Scleroma and Kidney Involvement
Critical Clarification: Scleroma vs. Scleroderma
If you are asking about rhinoscleroma (a chronic granulomatous infection), there is no established renal involvement—this is a localized upper respiratory tract disease caused by Klebsiella rhinoscleromatis that does not affect the kidneys.
If you are asking about scleroderma (systemic sclerosis), renal complications are well-documented and require systematic evaluation and management as outlined below. 1, 2
Renal Complications in Systemic Sclerosis (Scleroderma)
Spectrum of Kidney Disease
Renal involvement in systemic sclerosis encompasses several distinct entities beyond the classic scleroderma renal crisis (SRC):
Scleroderma renal crisis (SRC): Occurs in 2-15% of patients, typically within the first 3-5 years of diffuse cutaneous disease, characterized by acute hypertension, rising creatinine, oliguria, and thrombotic microangiopathy in ~50% of cases 1, 2
Subclinical renal impairment: Affects approximately 50% of scleroderma patients, manifesting as reduced GFR, proteinuria, or microalbuminuria without overt crisis 2, 3
Chronic kidney disease: GFR <90 ml/min occurs in 31.5% of patients, with GFR <60 ml/min in 19.5% 3
Other renal pathologies: ANCA-associated glomerulonephritis, penicillamine-associated renal disease, and secondary causes unrelated to scleroderma 2, 4
Screening and Risk Stratification
High-Risk Features for SRC
Patients with anti-RNA polymerase III antibodies have the strongest association with SRC and require intensive monitoring. 2
Additional risk factors include:
- Early diffuse cutaneous systemic sclerosis (within first 3-5 years) 1, 2
- Rapidly progressive skin involvement 5
- Pericardial effusion, cardiac involvement, or active interstitial lung disease 5
- Tendon friction rubs 5
- Male sex 5
- Glucocorticoid use 5
Monitoring Protocol
Home blood pressure monitoring should be encouraged in all patients with early diffuse cutaneous disease, particularly those positive for anti-RNA polymerase III antibodies 5, 2
Regular blood pressure checks at every clinical visit 5
Serum creatinine is inadequate for detecting renal impairment in scleroderma—18 of 19 patients with creatinine below the upper limit of normal had abnormal measured GFR 6
Assessment of Renal Function
GFR Calculation
Use the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) formula for GFR estimation in scleroderma patients, as it provides results most similar to measured GFR. 3
The MDRD formula shows good correlation (r=0.91) in patients with body surface area >1.4 m² not taking iloprost 6
The modified Cockcroft-Gault formula is less accurate in this population 6
All patients with measured GFR <60 ml/min were correctly identified using calculated GFR, making this a reliable screening tool 6
Baseline and Ongoing Assessment
- Obtain calculated GFR at diagnosis and annually thereafter 5, 3
- Screen for proteinuria with urine protein-to-creatinine ratio or 24-hour urine collection 2
- Monitor for hematuria 3
- Assess for other organ involvement (pulmonary arterial hypertension, interstitial lung disease, cardiac disease) as these may predict mortality when combined with subclinical renal impairment 2
Management Strategies
Scleroderma Renal Crisis
ACE inhibitors are first-line therapy for SRC and should be initiated immediately upon diagnosis, with rapid titration to control blood pressure. 1, 2
- Target blood pressure control within 72 hours 1
- Add additional antihypertensive agents as needed (calcium channel blockers, alpha-blockers) if ACE inhibitors alone are insufficient 2
- Continue ACE inhibitors even if dialysis is required, as renal recovery may occur months later 1
- Current 1-year survival is 70-82%, but 5-year survival remains only 50-60% despite dialysis 1
Subclinical Renal Impairment
For patients with reduced GFR or proteinuria without SRC, investigate non-scleroderma causes of kidney disease before attributing it to systemic sclerosis. 4
- Only 4% of diffuse scleroderma patients have unexplained kidney dysfunction or proteinuria 4
- Common alternative explanations include D-penicillamine toxicity, hypertensive nephropathy, diabetic nephropathy, and other primary renal diseases 4
- These patients rarely progress to end-stage renal disease requiring dialysis when SRC is excluded 4
General Renal Protection
- Avoid glucocorticoids at doses >15 mg/day in patients at high risk for SRC, as steroids are associated with increased SRC risk 5, 2
- Maintain adequate hydration 5
- Avoid nephrotoxic agents including NSAIDs 5
- Consider ACE inhibitors or ARBs for blood pressure control and renoprotection in patients with proteinuria or reduced GFR 5, 2
Kidney Transplantation
Patients with SRC who show no renal functional recovery despite timely blood pressure control are candidates for kidney transplantation. 1
- Transplantation should be considered after adequate time for potential recovery (typically 12-24 months) 1
- Recurrent SRC in the transplanted kidney is rare 1
Critical Pitfalls to Avoid
Do not rely on serum creatinine alone—it misses the majority of patients with impaired renal function in scleroderma 6
Do not delay ACE inhibitor therapy in suspected SRC while awaiting confirmatory tests; early treatment is critical for survival 1, 2
Do not assume all renal dysfunction in scleroderma is due to the disease itself—thoroughly evaluate for alternative causes, particularly medication toxicity 4
Do not discontinue ACE inhibitors if dialysis becomes necessary in SRC, as late renal recovery can occur 1
Do not use high-dose glucocorticoids (>15 mg/day prednisone equivalent) in patients with risk factors for SRC 5, 2