A rare presentation of subphrenic abscess caused by Proteus mirabilis in a non-immunocompromised patient: A case report

Abstract

Subphrenic abscesses are rare, yet clinically significant, and are often associated with intra-abdominal infections. The present case report describes the case of a 77-year-old male patient with an unusual presentation of a subphrenic abscess caused by Proteus mirabilis without typical predisposing factors. The patient experienced a prolonged 2-year course characterized by recurrent febrile episodes and respiratory symptoms. The diagnosis was confirmed through imaging and microbiological culture, with percutaneous drainage and culture-directed antibiotic therapy, including meropenem, leading to successful treatment. The multidrug-resistant nature of the pathogen, coupled with the atypical presentation of the patient, posed significant challenges in both diagnosis and management. The case described herein underscores the importance of comprehensive diagnostic imaging, timely intervention and individualized treatment strategies in managing such complex infections.

Keywords: Proteus mirabilis; intra-abdominal infections; multidrug resistance; percutaneous drainage; subphrenic abscess.

Figure 1

Computed tomography images illustrating a complex cystic mass measuring 11.5 cm in diameter, located in the right subdiaphragmatic region, extending into the thoracic soft tissue at the 7th and 8th intercostal spaces. The mass involved the right pleura and middle lobe of the lung, exerting compressive effects on the right liver lobe. Atelectasis was observed in the lower and middle lobes of the right lung and the lower lobe of the left lung. A small right-sided pleural effusion was also noted. The image on the left panel represents the upper axial slice, illustrating the superior aspect of the subdiaphragmatic abscess. The image on the right panel represents the lower axial slice, providing clearer visualization of the caudal extent of the abscess. Yellow arrows indicate the abscess in both images.