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

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.

A Rare Presentation of Sarcoidosis in a Young Male With Acute Renal Failure: A Case Report and Literature Review

Sarcoidosis presents in a variety of ways, but historically, renal involvement has been considered rare with an incidence of 0.7% and is seldom the presenting feature of the illness. Concomitant involvement of kidney and bone marrow is extremely rare. Atypical forms of presentation, such as in this case, may pose a true diagnostic challenge. A 20-year-old African-American male presented to the emergency department with vague symptoms including fatigue, malaise, anorexia, right-sided lower back pain, and nausea. Acute kidney injury was clearly evident, creatinine was 19.78 mg/dL (normal range 0.60-1.20 mg/dL), and BUN was 124.0 mg/dL (normal range 5.0-25.0 mg/dL). Laboratory results were also remarkable for leukopenia, microcytic anemia, hyperkalemia, anion gap metabolic acidosis, and non-PTH dependent hypercalcemia. Interestingly, urinalysis was equivocal and both chest x-ray (CXR) and abdominopelvic computed tomography (CT) scan were unrevealing. The patient was admitted to the hospital and required renal replacement therapy to stabilize his clinical condition while planning for a renal biopsy that was later performed. While awaiting pathological results, pancytopenia developed, and a bone marrow biopsy was then obtained. On further investigation, angiotensin-converting enzyme (ACE) turned out to be significantly elevated suggesting sarcoidosis. Renal biopsy showed moderate acute tubular injury, tubulitis, extensive interstitial edema, and infiltration by numerous non-caseating granulomas, which confirmed the diagnosis of sarcoidosis. Bone marrow histopathology revealed hypocellularity but no granulomatous infiltration. The patient remained largely asymptomatic throughout his hospital stay, with no signs or symptoms suggesting the involvement of other organs. High-dose corticosteroids were started and continued outpatient after discharge while still on hemodialysis. Pancytopenia resolved while on glucocorticoids and improvement in renal function was such that after roughly two months of steroids, renal replacement therapy was no longer necessary. Overall, kidney injury severe enough to require hemodialysis associated with pancytopenia in a previously healthy 20-year-old constitutes a rather rare sarcoidosis presentation. This highlights the importance of considering sarcoidosis as a possible cause of kidney and bone marrow dysfunction and emphasizes the need for timely biopsy to facilitate accurate diagnosis and early initiation of appropriate therapy to avoid delayed or inadequate care, especially considering that even severe damage is potentially reversible when identified early and treated promptly.

Hypercalciuria may predict better response to immunosuppressive therapy in renal sarcoidosis: a case series

BACKGROUND

Renal sarcoidosis is a rare cause of tubulointerstitial nephritits (TIN). The clinical and pathological characteristics, as well as outcomes, of renal sarcoidosis remain unclear.

METHODS

This single-center study retrospectively analyzed 18 patients affected by sarcoidosis with tubulointerstitial nephritis (TIN) and 53 patients with tubulointerstitial nephritis  not related to sarcoidosis. Patients were further stratified into the granulomatous (12 sarcoidosis and 6 non-sarcoidosis) and non-granulomatous (6 sarcoidosis and 47 non-sarcoidosis) TIN groups.

RESULTS

Half of the patients with renal sarcoidosis had signs of acute kidney injury at kidney biopsy, 94% of whom presented with extra-renal involvement. The prevalence of hypercalcemia, hypercalciuria, and elevated serum angiotensin-converting enzyme levels was 27.6%, 33.3%, and 31.3%, respectively. Renal sarcoidosis patients with eGFR < 30 mL/min/1.73 m2 scored higher for total chronic tubulointerstitial injury (p = 0.044) and glomerular sclerosis (p = 0.027). Compared to non-sarcoidosis patients, higher urinary calcium levels (for patients with GFR [Formula: see text] 40 mL/min/1.73 m2, p = 0.034), lower scores of acute tubular injury (p = 0.008), and more prominent glomerular sclerosis were observed in renal sarcoidosis. Similar characteristics of chronicity and hypercalciuria were also identified in granulomatous interstitial nephritis; however, interstitial inflammation was obvious (p = 0.001). Patients with renal sarcoidosis were initially treated with corticosteroids. Five patients receiving immunosuppressive agents showed better long-term renal recovery. High 24-h urine calcium (adjusted by weight) was identified as a factor associated with long-term remission.

CONCLUSION

Renal sarcoidosis is a systemic disease of insidious onset and chronic progression, sharing similar features of chronicity and hypercalciuria with granulomatous interstitial nephritis of other cause. Hypercalciuria may predict a better response to immunosuppressive therapy, presumably indicating active interstitial inflammation; thus, strengthened immunosuppression might be considered.

