5/12) of lung abscesses and 31% (18/58) of empyemas. CT alone was sufficient to correctly diagnose 100% (70/70) of cases. Diagnostic information not available from conventional chest radiographs was obtained in 47% (33/70) of cases; in an additional 34% of patients, CT more accurately defined the extent of disease. The most reliable CT features for the differential diagnosis of lung abscess and empyema were wall characteristics, pleural separation, and lung compression. Conventional radiographic features such as size, shape, and the angle of the lesion with the chest wall were less helpful, though also best assessed by CT.
Three weeks following a toothache, a 56-year-old man developed cough, sputum, fever, and pleuritic chest pain. He had mild periodontal disease and his chest radiographs and chest computed tomographic (CT) scans showed multiple pulmonary nodules. The CT scan strongly suggested septic pulmonary embolism. Aspirated pus from one of the nodules yielded pure growth of Streptococcus intermedius. Lesions resolved with antimicrobial therapy. The usual predisposing factors for septic pulmonary embolism were absent, and, the isolation of S intermedius from the pus, the antecedent toothache, and periodontal disease all suggested the gingiva as the source. We hypothesize that periodontal infection led to bacteremia, seeding of the lungs, and multiple anaerobic pulmonary abscesses, akin to reported instances of infective endocarditis from dental foci without any prior dental procedures. To our knowledge, this presentation of septic pulmonary embolism is unprecedented.
To determine whether transesophageal echocardiography (TEE) was superior to transthoracic echocardiography (TTE) in defining valvular vegetations and diagnosing clinical infective endocarditis (IE) in patients suspected of having this infection.
Between April 1989 and May 1991, 64 febrile patients with clinical and/or microbiologic risk factors for IE were prospectively enrolled. Patients underwent both TEE and TTE, which were interpreted in a blinded fashion as to the patient's clinical status. Clinical criteria for the diagnosis of IE were compared with TEE and TTE findings to delineate the ability of the two echocardiographic techniques to define valvular vegetations and to establish the clinical diagnosis of vegetative IE.
Thirty-four valves had typical valvular vegetations demonstrated by either TEE or TTE. Transesophageal echocardiography was more sensitive than TTE in identifying valvular vegetations (33/34 vs 23/34 instances, respectively; p = 0.004). Also, TEE was better at identifying smaller vegetations (< 1 cm) than TTE; 12 patients with such vegetations were identified by TEE as compared with only 5 of 12 identified by TTE (p = 0.02). Of the 64 patients enrolled, 30 (47 percent) were classified as having "definite" or "probable" IE by modified von Reyn criteria. Among these 30 patients, TEE was significantly more sensitive than TTE at documenting vegetative valvular lesions (26/30 [87 percent] vs 18/30 [60 percent], respectively) (p < 0.01). Both TEE and TTE were highly specific (91 percent) in delineating valvular vegetations in this patient population; two of the three false-positive TEE studies for valvular vegetations occurred in patients with a history of IE. All nine periannular complications of IE were identified by TEE, as compared with only two being defined by TTE (p = 0.001).
Transesophageal echocardiography is significantly more sensitive than TTE and highly specific in both confirming the clinical diagnosis of IE, as well as in identifying valvular vegetations in patients at risk for this infection. Our data also support the concept that TEE is the echocardiographic method of choice for defining small vegetations and periannular complications in IE.
Our aim was to determine the diagnostic value of transesophageal echocardiography in right-sided endocarditis.
Recent studies have demonstrated that transesophageal echocardiography is superior to transthoracic echocardiography in the detection of vegetations associated with left-sided endocarditis. Its diagnostic value in right-sided endocarditis has not been established.
Transthoracic and transesophageal echocardiography were prospectively performed in 48 patients who met specific criteria for the suspicion of right-sided endocarditis. All were intravenous drug abusers.
Vegetations were found in 22 of 48 patients by both transthoracic and transesophageal echocardiography. The vegetations were more precisely characterized by transesophageal echocardiography in 14 (63%) of 22 patients. In the remaining 26 patients, no vegetations were found by either transthoracic or transesophageal echocardiography. No statistically significant differences were found between the two techniques in the assessment of tricuspid regurgitation, which was detected in 21 (44%) of 48 patients.
We conclude that transesophageal echocardiography does not improve the diagnostic accuracy of transthoracic echocardiography in the detection of vegetations associated with right-sided endocarditis in intravenous drug abusers. Transesophageal echocardiography may not be indicated as a routine procedure in patients suspected of having right-sided endocarditis.
A meta-analysis was performed to summarize the impact of methicillin-resistance on mortality in Staphylococcus aureus bacteremia. A search of the MEDLINE database for studies published during the period of 1 January 1980 through 31 December
2000 and a bibliographic review identified English-language studies of S. aureus bacteremia. Studies were included if they contained the numbers of and mortality rates for patients with methicillin-resistant
S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) bacteremia. Data were extracted on demographic characteristics of the patients, adjustment for severity and comorbid
illness, source of bacteremia, and crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for in-hospital
mortality. When the results were pooled with a random-effects model, a significant increase in mortality associated with MRSA
bacteremia was evident (OR, 1.93; 95% CI, 1.54–2.42; P <.001); significant heterogeneity was present. We explored the reasons for heterogeneity by means of subgroup analyses. MRSA
bacteremia is associated with significantly higher mortality rate than is MSSA bacteremia.
