Diagnosis, management, and outcomes of immune checkpoint inhibitor induced acute interstitial nephritis: A single-center experience

BACKGROUND

Immune checkpoint inhibitor (ICI)-associated acute interstitial nephritis (AIN) is a recognized complication of immunotherapy (IO), but literature on its management and outcomes is limited.

METHODS

We retrospectively reviewed patients who received ICIs and developed biopsy-proven or clinically-suspected ICI-associated AIN at the University of Virginia Comprehensive Cancer Center from 2012-2023. We analyzed baseline characteristics and clinical outcomes, including treatment interruption and rechallenge rates. Acute kidney injury (AKI) was defined as a ≥ 1.5-fold increase in baseline creatinine under seven days, a two-fold increase above the upper limit of normal, or an increase by ≥0.3 mg/dL. Kidney function returning to within 0.3 mg/dL or less than twice baseline was considered complete (CRc) and partial (PRc) recovery, respectively.

RESULTS

We identified 12 cases of ICI-AIN: four by biopsy (33%) and eight (67%) by clinical suspicion. Two patients received anti-CTLA-4 and anti-PD1, six received anti-PD1 alone, and four received chemo-immunotherapy. The majority (58%) of patients developed AIN within the first 5 cycles. Eight patients developed ≥ Grade 3 AKI, and six developed multiple irAEs. ICI was permanently discontinued in seven patients (58%) and temporarily interrupted in four (30%). The CRc and PRc rates were 67% and 8%, respectively. Upon AIN onset, the best disease response was stable disease in five patients, partial response in three, and progressive disease in three. Median overall survival was 4.87 years, and progression-free survival was 1.5 years.

CONCLUSIONS

Rechallenge with IO after kidney irAE may be possible in some patients but requires careful evaluation on an individual basis.

The diagnosis of acute interstitial nephritis caused by infection versus antibiotic-induced interstitial nephritis: a narrative review

Acute interstitial nephritis (AIN) is a significant contributor to acute kidney injury and can be attributed to a variety of factors, including but not limited to allergens or drugs, infections, autoimmune or systemic diseases, and idiopathic forms of the disease. In some cases, AIN requires a therapeutic action according to a single specific etiology by handling the offending agent and applying an immunosuppressant. Although AIN can be diagnosed through renal biopsy, it is not able to pinpoint the precise cause when multiple causes are suspected to be present simultaneously. Such situations arise when a patient suffering from infection develops AIN during antibiotic therapy, the exact causative factor of which becomes a challenge for the clinicians to determine. This is attributed to the different approaches employed in different etiologies, wherein clinicians are required to maintain the current antibiotic therapy or augment the dose in cases of infection as AIN etiology, without resorting to immunosuppressant therapy as the primary objective is infection killing. In contrast, antibiotics as an etiology for AIN require an alternative drug from the antibiotics group, along with an immunosuppressant. In the interim, delaying the identification of the precise cause may result in interstitial fibrosis and chronic kidney disease. This narrative review highlights certain findings that can be typical of infection-associated ATIN compared with antibiotic-associated ATIN based on clinical history and physical examination, clinical presentation of different antibiotic drug classes, histopathological features, classical and novel biomarkers, serum and urine cytokines and chemokines, cellular biomarkers, and genetic biomarkers. Although these findings cannot provide conclusive and clear recommendations that can be useful in the clinical practice, they can entice researchers to conduct original research on these features to discover clear recommendations.

Severe acute interstitial nephritis induced by α-glucosidase inhibitor miglitol in an elderly patient with type 2 diabetic nephropathy

A 79-year-old male patient with type 2 diabetic nephropathy and hypertension was admitted to our hospital because of acute kidney injury with significantly elevated serum creatinine (8.12 mg/dL) and urinary β2-microglobulin (β2MG, 31,748 μg/L) levels. α-Glucosidase inhibitor (α-GI) miglitol, started two weeks prior to presentation, was discontinued because drug-induced acute interstitial nephritis (AIN) was suspected. Renal biopsy revealed AIN and diabetic nephropathy. The drug-induced lymphocyte stimulation test for miglitol was also positive. After the discontinuation of miglitol, the urinary β2MG levels decreased to the normal range. This case raises the possibility that α-GI miglitol can worsen the renal function in patients with underlying renal dysfunction.

Acute Tubulointerstitial Nephritis and Secondary Renal Amyloidosis: A Rare Complication of Atezolizumab

Lung cancer is the second most common malignancy in both genders and the most common cause of cancer-related deaths worldwide. Broadly, lung cancer is divided into two types: small-cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Non-small cell lung cancer accounts for 85% of the diagnoses of lung cancer. It is necessary to check for any targetable mutations, which can help in deciding the treatment plan for the patients. The patient we are reporting is a 70-year-old male with multiple co-morbidities diagnosed with non-small cell carcinoma, favoring adenocarcinoma on histopathology. He was started on Atezolizumab/Bevacizumab/Carboplatin/Paclitaxel (ABCP). He was switched to maintenance Atezolizumab/Bevacizumab after four cycles due to poor tolerance to carboplatin and paclitaxel. The patient presented with neutropenic colitis and acute kidney injury (AKI), requiring admission. workup revealed nephrotic range proteinuria with a high urinary albumin-to-creatinine ratio. He underwent a renal biopsy to ascertain the cause of his proteinuria, which showed marked acute and chronic tubulo-interstitial nephritis (TIN), amyloidosis, and global glomerulosclerosis. Secondary (AA) amyloidosis is characterized by the extracellular deposition of misfolded proteins. Although interstitial nephritis is a reported side effect of immune checkpoint inhibitors, AA amyloidosis is a rarer side effect. So, to determine the exact cause and early therapeutic intervention in immune checkpoint inhibitor-related kidney injury, large retrospective or prospective studies should be done.

Proton pump inhibitors and adverse kidney outcomes during immune checkpoint blockade: time to sound the alarm?