Granulomatous interstitial nephritis with CTLA-4 haploinsufficiency: a case report

BACKGROUND

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an essential inhibitory regulator of immune activation. CTLA-4 haploinsufficiency is known to be associated with dysregulation of FOXP3+ regulatory T cells, hyperactivation of effector T cells, and lymphocytic infiltration of multiple organs. However, there have only been a few reports of renal involvement with CTLA-4. Herein, we present a case of acute granulomatous tubulointerstitial nephritis (TIN) in a patient with CTLA-4 haploinsufficiency.

CASE PRESENTATION

A 44-year-old man presented with a 3-week history of fever and malaise, and subsequently developed acute kidney injury (AKI) a few days after treatment with levofloxacin (LVFX). A kidney biopsy and immunohistochemical staining revealed granulomatous TIN with dominantly infiltrating CD4+ T cells. General symptoms and renal impairment showed improvement after discontinuation of LVFX and initiation of oral steroids. However, they worsened following steroid tapering. Further, a colon biopsy analysis showed similar findings to the renal tissue analysis. We suspected that granulomatous TIN was possibly associated with CTLA-4 haploinsufficiency. Therefore, the patient was transferred to another hospital for further treatment of CTLA-4 haploinsufficiency using immunosuppressive agents.

CONCLUSIONS

There have been few reports regarding renal involvement of CTLA-4 haploinsufficiency. In the present case, granulomatous TIN could have arisen due to instability of immune regulatory functions, such as CTLA-4 haploinsufficiency, and treatment with LVFX could have triggered immunologic activation and severe inflammation as well as renal dysfunction.

Interferon-gamma Release Assay-positive Granulomatous Interstitial Nephritis in a Patient with a History of Diffuse Large B Cell Lymphoma

Tuberculosis is a common etiology of granulomatous interstitial nephritis (GIN). However, the absence of evidence of lung involvement and lack of mycobacterial isolation in cultures make the etiological diagnosis and treatment decision challenging. We herein report a 46-year-old man with severe renal failure, a persistent fever, and a history of lymphoma. A renal biopsy exhibited GIN. Despite no evidence of tuberculosis except for a positive interferon-gamma release assay (IGRA), the patient was successfully treated with anti-tuberculosis drugs. Our case suggests that anti-tuberculosis therapy should be considered for patients with IGRA-positive GIN after excluding other etiologies.

Efficacy and safety of methylprednisolone pulse followed by oral prednisone versus oral prednisone alone in sarcoidosis tubulointerstitial nephritis. A randomized, open-label, controlled clinical trial

OBJECTIVE

To determine the benefit of pulsed methylprednisolone for improving renal function in sarcoidosis tubulointerstitial nephritis (TIN).

PATIENTS AND METHODS

A multicenter, prospective, randomized, open-labeled, controlled trial in patients with biopsy-proven acute TIN due to sarcoidosis was conducted in 21 sites in France. Patients were randomly assigned to receive a methylprednisolone pulse 15 mg/kg/day for 3 days then oral prednisone (MP group) or oral prednisone 1 mg/kg/day alone (PRD group). The primary endpoint was a positive response at 3 months, defined as a doubling of eGFR as compared with before randomization.

RESULTS

We randomized 40 participants. Baseline eGFR before PRD was 22 ml/min/1.73m2 (interquartile range [IQR] 16-44) and before MP was 25 ml/min/1.73m2 (IQR 22-36) (P = 0.3). The two groups did not differ in underlying pathological lesions, including mean percentage of interstitial fibrosis and intensity of interstitial infiltrate. In the intent-to-treat population, the median eGFR at 3 months did not significantly differ between the PRD and MP groups: 45 (IQR 34-74) and 46 (IQR 39-65) ml/min/1.73m2. The primary endpoint at 3 months was achieved in 16/20 (80%) PRD patients and 10/20 (50%) MP patients (P = 0.0467). eGFR was similar between the two groups after 1, 3, 6, and 12 months of treatment. For both groups, eGFR at 1 month was highly correlated with eGFR at 12 months (P < 0.0001). The two groups did not differ in severe adverse events.

CONCLUSION

As compared with a standard oral-steroid regimen, intravenous MP may have no supplemental benefit for renal function in patients with TIN due to sarcoidosis. ClinicalTrials.gov: NCT01652417; EudraCT: 2012-000149-11.

Renal sarcoidosis

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

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.

[Renal involvement in sarcoidosis: Prognostic and predictive factors]

INTRODUCTION

Sarcoidosis is a systemic granulomatous disease that primarily affects the respiratory system and lymphatic vessels. Renal involvement is rare, poorly studied and found in less than 10% of cases. The objective of our study was to identify factors of poor renal prognosis and predictive factors of renal involvement during sarcoidosis.

