From the Guidelines
Sarcoidosis and Kidney Involvement
Kidney Affection in Sarcoidosis
Renal Implications of Sarcoidosis
Yes, sarcoidosis can affect the kidneys and cause impaired renal function, with abnormal renal function detected in 7% of patients 1. This can occur through two mechanisms: parenchymal granulomatous inflammation or altered calcium metabolism, leading to conditions such as nephrocalcinosis or nephrolithiasis 1. Patients with sarcoidosis should undergo routine serum creatinine testing to screen for renal sarcoidosis, even if they do not have renal symptoms, as timely treatment with immune suppression can attenuate sarcoidosis-induced renal complications 1. The most common findings in kidney biopsies of patients with abnormal renal function are granulomas and nephrocalcinosis, although the frequency of these findings can vary widely 1.
- Key renal implications of sarcoidosis include:
- Granulomatous interstitial nephritis
- Nephrocalcinosis
- Nephrolithiasis
- Impaired renal function
- Treatment may involve corticosteroids, such as prednisone, at a dose of 20-40 mg per day for several months, to manage kidney involvement and prevent further renal damage 1.
From the Research
Sarcoidosis and Kidney Involvement
Sarcoidosis can affect the kidneys and cause impaired renal function, as evidenced by several studies 2, 3, 4, 5, 6.
Types of Renal Involvement
The types of renal involvement in sarcoidosis include:
- Interstitial nephritis, which is the most common manifestation of renal sarcoidosis 3, 4, 5, 6
- Glomerulopathies, such as membranous nephropathy and IgA nephropathy 3, 5, 6
- Nephrocalcinosis and nephrolithiasis, which can occur due to hypercalcemia or hypercalciuria 2, 3, 4, 6
- Tubulointerstitial nephropathy, which is the most frequent renal manifestation observed in patients with sarcoidosis 4
Prevalence of Renal Involvement
The prevalence of renal involvement in sarcoidosis varies, with estimates ranging from 3-23% 2, 30% 3, and up to one third of all sarcoidosis patients 6.
Predictive Factors of Renal Involvement
Predictive factors of renal involvement in sarcoidosis include:
- Multi-organ involvement 4, 6
- Inflammatory syndrome 4
- Hypercalcemia 4, 6
- Advanced age at diagnosis of nephropathy 4
- Comorbidities 4
- Initial renal failure 4
- Interstitial fibrosis 4
- Renal granulomas 4
Treatment and Management
Treatment of renal sarcoidosis typically involves glucocorticoids and immunosuppressive therapy 2, 5, 6. However, a treatment guideline for renal sarcoidosis is urgently needed, and clinical trials are lacking 6.