Immune checkpoint inhibitors (ICIs) have significantly altered the treatment landscape for cancer in the last decade. However, their benefits are often offset by therapy-limiting immune-related adverse events (irAEs). Acute interstitial nephritis (AIN) is the most common renal irAE, but the exact mechanisms underlying its development are poorly understood. ICI-induced immune activation against drug-derived antigens, leading to an inflammatory response within the kidney interstitium, has been postulated, evidenced by current observations of a higher incidence of ICI-associated AIN in patients receiving AIN-inducing drugs such as proton pump inhibitors (PPIs). The role of PPIs in this specific context has garnered significant attention, given their ubiquitous use and sometimes misuse. In this issue of CKJ Miao et al. summarise and synthesize the best available evidence to clarify the interactions of PPIs with ICIs in the development of AIN and other adverse kidney outcomes. The sum of evidence provided appear to implicate PPIs in the development of clinically significant short- and long-term kidney-related adverse effects in patients on immune checkpoint blockade, although causality cannot be proven. In this editorial we discuss the key practical implications of these findings and emphasize the need for further quality studies to delineate the true relationship of ICIs and PPIs in the development of AIN.

Immunological mechanisms underlying clinical phenotypes and noninvasive diagnosis of immune checkpoint inhibitor-induced kidney disease

Immune checkpoint inhibitors (ICIs) have become a mainstay of cancer therapy, with over 80 FDA-approved indications. Used in a variety of settings and in combination with each other and with traditional chemotherapies, the hyperactive immune response induced by ICIs can often lead to immune-related adverse events in bystander normal tissues such as the kidneys, lungs, and the heart. In the kidneys, this immune-related adverse event manifests as acute interstitial nephritis (ICI-AIN). In the era of widespread ICI use, it becomes vital to understand the clinical manifestations of ICI-AIN and the importance of prompt diagnosis and management of these complications. In this review, we delve into the clinical phenotypes of ICI-AIN and how they differ from traditional drug-induced AIN. We also detail what is known about the mechanistic underpinnings of ICI-AIN and the important diagnostic and therapeutic implications behind harnessing those mechanisms to further our understanding of these events and to formulate effective treatment plans to manage ICI-AIN.

Acute Interstitial Nephritis with Glomerular Capillary IgA Deposition Following SARS-CoV-2 mRNA Vaccination

We herein report a case of acute kidney injury (AKI) presenting as acute interstitial nephritis (AIN) after the first dose of the BNT162b2 mRNA vaccine against coronavirus disease 2019 (COVID-19). A 69-year-old man with a history of diabetes and hypertension presented with AKI 4 days after receiving the vaccine. Despite the administration of methylprednisolone pulse treatment, his renal function worsened, which prompted us to initiate temporal hemodialysis. His renal function subsequently improved, and a renal biopsy confirmed AIN and glomerular capillary IgA deposition without apparent crescents. The clinical history and histological findings suggest a relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and AIN as a rare side effect.

A Rare Complication of Ascariasis: A Case of Acute Interstitial Nephritis

Acute interstitial nephritis (AIN) due to helminths is a rare cause of acute kidney injury (AKI). Helminthiases often progresses insidiously, making diagnosis difficult. This was the case of a 72-year-old man, who presented with renal failure, itching and diarrhoea. Urinalysis revealed leukocyturia, microhaematuria and mild proteinuria. A full blood count revealed leucocytosis with eosinophilia. A stool parasitological examination revealed fertilised eggs of Ascaris lumbricoides. Tubulointerstitial nephropathy secondary to A. lumbricoides infection was suspected. A percutaneous renal biopsy was not performed since the patient refused the anti-platelet therapy discontinuation. Mebendazole, albendazole and prednisone therapy was administered. After worm eradiation and discharge, recovery from the parasitosis, absence of pruritus and eosinophilia, and progressive improvement of renal function were observed, strongly suggesting a causal relationship between Ascaris infection and AIN. Parasite infection should be considered in the differential diagnosis of unexplained renal failure because early diagnosis and treatment are necessary to avoid irreversible complications.

Immune Checkpoint Inhibitor-Associated AKI: Debates in Diagnosis, Management, and Rechallenge

Immune checkpoint inhibitors (ICIs) are now established treatments for advanced cancer and their use is now ubiquitous. The high upside of ICIs is tempered by their toxicity profile affecting almost every organ, including the kidneys. Although acute interstitial nephritis is the major kidney-related adverse effect of checkpoint inhibitors, other manifestations such as electrolyte abnormalities and renal tubular acidosis have been described. With increasing awareness and recognition of these events, the focus has shifted to non-invasive identification of ICI-acute interstitial nephritis, with sophisticated approaches involving biomarkers and immunologic signatures being studied. Although the management of immune-related adverse events with corticosteroids is straightforward, there now are more data to help guide immunosuppressive regimens, ICI rechallenge, and delineate risk and efficacy in special populations such as individuals on dialysis or those who have received a transplant.

Alectinib - induced acute renal failure

Introduction: Alectinib is a potent and selective orally active tyrosine kinase inhibitor used for anaplastic lymphoma kinase-positive non-small cell lung cancer, which has a better safety profile than other inhibitors of anaplastic lymphoma kinase. We report a case of a mixed pattern of acute interstitial nephritis and acute tubular necrosis proven by renal biopsy upon starting alectinib therapy. Case report: A 68-year-old man with diabetes, hypertension, and dyslipidaemia, diagnosed with anaplastic lymphoma kinase-positive non-small cell lung cancer stage IV, had 27 days previously started alectinib 600 mg twice daily. He presented at the emergency room due to vomiting, nausea, and more dyspnoea than usual. A high creatinine level and metabolic imbalances were detected in laboratory tests. Management and outcomes: After a diagnosis of acute renal failure, the patient was admitted to hospital. Nephrotoxic drugs were suspended, and haemodialysis was required. After dismissing other causes, a probable diagnosis of acute interstitial nephritis due to alectinib was established. Corticotherapy was initiated and renal function returned to baseline levels. Renal biopsy showed a mixed pattern of acute interstitial nephritis and acute tubular necrosis. The patient was discharged, and alectinib therapy was modified to lorlatinib. No polymorphisms were found in a pharmacogenetic test. After 10 months with lorlatinib, renal function remains stable. Discussion: The relationship between acute renal failure and alectinib initiation is considered probable in this patient. Although it is an adverse effect reported in less than 1% of cases, it would be advisable to monitor renal function in this kind of patient.

Cytokines and Immune Cell Phenotype in Acute Kidney Injury Associated With Immune Checkpoint Inhibitors

Introduction

Immune checkpoint inhibitors (ICIs) induce impressive antitumor responses but may lead to acute kidney injury (AKI) associated with ICI therapy (AKI-ICI). Biomarkers distinguishing AKI-ICI from AKI because of other causes (AKI-other) are currently lacking. Because ICIs block immunoregulatory pathways, we hypothesized that biomarkers related to immune cell dysregulation, including tumor necrosis factor alpha (TNF-α) and other markers of B and T cell activation in the systemic circulation and kidney tissue, may aid with the diagnosis of AKI-ICI.

