Sarcoidosis in native and transplanted kidneys: incidence, pathologic findings, and clinical course

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.

Clinical, Biochemical, and Histological Manifestations and Long-Term Outcomes of Renal Sarcoidosis - A Single Center Study

Background

Renal involvement in sarcoidosis is rare. We evaluated the pattern of renal involvement in sarcoidosis, its clinical course, renal histology, and response to treatment.

Materials and Methods

We retrospectively analyzed the data of all cases with sarcoidosis exhibiting renal involvement referred to our department between January 2010 and December 2021.

Results

A total of 33 patients (age: 50.6 ± 12.6 years, males: 57.6%) were analyzed. Common presenting symptoms were weight loss (81.8%; n = 27), fever (75.8%; n = 25), and vomiting (63.6%; n = 21). A total of 14 (42.4%) patients had granulomatous interstitial nephritis (GIN), 13 (39.4%) had isolated hypercalcemia, and six (18.2%) had GIN along with hypercalcemia. Renal biopsy was performed in 20 (60.6%) patients, and all showed GIN, with concomitant glomerular disease in four (12.1%) patients. Mean serum creatinine and 24-h urine protein at presentation were 4.3 ± 2.1 mg/dL and 2.5 ± 0.9 g/day, respectively. All patients received oral prednisolone 1 mg/kg/day with subsequent tapering, concomitantly with azathioprine. Mycophenolate mofetil was used in three (9.1%) patients who developed azathioprine-induced hepatoxicity. After a median follow-up of 24 months (8-120 months), mean serum creatinine and 24-h urine protein improved to 1.9 ± 1.5 mg/dL and 1.1 ± 0.6 g/day, respectively, (P = 0.005). On follow-up, two patients (6.1%) became dialysis-dependent, and three (9.1%) succumbed: one due to a cardiovascular event and two to sepsis and septic shock.

Conclusion

Granulomatous interstitial nephritis was the most common diagnosis in sarcoidosis patients with kidney failure. Early steroid treatment improves kidney function.

Cutaneous Mycobacterium avium-intracellulare infection masquerading as sarcoidosis

Mycobacterium avium-intracellulare (MAC) infection may have different skin manifestations, including cutaneous granulomas. Granulomatous skin reactions have distinct morphologic and histopathologic appearances. We present the case of an adolescent male with cutaneous MAC, misdiagnosed as sarcoidosis after initial biopsy results, demonstrated preservation of reticulin fibers and absence of organisms within granulomas. Sarcoidal granulomas often stain positive for reticulin fibers, which could be used to distinguish them from the infectious kind. This case should alert clinicians to the fact that the presence or quantity of intact reticular fibers may not be a reliable tool to differentiate between a sarcoidal and an infectious granuloma. Our case also highlights the diagnostic challenge of cutaneous MAC infection.

Sarcoid Here, Sarcoid There, Sarcoid Everywhere

Although usually more associated with the lungs, sarcoidosis can have multiple extrapulmonary manifestations. We present a case of a patient with previous biopsy-proven sarcoidosis who was admitted to the hospital secondary to worsening shortness of breath. The patient was found to be positive for Respiratory Syncytial Virus (RSV) which was believed to have exacerbated his pulmonary symptoms. He was treated with IV steroids, nebulizers, and antibiotics which ultimately helped relieve his symptoms. In terms of his sarcoidosis, he was previously treated in the past with steroids in regards to this pathology (which is the mainstay of treatment); while on the regimen, the patient noted his breathing was improved. Of note, he did also have a history of renal cell carcinoma (RCC) status post nephrectomy which was initially evaluated for possible sarcoidosis involvement. This medical therapy could also have been the reason his sarcoidosis did not progress to involve other organs.

Renal replacement therapy in sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology. Kidney involvement in sarcoidosis may be present in up 25-30% of cases. An early diagnosis and prompt treatment with corticosteroids can improve the prognosis but rarely renal sarcoidosis can lead to kidney failure needing renal replacement therapy (RRT). Acute kidney injury (AKI) in sarcoidosis may be caused by granulomatous interstitial nephritis (GIN) or hypercalcemia. These disorders are usually clinically silent and may lead end stage renal disease (ESKD) if not diagnosed or detected too late. In patients with ESKD, dialysis and renal transplantation can offer results comparable to those observed in patients with other causes of kidney failure. Based on a review of literature, we present an overview of RRT in patients with AKI or chronic kidney disease (CKD) caused by sarcoidosis.