Septic pulmonary embolism (SPE) is an uncommon disorder with an insidious onset and is difficult to diagnose.
To characterize the presenting features and clinical course of patients with SPE.
Retrospective study.
Tertiary care, referral medical center.
Fourteen subjects with SPE diagnosed during a 6-year period between 1996 and 2002.
None.
The median age of these patients was 37.5 years (range, 14 to 81 years) and included five women. Presenting symptoms included fever (93%), dyspnea (36%), pleuritic chest pain (29%), cough (14%), and hemoptysis (7%). The median duration of symptoms before diagnosis was 18 days (range, 5 to 180 days). A potential source or underlying condition that predisposed to SPE was identified in all 14 patients and included Lemierre syndrome (4 patients), central venous catheter infection (3 patients), prosthetic cardiac valve (2 patients), and pacemaker infection (2 patients). Two patients had a focal extrapulmonary infection, and one patient was an IV drug user. Most common pathogens were staphylococcal species (eight patients) and fusobacterium (four patients). Chest radiographic presentation was usually nonspecific, but CT was more helpful and revealed multiple nodular opacities peripherally, often with cavitation. Transesophageal echocardiography was performed in eight patients and demonstrated infectious vegetations in four cases. Aside from antimicrobial therapy and removal of infected devices, the management of these patients included cardiac surgery (two patients), thoracoscopic surgery with decortication (one patient), and tube thoracostomy (one patient). All 14 patients recovered from their illness.
We conclude that SPE presents with variable and often nonspecific clinical and radiographic features. The diagnosis is usually suggested by the presence of a predisposing factor, febrile illness, and CT findings of multiple, nodular lung infiltrates peripherally, with or without cavitation.
Primary pneumonia and metastatic pulmonary infection have become more common in patients with invasive community-acquired Staphylococcus aureus disease at Texas Children's Hospital (TCH; Houston).
In this study, we sought to describe pulmonary involvement in children with community-acquired S. aureus invasive infection and to determine whether the presence of genes encoding Panton-Valentine leukocidin (PVL) (luk-S-PV and luk-F-PV) and collagen adhesin (cna) is correlated with pulmonary manifestations. Patients with invasive staphylococcal infections admitted to TCH between 1 August 2001 and 30 June 2004 were studied. Chest imaging and postmortem examination reports were reviewed. Isolates were tested for the presence of genes encoding PVL and collagen adhesin by PCR.
A total of 47 of 70 patients with community-acquired methicillin-resistant S. aureus (MRSA) infection had abnormal pulmonary imaging findings, compared with 12 of 43 patients with community-acquired methicillin-susceptible S. aureus (MSSA) infection (P < .001). Pneumonia and/or empyema, in addition to septic emboli, were the most common findings. Metastatic pulmonary disease occurred more frequently among patients with osteomyelitis. Severe necrotizing pneumonia was present in 3 children coinfected with influenza and parainfluenza virus. The presence of genes encoding PVL was investigated in 67 MRSA and 36 MSSA isolates. Abnormal chest imaging findings were observed for 51 of 80 patients with PVL-positive isolates, compared with 2 of 23 patients with PVL-negative isolates (P < .001). Only 2 isolates (both of which were MSSA) from patients with abnormal chest radiograph findings carried cna. PVL remained independently associated with abnormal chest imaging findings in patients with secondary pneumonia in a multivariate analysis (P = .03).
Pulmonary involvement is commonly observed in patients with invasive community-acquired S. aureus infections. Community-acquired MRSA may cause primary community-acquired pneumonia, as well as metastatic pulmonary disease. The presence of genes encoding PVL is highly associated with pulmonary involvement by S. aureus.
Septic embolisms are rare disorders which are associated with increased mortality and morbidity. We describe a rare case of septic intramuscular embolism accompanied by asymptomatic pulmonary embolism in a neutropenic patient. Methicillin-sensitive Staphylococcus aureus (S. aureus) was detected and multiple nodules were revealed in both thighs and lung. Although he was treated with sensitive antibiotics to .S. aureus, the symptoms remained unchanged during the neutropenic period. Fever subsided rapidly and his thigh pain disappeared after neutropenia resolved. A prompt diagnosis and optimal therapeutic decisions are critical for the reduction of mortality.
The aim of this study was to investigate the clinicoradiologic features, microbiologic data, primary sites of infection, and treatment results for patients with septic pulmonary embolism (SPE) in Korea.
We retrospectively analyzed 21 SPE patients including "definite" and "probable" cases.
On CT scan, peripheral nodules were the most common lesions (89.0%), followed by non-nodular infiltrates (7.0%) and wedge-shaped peripheral lesions (3.2%). Cavitation and feeding vessel sign, more specific to SPE were identified in 10.4% and 6% of all the lesions, respectively. Transthoracic echocardiography revealed significant abnormalities in three of 13 patients with an additional finding of vegetation in only one of five patients when studied by transesophageal echocardiography. In 15 patients, primary sites of infection were found, and three causative organisms were isolated in 16: K. pneumoniae (8); S. aureus (6); and viridans streptococci (2). All patients received parenteral antimicrobial therapy with or without drainage of the extrapulmonary infection and 18 recovered.