Methods

This is a prospective study consisting of 24 participants who presented with AKI during ICI therapy, adjudicated to either have AKI-ICI (n = 14) or AKI-other (n = 10). We compared markers of kidney inflammation and injury (neutrophil gelatinase-associated lipocalin, kidney injury molecule-1) as well as plasma and urine levels of T cell-associated cytokines (TNF-α, interferon-γ, interleukin (IL)-2, IL-4, IL-6, IL-8, IL-9, and IL-10) between groups. We also compared T-cell responses in the systemic circulation and in kidney tissue across groups, using mass cytometry systems.

Results

We observed increase in several specific immune cells, including CD4 memory, T helper cells, and dendritic cells in the kidney tissue, as well as in the urine cytokines IL-2, IL-10, and TNF-α, in patients who developed AKI-ICI compared to patients with AKI-other (P < 0.05 for all). The discriminatory ability of TNF-α on AKI cause was strong (area under the curve = 0.814, 95% confidence interval: 0.623-1.00. The CD4+ T cells with memory phenotype formed the dominant subset.

Conclusion

These results suggest that specific T-cell responses and their respective cytokines may be indicative of AKI associated with ICI therapy and may help to differentiate AKI-ICI from AKI-other. Urine TNF-α is a promising biomarker for AKI-ICI, which is most often caused by acute interstitial nephritis (AIN), and TNF-α pathway may serve as a potential target for therapeutic intervention.

Acute Kidney Injury: Medical Causes and Pathogenesis

Acute kidney injury (AKI) is a common clinical syndrome characterized by a sudden decline in or loss of kidney function. AKI is not only associated with substantial morbidity and mortality but also with increased risk of chronic kidney disease (CKD). AKI is classically defined and staged based on serum creatinine concentration and urine output rates. The etiology of AKI is conceptually classified into three general categories: prerenal, intrarenal, and postrenal. Although this classification may be useful for establishing a differential diagnosis, AKI has mostly multifactorial, and pathophysiologic features that can be divided into different categories. Acute tubular necrosis, caused by either ischemia or nephrotoxicity, is common in the setting of AKI. The timely and accurate identification of AKI and a better understanding of the pathophysiological mechanisms that cause kidney dysfunction are essential. In this review, we consider various medical causes of AKI and summarize the most recent updates in the pathogenesis of AKI.

Rifampin-induced acute kidney injury and hemolysis: A case report and literature review of a rare condition

Rifampicin is a bactericidal drug used in various infectious diseases, including tuberculosis (TB). Nephrotoxicity is a rare side effect of intermittent Rifampin use and even less commonly continued use. We report a case of Rifampin-induced acute tubular necrosis and hemolysis in a patient with latent TB with a relevant literature review.

Mesalazine-Induced Interstitial Nephritis in a Patient With Ulcerative Colitis

Acute interstitial nephritis (AIN) corresponds to a decline in kidney function due to an injury induced by drugs (in the majority of cases), infections, and autoimmune disorders. It is characterized by the presence of an interstitial inflammatory infiltrate in the kidney. Here, we describe a case of a man with a previous medical history relevant to ulcerative colitis (UC) who was admitted due to acute kidney injury (AKI) in the setting of AIN secondary to mesalazine.

Filler-Induced Interstitial Nephritis in a Male-to-Female Transgender Person: A Case Report

Transgender individuals experience lower overall health outcomes than cisgender individuals due to a higher burden of chronic illnesses in this demographic. An early loss in renal function is frequently seen in acute interstitial nephritis (AIN), which is defined by the presence of inflammatory infiltrates and edema inside the interstitium. Infections or medication use can cause interstitial nephritis. In two-thirds of cases, interstitial nephritis caused by drugs is detected. Few people are affected by it, thus, it's thought to be immune-mediated rather than dose-dependent. In this report, a 32-year-old transgender female was admitted to a hospital due to generalized swelling following filler injections in the buttocks region. It is important for doctors and patients to be informed about these procedures' potential risks. Additionally, more study has to be done on the negative effects of filler injections.

Immune checkpoint inhibitor related nephrotoxicity: Advances in clinicopathologic features, noninvasive approaches, and therapeutic strategy and rechallenge

Immune checkpoint inhibitors (ICIs) are used increasingly to treat more than 17 cancers and have shown promising therapeutic results. However, ICI use can result in a variety of immune-related adverse events (IRAEs) which can occur in any organ, including the kidneys. Acute kidney injury (AKI) is the most common nephrotoxicity, classically related to acute interstitial nephritis. Much more diverse patterns and presentations of ICI-related kidney injury can occur, and have implications for diagnostic and therapeutic management approaches. In this review, we summarize the recently approved ICIs for cancer, the incidence and risk factors for nephrotoxicity, our current understanding of the pathophysiological mechanisms and the key clinicopathological features of ICI-related AKI, and therapeutic strategies. We also explore important knowledge that require further investigation, such as the risks/benefits of ICI rechallenge in patients who recover from an episode of ICI-related AKI, and the application of liquid biopsy and microbiome to identify noninvasive biomarkers to diagnose and predict kidney injury and guide ICI therapy.

Urinary T cells are detected in patients with immune checkpoint inhibitor-associated immune nephritis that are clonotypically identical to kidney T cell infiltrates

Acute kidney injury (AKI) occurs in ~20% of patients receiving immune checkpoint inhibitor (ICI) therapy; however, only 2-5% will develop ICI-mediated immune nephritis. Conventional tests are nonspecific in diagnosing disease pathology and invasive procedures (i.e. kidney biopsy) may not be feasible. In other autoimmune renal diseases, urinary immune cells correlated with the pathology or were predictive of disease activity. Corresponding evidence and analysis are absent for ICI-mediated immune nephritis. We report the first investigation analyzing immune cell profiles of matched kidney biopsies and urine of patients with ICI-AKI. We demonstrated the presence of urinary T cells in patients with immune nephritis by flow cytometry analysis. Clonotype analysis of T cell receptor (TCR) sequences confirmed enrichment of kidney TCRs in urine. As ICI therapies become standard of care for more cancers, noninvasively assessing urinary immune cells of ICI therapy recipients can facilitate clinical management and an opportunity to tailor ICI-nephritis treatment.

