A case of septic pulmonary embolism caused by urinary tract infection
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Ernesto Lima Araujo Melo, Ligia Persici Rodrigues, Ricardo Reges Maia de Oliveira
Department of Urology, Saitama Medical Center and Department of Urology, Soka City Hospital
Radiology Page
Vol. 38 (6): 857-858, November - December, 2012
A 56-year-old woman with diabetes mellitus (DM) presented at our department with intermittent low-grade fever, right-side back pain and general fatigue, having taken antibiotics (cefotiam) for the preceding two weeks as prescribed at another healthcare facility. Despite the absence of any cough or sputum production, chest X-ray revealed multiple nodular lesions in the peripheral lung fields (Figure-1). These nodules were not observed at the time of initial treatment at the referring hospital. Chest CT indicated multiple nodules in the peripheral bilateral lung fields (Figure-2). The largest nodule in the mid-lung field shows eccentric cavitation, with thin rim centrally but thick margin extending to the pleural surface peripherally. Abdominal CT showed a swollen right kidney and diffuse abscesses (Figure-3). A diagnosis of septic pulmonary embolism accompanied by pyelonephrosis was made. Accordingly, an alternative antibiotic (cefotaxime) was administered against sepsis. The multiple nodules in the lung and the diffuse renal abscesses simultaneously disappeared within two months after this course of highly potent anti-bacterial therapy. DM control was also accomplished by insulin therapy.
Septic pulmonary embolism has been defined as a lung embolism caused by a blood clot infected with any of several bacterial or fungal species. Typically, patients present with high-grade fever, productive cough, general malaise and hemoptysis. The presence of DM has an unfavorable impact on disease progression and prognosis. The most common radiographic findings are bilateral peripheral nodules with feeding vessels and cavity formations less than 3 cm in diameter. Cavity parenchymal formations are caused by septic occlusion of the distal pulmonary arteries and the frequency of cavitary lesions was 40% of the patients with septic pulmonary emboli (1). Whereas, the common feature of cavity formations was a thinly wall, our case showed the large cavitary lesion with a thick peripheral wall extending to the pleural surface which indicated the progressive development of metastatic lung abscesses with the occlusion of pulmonary artery. Septic pulmonary emboli are classified according to their source, i.e. endocarditis, peripheral endogenous origin, or exogenous origin. Endogenous origins include peripheral abscesses without cardiac lesions (2). While septic pulmonary embolism occurring secondary to UTI appears to be rare (3, 4), it should be considered a possibility in DM patients with abnormal multiple nodules revealed in radiographic examinations. Although the mechanism underlying this disease is still unknown, it is well known that renal cell carcinoma can form tumor thrombi and metastasize to the lungs via the venous vessels rather than through lymphatic spread. Thus, the septic pulmonary embolism in our case was thought to have developed from an infected thrombus originating in a renal abscess derived from the patient's UTI.
References
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- MacMillan JC, Milstein SH, Samson PC: Clinical spectrum of septic pulmonary embolism and infarction. J Thorac Cardiovasc Surg. 1978; 75:670-9.
- Kiwamoto T, Endo T, Sekizawa K: A case of septic pulmonary embolism induced by urinary tract infection. Nihon Kokyuki Gakkai Zasshi. 2004; 42: 89-93.
- Takahashi S, Uehara T, Shima M, Takasugi S, Hashimoto K, Itoh N: Septic pulmonary embolism caused by Candida albicans after treatment for urinary multidrug-resistant Pseudomonas aeruginosa. J Infect Chemother. 2008; 14: 436-8.
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Correspondence address:
Dr. Y. Okada
Department of Urology, Saitama Medical Center
1981 Kamoda, Kawagoe, Saitama, Japan
Fax: + 81 49 228-3673
E-mail: okada@saitama-med.ac.jp