Although the pathogens of SPE may differ depending on the primary foci of infection, early diagnosis and prompt antimicrobial therapy with radiologic or surgical intervention can lead to a successful treatment outcome.
The objective of this study was to use high-resolution MDCT to assess the relation of the pulmonary vasculature to septic emboli with particular attention to the feeding vessel sign.
The MDCT scans of nine patients with septic emboli were retrospectively, blindly evaluated by two observers. A control group of 10 patients with documented pulmonary metastasis and pathologically proven carcinoma also were included. Transverse images, multiplanar reconstructions, and maximum intensity projections were used to analyze nodules and the pulmonary vasculature. The CT scans were obtained with 1- to 1.25-mm collimation on a 4-, 8-, or 16-MDCT scanner. The feeding vessel sign was defined as a vessel coursing directly into a nodule.
The patients with septic embolism had a total of 141 nodules and 52 wedge-shaped opacities. Transverse images showed that 52 (37%) of the nodules and 11 (22%) of the wedge-shaped opacities had a vessel that appeared to enter the nodule, but multiplanar reconstructions (without IV contrast enhancement) and maximum intensity projections (with IV contrast enhancement) showed the vessels passed around the nodules. Twenty-one (15%) of the spherical nodules and seven (13%) of the wedge-shaped opacities exhibited a central vessel entering the lesion in all imaging planes. All of these vessels were traced to the left atrium on transverse images, a finding consistent with pulmonary vein branches. Similar findings were seen in pulmonary metastatic lesions.
Although pulmonary septic emboli often appear to have a feeding vessel on conventional cross-sectional images, multiplanar reconstructions show that most of these vessels course around the nodule and that the others are pulmonary veins.
A 69-year-old man who had benign prostatic hypertrophy and hypertension was admitted to our hospital because of urinary retention and high grade fever. Chest radiograph showed the appearance of multiple cavitating nodules in both lung fields within a few days after admission. Staphylococcus aureus was isolated in blood and sputum cultures, though there were no pathogens in urine culture. Abdominal CT demonstrated bilateral hydronephrosis. Since we could not detect any other infectious focuses such as bacterial endocarditis, septic thrombophlebitis etc., we reached the diagnosis of septic pulmonary embolism (SPE) induced by urinary tract infection (UTI). After diagnosis, the patient was given intravenous meropenem, ciprofloxacin, sulbactam/ampicilin, and recovered. Although several cases of SPE induced by UTI in diabetes mellitus patients have been reported, the present case who had no severe underlying disorder is very rare.
A 25-year-old male who had no significant medical history presented abrupt onset of high-grade fever and chills without noticeable trigger. The patient sought for medical attention for subsequently developed dyspnea and chest pain. Radiological examinations revealed bilateral lung peripheral multiple opacities, some of which were cavitating, suggesting of septic pulmonary emboli (SPE). Isolation of Staphylococcus aureus in blood and sputum culture confirmed the diagnosis. Extensive examinations disclosed neither underlying immunocompromising conditions nor infectious foci, which are usually notable in patients with SPE. The present patient illustrates that there are patients with SPE in whom underlying conditions or infectious foci are difficult to determine, and that suspicion of the disease based on characteristic radiological findings is critical for appropriate management in those patients.
To describe and compare the computed tomographic (CT) findings of pulmonary septic emboli in causative microorganisms.
The CT findings of 16 patients (8 men and 8 women; age range, 17 to 80 years; mean, 53.1 years) with documented pulmonary septic emboli were retrospectively reviewed by 2 radiologists; their decisions on the findings were reached by consensus. Statistical analysis was performed using the t test and the chi test.
A total of 197 peripheral nodules were seen in 6 gram-positive (n = 88) and 10 gram-negative (n = 109) septic pulmonary emboli patients, respectively. The sizes of the nodules (15.94 mm; range, 3-46 mm) in gram-positive septic emboli were larger than those (12.29 mm; range, 4-44 mm) in gram-negative septic emboli (P = 0.006). Cavitation (n = 30 [34%] vs n = 23 [21%]; P = 0.041) and air bronchogram (n = 12 [14%] vs n = 4 [4%]; P = 0.008) within the nodules were more commonly seen in gram-positive septic emboli. A ground-glass attenuation halo around a nodule (n = 69 [63%] vs n = 32 [36%]; P = 0.000) and feeding vessel signs (n = 56 [51%] vs n = 25 [28%]; P = 0.001) were more commonly seen in gram-negative septic emboli. Wedge-shaped peripheral lesions abutting the pleura were seen in 4 gram-positive (67%) and in 1 gram-negative (10%) septic emboli patients, respectively (P = 0.047).
The detailed CT characteristics of peripheral nodules in pulmonary septic emboli may be able to differentiate the causative microorganisms and to provide additional information regarding treatment plans in patients with sepsis.