Paraprotein-Related Kidney Disease: Evaluation and Treatment of Myeloma Cast Nephropathy

Renal outcome in multiple myeloma patients with cast nephropathy: a retrospective analysis of potential predictive values on clinical and renal outcome

OBJECTIVE

Cast nephropathy (CN) is the leading cause of acute kidney injury (AKI) in multiple myeloma (MM). Since it is sparsely documented why some patients with CN do achieve a renal response while others do not, we describe a single-center cohort of patients with multiple myeloma and biopsy-confirmed CN to evaluate potential markers of renal response.

METHODS

The data was collected as a retrospective, single-center analysis of CN-patients treated at the Medical University Vienna between 01/01/2004 and 01/01/2022. Baseline parameters and clinical outcome was compared between renal responders and non-responders.

RESULTS

Among 28 patients with CN, n = 23 were assessed for renal response (14 responders; 9 non-responders). Renal responders were younger (median age: 61 years; 77 years, p = 0.039), showed higher overall survival (153months; 58months, p = 0.044) and achieved hematologic response (≥PR) to first-line therapy (p = 0.029), and complete hematologic response (CR) at any time (p = 0.025) significantly more often. Further, we could show that rapid initiation of anti-myeloma therapy after initial presentation correlated significantly with renal response (median 9 days; 27 days, p = 0.016). Analyses of kidney biopsy specimens revealed that patients with a high IF/TA score showed end stage renal disease (dialysis ≥ 3 months) significantly more often (p = <0.001).

DISCUSSION

In summary, our data suggests, that a rapid start with systemic hematologic treatment in patients with MM and CN is crucial and achieving an early hematologic response is important for renal recovery. Moreover, achieving a deep hematologic response and subsequent renal recovery improves clinical outcome as reflected by an overall survival benefit.

Crystalline Light Chain Casts and Hypercalcemia Induced Acute Kidney Injury: A Rare Presentation of Multiple Myeloma

The most common cause of acute kidney injury (AKI) in multiple myeloma is light-chain cast nephropathy (LCCN), which consists of a light chain and Tamm-Horsfall protein (THP). We herein report a 46-year-old woman with hypercalcemia and AKI. A renal biopsy showed crystalline casts, which were consistent with lambda light chains but not THP. Hydration therapy and treatment to lower her serum calcium concentration were initiated immediately. She subsequently received bortezomib-based anti-myeloma therapy and recovered successfully. This was a rare case of LCCN, suggesting that hypercalcemia may play a role in the development of crystalline LCCN.

Acute kidney injury in bortezomib-treated patients with multiple myeloma

BACKGROUND

The nephrotoxicity of bortezomib, a proteasome inhibitor, has not yet been elucidated, although tumor lysis syndrome (TLS) associated with multiple myeloma (MM) has been reported to increase after introduction of the drug. This study compared the incidence and risk factors for acute kidney injury (AKI) and TLS in patients with MM after bortezomib-based chemotherapy to investigate drug-related nephrotoxicity.

METHODS

From 2006 to 2017, 276 patients who underwent a first cycle of bortezomib-based chemotherapy for MM were identified in a single tertiary hospital. Laboratory TLS was defined according to the Cairo-Bishop definition. Development of AKI was assessed by AKI Network criteria within 7 days of the first chemotherapy.

RESULTS

The median (interquartile range) age was 65 (56-72) years, and baseline estimated glomerular filtration rate (eGFR) was 61.3 (34.1-89.1) mL/min/1.73 m2. The incidences of AKI and laboratory TLS were 17% (n = 47) and 13% (n = 36), respectively. Ten (3.6%) subjects met both AKI and TLS criteria. Multivariate analyses showed that lower eGFR category [30-59, odds ratio (OR) 3.005 (95% confidence interval 1.163-7.976); 15-29, OR 4.225 (1.183-15.000); <15, OR 16.154 (3.831-70.920) vs ≥60, P < .001], lower serum albumin level [per 1 increase, OR 0.479 (0.256-0.871), P = .018], renal amyloidosis [OR 13.039 (4.108-44.041), P < .001] and use of acyclovir during bortezomib treatment [OR 3.689 (1.133-14.469), P = .042] were predictors of AKI. MM stages and β-2-microglobulin were not associated with increased risk of AKI. Regarding laboratory TLS, MM stage and β-2-microglobulin were higher in those with TLS than in others. In multivariate analyses, β-2-microglobulin level [OR 1.204 (1.005-1.461), P = .038] and absence of high-risk chromosome abnormalities [OR 0.143 (0.022-0.588), P = .016] were associated with higher risk of TLS.