Case Report: Vancomycin-Associated Tubulointerstitial Nephritis in Clinical Practice-Case Report and Review of Literature

Nephrotoxicity is one of the major limiting factors for vancomycin use. The most common histological patterns of kidney injury are acute tubulointerstitial nephritis and acute tubular necrosis. Patients who develop acute tubulointerstitial nephritis are prone to develop acute kidney injury with vancomycin rechallenge and, in most cases, present alone or as a part of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). The purpose of the review study is to identify biopsy-proven vancomycin-associated-tubulointerstitial nephritis in literature, determine possible underlying pathophysiology and identify the consequences of vancomycin rechallenge in such patients.

Acute interstitial nephritis with Prothionamide

Among drug-related complications, drug-related nephrotoxicity is the commonest. It is the cause for 7% of all drug-related toxicities among inpatients and accounts for 20% to 30% of acute renal failure. Acute interstitial nephritis is one of the drug-related adverse reactions and occurs due to a drug-related type 4 hypersensitivity reaction. In this case report, we reported acute interstitial nephritis that causes acute renal failure (acute kidney injury) in a patient taking Prothionamide therapy. This drug-related side effect had not been reported. In this case report, we report a patient who develops fatigability, rash, and intermittent fever after 14 days of taking the drug Prothionamide. The main aims of this case report are to use it as a pharmacovigilance report for drug-producing companies and to consider a further study on this side effect. It is also an alert for clinicians to consider this side effect when patients develop acute interstitial nephritis while taking Prothionamide.

Drug-Induced Acute Kidney Injury

Medications are a common cause of AKI especially for patients admitted to hospital wards and the intensive care unit. Although drug-related kidney injury occurs through different mechanisms, this review will focus on three specific types of tubulointerstitial injury. Direct acute tubular injury develops from several medications, which are toxic to various cellular functions. Their excretory pathways through the proximal tubules contribute further to AKI. Drug-induced AKI may also develop through induction of inflammation within the tubulointerstitium. Medications can elicit a T cell-mediated immune response that promotes the development of acute interstitial nephritis leading to AKI. Although less common, a third pathway to kidney injury results from the insolubility of drugs in the urine leading to their precipitation as crystals within distal tubular lumens, causing a crystalline-related AKI. Intratubular obstruction, direct tubular injury, and localized inflammation lead to AKI. Clinicians should be familiar with the pathogenesis and clinical-pathologic manifestations of these forms of kidney injury. Prevention and treatment of AKI relies on understanding the pathogenesis and judiciously using these agents in settings where AKI risk is high.

Risk of bias in non-randomized observational studies assessing the relationship between proton-pump inhibitors and adverse kidney outcomes: a systematic review

BACKGROUND

Proton-pump inhibitors (PPIs) are widely prescribed as acid-suppression therapy. Some observational studies suggest that long-term use of PPIs is potentially associated with certain adverse kidney outcomes. We conducted a systematic literature review to assess potential bias in non-randomized studies reporting on putative associations between PPIs and adverse kidney outcomes (acute kidney injury, acute interstitial nephritis, chronic interstitial nephritis, acute tubular necrosis, chronic kidney disease, and end-stage renal disease).

METHODS

We searched the medical literature within 10 years of 17 December 2020. Pre-specified criteria guided identification of relevant English language articles for assessment. Risk of bias on an outcome-specific basis was evaluated using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool by two independent reviewers.

RESULTS

Of 620 initially identified records, 26 studies met a priori eligibility criteria and underwent risk of bias assessment. Nineteen studies were judged as having a moderate risk of bias for reported adverse kidney outcomes, while six studies were judged as having a serious risk of bias (mainly due to inadequate control of confounders and selection bias). We were unable to determine the overall risk of bias in two studies (one of which was assessed as having a moderate risk of bias for a different adverse kidney outcome) due to insufficient information presented. Effect estimates for PPIs in relation to adverse kidney outcomes varied widely (0.24-7.34) but associations mostly showed increased risk.

CONCLUSION

Using ROBINS-I, we found that non-randomized observational studies suggesting kidney harm by PPIs have moderate to serious risk of bias, making it challenging to establish causality. Additional high-quality, real-world evidence among generalizable populations are needed to better understand the relation between PPI treatment and acute and chronic kidney outcomes, accounting for the effects of varying durations of PPI treatment, self-treatment with over-the-counter PPIs, and potential critical confounders.

Case Report: SARS-CoV-2 Associated Acute Interstitial Nephritis in an Adolescent

Acute interstitial nephritis (AIN) has been recently recognized as one of the infrequent kidney involvement phenotypes among adult patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although SARS-CoV-2 associated intrinsic kidney disease has been scarcely reported in children, only one case of AIN temporally associated with the infection has been described in the pediatric population so far. We presented a case of a 12-year old boy who presented with fatigue, anorexia, and polydipsia following an RT-PCR that confirmed SARS-CoV-2 infection seven weeks prior to admission. Initial workup revealed increased serum creatinine (235 μmol/L), glucosuria, low-molecular-weight proteinuria, mild leukocyturia, and microhematuria with hyaline and granular casts on microscopy. Antibodies against the SARS-CoV-2 S protein receptor-binding domain confirmed prior infection with high titers. Kidney biopsy showed diffuse active interstitial nephritis with negative immunofluorescence and positive immunohistochemistry for SARS-CoV-2 in the inflammatory cells within the interstitium. Electron microscopy revealed several SARS-CoV-2-like particles. Kidney function continued to deteriorate despite several days of supportive therapy only (peak serum creatinine 272 μmol/L); thus, treatment with methylprednisolone pulse-dose therapy was initiated and was followed by oral prednisolone with gradual tapering. Kidney function completely recovered after 3 weeks post-discharge and remained normal after 11 weeks of follow-up (last estimated glomerular filtration rate 106 ml/min/1.73 m²) with only residual microhematuria. Our case adds to the emerging evidence of SARS-CoV-2 as a potential etiological agent of AIN in children and also suggests that interstitial kidney injury may result from secondary inflammatory damage. Epidemiological history, serologic testing, and SARS-CoV-2 detection in biopsy should be considered in the work-up of children with AIN of unknown etiology.

A Case of Acute Interstitial Nephritis After Two Doses of the BNT162b2 SARS-CoV-2 Vaccine

Background

The development of vaccines to prevent COVID-19 breakouts came with highly positive results but some unexpected side effects. Rare side effects have been seen with the BNT162b2 SARS-CoV 2 vaccine.