Renal sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology. The pathogenesis rests on an aberrant T cell response to unidentified antigens in individuals predisposed by genetic and environmental factors. Increased expression of polarized macrophages and disequilibrium between effector and regulator T cells contribute to the formation of noncaseating granulomas, that are frequently found in affected organs. The main kidney abnormalities in sarcoidosis are granulomatous interstitial nephritis (GIN) and hypercalcemia-related disorders. The clinical diagnosis is difficult. The outcome is variable, ranging from spontaneous remission to end-stage kidney disease (ESKD). Early diagnosis and prompt treatment with corticosteroids can improve the prognosis. Hypercalcemia may be responsible for acute kidney injury (AKI) caused by vasoconstriction of afferent arterioles. Complications of persistent hypercalcemia include nephrocalcinosis and renal stones. In patients with ESKD, dialysis and transplantation can offer results comparable to those observed in patients with other causes of kidney failure. Based on a review of the literature, we present an overview of the etiopathogenesis, the renal manifestations of sarcoidosis and their complications, management and prognosis.

Renal involvement in sarcoidosis: histological patterns and prognosis, an Italian survey

Background

Granulomatous interstitial nephritis in sarcoidosis (sGIN) is generally clinically silent, but in <1% causes acute kidney injury (AKI).

Methods

This Italian multicentric retrospective study included 39 sarcoidosis-patients with renal involvement at renal biopsy: 31 sGIN-AKI, 5 with other patterns (No-sGIN-AKI), 3 with nephrotic proteinuria. We investigate the predictive value of clinical features, laboratory, radiological parameters and histological patterns regarding steroid response. Primary endpoint: incident chronic kidney disease (CKD) beyond the 1°follow-up (FU) year; secondary endpoint: response at 1°line steroid therapy; combined endpoint: the association of initial steroid response and outcome at the end of FU.

Results

Complete recovery in all 5 No-sGIN-AKI-patients, only in 45% (13/29) sGIN-AKI-patients (p=0.046) (one lost in follow-up, for another not available renal function after steroids). Nobody had not response. Primary endpoint of 22 sGIN-AKI subjects: 65% (13/20) starting with normal renal function developed CKD (2/22 had basal CKD; median FU 77 months, 15-300). Combined endpoint: 29% (6/21) had complete recovery and final normal renal function (one with renal relapse), 48% (10/21) had partial recovery and final CKD (3 with renal relapse, of whom one with basal CKD) (p=0.024). Acute onset and hypercalcaemia were associated to milder AKI and better recovery than subacute onset and patients without hypercalcaemia, women had better endpoints than men. Giant cells, severe interstitial infiltrate and interstitial fibrosis seemed negative predictors in terms of endpoints.

Conclusions

sGIN-AKI-patients with no complete recovery at 1°line steroid should be treated with other immunosuppressive to avoid CKD, in particular if males with subacute onset and III stage-not hypercalcaemic AKI.

Granulomatous Tubulointerstitial Nephritis in a Kidney Transplant Recipient: Case Report and Review of the Literature

BACKGROUND

Granulomatous tubulointerstitial nephritis (GTIN) is a rare pathologic finding on kidney biopsy. GTIN can be associated with drugs, infection, systemic granulomatous disease, and tubulointerstitial nephritis with uveitis syndrome. We present a case of GTIN in a kidney transplant recipient (KTR) and a literature review of published cases of GTIN in KTRs.

CASE PRESENTATION

A 65-year-old man with a history of pulmonary and ocular tuberculosis (TB), who had undergone deceased donor kidney transplant 8 years prior, was admitted for acute kidney injury, hypercalcemia, and uveitis. His medications included rifabutin, isoniazid, and tacrolimus. Serum laboratory tests revealed creatinine of 2.65 mg/dL (baseline 1.1-1.5 mg/dL) and corrected calcium of 13.2 mg/dL. Hypercalcemia workup showed parathyroid hormone 7 pg/mL, 1,25(OH) vitamin D 54 pg/mL, parathyroid hormone-related peptide <2.0 pmol/L, and angiotensin-converting enzyme 47 U/L. Kidney biopsy showed GTIN with noncaseating granulomas. Universal polymerase chain reaction testing for acid-fast bacilli, fungus, and bacteria was negative. He was treated with prednisone, and his kidney function returned to baseline, and his hypercalcemia resolved.

DISCUSSION

GTIN is a rare entity seen in less than 1% of transplanted kidney biopsies. The exactly etiology of this GTIN case remains unknown. TB could not be entirely ruled out, because the patient was receiving active anti-TB therapy. Our literature review showed infection to be the leading cause of GTIN in KTRs and that GTIN with concomitant uveitis remains exceedingly rare. Steroids may be useful in certain cases.