METHODS

It's a retrospective study including patients hospitalized in our department for sarcoidosis with renal involvement over a period of 40 years. To study renal survival, we identified two groups of patients with renal manifestations of sarcoidosis by following their evolution: group A (n=26) represents those with renal remission or deterioration of renal function but without progression to end-stage renal disease and group B (n=8) those with progression to end-stage renal disease. To detect the predictive factors of end-stage renal disease in patients with sarcoidosis, we compared the clinical and paraclinical characteristics of our patients (group 1) to those of 44 patients with sarcoidosis without renal impairment followed in our department during the same period (group 2).

RESULTS

Renal involvement was observed in 34 patients hospitalized for sarcoidosis (43.6%). There were 28 women and 6 men with a sex ratio of 0,21. The mean age at diagnosis of sarcoidosis was 47.1 years. The median time from sarcoidosis diagnosis to renal disease was 2 months (range 1-72). Tubulointerstitial nephropathy was the most frequent renal manifestation observed in 24 patients (70.6%). Hypercalcemia and hypercalciuria were found in 52.9% and 46.4% respectively. Renal failure was noted in 25 patients (73.5%). Corticosteroid therapy was initiated in 33 patients (97%) associated with immunosuppressive therapy in 3 cases. Predictive factors of end-stage renal disease were advanced age at diagnosis of nephropathy (P=0.007), comorbidities (P=0.002), multi-organ involvement (P=0.041), initial renal failure (P=0.013), interstitial fibrosis (P=0.006) and renal granulomas (P=0.007). Predictive factors of renal impairment during sarcoidosis were multi-organ involvement, inflammatory syndrome and hypercalcemia.

CONCLUSION

Renal envolvement, although rare during sarcoidosis, can influence the prognosis hence the great interest of its early detection to prevent progression to end-stage renal failure.

Tubulointerstitial nephritis and uveitis syndrome following meningitis and systemic lymphadenopathy with persistent Toxoplasma immunoglobulin M: a case report

Background

Tubulointerstitial nephritis and uveitis syndrome is a rare lymphocyte-related oculorenal inflammatory disease presumed to be associated with drug use and infectious agents. Toxoplasma gondii is one of such pathogens that could exhibit encephalitis, meningitis, and uveitis in immunocompromised or in some immunocompetent individuals. If the immunoglobulin M of Toxoplasma is positive on screening, the interpretation of the result is not simple, especially when immunoglobulin M stays positive persistently.

Case presentation

A 34-year-old Asian male developed fever, headache, and lymphadenopathy with tenderness, which was initially diagnosed as meningitis. Antibiotics were started, and diclofenac sodium was used for the fever. Although his symptoms were alleviated in a week by the treatment, gradual decline in renal function was noted, prompting a renal biopsy that indicated acute granulomatous interstitial nephritis. A week later, tenderness in both eyes with blurred vision appeared and revealed iritis and keratic precipitations in both eyes; hence, the diagnosis of acute tubulointerstitial nephritis and bilateral uveitis syndrome was made. Toxoplasma gondii-specific immunoglobulin G and immunoglobulin M titers were both positive. Although we could not rule out recent infection of Toxoplasma gondii, which may cause uveitis initially, Toxoplasma immunoglobulin G avidity test indicated a distant infection, which allowed us to rule out meningitis and uveitis as responsible for the complication of recent Toxoplasma gondii infection. Drug-induced lymphocyte stimulation test, or lymphocyte transformation test of diclofenac sodium, was solely positive among the tested drugs. Uveitis was alleviated only with ophthalmic steroid, and renal function returned to normal without administration of systemic steroid.

Conclusions

We experienced a case of diclofenac-induced tubulointerstitial nephritis and uveitis syndrome. In ruling out infections, Toxoplasma immunoglobulin M was persistently positive, and Toxoplasma immunoglobulin G avidity test indicated a “distant” infection. From these two results, we ruled out recent infection. However, it should be noted that “distant” infection indicated by commercial immunoglobulin G avidity is still a multiplex profile consisting of reinfection, reactivation, and latent infection. Narrowing down the infection profile of Toxoplasma is challenging in some cases. Therefore, careful diagnosis and extended follow-up of such patients are needed.

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.