Case Presentation

We present the case of a 45-year-old female patient who developed an acute kidney injury needing urgent hemodialysis one week after the second administration of the BNT162b2 SARS-CoV 2 vaccine. She developed a macular rash on her lower limbs and palms as well. A kidney biopsy was performed 10 days after vaccine inoculation, diagnosing acute interstitial nephritis and acute tubular necrosis with cellular casts. The patient was treated with three corticosteroid pulses followed by daily prednisolone. We witnessed clinical improvement 4 days after the initial corticosteroid treatment with progressive recovery of kidney function and hemodialysis withdrawal. After 2 weeks, the patient had recovered her kidney function. Immunophenotyping was performed, diagnosing a hypersensitivity to the vaccine and the polyethylene glycol excipient.

Conclusion

Patients may develop acute reactions to vaccines. In this case, symptoms seem to correlate significantly with its inoculation and, although this case had a favourable outcome, these side effects must be made aware for clinicians and patients.

Cocaine Hurts Your Kidneys Too: A Rare Case of Acute Interstitial Nephritis Caused by Cocaine Abuse

Cocaine is a powerfully addictive recreational drug that is extracted from the leaves of the Erythroxylon coca plant native to Central and South America. It is a widely abused substance, despite being banned since the early 19th century due to fatalities. Cocaine may result in acute kidney injury (AKI) by different mechanisms, but acute interstitial nephritis (AIN) is scarcely recognized as the cause of acute kidney injury (AKI). Here, we present a case of AKI from both AIN and acute tubular necrosis (ATN) following cocaine insufflation. The purpose of this article is to review the rare but significant association of AIN associated with cocaine use. The nature of the treatment of cocaine-related kidney disease may differ from other causes of acute kidney insult. Prompt recognition of the underlying cause of renal dysfunction is vital for this group of patients to prevent the rapid deterioration of renal function.

Ibrutinib-induced acute kidney injury via interstitial nephritis

The introduction of Bruton's tyrosine kinase inhibitor ibrutinib has made a significant progress in the treatment of chronic lymphocytic leukemia and other B-cell malignancies. Due to the reduction of cytokine release, it is effective in chronic graft-versus-host disease, and its use has also been suggested in autoimmune diseases and in prevention of COVID-19-associated lung damage. Despite this effect on the immune response, we report a severe hypersensitivity reaction in a 76-year-old male patient diagnosed with prolymphocytic leukemia. Four weeks after the ibrutinib start, non-oliguric acute kidney injury with proteinuria and microscopic hematuria developed and that was accompanied by lower limb purpuras and paresthesia. Renal biopsy revealed acute interstitial nephritis. Employing 1 mg/kg methylprednisolone administration, serum creatinine decreased from 365 μmol/L to 125 μmol/L at 11 days and the proteinuria-hematuria as well as the purpura, paresthesia resolved. Three months later at stabile eGFR of 56 ml/min/1.73 m2 methylprednisolone was withdrawn and a rituximab-venetoclax treatment was initiated without side effects. We conclude that despite the beneficial effect on cytokines response in Th1 direction, ibrutinib can cause acute interstitial nephritis. Early detection, discontinuation of ibrutinib, glucocorticoid administration may help to better preserve renal function, thereby lowering the risk of potential subsequent kidney injury.

Immune Checkpoint Inhibitors and Kidney Toxicity: Advances in Diagnosis and Management

Immune checkpoint inhibitors are now approved for more than 50 indications, and increasing numbers of patients with advanced cancer are receiving immunotherapy. Immune-related adverse events that result from checkpoint inhibitors can affect any organ system. The most common kidney side effect is acute kidney injury, typically caused by acute interstitial nephritis. This review covers the most recent advances in immune checkpoint inhibitor-induced acute kidney injury. The review focuses on the differences between checkpoint inhibitor classes in causing acute kidney injury and differentiating immune checkpoint inhibitor-induced kidney damage from other causes of acute kidney injury. We describe the appropriate use of a kidney biopsy in the diagnosis of acute kidney injury and highlight the need for identification of noninvasive diagnostic and predictive biomarkers of immune checkpoint inhibitor-induced acute kidney injury. In the treatment section, approaches to corticosteroid use and the risks and benefits of rechallenging patients who experience acute kidney injury are debated. We also clarify the long-term adverse effects of immune checkpoint inhibitors on kidney function and the risk of chronic kidney disease in cancer survivors.

Is Rechallenge Appropriate in Patients that Develop Immune Checkpoint Inhibitor-Associated AKI?: CON

This is an Early Access article. Please select the PDF button, above, to view it. Be sure to also read the PRO: 10.34067/KID.0003962021 and the COMMENTARY 10.34067/KID.0005592021

Acute Interstitial Nephritis: A Rare and Unusual Side Effect of Omalizumab

Acute interstitial nephritis (AIN) is a relatively common cause of acute kidney injury with etiologies that include drug therapy, infections, and systemic diseases. Of these etiologies, drug therapy accounts for ~70% of AIN cases. Although any drug can cause AIN, there are no reported cases of AIN caused by omalizumab, a humanized monoclonal antibody that binds to and inhibits circulating immunoglobulin E. In this article, we share the first reported case of AIN following administration of omalizumab for the treatment of moderate to severe persistent asthma.

[CME Sonography 99/Answers: Kidney Echo Changes]

CME Sonography 99/Answers: Kidney Echo Changes Abstract. Normal kidneys have a smooth contour, kidney length 9-12 cm, volume 90-180 ml/1.73 m2 body surface, parenchyma width 13-18 mm and an echogenicity of the cortex which is hypoechoic compared to the liver and spleen, as well as medullary pyramids, which are again hypoechoic compared to the cortex. Digital ultrasound images enable the echogenicity to be measured between 0 (black) and 255 (white). A normal quotient between the echogenicity of the liver and the renal cortex is 1.0-1.4. A normal quotient between the spleen and the renal cortex is> 1.0. The normal quotient between the renal cortex and the renal medulla is> 1.0. In diffuse renal parenchyma diseases, changes in echogenicity are observed. There are kidneys with increased echogenicity of the cortex and a ratio to liver and spleen of <1.0 and kidneys with hyperechoic renal medulla and the ratio between renal cortex and renal medulla <1.0.

