Septic pulmonary emboli detected by 18F-FDG PET/CT in children with S. aureus catheter-related bacteremia

Septic Pulmonary Embolism: A Contemporary Profile

Septic pulmonary embolism (SPE) is a rare clinical entity that is distinct from the classic and more common non-septic thrombotic pulmonary embolism. SPE should be suspected in patients with a systemic acute inflammatory reaction or sepsis who develop signs and symptoms of pulmonary involvement. The diagnosis of SPE depends on the specific radiologic finding of multiple, peripheral, nodular, possibly cavitated lesions. SPE should prompt an immediate search for the primary source of infection; typically, right-sided infective endocarditis, cardiac implantable electronic devices, and septic thrombophlebitis as a complication of bone, skin, and soft tissue infection including Lemierre's syndrome, indwelling catheters, or direct inoculation via injection drug use. Invasive treatment of the infection source may be necessary; in thrombophlebitis, the efficacy and safety of anticoagulation remain undefined. Blood cultures may be negative, particularly among patients with recent antibiotic exposure, and broad-spectrum antimicrobial therapy should be considered. The in-hospital mortality of SPE ranges up to 20% in published case series. While trends in the incidence of SPE are unknown, the opioid epidemic, the growing use of cardiac implantable electronic devices worldwide, and the reported increase in cases of septic thrombophlebitis may be leading to an escalation in SPE cases. We provide a contemporary profile of SPE and propose a clinical management algorithm in patients with suspected or confirmed SPE.

Clinical and radiological variants of lung damage in the infection caused by staphylococcus aureus

Despite the high level of modern technologies in the field of laboratory methods and imaging of the respiratory system, the problem of early and accurate differential diagnosis of inflammatory lung diseases remains important in practical medicine. It leads to improved treatment results and a reduction in the number of complications (pleural empyema, fistulas, mediastinitis, sepsis, etc.), and in some cases allows suspecting the presence of a primary purulent source in the body, such as that in the case of septic pulmonary embolism. The review covers the Staphylococcus aureus specifics as a pathogen of lung diseases, relevant epidemiology, pathogenesis, clinical features and imaging diagnostics of various types of inflammatory changes in the lungs with a focus on destruction.

PET/Computed Tomography in the Evaluation of Fever of Unknown Origin and Infectious/Inflammatory Disease in Pediatric Patients

Fever in children is common. If it persists and its cause cannot be identified in a reasonable time, along with laboratory and conventional imaging investigations, it is defined as fever of unknown origin (FUO). 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) is well established in the evaluation of malignancy, which is a possible cause of FUO. FDG often locates inflammatory and infectious lesions considered nonspecific or false-positive for oncology; however, these findings are beneficial in FUO evaluation because infectious and inflammatory diseases are important FUO causes. FDG-PET/CT is being increasingly used for investigation of FUO as well as infectious/inflammatory disease.

The Diagnostic Value of FDG PET/CT and Thin-Slice High-Resolution Chest CT in Pulmonary Intravascular Metastasis

OBJECTIVE. Pulmonary intravascular metastasis is a special type of pulmonary metastasis of malignancies; however, few relevant studies have been performed. This study aimed to determine the characteristics of pulmonary intravascular metastasis and improve understanding of the disease by retrospective analysis of FDG PET/CT and thin-layer high-resolution CT (HRCT) imaging of the chest in patients with tumors. MATERIALS AND METHODS. We identified all patients who underwent FDG PET/CT at two hospitals between January 2016 and February 2019 and conducted a comparative analysis of HRCT and PET/CT images. In total, 84 patients (38 women and 46 men) ranging in age from 35 to 82 years old (mean age, 54.7 ± 14.5 [SD] years) participated in the study. Patient characteristics were summarized, and diagnosis was confirmed by chest CT or PET/CT follow-up. RESULTS. A total of 260 pulmonary intravascular metastases were found, which were classified as type I (no significant abnormality, n = 5), type II (abrupt and uneven thickening of the pulmonary vessel, n = 118), type III (simultaneous invasion of adjacent pulmonary vessel, n = 121), and type IV (large strip-shaped high-density mass, n = 16). The majority were located in peripheral pulmonary vessels (94.2% [245/260]). FDG up-take was increased in 252 lesions, and the mean SUV_max was 4.6 ± 2.5. CONCLUSION. The combination of PET/CT and chest HRCT is an effective approach for detecting pulmonary intravascular metastasis. The linear pattern of FDG uptake, abnormal pulmonary blood vessel morphology, and location (below the lung segment) are specific indicators for the diagnosis of pulmonary intravascular metastasis and should be recognized by clinicians and radiologists.

Early differentiation between uncomplicated and complicated Staphylococcus aureus bacteraemia: Potential value and limitations of a clinical risk score

OBJECTIVE

A cornerstone in the management of Staphylococcus aureus bacteraemia (SAB) is the differentiation between a complicated and an uncomplicated SAB course. The ability to early and accurately identify patients with - and without - complicated bacteraemia may optimise the utility of diagnostics and prevent unnecessary prolonged antibiotic therapy.

METHODS

Development and validation of a prediction score in SAB using demographic, clinical, and laboratory data from two independent Dutch cohorts; estimating the risk of complicated disease at the time of the first positive blood culture. Models were developed using logistic regression and evaluated by c-statistics, ie area under the ROC-curve, and negative predictive values (NPV).

RESULTS

The development- and validation cohorts included 150 and 183 patients, respectively. The most optimal prediction model included: mean arterial pressure, signs of metastatic infection on physical examination, leucocyte count, urea level and time to positivity of blood cultures (c-statistic 0.82, 95% CI 0.74-0.89). In the validation cohort, the c-statistic of the prediction score was 0,77 (95% CI 0.69-0.84). The NPV for complicated disease for patients with a score of ≤2 was 0.83 (95% CI 0.68-0.92), with a negative likelihood ratio of 0.14 (95% CI 0.06-0.31).

CONCLUSION

The early SAB risk score helps to identify patients with high probability of uncomplicated SAB. However, the risk score's lacked absolute discriminative power to guide decisions on the management of all patients with SAB on its own. The heterogenicity of the disease and inconsistency in definitions of complicated SAB are important challenges in the development of clinical rules to guide the management of SAB.

18F-FDG-PET/CT Imaging to Diagnose Septic Emboli and Mycotic Aneurysms in Patients with Endocarditis and Cardiac Device Infections

PURPOSE OF REVIEW

This review analyzes recent studies evaluating the diagnostic value of ¹⁸F-FDG-PET/CT for the detection of peripheral emboli and secondary infectious foci in patients with infective endocarditis and cardiac device infections.

RECENT FINDINGS

Detection of extracardiac septic localizations in patients with infective endocarditis and cardiac device infections is crucial, as it may impact the diagnosis, prognosis, and therapeutic management. Recent literature substantiated the clinical usefulness of ¹⁸F-FDG-PET/CT in this setting. ¹⁸F-FDG-PET/CT has proven its high diagnostic value for the detection of peripheral emboli in patients with infective endocarditis and cardiac device infections, substantially affecting patients' outcome and treatment. A multimodal approach, combining the high sensitivity of ¹⁸F-FDG-PET/CT with morphological imaging seems promising.