Granulomatous Inflammation in ANCA-Associated Vasculitis

ANCA-associated vasculitis (AAV) comprises granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). While systemic vasculitis is a hallmark of all AAV, GPA is characterized by extravascular granulomatous inflammation, preferentially affecting the respiratory tract. The mechanisms underlying the emergence of neutrophilic microabscesses; the appearance of multinucleated giant cells; and subsequent granuloma formation, finally leading to scarred or destroyed tissue in GPA, are still incompletely understood. This review summarizes findings describing the presence and function of molecules and cells contributing to granulomatous inflammation in the respiratory tract and to renal inflammation observed in GPA. In addition, factors affecting or promoting the development of granulomatous inflammation such as microbial infections, the nasal microbiome, and the release of damage-associated molecular patterns (DAMP) are discussed. Further, on the basis of numerous results, we argue that, in situ, various ways of exposure linked with a high number of infiltrating proteinase 3 (PR3)- and myeloperoxidase (MPO)-expressing leukocytes lower the threshold for the presentation of an altered PR3 and possibly also of MPO, provoking the local development of ANCA autoimmune responses, aided by the formation of ectopic lymphoid structures. Although extravascular granulomatous inflammation is unique to GPA, similar molecular and cellular patterns can be found in both the respiratory tract and kidney tissue of GPA and MPA patients; for example, the antimicrobial peptide LL37, CD163⁺ macrophages, or regulatory T cells. Therefore, we postulate that granulomatous inflammation in GPA or PR3-AAV is intertwined with autoimmune and destructive mechanisms also seen at other sites.

A Rare Case of Renal Sarcoidosis

Sarcoidosis is a multisystem granulomatous disorder characterized by non-caseating granulomas in multiple organs. It most commonly involves lungs and it is very rare to find isolated cases affecting other organ systems with no associated pulmonary findings. We hereby present a case of a young 30-year-old male who was referred to the hospital by his primary medical doctor due to right eye pain secondary to iritis and acute kidney injury (AKI). His initial laboratory studies revealed anemia, AKI, mild hypercalcemia, and the urinary analysis revealed proteinuria. Imaging studies were negative and a kidney biopsy was performed and showed results from the biopsy that revealed diffuse tubulointerstitial disease with early fibrosis, widespread moderate inflammation, multifocal tubulitis, and focal aggregate of epithelioid cells suggestive of granuloma consistent with sarcoidosis. The patient was treated with prednisone. Renal involvement of sarcoidosis is extremely rare (around 0.7%). It has a wide spectrum of presentation including abnormal calcium metabolism, nephrolithiasis, nephrocalcinosis, and acute tubulointerstitial nephritis with or without granulomas. This is a unique case as it shows renal sarcoidosis without coexisting pulmonary finding of hilar lymphadenopathy on chest X-ray. There are very few reported cases of renal sarcoidosis in the literature and this case can add to the pool of those cases. It also emphasizes the need for urgent renal biopsy in the settings of AKI associated with mild to moderate proteinuria. Lack of availability of comprehensive research on the disease may lead to misdiagnosis and delay in treatment.

Sarcoidosis: A Clinical Overview from Symptoms to Diagnosis

Sarcoidosis is a multi-system disease of unknown etiology characterized by the formation of granulomas in various organs. It affects people of all ethnic backgrounds and occurs at any time of life but is more frequent in African Americans and Scandinavians and in adults between 30 and 50 years of age. Sarcoidosis can affect any organ with a frequency varying according to ethnicity, sex and age. Intrathoracic involvement occurs in 90% of patients with symmetrical bilateral hilar adenopathy and/or diffuse lung micronodules, mainly along the lymphatic structures which are the most affected system. Among extrapulmonary manifestations, skin lesions, uveitis, liver or splenic involvement, peripheral and abdominal lymphadenopathy and peripheral arthritis are the most frequent with a prevalence of 25-50%. Finally, cardiac and neurological manifestations which can be the initial manifestation of sarcoidosis, as can be bilateral parotitis, nasosinusal or laryngeal signs, hypercalcemia and renal dysfunction, affect less than 10% of patients. The diagnosis is not standardized but is based on three major criteria: a compatible clinical and/or radiological presentation, the histological evidence of non-necrotizing granulomatous inflammation in one or more tissues and the exclusion of alternative causes of granulomatous disease. Certain clinical features are considered to be highly specific of the disease (e.g., Löfgren's syndrome, lupus pernio, Heerfordt's syndrome) and do not require histological confirmation. New diagnostic guidelines were recently published. Specific clinical criteria have been developed for the diagnosis of cardiac, neurological and ocular sarcoidosis. This article focuses on the clinical presentation and the common differentials that need to be considered when appropriate.