Prognosis of severe drug-induced acute interstitial nephritis requiring renal replacement therapy

Objective

Drug-induced acute interstitial nephritis (DAIN) is often associated with improved outcomes, whereas some patients may still progress to chronic kidney disease (CKD). The aim of this study was to evaluate the prognosis of patients with severe DAIN requiring renal replacement therapy (RRT) at baseline, and to explore the risk factors of progression to CKD.

Methods

We performed a retrospective study of patients with severe DAIN confirmed by renal biopsies in our center over a 10 years period, all the patients received RRT at presentation. The clinical and pathological characteristics at baseline were recorded, and the outcomes (renal function recovered or progressed to CKD) during follow-ups were also evaluated. Univariate and multivariate logistic regression analysis were performed to identify the independent risk factors of progression to CKD.

Results

Seventy-two patients who met the inclusion criteria were enrolled, 13 patients (18.0%) progressed to CKD (GFR < 60 ml/min/1.73 m²) after at least 6 months of follow-up, the remaining 59 patients achieved a favorable renal function recovery. Compared with patients who achieved renal function recovery (recovery group), the patients progressed to CKD (progression group) were older and had longer interval from symptom onset to treatment with steroids. The peak serum cystatin C concentration was higher in progression group than recovery group. Higher score of interstitial fibrosis/tubular atrophy (IFTA) and more interstitial inflammatory cells infiltration were detected in renal tissue in progression group. According to multivariable analysis, higher peak cystatin C concentration (OR = 2.443, 95% CI 1.257, 4.746, p = 0.008), longer interval to treatment with corticosteroids (OR = 1.183, 95% CI 1.035, 1.352, p = 0.014) were independent risk factors of progression to CKD. The cutoff value of cystatin C concentration was 4.34 mg/L, at which the sensitivity and specificity were 76.9% and 89.3%, respectively; the cutoff value of interval to treatment with corticosteroids was 22.5 days, at which the sensitivity and specificity were 81.8% and 79.5%, respectively.

Conclusion

Renal function was reversible in majority of patients with severe DAIN requiring RRT when early identification and treatment. Higher peak cystatin C concentration and longer interval to treatment with corticosteroids associated with worse renal prognosis.

Ibuprofen-associated minimal change disease and acute interstitial nephritis with possibly linked membranous glomerulonephritis

Non-steroidal anti-inflammatory drugs are not only potent analgesics and antipyretics but also nephrotoxins, and may cause electrolyte disarray. In addition to the commonly expected effects, including hyperkalemia, hyponatremia, acute renal injury, renal cortical necrosis, and volume retention, glomerular disease with or without nephrotic syndrome or nephritis can occur as well including after years of seemingly safe administration. Minimal change disease, secondary membranous glomerulonephritis, and acute interstitial nephritis are all reported glomerular lesions seen with non-steroidal anti-inflammatory use. We report a patient who used non-steroidal anti-inflammatory drugs for years without diabetes, chronic kidney disease, or proteinuria; he then developed severe nephrotic range proteinuria with 7 g of daily urinary protein excretion. Renal biopsy showed minimal change nephropathy, a likely secondary membranous glomerulonephritis, and acute interstitial nephritis present simultaneously in one biopsy. Cessation of non-steroidal anti-inflammatory drug use along with steroid treatment resulted in a moderate improvement in renal function, though residual impairment remained. Urine heavy metal screen returned with elevated levels of urine copper, but with normal ceruloplasmin level. Workup suggested that the elevated copper levels were due to cirrhosis from non-alcoholic fatty liver disease. The membranous glomerulonephritis is possibly linked to non-steroidal anti-inflammatory drug exposure, and possibly to heavy metal exposure, and is clinically and pathologically much less likely to be a primary membranous glomerulonephritis with negative serological markers.

Cocaine-Induced Acute Interstitial Nephritis: A Comparative Review of 7 Cases

Acute interstitial nephritis is a well-known cause of acute kidney injury, but its association with cocaine use is extremely rare. In this article, we chronicle the case of a patient who developed acute interstitial nephritis secondary to cocaine insufflation. Furthermore, we conducted a systematic literature search of MEDLINE, Cochrane, Embase, and Scopus databases regarding cocaine-induced acute interstitial nephritis. A comprehensive review of the search results yielded a total of 7 case reports only. The data on patient characteristics, clinical features, biochemical profiles, treatment, and outcomes were collected and analyzed. This paper illustrates that acute interstitial nephritis may be added to the list of differentials in patients with acute kidney injury and a history of cocaine use. The therapeutic approach for cocaine-related kidney disease may be different than other etiologies responsible for acute renal insult. Prompt recognition of this entity is crucial because such patients may ultimately develop severe deterioration in renal function.

[CME Sonography 99: Kidney Echo Changes]

CME Sonography 99: Kidney Echo Changes Abstract. Normal kidneys have a smooth contour, kidney length 9-12 cm, volume 90-180 ml/1.73 m2 body surface, parenchyma width 13-18 mm and an echogenicity of the cortex which is hypoechoic compared to the liver and spleen, as well as medullary pyramids, which are again hypoechoic compared to the cortex. Digital ultrasound images enable the echogenicity to be measured between 0 (black) and 255 (white). A normal quotient between the echogenicity of the liver and the renal cortex is 1.0-1.4. A normal quotient between the spleen and the renal cortex is >1.0. The normal quotient between the renal cortex and the renal medulla is >1.0. In diffuse renal parenchyma diseases, changes in echogenicity are observed. There are kidneys with increased echogenicity of the cortex and a ratio to liver and spleen of <1.0 and kidneys with hyperechoic renal medulla and the ratio between renal cortex and renal medulla <1.0.

Acute interstitial nephritis associated with immune checkpoint inhibitors: a single-centre experience

BACKGROUND

Checkpoint inhibitors (CPIs) are used to treat solid organ metastatic malignancies. They act by triggering a vigorous immune response against tumoural cells, preventing their proliferation and metastasis. However, this is not a selective response and can cause immune-related adverse events (irAEs). The kidney can potentially be damaged, with an incidence of irAEs of 1-4%. The most frequent type of toxicity described is acute interstitial nephritis (AIN).

METHODS

We conducted a study of patients with solid organ metastatic malignancies treated with immunotherapy who developed acute renal injury and underwent kidney biopsy in the last 14 months at the Vall d'Hebron University Hospital.

