Sarcoidosis with membranous nephropathy and granulomatous interstitial nephritis

Kidney manifestations of sarcoidosis

Renal involvement is a clinically relevant organ manifestation of sarcoidosis, leading to increased morbidity and complications. Although the exact incidence remains unknown, renal disease is likely to occur in up to one third of all sarcoidosis patients. Every patient with newly diagnosed sarcoidosis should receive a renal work-up and screening for disrupted calcium metabolism. Amid various forms of glomerulonephritis, granulomatous interstitial nephritis is the most common one, but it rarely leads to renal impairment. Histologically, granulomas can be absent. Nephrocalcinosis and nephrolithiasis are frequent forms when hypercalcaemia or hypercalciuria occur. Drugs used for treatment of systemic sarcoidosis can also cause renal damage. Due to its high heterogeneity, renal sarcoidosis can be difficult to treat. Glucocorticoids and various immunosuppressive treatments have been proven to be effective based on case series, but clinical trials are lacking. A treatment guideline for renal sarcoidosis is urgently needed. In this review article, we present an overview of the different forms of renal sarcoidosis and the diagnostic steps to confirm renal involvement; in addition, we provide insights on the management and available treatments. A better understanding regarding the pathogenesis of sarcoidosis is the key for the development of more specific, targeted therapies.

Renal disease in sarcoidosis patients in a German multicentric retrospective cohort study

INTRODUCTION

Sarcoidosis is a systemic granulomatous disease potentially affecting every organ system. Renal involvement is reportedly rare, and the evidence consists of case reports and cohort studies. Systematic investigations are scarce and show a varying prevalence ranging from <1% to 30-50%.

METHODS

We retrospectively analyzed data from patients with a recent diagnosis of sarcoidosis from five tertiary care centers focusing on renal sarcoidosis.

RESULTS

We analyzed data from 327 patients with sarcoidosis between 2001 and 2021. Of 327 patients, 109 (33.3%) had probable or definite renal sarcoidosis. 90 (27.5%) had histopathologic confirmation. 57 (64%) had an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m². The most prominent associated finding was an elevated soluble interleukin-2 receptor. Patients with renal sarcoidosis more frequently received glucocorticoids than other non-renal sarcoidosis patients (92% vs. 78%, p < 0.01). Also, azathioprine (38% vs. 16%, p < 0.001) and mycophenolate mofetil (5% vs. 1%, p < 0.05) were more frequently used in renal sarcoidosis compared to non-renal sarcoidosis, whereas methotrexate was used less frequently (7% vs. 17%, p < 0.05).

CONCLUSIONS

Our data of the largest cohort with biopsy-confirmed renal sarcoidosis demonstrate a higher prevalence (27.5% of all patients) than previously published with a relevant disease burden. The urinary findings in most cases were only mildly abnormal, and some patients did not have renal biopsy despite abnormal urinary results. A renal workup should be performed in all patients with a new diagnosis of sarcoidosis.

Secondary Membranous Nephropathy. A Narrative Review

Membranous nephropathy (MN) is a common cause of proteinuria and nephrotic syndrome all over the world. It can be subdivided into primary and secondary forms. Primary form is an autoimmune disease clinically characterized by nephrotic syndrome and slow progression. It accounts for ~70% cases of MN. In the remaining cases MN may be secondary to well-defined causes, including infections, drugs, cancer, or autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), urticarial vasculitis, sarcoidosis, thyroiditis, Sjogren syndrome, systemic sclerosis, or ankylosing spondylitis. The clinical presentation is similar in primary and secondary MN. However, the outcome may be different, being often related to that of the original disease in secondary MN. Also, the treatment may be different, being targeted to the etiologic cause in secondary MN. Thus, the differential diagnosis between primary and secondary MN is critical and should be based not only on history and clinical features of the patient but also on immunofluorescence and electron microscopy analysis of renal biopsy as well as on the research of circulating antibodies. The identification of the pathologic events underlying a secondary MN is of paramount importance, since the eradication of the etiologic factors may be followed by remission or definitive cure of MN. In this review we report the main diseases and drugs responsible of secondary MN, the outcome and the pathogenesis of renal disease in different settings and the possible treatments.

