What is the best treatment approach for a patient with back pain, bilateral hydronephrosis, history of splenectomy, retroperitoneal fibrosis, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE)?

Management of Complex Autoimmune Disease with Retroperitoneal Fibrosis and Bilateral Hydronephrosis

This patient requires urgent urological decompression followed by high-dose corticosteroid therapy (prednisone 1 mg/kg/day or equivalent) to address the retroperitoneal fibrosis causing bilateral hydronephrosis, while simultaneously managing the underlying autoimmune conditions with a multidisciplinary rheumatology-centered approach. 1, 2, 3

Immediate Priorities: Address the Hydronephrosis

Urological Assessment and Intervention

• Bilateral hydronephrosis from retroperitoneal fibrosis (RPF) requires urgent evaluation to prevent irreversible renal damage and progression to kidney failure 2, 3, 4
• Obtain immediate imaging with CT scan to assess the extent of ureteral compression and rule out other causes of obstruction 3, 5
• If renal function is deteriorating or if there is acute kidney injury, proceed with bilateral ureteral stent placement before initiating immunosuppressive therapy 3, 5
• Delayed treatment (≥1 month after symptom onset) is associated with poor outcomes, particularly in patients with autoimmune disease 5

Critical Diagnostic Considerations

• First, verify the diagnosis of RA and SLE - the coexistence of both conditions ("Rhupus syndrome") is rare and should prompt reconsideration of the diagnosis 1
• Rule out misdiagnosis or mimicking conditions including crystal arthropathies, vasculitis, IgG4-related disease, or malignancy 1, 2
• Obtain FDG-PET scan to assess metabolic activity of the retroperitoneal mass and exclude malignancy 3
• Check IgG4 levels - approximately 50% of idiopathic RPF cases are associated with IgG4-related disease 2, 3

Corticosteroid Therapy for Retroperitoneal Fibrosis

Initial Treatment Regimen

• Initiate high-dose corticosteroids (prednisone 1 mg/kg/day or equivalent) as first-line therapy for idiopathic RPF 2, 3, 5
• Treatment with corticosteroids alone leads to favorable outcomes in 73% of SLE patients with hydronephrosis, with resolution of urinary obstruction in the majority (73%) without urological intervention 5
• Monitor inflammatory markers (ESR, CRP) to assess treatment response 3
• Follow-up imaging at 4-6 weeks to assess response; if no improvement, consider adding immunosuppressants 2, 5

Steroid-Sparing Immunosuppression

• If corticosteroids alone are insufficient or for long-term maintenance, consider adding:
  • Mycophenolate mofetate (MMF) as preferred agent for both lupus nephritis and RPF 1, 2
  • Azathioprine as alternative 1, 2
  • Methotrexate for RA component 1

Management of Underlying Autoimmune Conditions

Rheumatoid Arthritis Management

• Assess for true inflammatory activity using clinical examination and consider ultrasonography if doubt exists about disease activity 1
• Composite disease activity indices may be unreliable in the presence of multiple comorbidities 1
• Do not escalate DMARD therapy if inflammatory activity is absent 1
• Continue or initiate conventional synthetic DMARDs (methotrexate preferred) if inflammatory RA is confirmed 1

Systemic Lupus Erythematosus Management

• Confirm active lupus by checking anti-dsDNA antibodies, complement levels (C3/C4), and assessing for other organ involvement 1
• Hydroxychloroquine 400 mg/day (or 6.5 mg/kg/day, whichever is lower) should be continued - it reduces renal relapses and improves outcomes in lupus nephritis 1
• If lupus nephritis is present (check urine protein:creatinine ratio, urinalysis for cellular casts), consider adding mycophenolate mofetate 1
• For active lupus nephritis, belimumab 10 mg/kg IV can be added to standard therapy (corticosteroids plus mycophenolate) 6

Addressing Post-Splenectomy Status

• This patient has significantly increased infection risk due to asplenia combined with immunosuppressive therapy 7
• Ensure vaccination status is current: pneumococcal (PCV13 followed by PPSV23), meningococcal, Haemophilus influenzae type B, and annual influenza 7
• Maintain high index of suspicion for encapsulated bacterial infections (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis) 7
• Consider prophylactic antibiotics (penicillin V or amoxicillin) in high-risk situations 7

Monitoring and Follow-Up Strategy

Short-Term Monitoring (First 3 Months)

• Weekly assessment initially for signs of infection, worsening renal function, or treatment complications 1
• Monitor serum creatinine, eGFR, complete blood count, and inflammatory markers (ESR, CRP) every 2-4 weeks 1, 3
• Repeat imaging (CT or ultrasound) at 4-6 weeks to assess hydronephrosis response 5
• If no improvement in hydronephrosis after 1 month of corticosteroids, consider surgical intervention or escalation of immunosuppression 5

Long-Term Management

• Transition to a rheumatology-centered multidisciplinary team including nephrology, urology, and infectious disease specialists 1
• Gradual corticosteroid taper once disease control achieved, aiming to minimize long-term steroid exposure 1
• Monitor for treatment adherence - nonadherence rates exceed 60% in SLE patients 1
• Annual monitoring for malignancy risk given immunosuppression and autoimmune disease 1

Critical Pitfalls to Avoid

• Do not delay urological intervention if renal function is deteriorating - bilateral hydronephrosis can rapidly progress to irreversible kidney damage 3, 5
• Do not assume all symptoms are from active autoimmune disease - comorbidities including fibromyalgia, osteoarthritis, and chronic pain syndromes may mimic inflammatory activity 1
• Do not overlook infection risk - this asplenic patient on immunosuppression requires aggressive infection prevention and early treatment of suspected infections 7
• Do not use live vaccines while on immunosuppressive therapy 1
• Avoid nephrotoxic agents including NSAIDs and calcineurin inhibitors unless specifically indicated 1