RESULTS

In all, 826 solid organ malignancies were treated with immunotherapy in our centre, 125 of them (15.1%) developed acute kidney injury (AKI), 23 (18.4% of AKI) visited the nephrology department and 8 underwent kidney biopsy. The most frequent malignancy was lung cancer, in five patients (62%), followed by two patients (25%) with melanoma and one patient (12%) with pancreatic cancer. Four patients (50%) had already received previous oncological therapy, and for the remaining four patients (50%), CPI was the first-line therapy. Five patients (62%) were treated with anti-programmed cell death protein 1, three patients (37%) received anti-programmed death ligand 1 and two (25%) patients were treated in combination with anti-cytotoxic T-lymphocyte antigen 4. The time between the start of CPI and the onset of the AKI ranged from 2 to 11 months. The most frequent urine findings were subnephrotic-range proteinuria, with a mean protein:creatinine ratio of 544 mg/g (standard deviation 147) and eosinophiluria. All patients were biopsied after being diagnosed with AIN. Three patients (37%) received treatment with pulses of methylprednisolone 250-500 mg/day and five patients (62%) received prednisone 1 mg/kg/day. Seven patients (87%) experienced recovery of kidney function and one patient (12%) progressed to chronic kidney disease.

CONCLUSIONS

We report on eight patients with CPI-related AIN diagnosed in the last 14 months at our centre. The novel immunotherapy treatment of metastatic solid organ malignancies carries a higher risk of irAEs. The kidney is one of the most commonly affected organs, frequently presenting as an AIN and exhibiting a favourable response to steroid treatment.

Nitrofurantoin-Associated Acute Granulomatous Interstitial Nephritis

We report the case of a 71-year-old female who was incidentally found to have nonoliguric acute kidney injury on a routine workup for new-onset visual hallucination. Further history revealed inadvertent usage of nitrofurantoin for 3 months for an anticipated urological procedure. Renal biopsy demonstrated acute granulomatous interstitial nephritis. The renal function significantly improved following discontinuation of nitrofurantoin and corticosteroid administration. We highlight a rare association of nitrofurantoin with acute granulomatous interstitial nephritis through this case report.

A Case of Cefepime-Induced Neurotoxicity: Renal Function Missing in Action

Cefepime is a renally excreted, fourth-generation cephalosporin used in the treatment of severe abdominal, skin, soft tissue, and urinary tract infections due to its broad-spectrum coverage. Cefepime-induced neurotoxicity is a rare but serious side effect that has increased in recent years likely due to increased antibiotic use, increased drug resistance, and increased symptom recognition. While decreased glomerular filtration rate is an important risk factor for developing elevated serum cefepime levels, recent literature has suggested that a significant proportion of patients with normal renal function can also develop neurotoxicity from cefepime. Here, we present a case of cefepime-induced neurotoxicity to demonstrate the importance of monitoring mental status changes in all patients being treated with cefepime.

Infliximab for the treatment of patients with checkpoint inhibitor-associated acute tubular interstitial nephritis

Acute tubular interstitial nephritis (ATIN) is the most frequently reported pathology in patients with checkpoint inhibitor (CPI) induced acute kidney injury (AKI). Glucocorticoid (GC) therapy and discontinuation of CPI are the mainstay of treatment to prevent permanent renal dysfunction and dialysis. However, less than 50% of patients have complete kidney recovery and relapse of ATIN can occur. Infliximab is effective in treating other immune-related adverse events but its use for the treatment of CPI-ATIN is not well established. We report the first retrospective study examining the steroid-sparing potential of infliximab in achieving durable and complete renal recovery for patients with CPI-ATIN. Data were collected from medical records of patients diagnosed with CPI-AKI with a kidney biopsy or clinical diagnosis of ATIN that was managed with GC and infliximab. Infliximab-containing regimens were used to treat 10 patients with CPI-ATIN. Four patients relapsing after GC therapy achieved durable and complete renal recovery, four patients experienced partial renal recovery, and two patients showed no improvement in kidney function. This is the first study evaluating clinical outcomes using an infliximab-containing regimen for treatment of relapsed CPI-ATIN in patients or patients failing to achieve complete response after primary therapy. Our data suggest that infliximab may be a treatment option for achieving durable and complete renal recovery in this patient population and represents a potential steroid-sparing strategy in challenging cases of CPI-ATIN. Rigorous clinical studies are warranted to evaluate the risk-benefit analysis for infliximab usage in CPI-ATIN patients.

Acute interstitial nephritis and PR3-ANCA following reintroduction of pembrolizumab: a case report

Renal toxicity from immune checkpoint inhibitors (ICIs) is an increasingly recognized cause of acute kidney injury among patients with cancer. ICI-associated acute kidney injuries typically present as acute interstitial nephritis and the timing of onset is highly variable. Herein, we present a case of a patient with relapsed metastatic melanoma previously treated with pembrolizumab who developed grade 3 immune-related renal toxicity after reintroduction of the same ICI, secondary to acute interstitial nephritis with accompanying high PR3-antineutrophil cytoplasmic antibody titer. The patient improved after steroid treatment and discontinuation of pembrolizumab. This case highlights the importance of not excluding ICI-related nephrotoxicity as a possible cause of renal failure, including in those who previously tolerated ICI treatment, since it is a treatable entity.

Acute interstitial nephritis and nephrogenic diabetes insipidus following treatment with sulfamethoxazole-trimethoprim and temozolomide

We report a case of acute interstitial nephritis with associated nephrogenic diabetes insipidus in a patient treated with temozolomide and sulfamethoxazole-trimethoprim for glioblastoma multiforme. Kidney biopsy demonstrated focal tubulointerstitial change with tubular dilatation, epithelial change and interstitial inflammation. The patient's kidney function improved with cessation of sulfamethoxazole-trimethoprim and treatment with hydrochlorothiazide for nephrogenic diabetes insipidus. Recommencement of temozolomide did not result in further deterioration in kidney function. In this case report, we discuss the novel association between sulfamethoxazole-trimethoprim-induced acute interstitial nephritis and nephrogenic diabetes insipidus, and suggest possible mechanisms involved.

Renal Tubular Acidosis and Immune Checkpoint Inhibitor Therapy: An Immune-Related Adverse Event of PD-1 Inhibitor-A Report of 3 Cases

The main cause of acute kidney injury in patients receiving immune checkpoint inhibitors (ICIs) is acute interstitial nephritis. However, as their use continues to increase, other kidney manifestations are being described. We report 3 cases of patients treated with ICIs who developed predominantly electrolyte disorders secondary to renal tubular acidosis as an immune-related adverse event and discuss the potential mechanism. Nongap acidosis in combination with hypokalemia should raise suspicion for distal renal tubular acidosis in patients treated with ICIs.