Renal sarcoidosis: approach to diagnosis and management

PURPOSE OF REVIEW

The purpose of this article is to provide understanding of renal sarcoidosis, the different types of renal sarcoidosis, disease burden of renal involvement, and treatment options.

RECENT FINDINGS

The frequency of renal involvement seems to be underestimated, but renal sarcoidosis represents a relevant group of organ manifestations and significantly adds to the patient's morbidity. Because histopathological analysis of renal biopsy specimens can reveal various entities, a diagnostic workup is necessary in every patient with sarcoidosis.

SUMMARY

If systematically screened for renal manifestations are likely to occur in up to 25-30% of all sarcoidosis patients. The most common histological form of renal sarcoidosis is the granulomatous interstitial nephritis; however, granulomas can be absent. Furthermore, one can find various forms of secondary glomerulonephritis. In cases with dysregulated calcium homeostasis, nephrocalcinosis and nephrolithiasis are commonly detectable kidney diseases. AA amyloidosis or renal masses because of granuloma formation are considered to be rare manifestations. In addition to glucocorticoids various immunosuppressive treatments such as tumor necrosis factor alpha inhibitors have proven to be effective based on case series.

Granulomatous interstitial nephritis

Granulomatous interstitial nephritis (GIN) is a rare entity detected in ∼0.5–0.9% of all renal biopsies. GIN has been linked to several antibiotics such as cephalosporins, vancomycin, nitrofurantoin and ciprofloxacin. It is also associated with NSAIDs and granulomatous disorders such as sarcoidosis, tuberculosis, fungal infections, and granulomatosis with polyangiitis. Renal biopsy is critical in establishing this diagnosis, and the extent of tubular atrophy and interstitial fibrosis may aid in determining prognosis. Retrospective data and clinical experience suggest that removal of the offending agent in conjunction with corticosteroid therapy often results in improvement in renal function. We describe a patient with a history of multiple spinal surgeries complicated by wound infection who presented with confusion and rash with subsequent development of acute kidney injury. Urinalysis demonstrated pyuria and eosinophiluria, and renal biopsy revealed acute interstitial nephritis with granulomas. These findings were attributed to doxycycline treatment of his wound infection. This review explores the clinical associations, presentation, diagnosis, and treatment of this uncommon cause of acute kidney injury.

Clinicopathological study of glomerular diseases associated with sarcoidosis: a multicenter study

Background

The association between sarcoidosis and glomerular diseases has not been extensively investigated in a large series and the potential features of this uncommon association remain to be determined.

Methods

We retrospectively identified 26 patients with biopsy-proven glomerular lesions that occurred in a sarcoidosis context. Potential remission of glomerular disease and sarcoidosis under specific treatment (steroid and/or immunosuppressive agents) was recorded for all patients. Demographic, clinical and biological characteristics were assessed at the time of kidney biopsy for each patient. Therapeutic data were analyzed for all patients.

Results

Glomerular disease occurred after the diagnosis of sarcoidosis in 11 of 26 cases (42%) (mean delay of 9.7 years). In six patients (23%), the glomerulopathy preceded the sarcoidosis diagnosis (mean delay 8 years). In the last nine patients (35%), both conditions occurred simultaneously. The most frequent glomerular disease occurring in sarcoidosis patients was membranous nephropathy in eleven cases. Other glomerular lesions included IgA nephropathy in six cases, focal segmental glomerulosclerosis in four patients, minimal change nephrotic syndrome for three patients and proliferative lupus nephritis in two patients. Granulomatous interstitial nephritis was associated with glomerular disease in six patients and was exclusively found in patients in whom the both disease occurred simultaneously. In nine patients with simultaneous glomerular and sarcoidosis diseases, we observed a strong dissociation between glomerular disease and sarcoidosis in terms of steroid responsiveness. At the end of the follow-up (mean of 8.4 years), six patients had reached end-stage renal disease and three patients had died.

Conclusions

A wide spectrum of glomerular lesions is associated with sarcoidosis. The close temporal relationship observed in some patients suggests common causative molecular mechanisms of glomerular injury but complete remission of both diseases in response to exclusive steroid therapy is infrequent.