Idiopathic granulomatous interstitial nephritis and isolated renal sarcoidosis: Two diagnoses of exclusion

Granulomatous interstitial nephritis is a rare finding in renal biopsy caused by drugs, infections, and inflammatory or autoimmune diseases. Idiopathic cases account for 18% of granulomatous interstitial nephritis in native kidneys. Sarcoidosis and drugs are the most common causes of granulomatous interstitial nephritis in Western countries, while in India tuberculosis prevails. Few cases of renal sarcoidosis without extrarenal involvement, that is, isolated renal sarcoidosis, have been reported. The diagnostic criteria of isolated renal sarcoidosis remain, however, unclear. Extrarenal sarcoidosis and other etiologies of granulomatous interstitial nephritis, in particular drug-related, have to be excluded. Some of these patients may develop extrarenal manifestations during follow-up. Changes in calcium and vitamin D metabolism are frequently observed in renal sarcoidosis and support its diagnosis. While non-necrotizing granulomas are a feature of sarcoidosis and drug-induced granulomatous interstitial nephritis, they also prevail in tuberculosis-associated granulomatous interstitial nephritis. Granulomatous interstitial nephritis caused by sarcoidosis and drugs usually responds to steroid therapy. A poor response to steroids may indicate an infectious etiology such as tuberculosis and should lead to a review of the initial diagnosis. This article gives an overview of the various etiologies of granulomatous interstitial nephritis, their frequency and histopathological characteristics, as well as potential biomarkers associated with renal sarcoidosis.

Sarcoidosis in the renal allograft of a recipient whose primary disease was autosomal dominant polycystic kidney disease

We report a 55-year-old man with a renal allograft that developed sarcoidosis. His autosomal dominant polycystic kidney disease (ADPKD) progressed to end-stage stage renal disease when he was 52 years old, and he underwent living-donor kidney transplantation at the age of 53 years. His proteinuria worsened at 19 months post-transplantation, and his renal function began to decline at 29 months post-transplantation. A renal allograft biopsy performed at 31 months post-transplantation revealed non-caseating granulomatous interstitial nephritis. The patient was treated with prednisolone (0.5 mg/kg/day), with gradual reduction in the dose. His proteinuria improved and renal function did not deteriorate any further. To the best of our knowledge, this is the first case of sarcoidosis in a renal allograft recipient whose primary renal disease was ADPKD.

Granulomatous inflammation in BK polyomavirus-associated nephropathy

Evolving BK polyomavirus-associated nephropathy (BKPyVAN) is characterized by tubulointerstitial inflammation that closely resembles acute T-cell-mediated allograft rejection if tubulitis is significant. The cellular composition of the inflammation varies during the course of BKPyVAN, and clusters of plasma cells may herald resolution of the infection. Less commonly, BKPyVAN can present with a predominance of histiocytes and granuloma formation. Granulomatous interstitial nephritis is uncommon in biopsies of either native or transplant kidneys. In both settings, this distinctive type of inflammatory response requires a systematic approach with careful clinicopathological assessment to determine its etiology. We present three patients with granulomatous BKPyVAN in the first year post-transplantation. These allograft biopsies at 4, 6, and 12 months post-transplant exemplify spontaneously resolving BKPyVAN, resolving infection after immunosuppression reduction, and early BKPyVAN, respectively. In immunosuppressed patients, BKPyVAN should be added to the relatively broad differential diagnosis of granulomatous tubulointerstitial nephritis.

A curious case of growth failure and hypercalcemia: Answers

BACKGROUND

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that rarely presents in childhood. Here, we report a case of pediatric sarcoidosis, presenting with renal failure and hypercalcemia.

CASE DIAGNOSIS/TREATMENT

A previously well 14-year-old Caucasian boy was admitted to the Hospital for Sick Children, Canada, for hypertension and renal failure following work-up by his family physician for initial concerns of growth failure. On admission, his weight was 35 kg (<3rd percentile), his height was 148 cm (<<3rd percentile), and his blood pressure was 154/116 mmHg (>99th percentile for height). Laboratory findings showed elevated creatinine (218 umol/L), hypercalcemia (3.21 mmol/L), and normocytic anemia (hemoglobin 105 g/L). His further assessment showed a urinary concentrating defect with hypercalciuria (calcium/creatinine 1.76 mmol/mmol) and nephrocalcinosis on ultrasound. His eye examination showed uveitis with conjunctival biopsy remarkable for granulomas, which led to pursuit of a diagnosis of possible sarcoidosis. Angiotensin Angiotensin-converting enzyme was found to be high at 96 U/L, and he had a renal biopsy that was consistent with interstitial nephritis with granulomas. Treatment was started with prednisone leading to resolution of his hypercalcemia but persistence of his mild chronic kidney disease.

CONCLUSIONS

This case represents an atypical presentation of a rare pediatric disease and highlights the spectrum of renal manifestations and treatment options in sarcoidosis.