[Renal granulomatous nephritis: Histopathological point of view]

Granulomatous interstitial nephritis (NIG) is a rare form of interstitial nephritis that can be related to acute or chronic clinical presentation. NIG is characterized by granulomas located to the renal interstitium and composed of either epithelioid histiocytes with giant cells and/or of foreign body reaction. The symptoms are unspecific and associate varying degrees of renal failure with abnormal urinanalysis. Extra-renal signs may point to systemic disease. Pathological examination from kidney percutaneous biopsy or surgical resection is required to assert NIG diagnosis and to guide the etiological research. The main causes of NIG are sarcoidosis, drug reactions, mycobacterial infections and crystalline nephropathies. Sarcoidosis is characterized by non-necrotic and well-formed giant cell epithelioid interstitial granulomas. Drug reactions have less well-defined granulomas with inconstant eosinophils. The presence of caseous necrosis within giant cell and epithelioid granulomas leads to infectious NIG diagnosis (tuberculosis and fungal infection). Identification of crystals within foreign body reaction can be improved by polarized light study. Xanthogranulomatous pyelonephritis and malakoplakia are rarer causes of NIG characterized by patches of histiocytes associated with inconstant giant cells. Differential diagnoses of NIG are represented by granulomatous reactions centered on glomeruli and vessels (vasculitis and emboli of cholesterol crystals). Less than 10% of NIG are idiopathic. The prognosis and the treatment vary according to the cause. The factors of poor renal prognosis are chronic irreversible tubulo-interstitial injury (tubular atrophy and interstitial fibrosis).

HIV, drugs and the kidney

Human immunodeficiency virus (HIV) affects over 36 million people worldwide. Antiretroviral therapy (ART) is expanding and improving HIV viral suppression, resulting in increasing exposure to drugs and drug interactions. Polypharmacy is a common complication as people are living longer on ART, increasing the risk of drug toxicities. Polypharmacy is related not only to ART exposure and medication for opportunistic infections, but also to treatment of chronic lifestyle diseases. Acute kidney injury (AKI) is frequent in HIV and is commonly the result of sepsis, dehydration and drug toxicities. Furthermore, HIV itself increases the risk of chronic kidney disease (CKD). Drug treatment is often complicated in people living with HIV because of a greater incidence of AKI and/or CKD compared to the HIV-negative population. Impaired renal function affects drug interactions, drug toxicities and importantly drug dosing, requiring dose adjustment. This review discusses ART and its nephrotoxic effects, including drug–drug interactions. It aims to guide the clinician on dose adjustment in the setting of renal impairment and dialysis, for the commonly used drugs in patients with HIV.

Granulomatous interstitial nephritis: a rare diagnosis with an overlooked culprit

Granulomatous interstitial nephritis (GIN) is a rare entity identified in <1% of native kidney biopsies. The most frequent aetiology is drug-related, followed by systemic granulomatous conditions. Among drugs implicated in GIN, antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) are the most frequent. We report the case of a 45-year-old white man referred to a nephrology consult due to chronic kidney disease. He had a history of arterial hypertension with 10 years of evolution, hyperuricaemia, medicated with allopurinol and NSAID abuse for at least 20 years. Urine sediment was blunt, without proteinuria. Renal ultrasound was normal. A kidney biopsy revealed well-defined epithelioid granulomas with glomerular wrinkling and collapse. Infectious and systemic conditions were excluded, favouring the hypothesis of drug-induced GIN, probably related to NSAIDs. Kidney biopsy remains the gold standard for the diagnosis of GIN. Facing a patient with renal failure without significant proteinuria or active sediment, one should look for causes of tubulointerstitial injury.

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 on renal biopsy in human immunodeficiency virus positive patients: Prevalence and causes in Cape Town, South Africa

South Africa continues to be burdened by human immunodeficiency virus (HIV) and tuberculosis (TB). In Cape Town, the epidemic of HIV-TB co-infection is as high as 70%. Granulomatous interstitial nephritis (GIN) has increased in frequency on renal biopsy. This study aimed to determine GIN prevalence and causes in HIV-positive patients as well as renal outcomes, patient survival and associated factors. This observational cohort study reviewed HIV-positive renal biopsies for GIN from 2005 to 2012. Causes of GIN (medications, TB, fungal and other), and baseline characteristics were analysed. A comparison of baseline data, renal function and survival was made between GIN and non-GIN cohorts. There were 45/316 biopsies demonstrating GIN. TB was the likely cause of GIN in 27 (60%) and 9 (20%) were due to a drug. Low estimated glomerular filtration rate was a statistically significant factor associated with mortality in both GIN (P = 0.045) and non-GIN cohorts (P < 0.000). In the GIN group, there were 12 (26.7%) deaths. Mortality for all patients was greatest in the first 6 months (P = 0.057). TB co-infection in both cohorts was associated with a higher mortality. The multivariate logistic regression demonstrated that a higher urine protein/creatinine ratio (uPCR) and lower estimated glomerular filtration rate were statistically associated with death. GIN is common in HIV-positive renal biopsies in Cape Town. TB-GIN was the commonest cause and associated with a high early mortality. GIN should be considered in HIV-positive patients with acute kidney injury, its presence conveys a survival benefit. There is a need for improved diagnostic accuracy and treatment strategies of TB-GIN.

