Retroperitoneal fibrosis (RPF) is an inflammatory, fibrotic process that compresses the retroperitoneal structures, including the ureters. The mass typically centres on the distal aorta at L4–L5 and wraps around the ureters, causing hydronephrosis by extrinsic compression or by interfering with ureteral peristalsis.
Background and Etiology
- Idiopathic (70%) — associated with chronic aortitis.
- Identifiable cause (30%) — most notably medications: methysergide (and other ergot alkaloids), β-blockers, and phenacetin.
The pathogenesis is unknown but appears autoimmune.
Diagnosis and Evaluation
Symptoms and signs are usually non-specific. Labs may show an elevated ESR and CRP, moderate leukocytosis, anaemia, and variable renal insufficiency with electrolyte abnormalities. Although most patients with malignant RPF have a prior cancer history, a thorough work-up for occult malignancy is essential — the most common malignancy in RPF is lymphoma.
Management
- Decompression — patients with hydronephrosis and uraemia need emergent decompression by nephrostomy or stent. Stent placement is usually straightforward in RPF and allows retrograde pyelography and internal drainage; a nephrostomy is favoured in the critically ill patient with electrolyte derangement and little urine output. Monitor for post-obstructive diuresis afterward.
- Medications — steroids are the primary medical therapy, and patients with active inflammation (raised ESR/CRP/leukocytosis or active inflammation on biopsy) respond best. Immunosuppressants (azathioprine, mycophenolate, cyclosporine, cyclophosphamide, colchicine) are reserved for steroid failure — relapse during steroid taper is as high as 50%. Other agents include medroxyprogesterone, progesterone, and particularly tamoxifen.
- Ureterolysis — performed open or laparoscopically. Because the process is generally bilateral (even when hydronephrosis appears unilateral), bilateral ureterolysis is usually required, with the ureters protected by intraperitonealisation or omental wrapping; if ureterolysis is not feasible, renal autotransplantation is an option.
Self-Test
1. Which medications are associated with retroperitoneal fibrosis? Methysergide (and other ergot derivatives), β-blockers, and phenacetin.