Diagnostic utility of kidney biopsy in patients with sarcoidosis and acute kidney injury

BACKGROUND

Sarcoidosis is an idiopathic multisystem disease characterized by noncaseating granulomatous inflammation. Renal biopsy is often performed to evaluate the patient with sarcoidosis and acute kidney injury (AKI). Diagnosis rests on the demonstration of noncaseating granulomas and exclusion of other causes of granulomatous inflammation. This paper reports a patient with pulmonary sarcoidosis and AKI whose renal function improved after prednisone therapy despite the absence of kidney biopsy findings characteristic of sarcoidosis.

CASE REPORT

A 63-year-old Caucasian male with history of hypertension was treated for pulmonary sarcoidosis with a 6-month course of prednisone. His creatinine was 1.6 mg/dL during the course. Two months after finishing treatment, he presented with creatinine of 4 mg/dL. A kidney biopsy was performed, which showed nonspecific changes without evidence of granuloma or active interstitial inflammation. He was empirically started on prednisone for presumed renal sarcoidosis, even with a nondiagnostic kidney biopsy finding. Within a month of treatment, his serum creatinine improved to 2 mg/dL, though not to baseline. He continues to be stable on low-dose prednisone. With this case as a background, we aimed to determine the incidence of inconclusive kidney biopsies in patients with sarcoidosis presenting with AKI and to identify the various histological findings seen in this group of patients.

METHODS

In this retrospective study, all patients who had native renal biopsies read at The Ohio State University over the period of 6 years were identified. Those patients with a diagnosis of sarcoidosis, presenting with AKI, were included for further review.

RESULTS

Out of 21 kidney biopsies done in patients with sarcoidosis over a period of 6 years, only four (19%) showed granulomatous interstitial nephritis (GIN). An equal number of patients (4 [19%]) had presence of membranous nephropathy. Nephrocalcinosis was seen in three patients (14%). Almost half of the biopsies had findings suggestive of diabetic nephropathy or other nonspecific changes not characteristic of renal sarcoidosis (48%).

CONCLUSION

Renal sarcoidosis can be focal in nature and characteristic lesions can be missed in a small-needle core biopsy. Inconclusive renal biopsies with only nonspecific findings are frequent in patients with sarcoidosis and AKI. The presence of GIN on renal biopsy, although classic, is uncommon. Renal sarcoidosis remains a presumptive clinical diagnosis and empiric treatment with steroids may be initiated in cases with a strong clinical suspicion even in the absence of characteristic renal biopsy findings.

Isolated renal relapse of sarcoidosis under low-dose glucocorticoid therapy

Sarcoidosis is a multisystem disease of unknown etiology. Renal manifestation is rare and usually caused by hypercalcemia and nephrocalcinosis. Moreover, renal disease can occur as granulomatous interstitial nephritis (GIN), which is a histological diagnosis. We describe a case of sarcoidosis first presenting with multiple organ involvement including renal failure caused by severe GIN and subsequent remission on glucocorticoid therapy. After 18 months under low-dose prednisolone, the patient was readmitted with acute renal failure, histologically confirmed to be a relapse of renal sarcoidosis. Extrarenal manifestations of sarcoidosis were not present. Glucocorticoid dose was raised and kidney function again recovered significantly. Usual serologic markers of disease activity were not appropriate to indicate disease activity. Renal manifestation of sarcoidosis should be diagnosed by renal biopsy to guide therapy and probably requires larger glucocorticoid doses and prolonged treatment to prevent relapse.

Renal granulomatoses: a retrospective study of 40 cases and review of the literature