Tubulointerstitial Nephritis

Tubulointerstitial nephritis (TIN) is a cause of acute kidney injury in children characterized histologically by an inflammatory cell infiltrate in the kidney interstitium. The most common causes of TIN in children include medications, infections, inflammatory disorders, and genetic conditions. TIN typically presents with nonoliguric acute kidney injury and may be associated with systemic symptoms, including fever, rash, and eosinophilia. The long-term prognosis is generally favorable, with full kidney recovery; however, some patients may develop progressive chronic kidney disease. Immunosuppressive therapy may be indicated for severe or prolonged disease.

Renal sarcoidosis: a rare case

Sarcoidosis is a multisystemic granulomatous disease with rare renal involvement. We describe a case of a 45-year-old female patient admitted to the hospital with severe acute kidney injury and uveitis. After clinical investigation, sarcoidosis with renal, hepatic and ocular involvement was diagnosed. Renal biopsy revealed acute granulomatous interstitial nephritis and treatment with systemic corticosteroids was started with marked improvement in renal function.

Acute and Chronic Tubulointerstitial Nephritis of Rheumatic Causes

Tubulointerstitial nephritis (TIN) is the second most common cause of acute intrinsic kidney injury after acute tubular necrosis. Although drug-induced forms of TIN represent the vast majority, rheumatic disease is another common cause and often underdiagnosed. Early diagnosis of acute interstitial nephritis and prompt withdrawal of the culprit medication or a correct treatment can avoid chronic damage and progressive chronic kidney disease. This review highlights the recent updates, clinical features, and treatment in TIN in autoimmune rheumatic disease.

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).

Medication-Induced Interstitial Nephritis in the 21st Century

Interstitial nephritis is an immune mediated form of tubulointerstitial kidney injury that may occur secondary to drugs, autoimmune disease, infections, and hematologic disorders or as a reactive process. Drug-induced acute interstitial nephritis (DI-AIN) occurs in 0.5%-3% of all kidney biopsies and in 5%-27% of biopsies performed for acute kidney injury. Drugs are implicated in 70%-90% of biopsy-proved IN with a prevalence of 50% in less developed to 78% in more developed countries. DI-AIN typically is idiosyncratic because of a delayed hypersensitivity reaction, although some chemotherapeutic agents are permissive for immune upregulation and injure the kidney in a dose-related manner. Antibiotics are the most implicated class of medication in DI-AIN, followed by proton pump inhibitors, nonsteroidal anti-inflammatory agents, and 5-aminosalicylates. Diuretics, allopurinol, phenytoin and other anti-seizure medications, and H2 receptor antagonists are known offenders while chemotherapeutic agents are an under-recognized cause. The symptoms of DI-AIN are variable and often not specific; thus, kidney biopsy is required to make a firm diagnosis. The incidence of DI-AIN appears to be increasing, particularly in the elderly in whom kidney biopsy is underused, and identification of the offending agent may be complicated by polypharmacy. As rapid drug discontinuation may improve prognosis, the possibility of DI-AIN should always be considered in a patient with acute kidney injury.

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.

Granulomatous interstitial nephritis secondary to chronic lymphocytic leukemia/small lymphocytic lymphoma

Granulomatous interstitial nephritis (GIN) is an uncommon pathologic lesion encountered in 0.5% to 5.9% of renal biopsies. Drugs, sarcoidosis, and infections are responsible for most cases of GIN. Malignancy is not an established cause of GIN. Here, we report a series of 5 patients with GIN secondary to chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Patients were mostly elderly white males with an established history of CLL/SLL who presented with severe renal impairment (median peak serum creatinine, 7.3 mg/dL), leukocyturia, and mild proteinuria. One had nephromegaly. In 2 patients, the development and relapse of renal insufficiency closely paralleled the level of lymphocytosis. Kidney biopsy in all patients showed GIN concomitant with CLL/SLL leukemic interstitial infiltration. Granulomas were nonnecrotizing and epithelioid and were associated with giant cells. One biopsy showed granulomatous arteritis. One patient had a granulomatous reaction in lymph nodes and skin. Steroids with/without CLL/SLL-directed chemotherapy led to partial improvement of kidney function in all patients except 1 who had advanced cortical scarring on biopsy. In conclusion, we report an association between CLL/SLL and GIN. Patients typically present with severe renal failure due to both GIN and leukemic interstitial infiltration, which tends to respond to steroids with/without CLL/SLL-directed chemotherapy. The pathogenesis of GIN in this clinical setting is unknown but may represent a local hypersensitivity reaction to the CLL/SLL tumor cells.

