Radiation nephropathy: Dose, management, and population risk

Radiation nephropathy is renal injury caused by a sufficient dose of irradiation. It can result from external beam irradiation or internal irradiation as might occur from therapeutic radioisotopes. Its usual clinical presentation is as chronic kidney disease occurring some months after irradiation, and it can evolve to end-stage-renal-disease. While the immediate cellular injury from irradiation depends on radiolysis of water and oxidative DNA damage, there is no conclusive evidence for chronic persistent oxidative stress or inflammation as the cause of the multi-tissue scarring that ensues. Antagonists of the renin-angiotensin system are effective treatments for experimental radiation nephropathy but their preferential value in human clinical medicine is unproven.

Amyloid cast nephropathy: A rare presentation of multiple myeloma–associated light chain amyloidosis

Introduction: Monoclonal immunoglobulins can cause a variety of histologic patterns of kidney injury, depending on the physicochemical properties. Multiple myeloma manifests more often as light-chain nephropathy. On the other hand, light-chain amyloidosis leads to glomerular and vascular amyloid deposits, but a less common presentation with amyloid casts has also been described. Rarely, more than one histologic pattern can be present in the same patient. Case report: We report a case of a 73-year-old man, diagnosed with multiple myeloma that 8 months after achieving partial response to chemotherapy develops acute kidney injury and nephrotic syndrome. Kidney biopsy revealed features of light-chain nephropathy, amyloid cast nephropathy, and glomerular and vascular amyloid deposits. Immunofluorescence was positive for IgA (++) and lambda chains (+++) and negative for kappa chains. After the diagnosis of multiple myeloma-associated light-chain amyloidosis, chemotherapy was initiated; unfortunately, the patient died 1 month after the diagnosis. Conclusion: Amyloid casts, isolated or accompanied by other renal or extra-renal amyloid deposits, are another form of tubular toxicity caused by dysproteinemias and should be systematically screened in kidney biopsies.

Pregnancy associated atypical hemolytic uremic syndrome triggered by massive uterine bleeding after outpatient dilatation and evacuation

Background: Atypical Hemolytic Uremic Syndrome (aHUS) is a renal threatening multi-system disorder with significant hematologic findings of microangiopathic hemolytic anemia (MAHA) and thrombocytopenia. Early recognition and institution of late complement inhibitors can interrupt a cycle of progressive hemolysis and renal injury. Methods: We present an informative case of aHUS triggered by pregnancy termination. Diagnostic, laboratory, and treatment measures are reviewed. Results: Clinical evidence demonstrates immediate improvement in hemolysis, platelet consumption, and acute kidney injury following initiation of eculizumab. Conclusion: Pregnancy is a recognized trigger of aHUS and its proper management requires early recognition and institution of late complement blockade. Genetic testing can be sent for genetic counseling purposes, but initiation of treatment should neither await these results nor be discontinued when high-risk polymorphisms are absent.

A case of immune-complex mediated glomerulonephritis associated with pembrolizumab

Introduction: Immune checkpoint inhibitors (ICI) are changing the way we treat cancer. However, these novel agents have various systemic adverse events that may preclude its use and cause poor patient outcomes. ICI-associated acute kidney injury is an emerging complication of this treatment. While tubulointerstitial disease is the most common pathologic finding of patients with ICI-associated AKI, there is sparse data in medical literature describing its association with glomerular disease. Case report: Here, we present a patient with metastatic lung adenocarcinoma who developed acute kidney injury and significant proteinuria after receiving pembrolizumab. The kidney biopsy revealed a membranoproliferative and diffuse segmental endocapillary proliferative pattern of glomerular injury. Management and outcome: Pembrolizumab was then held and high-dose prednisone was initiated, resulting in a rapid and dramatic improvement in kidney function and proteinuria. Discussion: We highlight a report of a patient diagnosed with immune-complex mediated glomerulonephritis associated with the use of pembrolizumab, who was successfully treated with drug withdrawal and corticosteroids.

Thrombotic microangiopathy and smoldering multiple myeloma after kidney transplant in a patient with MCP mutation

The most frequent cause of atypical hemolytic uremic syndrome (aHUS) is defective regulation of complement activation because of genetic anomalies. We present the case of 53-year-old man with a kidney transplant and stabilized kidney function (creatinine 2.5 mg/dL; proteinuria 0.4 g/24 h) with mycophenolate/tacrolimus/prednisone who was diagnosed of Thrombotic Microangiopathy (TMA). This diagnosis was associated with creatinine and proteinuria rise (3 mg/dL; 2.4 g/24 h) and a new monoclonal IgA/lambda component. Renal biopsy showed membranoproliferative glomerulonephritis; a pathogenic variant in the Membrane cofactor protein (MCP) gene with a polymorphism ggaac, typically associated to secondary aHUS, was identified. We suspected that immunoglobulin could be acting as a trigger for TMA in a genetically susceptible patient, so “clone-directed” therapy with bortezomib and dexamethasone was initiated.

Scleroderma renal crisis in a patient with paraneoplastic systemic sclerosis

The incidence of malignancy is increased in systemic sclerosis (SS). Nevertheless, only a few cases of paraneoplastic SS (pSS) have been described. Scleroderma renal crisis is an uncommon but severe complication of SS, with acute kidney failure, abrupt onset of hypertension and microangiopathy. We present the case of a previously healthy patient who was diagnosed with ovarian carcinoma and underwent chemotherapy with carboplatin and paclitaxel. In association with the cancer, she developed SS and scleroderma renal crisis. She received initial supportive treatment, but her renal function worsened, and she started on hemodialysis. Furthermore, she received adjuvant surgical treatment for the cancer. Eighty-four days after cytoreductive surgery, her renal function recovered, and her SS manifestations improved.

