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Clinical Characteristics of Retroperitoneal Fibrosis Patients at a Tertiary Hospital in Japan
Miho Ando1, Yoshihisa Hanayama1, Yoshito Nishimura1,2
1Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences.
Abstract:
Retroperitoneal fibrosis (RPF) is a rare cause of hydronephrosis and progressive renal dysfunction with unidentified origin. RPF is categorized into idiopathic RPF with/without immunoglobulin G4 (IgG4)-related disease (IgG4-RD), and secondary RPF. Identifying the underlying cause is challenging and often associated with delayed diagnosis or therapeutic interventions. We investigated RPF's clinical characteristics based on different etiologies and factors that may help distinguish the underlying causes. We analyzed the cases of 49 patients with RPF that was radiographically diagnosed at our institution (2008-2022). The cohort was 77.6% males; 75.5% had idiopathic RPF and 24.5% had secondary RPF. Among the idiopathic patients, 54.1% had IgG4-RD. The patients were likely to have abdominal pain, lower back pain/lumbago, and constitutional symptoms including generalized fatigue and fever. The idiopathic patients were likely to have higher serum IgG4 and IgG levels and lower serum C3 levels compared to secondary RPF. The IgG4-RPF patients were likely to have higher serum IgG4 levels and lower serum C-reactive protein, ferritin, and C3 levels compared to the idiopathic RPF patients without IgG4-RD. These findings might reflect underlying systemic inflammatory responses. Comprehensive laboratory testing, including serum inflammatory markers and immunological panels, is recommended for radiologically diagnosed RPF patients.
Insights
Retroperitoneal fibrosis (RPF) is a rare condition. Differentiating its causes, like idiopathic or secondary RPF, is key for diagnosis, with specific lab tests aiding in identifying immunoglobulin G4-related disease (IgG4-RD).
Area of Science:
- Nephrology
- Immunology
- Radiology
Background:
- Retroperitoneal fibrosis (RPF) is a rare condition causing hydronephrosis and renal dysfunction.
- RPF is classified as idiopathic or secondary, with idiopathic RPF sometimes linked to immunoglobulin G4-related disease (IgG4-RD).
- Distinguishing RPF causes is challenging, often leading to diagnostic delays.
Purpose of the Study:
- To investigate the clinical characteristics of RPF based on etiology.
- To identify factors that help differentiate between idiopathic and secondary RPF.
- To explore the association between RPF subtypes and laboratory findings.
Main Methods:
- Retrospective analysis of 49 RPF patients diagnosed radiographically between 2008-2022.
- Categorization of patients into idiopathic RPF (with/without IgG4-RD) and secondary RPF.
- Comparison of clinical symptoms and laboratory markers (serum IgG4, IgG, C3, C-reactive protein, ferritin) across subgroups.
Main Results:
- The cohort was predominantly male (77.6%); 75.5% had idiopathic RPF, and 24.5% had secondary RPF.
- Among idiopathic cases, 54.1% had IgG4-RD.
- Idiopathic RPF patients showed higher serum IgG4/IgG and lower C3 levels than secondary RPF. IgG4-RPF patients had higher IgG4 and lower C-reactive protein, ferritin, and C3 levels compared to idiopathic RPF without IgG4-RD.
Conclusions:
- Clinical presentation and laboratory findings can help distinguish RPF etiologies.
- Elevated serum IgG4 and altered inflammatory markers suggest specific RPF subtypes.
- Comprehensive laboratory testing is recommended for radiologically diagnosed RPF to guide diagnosis and management.
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