[Systemic sarcoidosis and membranous glomerulonephritis]

Renal involvement in sarcoidosis is rare and more often related to calcium metabolism disorders or granulomatous interstitial nephritis. Glomerulonephritis is exceptional. There may be a long latency period between the development of active sarcoidosis and glomerular involvement and inversely. We report a case membranous glomerulonephritis revealing systemic sarcoidosis.

Renal confined sarcoidosis: Natural history and diagnostic challenge

A 69 year old male referred to nephrology clinic for uncontrolled hypertension. During his follow up over two years, he developed renal disease and hypercalcemia. He was found to have monoclonal gammopathy (MGUS). Urinalysis was negative except for Monoclonal IgG on immunoelectrophoresis. Workup for malignancy was negative including chest X-ray and bone marrow biopsy. He progressed into renal failure and ended up on dialysis. Interestingly, the renal biopsy showed non-caseating granulomas, and the patient was diagnosed with renal confined sarcoidosis which is extremely rare. PPD was negative. He was treated with Prednisone 60 mg daily. Surprisingly, his kidney disease was not responsive to steroids. Despite improvement in his calcium with treatment, his kidney function did not improve and he remained on hemodialysis but needed to stay on small dose of Prednisone to keep his calcium under control. Our case is the first in the literature that demonstrates the natural history of renal-confined sarcoidosis. In addition, the presence of MGUS created a diagnostic challenge and delayed diagnosis of sarcoidosis. Although the renal biopsy did not show direct damage from MGUS, a potential relation between renal sarcoidosis and MGUS is worth studied.

Acute Interstitial Nephritis: Etiology, Pathogenesis, Diagnosis, Treatment and Prognosis

Acute interstitial nephritis (AIN) is an important and common cause of acute kidney injury, particularly in hospitalized patients. The classic presentation of AIN includes fever, rash, arthralgias, eosinophilia, and acute kidney injury. While renal biopsy is considered the gold standard for diagnosis, the clinical presentation of fever and rash along with laboratory evidence of peripheral blood eosinophilia, eosinophiluria, and low-grade proteinuria strongly suggest the diagnosis. Histologically, interstitial inflammation with interstitial edema and tubulitis is the hallmark of interstitial nephritis. The most common causative factors are drugs, infections, and certain immune-mediated disorders. Discontinuation of the offending agent is considered the mainstay of therapy while the use of corticosteroids to hasten renal recovery may be beneficial. The role of interstitial nephritis in the pathogenesis of chronic kidney disease and end-stage renal disease is increasingly recognized, further emphasizing the importance of its early diagnosis and timely treatment.

Granulomatous interstitial nephritis: Our experience of 14 patients

Granulomatous interstitial nephritis (GIN) is a rare condition. Drugs, infections, immune processes, and foreign body reaction are the main causes. We identified a total of 14 patients with GIN during a period of 13 years in 2798 renal biopsies. There were 8 males and 6 females in the age range of 20-70 (mean 35 ± 12) years. The serum creatinine at presentation was 6.7 ± 3.8 (range: 2.3-14.7) mg/dl. In nine patients tuberculosis was the causative agent. Drugs (n = 2) and Wegener's granulomatosis (n = 1) were other etiologies. Systemic lupus erythematosis (SLE) and Immunoglobulin A nephropathy (IgAN) were seen in one patient each. Patients with tuberculosis were treated with antituberculous therapy and three of them improved. Four out of six patients who required dialysis at presentation remained dialysis dependent, one of whom underwent renal transplantation. Two patients progressed to end stage renal disease after 7 years and 9 years each. The patients with drug induced GIN had improvement in renal function after prednisolone treatment. Patients with SLE, and Wegener's granulomatosis responded to immunosuppression. Patient with IgAN was on conservative management. Finally, six patients were on conservative management for chronic renal failure.

Renal involvement in Crohn's disease: granulomatous inflammation in the form of mass lesion

Extraintestinal manifestations of Crohn's disease (CD) are varied and concentrated mainly to the skin and eye. Urinary tract or renal involvement is extremely rare. Herein we report on a case of renal lesion of a 50-year-old woman with a 15-year history of CD. Abdominal computed tomography scan of the patient identified heterogeneous multinodular mass lesions in the left kidney. Histology proved classic granulomatous inflammatory nodules with multinucleated giant cells, eosinophils, plasma cells, epithelioid cells, and spindle-shaped myofibroblasts in the areas, where the computed tomography scan indicated. After the extensive PubMed search in the literature, this is the first macroscopically documented and histologically proved, mass-like renal involvement in CD. From now on, differential diagnostics of renal mass lesions in CD should include the tumor-like, Crohn's-type granulomatous inflammation as direct kidney manifestation of the disease.