Paraneoplastic tubulointerstitial nephritis exacerbated by immune checkpoint inhibitor

Background: With the expanding indications and thus broader use of immune checkpoint inhibitors, clinicians are faced with a new kind of immune-related adverse events. Because of their immune modulating effects, immune checkpoint inhibitors have the potential to worsen autoimmunity in general. Paraneoplastic syndromes can be caused by tumor-induced autoimmune mechanisms. The use of immune-activating substances such as checkpoint inhibitors might lead to exacerbation of paraneoplastic syndromes causing premature discontinuation of the immunotherapy. Case presentation: We report on a 64-year-old patient with metastasized renal cell carcinoma who developed acute kidney failure after cytoreductive nephrectomy. Work-up revealed a paraneoplastic syndrome that caused tubulointerstitial nephritis (TIN). Glucocorticoid therapy successfully reversed the acute kidney injury. However, adjuvant therapy with Nivolumab provoked a flare-up of the paraneoplastic syndrome on two occasions, eventually leading to a treatment discontinuation. Conclusions: Many cases of Nivolumab-induced TIN have been described lately. However, our case demonstrates therapy failure due to a flare-up of a pre-existing paraneoplastic syndrome of the renal cancer. Against this background, it can only be speculated that some of the TIN cases discussed in prior literature might also have been flare-ups of subclinical autoimmunity.

177Lu-dotatate use in chronic kidney disease patients: A single center experience

Background: Peptide receptor radionuclide therapy with 177Lu-dotatate is a novel therapy for metastatic neuroendocrine cancers. It undergoes reabsorption at the proximal tubule; after the breakdown of the peptide fragment, 177Lu is retained and continues its decay process exposing the nephron to continuous low dose radiation. Pivotal NETTER-1 trial did not include patients with eGFR <50 and so its effects in CKD patients is not known. Methods: We performed a retrospective chart review of all consecutive adult patients that received 177Lu-dotatate over 1 year at Mayo Clinic, Rochester. We analyzed renal and hematological laboratory data obtained prior to each of four treatment cycles and at 3- and 6-month post completion of all treatment. We defined CKD as eGFR <60 ml/min and AKI as creatinine increase of ⩾0.3 from baseline by AKIN criteria. Results: Overall 86 patients were included in the study with 39 (45%) with known CKD. About three patients had CKD, four with eGFR of 20–30 ml/min. About 4 (4.6%) patients had AKI and the predominant cause being hypotension. Among the CKD patients the average eGFR improved after the first cycle of PRRT therapy from baseline of 49 (13) to 53.5 (17) ml/min ( p = 0.01) with no significant decline of renal function noted at 3- and 6-months post treatment follow up. Rate of thrombocytopenia and leukopenia were significantly more in the CKD patients starting even after single treatment. No drug dose correlation was noted. Conclusion: Patients with CKD are at a higher risk of hematological toxicity especially with thrombocytopenia and require close monitoring and ongoing dose adjustment. Ongoing safety studies to assess the long-term impact of 177Lu-dotatate on the kidney are needed.

Avoiding immunogenic drugs is key to preserve renal function in patients receiving immune checkpoint inhibitors: Lessons learned from three illustrative cases

Background: In the recent years, new immunotherapy agents are showing promising results in the treatment of cancer. Immune checkpoint inhibitors (ICI), which block neoplasm-induced lymphocyte inhibition and enhance cancer immunosurveillance mechanisms, are associated to acute tubulointerstitial nephritis (ATIN). The mechanisms of this adverse effect are debated. Methods: We present a three-case series of ATIN in the setting of ICI therapy managed in our Nephrology department. We detail the clinical course of the episodes, emphasizing on the concomitant medications administered. We also conducted a literature review of the altered drug immunogenicity in patients under immunotherapy drugs. Results: The three reported ATIN cases illustrate closer temporal association with the concomitant medication rather than the ICI itself. This suggests a scenario where the tolerance to previously accepted drugs seems to be lost. Moreover, one of the patients presented an ATIN flare after ICI discontinuation, suggesting an state of leukocyte hyperactivation. Conclusions: Unraveling the exact patho-mechanisms by which ICI-related ATIN occurs will allow the prevention of the development of this side effect and determine whether ICI re-challenge in patients previously affected by ICI-ATIN is safe.

Renal cell carcinoma with malignant pleural effusion: Case report and systematic review of literature

Introduction: Renal cell carcinoma metastasizes commonly to visceral organs such as adrenals, liver, lungs, or to bones. Metastases to body cavities such as pleura, pericardium and peritoneum are rare, and almost never in isolation. Case discussion: We discuss here a patient who was diagnosed with renal cell carcinoma following an episode of hematuria and underwent radical nephrectomy for the same. Within a month of surgery, he was evaluated for sudden onset breathlessness and detected to have massive left-sided pleural effusion, which returned malignant on pleural biopsy. The patient was treated with oral multikinase inhibitor following symptomatic therapy, with a favorable response. The imaging findings and relevant literature exploring the incidence of such presentations are discussed. Conclusion: Malignant effusions usually portend a poor prognosis but owing to the rarity of this condition and availability of newer therapies, long-term durable control may be expected.