Diagnostics of septic arthritis in the sternoclavicular region: 10 consecutive patients and literature review.

BACKGROUND: Septic arthritis in the sternoclavicular (SC) region is rare and may be difficult to diagnose clinically and radiologically. It mainly affects immunocompromised persons, and can clinically be misinterpreted as tumor and rheumatic disorders. Lacking radiological reference standard, a multimodality approach may contribute to a prolonged diagnostic process. PURPOSE: To describe the diagnostics of septic arthritis in the SC region. MATERIAL AND METHODS: Between 2001 and 2011 10 patients with Staphylococcus infection in the SC region were investigated in our institution. Clinical, biochemical, radiological, and microbiological findings were studied retrospectively; all CT and MR examinations were re-evaluated. RESULTS: Initial radiography in nine patients and ultrasonography in six patients were inconclusive resulting in supplementary MRI and/or CT. Five patients examined by MRI were immediately diagnosed with septic arthritis whereas CT in five patients led to the diagnosis in only one. Three were subsequently diagnosed by MRI, but delayed more than 2.5 weeks, and one was diagnosed by surgery. The median time to diagnosis was 1.5 weeks. The delay caused by imaging was 0 days to 11.5 weeks (median 0 days). By re-evaluation overlooked complications included mediastinitis in seven patients (three diffuse, four localized), and abscesses and pleuritis each in four patients. CONCLUSION: Awareness of infection in the SC region is important to avoid diagnostic delay. MRI is proposed as the initial imaging procedure.

Increased renal adrenomedullin expression in rats with ureteral obstruction.

Ureteral obstruction is characterized by decreased renal blood flow that is associated with hypoxia within the kidney. Adrenomedullin (AM) is a peptide hormone with tissue-protective capacity that is stimulated through hypoxia. We tested the hypothesis that ureteral obstruction stimulates expression of AM and hypoxia-inducible factor-1 (HIF-1alpha) in kidneys. Rats were exposed to bilateral ureteral obstruction (BUO) for 2, 6, 12, and 24 h or sham operation and compared with unilateral obstruction (UUO). AM mRNA expression was measured by quantitative PCR in cortex and outer medulla (C+OM) and inner medulla (IM). AM and HIF-1alpha protein abundance and localization were determined in rats subjected to 24-h BUO. AM mRNA expression in C+OM increased significantly after 12-h BUO and further increased after 24 h. In IM, AM mRNA expression increased significantly in response to BUO for 6 h and further increased after 24 h. AM peptide abundance was enhanced in C+OM and IM after 24-h BUO. Immunohistochemical labeling of kidneys showed a wider distribution and more intense AM signal in 24-h BUO compared with Sham. In UUO rats, AM mRNA expression increased significantly in IM of the obstructed kidney compared with nonobstructed and Sham kidney whereas AM peptide increased in IM compared with Sham. HIF-1alpha protein abundance increased significantly in IM after 24-h BUO compared with Sham and HIF-1alpha immunoreactive protein colocalized with AM. In summary, AM and HIF-1alpha expression increases in response to ureteral obstruction in agreement with expected oxygen gradients. Hypoxia acting through HIF-1alpha accumulation may be an important pathway for the renal response to ureteral obstruction.