[Granulomatous interstitial nephritis: A retrospective study of 44 cases]

PURPOSE

Granulomatous interstitial nephritis (GIN) are identified in 0.5 to 1,3% of all renal biopsies. Renal outcome and treatment modalities are not clearly established in the literature.

METHODS

We retrospectively analyzed a case series of 44 GIN identified among all renal biopsies performed between 1984 and 2005 in the Rhône-Alpes area.

RESULTS

The study population included 25 men and 19 women with a mean age of 56 years, and mean diagnostic delay was 11 months. Renal function was severely impaired (mean creatinine clearance 24mL/min). Proteinuria was observed in 77% (mean value 0,9 g/24h) of the patients and associated with microscopic hematuria and leukocyturia in 30% and 25%, respectively. The most common diagnosis was sarcoidosis (25%, n = 11), followed by drug-induced GIN (9%, n = 4), tuberculosis (6,8%, n=3), hemopathy-related paraneoplastic GIN (6,8%, n = 3), HIV infection (n = 1) and chronic renal allograft rejection (n = 1). In other patients, no aetiology was found (48%, n = 21). Severity of renal failure justified hemodialysis in 34% (n = 15) of the patients. Three patients underwent renal transplantation. Nonetheless, renal outcome was generally favorable: renal function improved in 41% (n = 18) and stabilized in 34% (n = 15) of patients.

CONCLUSIONS

Sarcoidosis, drug-induced and infections represent the main causes of GIN. Histologic features are not specific enough to determine the aetiology. Corticosteroids is the gold standard in sarcoidosis, drug-induced, and idiopathic GIN. Treatment is etiologic in the other cases.

Renal sarcoidosis: clinical, laboratory, and histologic presentation and outcome in 47 patients

We conducted the current study to investigate the clinical, laboratory, and histologic features at presentation and the outcome of renal sarcoidosis (RS). Exhaustive retrospective data were collected by the French Sarcoidosis Group. Forty-seven adult patients were assessed (30 male/17 female, M/F ratio: 1.76). Median estimated glomerular filtration rate (eGFR) was 20.5 mL/min per 1.73 m(2) (range, 4-93 mL/min per 1.73 m(2)). Moderate proteinuria was found in 31 (66%) patients (median, 0.7 g/24 h; range, 0-2.7 g/24 h), microscopic hematuria in 11 (21.7%) patients, aseptic leukocyturia in 13 (28.7%) patients. Fifteen of 47 (32%) patients had hypercalcemia (>2.75 mmol/L). Eleven of the 22 (50%) patients diagnosed between June and September had hypercalcemia compared with only 4 of the 25 (16%) cases diagnosed during the other months (p < 0.001). Thirty-seven patients presented with noncaseating granulomatous interstitial nephritis (GIN), and 10 with interstitial nephritis without granulomas. Apart from hypercalcemia, the clinical phenotype was also remarkable for the high frequency of fever at presentation. All patients initially received prednisone (median duration, 18 mo), 10 received intravenous pulse methylprednisolone. eGFR increased from 20 +/- 19 to 44 +/- 24.7 mL/min per 1.73 m(2) at 1 month (p < 0.001, n = 38), to 47 +/- 19.9 mL/min per 1.73 m(2) at 1 year (p < 0.001, n = 46), to 49.13 +/- 25 mL/min per 1.73 m(2) at last follow-up (p < 0.001, n = 47). A complete response to therapy at 1 year and at last follow-up was strongly correlated with complete response at 1 month (p < 0.01). Renal function improvement was inversely related to initial histologic fibrosis score. A complete response to therapy at 1 year was strongly correlated with hypercalcemia at presentation (p = 0.003). Relapses were purely renal (n = 3) and purely extrarenal (n = 10) or both (n = 4), often a long time after presentation, with in some cases severe cardiac or central nervous system involvement. We conclude that hypercalcemia and fever at presentation are often associated with RS; RS is most often and permanently responsive to corticosteroid treatment, but some degree of persistent renal failure is highly frequent and its degree of severity in the long run is well predicted from both histologic fibrotic renal score and response obtained at 1 month.

Renal involvement in Wegener's granulomatosis

The term pauci-immune glomerulonephritis with vasculitis encompasses a group of auto-immune disorders, which includes Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome, and renal-limited vasculitis. Over the past few years, progress has been made in understanding the epidemiology and environmental and genetic risk factors of the role of antineutrophil cytoplasmic antibodies (ANCA) in kidney pathogenesis and the utilization of ANCA in diagnosis. However, certain aspects are still subject to debate including the classification and the place of ANCA in treatment.