Psoas abscess during treatment with intravenous tocilizumab in a patient with rheumatoid arthritis: a case-based review

Psoas and Mediastinal Abscesses during Intravenous Tocilizumab Treatment in Multicentric Castleman Disease

Tocilizumab has been used to treat idiopathic multicentric Castleman disease (iMCD). As tocilizumab prevents interleukin-6 from exerting pro-inflammatory effects, there is some concern about a delayed diagnosis of severe infections during tocilizumab treatment. Although serious infections during tocilizumab therapy have been previously described in patients with rheumatoid arthritis, they have not been reported in iMCD. We herein report a case of disseminated Staphylococcus aureus infection after a superficial skin wound followed by psoas and mediastinal abscesses with pyogenic spondylodiscitis in an iMCD patient with diabetes. Physicians should be alert for the occurrence of disseminated S. aureus infection after even minor skin injury during tocilizumab therapy.

Pleural empyema caused by dropped gallstones after laparoscopic cholecystectomy for acute cholecystitis: a case report

BACKGROUND

Dropped gallstones during laparoscopic cholecystectomy (LC) sometimes induce postoperative infectious complications. However, pleural empyema rarely occurs as a complication of LC.

CASE PRESENTATION

We present the case of a 66-year-old woman with right pleural empyema. She previously underwent LC for acute gangrenous cholecystitis 11 months ago. The operative report revealed iatrogenic gallbladder perforation and stone spillage. The bacterial culture of the gallbladder bile was positive for Escherichia coli. Chest and abdominal computed tomography revealed right pleural effusion, perihepatic fluid collection, and multiple small radiopaque density masses. Although ultrasound-guided transthoracic drainage was performed, the drainage was incomplete, and systemic inflammatory reaction persisted. Consequently, thoracotomy and laparotomy with gallstone retrieval were performed, and the patient recovered completely. The patient has remained well without complications after 14 months of follow-up.

CONCLUSIONS

We report a rare case of pleural empyema caused by dropped gallstones after LC. This case emphasized the importance of completely retrieving the dropped gallstones to prevent late infectious complications after LC.

Detection of mecA and 16S rRNA Genes Using Real-Time PCR Can Be Useful in Diagnosing Iliopsoas Abscess, Especially in Culture-Negative Cases: RT-PCR for Iliopsoas Abscess

The rapid detection of etiological agents is important for the successful treatment of iliopsoas abscess (IPA). The purpose of this study was to investigate the clinical utility of a real-time polymerase chain reaction (PCR) that targets the mecA gene for methicillin-resistant staphylococci (MRS) and the 16S rRNA gene for pan-bacteria. Our retrospective diagnostic study included 22 patients exhibiting IPAs and four patients with noninfectious iliopsoas mass regions who underwent computerized tomography or ultrasonography-guided biopsy and/or surgical treatment. Clinical symptoms, serum data, imaging analysis, and tissue microbiological culture were utilized for the diagnosis of IPA. The diagnostic accuracy of real-time PCR was determined based on the diagnosis of IPA and microbiological culture results. The microbiological culture was positive for 12 IPA cases that included 2 MRSA infections. Among 12 culture-positive IPA cases, 16S rRNA-PCR was positive in 12 and MRS-PCR in two. Among 10 culture-negative IPA cases, including 3 TB cases, 16S rRNA-PCR was positive in 8 and MRS-PCR in 2. In noninfectious iliopsoas mass patients, neither 16S rRNA nor MRS-PCR detected bacterial DNA. The sensitivity, specificity, positive predictive, and negative predictive values of 16S rRNA-PCR for diagnosing IPA were 0.91, 1.00, 1.00, and 0.67, respectively, while those for the diagnosis of MRS infection with MRS-PCR were 1.00, 0.92, 1.00, and 0.50, respectively. Real-time PCR targeting bacterial DNA can detect bacterial DNA in culture-negative cases and offer improved detectability of MRS infection in IPA patients.