A case of septic pulmonary embolism associated with renal abscess mimicking pulmonary metastases of renal malignancy

Metastatic Infection Following Ear Piercing Detected by FDG PET/CT

ABSTRACT

Ear piercing is currently a common practice. Although rare, ear piercing can cause systemic infections. We present a case of an 18-year-old woman who underwent FDG PET/CT for prolonged fever and bacteremia. FDG PET/CT showed multifocal FDG uptake at the site of piercing in the left ear, and in the spleen and left atrium and deep thigh vessel. The patient was diagnosed with an ear piercing infection with multiple metastatic infections.

Pitfalls in interpretation of FDG PET/CT: Septic pulmonary emboli mimicking metastases in a case of gastric carcinoma

Inflammatory lesions may sometimes show intense tracer uptake and mimic neoplastic lesions on (18) F-fluoro-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). We report one such false positive case on FDG PET/CT, where septic pulmonary emboli (SPE) mimicked pulmonary metastases. A 45-year-old man with stomach cancer had an indwelling central venous catheter (CVC) in situ while on neoadjuvant chemotherapy. He underwent FDG PET/CT scan for response assessment and the images revealed multiple, intensely FDG avid, peripheral, lung nodules with feeding vessels, which were suspicious for pulmonary metastases. A day later, the patient developed fever with chills and his blood culture showed bacterial growth (Enterobacter cloacae). A provisional diagnosis of SPE from an infected CVC was made. Chemotherapy was withheld, CVC removed, and the catheter tip was sent for bacterial culture. Following a 4-week course of antibiotic treatment, the patient became afebrile. Culture from the CVC tip grew the same organism, as was seen earlier in the patient's blood culture, thus pin-pointing the source of infection in our case. Diagnosis of SPE was clinched when follow-up CT chest done after completion of antibiotic course showed complete resolution of the lung lesions.

Acute Findings on FDG PET/CT: Key Imaging Features and How to Differentiate Them from Malignancy

PURPOSE OF REVIEW

To review acute findings commonly encountered during routine clinical FDG PET/CT studies and present key imaging features to differentiate them from malignant counterparts.

RECENT FINDINGS

FDG PET/CT is extensively used in routine clinical practice for oncology patients. Incidental acute findings in patients undergoing FDG PET/CT are increasingly common, and awareness of these findings and their mimics are important in delivering a clinically relevant and accurate radiological report for directing further management.

SUMMARY

This article will review examples of common acute findings encountered during routine FDG PET/CT scans, compare them against examples of FDG-avid malignancy that can mimic these findings and emphasize key imaging findings to differentiate acute findings from their malignant mimics.

A case of septic pulmonary embolism caused by P. aeruginosa in a hemodialysis patient and review of the literature

Background

Septic pulmonary embolism (SPE) is an uncommon but serious complication resulting from infection of the blood. Gram-positive cocci, including methicillin-susceptible Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, are the most common causative organisms of SPE. Few case reports have been published on SPE caused by Pseudomonas aeruginosa (P. aeruginosa), and thus, the consensus treatment of SPE caused by P. aeruginosa infections remains undetermined. Management of P. aeruginosa infection can be challenging due to its poor prognosis and antimicrobial resistance. Here, we report a case of successful combination antibiotic therapy for SPE associated with infective endocarditis (IE) caused by P. aeruginosa in a hemodialysis patient, with a review of the literature.

Case presentation

A 62-year-old man receiving maintenance hemodialysis as treatment for end-stage renal disease due to IgA nephropathy was admitted to our hospital with high fever and chills lasting 10 days. Chest computed tomography revealed multiple nodular shadows, and gram-negative rods were confirmed by blood culture obtained on admission. We suspected SPE and initiated meropenem (MEPM) treatment. P. aeruginosa was identified in blood cultures, and transesophageal echocardiography demonstrated vegetation on the tricuspid valve. Therefore, a diagnosis of SPE associated with IE caused by P. aeruginosa was made. P. aeruginosa isolates showed good susceptibility to MEPM, but no symptomatic improvement was observed. Thus, antibiotics were changed from MEPM to a combination of ceftazidime and tobramycin (TOB). The patient exhibited a favorable response to the combination therapy, although we discontinued TOB on day 23 because of tinnitus symptoms.

Conclusions

We report a rare case of SPE associated with IE caused by P. aeruginosa in a hemodialysis patient. Combination antibiotic therapy may be effective in this situation.

The impact of infection and inflammation in oncologic 18F-FDG PET/CT imaging

Sites of infection and inflammation can be misleading in oncology PET/CT imaging because these areas commonly show ¹⁸F-FDG activity. Caution in the interpretation must be taken to avoid the misdiagnosis of malignancy. Utilization of both CT findings as well as patient history can help differentiate benign infectious and inflammatory processes from malignancy, although occasionally additional work-up may be required. This article discusses the mechanism of ¹⁸F-FDG uptake in infection and inflammation with illustrative examples.

Septic Pulmonary Embolism Requiring Critical Care: Clinicoradiological Spectrum, Causative Pathogens and Outcomes

OBJECTIVES:

Septic pulmonary embolism is an uncommon but life-threatening disorder. However, data on patients with septic pulmonary embolism who require critical care have not been well reported. This study elucidated the clinicoradiological spectrum, causative pathogens and outcomes of septic pulmonary embolism in patients requiring critical care.

METHODS:

The electronic medical records of 20 patients with septic pulmonary embolism who required intensive care unit admission between January 2005 and December 2013 were reviewed.

RESULTS:

Multiple organ dysfunction syndrome developed in 85% of the patients, and acute respiratory failure was the most common organ failure (75%). The most common computed tomographic findings included a feeding vessel sign (90%), peripheral nodules without cavities (80%) or with cavities (65%), and peripheral wedge-shaped opacities (75%). The most common primary source of infection was liver abscess (40%), followed by pneumonia (25%). The two most frequent causative pathogens were Klebsiella pneumoniae (50%) and Staphylococcus aureus (35%). Compared with survivors, nonsurvivors had significantly higher serum creatinine, arterial partial pressure of carbon dioxide, and Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores, and they were significantly more likely to have acute kidney injury, disseminated intravascular coagulation and lung abscesses. The in-hospital mortality rate was 30%. Pneumonia was the most common cause of death, followed by liver abscess.

CONCLUSIONS:

Patients with septic pulmonary embolism who require critical care, especially those with pneumonia and liver abscess, are associated with high mortality. Early diagnosis, appropriate antibiotic therapy, surgical intervention and respiratory support are essential.