CONCLUSIONS

Development of AKI was often observed in the absence of TLS in patients with MM after treatment with bortezomib. In addition, the risk factors for AKI and TLS varied widely. These findings indicate the potential nephrotoxicity of bortezomib irrespective of TLS in patients with decreased kidney function.

The mechanisms of alkali therapy in targeting renal diseases

Chronic kidney disease (CKD) is characterized by progressive reduction in kidney function and treatments aiming at stabilizing or slowing its progression may avoid or delay the necessity of kidney replacement therapy and the increased mortality associated with reduced kidney function. Metabolic acidosis, and less severe stages of the acid stress continuum, are common consequences of CKD and some interventional studies support that its correction slows the progression to end-stage kidney disease. This correction can be achieved with mineral alkali in the form of bicarbonate or citrate salts, ingestion of diets with fewer acid-producing food components or more base-producing food components, or a pharmacological approach. In this mini-review article, we summarize the potential mechanisms involved in the beneficial effects of alkali therapy. We also discuss the perspectives in the field and challenges that must be overcome to advance our understanding of such mechanisms.

Light Chain Restriction in Proximal Tubules-Implications for Light Chain Proximal Tubulopathy

Monoclonal gammopathy (MG) causes various nephropathies, which may suffice for cytoreductive therapy even in the absence of diagnostic criteria for multiple myeloma or B-cell non-Hodgkin lymphoma. The aim of this study was to better understand the significance of light chain (LC) restriction or crystals (LC-R/C) in proximal tubules in the spectrum of LC-induced nephropathies. A consecutive cohort of 320 renal specimens with a history of B-cell dyscrasia was characterized. Special attention was paid to immunohistochemical LC restriction in proximal tubules, tubular crystals or constipation, and ultrastructural findings. Complementary cell culture experiments were performed to assess the role of LC concentrations in generating LC restriction. Light chain restriction or crystals in proximal tubules was found in a quarter of analyzed cases (81/316) and was associated with another LC-induced disease in 70.4% (57/81), especially LC cast-nephropathy (cast-NP) and interstitial myeloma infiltration. LC restriction without significant signs of acute tubular injury was observed in 11.1% (9/81). LC-R/C was not associated with inferior renal function compared to the remainder of cases, when cases with accompanying cast-NP were excluded. Besides crystals, cloudy lysosomes were significantly associated with LC-R/C on an ultrastructural level. In summary, LC-R/C is frequent and strongly associated with cast-NP, possibly indicating that a high load of clonal LC is responsible for this phenomenon, supported by the observation that LC restriction can artificially be generated in cell culture. This and the lack of significant tubular injury in a subgroup imply that in part LC-R/C is a tubular trafficking phenomenon rather than an independent disease process.

Unusual cause of light chain cast nephropathy

Acute kidney injury due to light chain cast nephropathy is increasingly recognised in patients with haematological malignancies; however, the management and prognosis of this disease remain poorly understood. We describe a case of a 78-year-old woman with known chronic lymphocytic leukaemia (CLL) who presented with fatigue and weight loss. She was found to have acute kidney injury, which rapidly worsened during admission. Kidney biopsy showed light chain cast nephropathy and bone marrow biopsy confirmed B-cell CLL. She was started on ibrutinib, halting further deterioration in her renal function and avoiding renal replacement therapy in the first 8 months.