Renal granulomatoses represent 0.5%-0.9% of nephropathies examined by renal biopsies. Granulomas can be isolated to the kidney or associated with other tissue involvement. We describe 40 consecutive patients with renal granulomatoses, associated with pauci-immune crescentic glomerulonephritis in 2 patients and with vasculitis in another, seen in northeastern Paris hospitals between January 1991 and February 2004. The criterion for inclusion was the presence of 1 or more epithelioid granulomas in the renal interstitium. Our population of 25 men and 15 women had a median age of 53 years. All patients suffered from renal insufficiency with median creatininemia of 236.8 micromol/L (range, 124-805 micromol/L), associated with hypertension (25%), median proteinuria of 0.6 g/24 h (range, 0.08-3.00 g/24 h), microscopic hematuria (15%) and leukocyturia (22.5%). Histologic examination of extrarenal specimens detected granulomas in 82.4% of the bronchial biopsies taken, and in 100% of the 2 skin biopsies, the 2 lymph-node biopsies, and the liver and colon biopsies. The following etiologies were retained: sarcoidosis for 20 (50%) patients, drug-induced for 7 (17.5%), tuberculosis for 3 (7.5%), Wegener granulomatosis for 2 (5%), and leprosy, Mycobacterium avium infection, and Crohn disease for 1 (2.5%) patient each. No etiology could be identified for 5 (12.5%) patients. Treatment must be adapted to the etiology of each case. The renal outcome after treatment was generally favorable, with the estimated median creatinine clearance increasing from 26 mL/min (range, 5.4-80.0 mL/min) to 46.5 mL/min (range, 0-118 mL/min) after a median follow-up of 35.5 months (range, 3-158 mo). Nonetheless, 32 patients had persistent renal insufficiency; 1 required hemodialysis and another underwent renal transplantation. Sarcoidosis and medications are the most common causes of renal granulomatosis. Idiopathic and drug-induced forms do not relapse after treatment discontinuation, and remission persists at long-term follow-up.

Granulomatous Interstitial Nephritis

Granulomatous interstitial nephritis (GIN) is a rare histologic diagnosis. This series reports the presenting features, associated conditions, treatment, and outcome of patients with a diagnosis of GIN in Glasgow during a 15-yr period and compares this with the available literature. Eighteen cases were identified: Five cases were associated with sarcoidosis, two were associated with tubulointerstitial nephritis and uveitis, two were associated with medication, and nine were idiopathic. Patients presented with advanced renal failure (median estimated creatinine clearance 21 ml/min) and minimal proteinuria (urine albumin-to-creatinine ratio 9.9 mg/mmol). Sixteen patients were treated with prednisolone for a mean of 25 mo. Six patients relapsed with reduction in prednisolone dosage, and four patients required steroid-sparing agents. During the mean follow-up of 45 mo, renal function improved or stabilized in 17 patients; the rate of improvement in renal function was most marked in the first year after diagnosis with a gain in function of +1.9 ml/min per mo. The median estimated creatinine clearance at final visit was 56 ml/min. One patient required renal replacement therapy at diagnosis but recovered renal function with treatment. No patient required long-term renal replacement therapy. There was no correlation between the degree of fibrosis or inflammation on biopsy and renal outcome, and the features on biopsy did not help to determine the cause of GIN. GIN is a treatable cause of renal failure that highlights the value of renal biopsy in patients who present with renal failure even when there is minimal proteinuria. The rarity of GIN demonstrates the need for systematic data collection.

A case of renal sarcoidosis with complement activation via the lectin pathway

A 57-year-old woman with pulmonary sarcoidosis was admitted to the hospital because of an elevation of serum creatinine and blood urea nitrogen. On admission, the laboratory data suggested interstitial nephritis without proteinuria and hematuria, whereas a renal biopsy showed granulomatous interstitial nephritis and mild mesangial proliferative glomerulonephritis. Immunoglobulin and C1q deposits were negative, but mannose-binding lectin, C3, C4d, and C5b-9 deposits were marked in the glomerular mesangial areas. The lectin pathway of complement activation may have contributed to the development of glomerular injury in this patient. DNA of Propionibacterium acnes , which is now strongly suspected as the pathogen of sarcoidosis, was detected in the patient's glomerular mesangial cells; tubular epithelial cells, which were involved in granulomatous inflammation; and mononuclear cells in epithelioid granulomas by in situ hybridization. These findings may add new insights to the pathogenesis of renal sarcoidosis, including its relation to infection, because mannose-binding lectin plays a crucial role in the host defense against various pathogens. From this case of renal sarcoidosis, it is hypothesized that P acnes may be involved in pathogenesis of granulomatous interstitial nephritis and that it plays a role in glomerular complement activation via the lectin pathway.