Clinical characteristics of biopsy-proven renal sarcoidosis in Japan

Background: Although some articles have described renal sarcoidosis, the incidence among biopsy cases remains unclear. Here, we defined the incidence of renal sarcoidosis among renal biopsy cases and analyzed the clinical course. Methods: We performed an epidemiological study examining renal biopsy cases treated at 5 centers between January 2000 and September 2015 and identified 16 cases (7 men, 9 women; mean (±SD) age, 59.4±18.6 years) out of a total of 14191 renal biopsy cases. Renal involvement of sarcoidosis was defined as granulomatous tubulointerstitial nephritis, tubulointerstitial nephritis without granulomatous lesions, and renal calcinosis. Fifteen of the cases were treated with steroid therapy. One case initially received steroid pulse therapy. The outcome was evaluated based on the estimated glomerular filtration rate (eGFR), CKD stage, and the change in eGFR (ΔeGFR) after treatment. A favorable response was defined as ΔeGFR ≥25%. Results: The incidence of renal sarcoidosis was 0.11%. The mean eGFR was 28.2±16.1 mL/min/1.73 m². At the last observation, the mean eGFR was 43.7±19.7 mL/min/1.73 m². Although a favorable response to steroid therapy was found in the majority of cases (10/15, 67%), 12 of the 15 cases (80%) had residual renal dysfunction at the last observation and 8 cases (53%) had moderate to severe renal dysfunction. Conclusion: Renal sarcoidosis is extremely rare among renal biopsy cases. Among cases with an unfavorable response to steroid therapy, pathogenetic mechanisms other than sarcoidosis and severe nephron damage were observed. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 252-260).

Granulomas within renal epithelial neoplasms in patients with sarcoidosis: A causal association?

Sarcoidosis is a chronic granulomatous disease that can involve virtually every organ system, but most commonly presents as lung, skin, or lymph node disease. Although kidney involvement is usually clinically silent, granulomatous interstitial nephritis - the hallmark of renal sarcoidosis - can lead to functional impairment and organ failure. Also, recent studies have suggested an association between sarcoidosis and an increased risk of developing kidney tumors. While a sarcoid-like granulomatous reaction (SLGR) to renal epithelial neoplasms in patients without sarcoidosis has been well documented, direct involvement of the tumor parenchyma by sarcoidosis has been reported only rarely. Here we present two renal epithelial tumors directly involved by sarcoidosis with a common pattern of distribution of non-caseating granulomas.

Renal allograft granulomatous interstitial nephritis: observations of an uncommon injury pattern in 22 transplant recipients

Background: Granulomatous interstitial nephritis (GIN) is uncommon in native kidneys, and descriptions in allografts are few. We report clinical and pathologic findings in 22 allograft recipients with GIN identified in renal allograft biopsies and nephrectomies.

Methods: Renal allografts with GIN were retrieved from the pathology files of two academic medical centers. Available clinical and pathologic data were compiled retrospectively for a 23-year period.

Results: GIN was present in 23 specimens from 22 patients (15 males and 7 females) with allograft dysfunction [serum creatinine averaged 3.3 mg/dL (range 1.4–7.8)], at a mean age of 48 years (range 22–77). GIN was identified in 0.3% of biopsies at a mean of 552 days post transplantation (range 10–5898). GIN was due to viral (5), bacterial (5) and fungal (2) infections in 12 (54.5%), and drug exposure was the likely cause in 5 cases (22.7%). One had recurrent granulomatosis with polyangiitis. In 4 cases, no firm etiology of GIN was established. Of 18 patients with follow up data, 33.3% had a complete response to therapy, 44.5% had a partial response and 22.2% developed graft loss due to fungal and E. coli infections. All responders had graft survival for more than 1 year after diagnosis of GIN.

Conclusions: Allograft GIN is associated with a spectrum of etiologic agents and was identified in 0.3% of biopsies. Graft failure occurred in 22% of this series, due to fungal and bacterial GIN; however, most had complete or partial dysfunction reversal and long–term graft survival after appropriate therapy.

[Prognosis and therapy of inflammatory rheumatic diseases : Impact of renal manifestations]

BACKGROUND

Inflammatory rheumatic diseases and their treatment cause various renal manifestations requiring modification of treatment.

OBJECTIVES

Discussion of renal manifestations in selected rheumatic diseases, including their impact on general prognosis and therapy.

MATERIALS AND METHODS

Basic literature and expert opinions are analyzed and discussed.

RESULTS

Inflammatory rheumatic diseases and their treatment cause various renal manifestations, including glomerular, tubular, interstitial, and vascular damage. The type of damage determines both, associated clinical symptoms (i.e. hematuria, proteinuria, loss of kidney function) and the renal and overall survival as will be discussed here for rheumatoid arthritis, systemic lupus erythematosus, scleroderma, Sjögrens syndrome, cryoglobulinemia and ANCA-associated vasculitis.

CONCLUSION

Renal manifestations are generally indicators of high disease activity and usually require more intensive treatment of the underlying rheumatic disease. Early and rigorous treatment, which has to be adapted to renal function, is capable of improving renal and overall survival in many of the affected patients.