Incidence and Clinical Features of Immune-Related Acute Kidney Injury in Patients Receiving Programmed Cell Death Ligand-1 Inhibitors

Background

Programmed cell death receptor ligand 1 (PD-L1) inhibitors are immune checkpoint inhibitors (ICIs) with a side effect profile that may differ from other classes of ICIs such as those directed against cytotoxic T-lymphocyte−associated protein 4 (CTLA-4) and programmed cell death 1 receptor (PD-1). Being the more recently approved class of checkpoint inhibitors, there are no studies investigating the frequency, etiology and predictors of acute kidney injury (AKI) in patients receiving PD-L1 inhibitors.

Methods

This was a retrospective cohort study of patients who received PD-L1 inhibitors during 2017 to 2018 in our healthcare system. AKI was defined by a ≥1.5-fold rise in serum creatinine from baseline. The etiology of all cases of sustained AKI (lasting >48 hours) and clinical course were determined by review of electronic health records.

Results

The final analysis included 599 patients. Within 12 months of ICI initiation, 104 patients (17%) experienced AKI, and 36 (6%) experienced sustained AKI; however, only 5 (<1%) experienced suspected PD-L1–related AKI. The PD-L1–related AKI occurred a median of 99 days after starting therapy. All patients concurrently received another medication known to cause acute interstitial nephritis (proton pump inhibitors, nonsteroidal anti-inflammatory drugs, or antibiotics) at the time of the suspected PDL1-related AKI.

Conclusion

Although AKI is common in patients receiving PD-L1 therapy, the incidence of suspected PD-L1–related AKI is low (<1%) and may be less common when compared to other classes of ICIs. This cohort provides further validation that other drugs associated with acute interstitial nephritis may be involved in the pathogenesis of ICI-related AKI.

Rifampin-Induced Acute Intravascular Hemolysis Leading to Heme Pigment-Related Kidney Injury

Rifampin-induced acute kidney injury is very rare. Most cases of acute renal injury from rifampin use are related to acute tubular necrosis and acute interstitial nephritis. In this case report, we detail a unique presentation of rifampin-associated acute intravascular hemolysis and subsequent tubular injury in a tuberculosis patient. The patient had presented to the hospital with acute kidney injury and oliguria from intravascular volume depletion secondary to intractable vomiting. The patient had stopped taking his antituberculosis medications two weeks before hospitalization. At the time of hospital admission, his antituberculosis regimen of rifampin and isoniazid was reinstituted. Within four days of initiation of rifampin, he developed acute hemolytic anemia. His kidney biopsy revealed hemoglobin pigment deposition in the kidney tubules. Rifampin was discontinued, and he received a total of eight hemodialysis treatments spanning over 17 days. Subsequently, after discontinuing rifampin, his anemia and oliguria resolved with renal function markedly improved to near normal baseline levels. This case report also offers a review of known mechanisms of rifampin-induced acute hemolysis and acute renal failure, along with a discussion of contemporary literature.

[Renal Monomorphology in COVID-19 with Acute Renal Insufficiency]

Renal Monomorphology in COVID-19 with Acute Renal Insufficiency Abstract. A 78-year-old ventilator-dependent COVID-19 patient developed severe renal failure with an estimated glomerular filtration rate of 20 ml/min per 1.73 m2 and nephrotic proteinuria. Sonography showed echo-dense and enlarged kidneys with high resistance indices (>0.8). Echocontrast sonography showed a delayed renal perfusion. In the further course of the disease renal function recovered, kidney size decreased and the renal perfusion normalized. An acute COVID-19-associated interstitial nephritis is postulated.

Megalin/lipoprotein receptor-related protein 2 autoimmunity and kidney disease

In this issue of Clinical Kidney Journal, Gamayo et al. describe two cases of anti-low-density lipoprotein receptor-related protein 2 (LRP2) nephropathy. This is a recently described entity that has features of both tubulointerstitial disease and segmental membranous nephropathy. The originality of the present report consists of the association of a disease thought to be rare (only 13 in prior described patients, 11 in the past year) with B-cell lymphoproliferative disease. Together with the finding of a third case among 224 elderly patients studied, this raises the issue of the underdiagnoses of LRP2 nephropathy, on top of the potential association to B-cell malignancy. We now put these findings in context within the wider frame of autoimmunity against megalin/LRP2 and related antigens such as Fx1A and CD69.

Characterization of acute kidney injury in critically ill patients with severe coronavirus disease 2019

BACKGROUND

Coronavirus disease 2019 (COVID-19)-associated acute kidney injury (AKI) frequency, severity and characterization in critically ill patients has not been reported.

METHODS

Single-centre cohort performed from 3 March 2020 to 14 April 2020 in four intensive care units in Bordeaux University Hospital, France. All patients with COVID-19 and pulmonary severity criteria were included. AKI was defined using Kidney Disease: Improving Global Outcomes (KDIGO) criteria. A systematic urinary analysis was performed. The incidence, severity, clinical presentation, biological characterization (transient versus persistent AKI; proteinuria, haematuria and glycosuria) and short-term outcomes were evaluated.

RESULTS

Seventy-one patients were included, with basal serum creatinine (SCr) of 69 ± 21 µmol/L. At admission, AKI was present in 8/71 (11%) patients. Median [interquartile range (IQR)] follow-up was 17 (12-23) days. AKI developed in a total of 57/71 (80%) patients, with 35% Stage 1, 35% Stage 2 and 30% Stage 3 AKI; 10/57 (18%) required renal replacement therapy (RRT). Transient AKI was present in only 4/55 (7%) patients and persistent AKI was observed in 51/55 (93%). Patients with persistent AKI developed a median (IQR) urine protein/creatinine of 82 (54-140) (mg/mmol) with an albuminuria/proteinuria ratio of 0.23 ± 20, indicating predominant tubulointerstitial injury. Only two (4%) patients had glycosuria. At Day 7 after onset of AKI, six (11%) patients remained dependent on RRT, nine (16%) had SCr >200 µmol/L and four (7%) had died. Day 7 and Day 14 renal recovery occurred in 28% and 52%, respectively.

CONCLUSION

Severe COVID-19-associated AKI is frequent, persistent, severe and characterized by an almost exclusive tubulointerstitial injury without glycosuria.