Recent Advances of Acute Kidney Injury in Hematopoietic Cell Transplantation

Acute kidney injury (AKI) is a common complication of allogeneic hematopoietic cell transplantation (allo-HCT) and is associated with non-relapse mortality (NRM) and quality of life (QOL). Multiple factors may contribute to AKI during allo-HCT and are often present at the same time making it difficult to determine the cause of AKI in each patient. Nephrotoxic drugs, infections, thrombotic microangiopathy (TMA), and sinusoidal obstruction syndrome (SOS) are well described causes of AKI during allo-HCT. Acute graft-versus-host disease (aGVHD) is a major complication of allo-HCT that mainly targets the intestines, liver, and skin. However, recent studies suggest aGVHD may also attack the kidney and contribute to AKI following allo-HCT. For example, severe aGVHD is associated with AKI, suggesting a link between the two. In addition, animal models have shown donor immune cell infiltration and increased expression of inflammatory cytokines in recipient kidneys after allo-HCT. Therefore, aGVHD may also target the kidney and contribute to AKI following allo-HCT. Herein, we describe the etiology, diagnosis, risk factors, pathophysiology, prevention, and treatment of renal injury after allo-HCT. In addition, we highlight emerging evidence that aGVHD may contribute to the development of AKI after allo-HCT.

Monoclonal Gammopathy-Related Kidney Diseases

Monoclonal gammopathies occur secondary to a broad range of clonal B lymphocyte or plasma cell disorders, producing either whole or truncated monoclonal immunoglobulins. The kidneys are often affected by these monoclonal proteins, and, although not mutually exclusive, can involve the glomeruli, tubules, interstitium, and vasculature. The nephrotoxic potential of these monoclonal proteins is dependent on a variety of physicochemical characteristics that are responsible for the diverse clinicopathologic manifestations, including glomerular diseases with organized deposits, glomerular diseases with granular deposits, and other lesions, such as C3 glomerulopathy and thrombotic microangiopathy with unique pathophysiologic features. The diseases that involve primarily the tubulointerstitial and vascular compartments are light chain cast nephropathy, light chain proximal tubulopathy, crystal-storing histiocytosis, and crystalglobulin-induced nephropathy with distinct acute and chronic clinicopathologic features. The diagnosis of a monoclonal gammopathy-related kidney disease is established by identification of an underlying active or more commonly, low-grade hematologic malignancy, serologic evidence of a monoclonal gammopathy when detectable, and most importantly, monoclonal protein-induced pathologic lesions seen in a kidney biopsy, confirming the association with the monoclonal protein. Establishing a diagnosis may be challenging at times, particularly in the absence of an overt hematologic malignancy, with or without monoclonal gammopathy, such as proliferative glomerulonephritis with monoclonal immunoglobulin deposits. Overall, the treatment is directed against the underlying hematologic disorder and the potential source of the monoclonal protein.

Renal Impairment Detectors: IGFBP-7 and NGAL as Tubular Injury Markers in Multiple Myeloma Patients

Background and Objectives: Urine insulin-like growth factor-binding protein 7 (IGFBP-7), tissue inhibitor of matrix metalloproteinase 2 (TIMP-2), and neutrophil gelatinase-associated lipocalin (NGAL) monomer are novel tubular kidney injury biomarkers. In multiple myeloma (MM), immunoglobulin free light chains (FLCs) play an integral role in renal impairment. This study aimed to investigate the correlation between new biomarkers and acclaimed parameters of renal failure, MM stage, and prognosis. Materials and Methods: The examined parameters included: urinary and serum cystatin-C, IGFBP-7, and TIMP-2, and urinary NGAL monomer in 124 enrolled patients. Results: Urinary and serum IGFBP-7 and urinary NGAL were higher among patients with an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2, and positively correlated with urine light chains. Serum and urine IGFBP-7 and urine NGAL were greater among patients with a higher disease stage. In the whole study group, urinary concentrations of the studied markers were positively correlated with each other. In multiple linear regression, urinary IGFBP-7 and NGAL were associated with lower eGFR, independently of other urinary markers. Conclusions: Urinary IGFBP-7 and NGAL monomer may be useful markers of tubular renal damage in patients with MM. Biomarker-based diagnostics may contribute to earlier treatment that may improve renal outcomes and life expectancy in MM.

Light Chain Multiple Myeloma: High Serum Free Light Chain Concentrations Portend Renal Damage and Poorer Survival

BACKGROUND

Monoclonal immunoglobulins provide an indication of the tumor burden in patients with plasma cell neoplasms. Higher concentrations of serum free light chains in light chain predominant multiple myeloma have been shown to correlate with a poorer outcome. We examined the correlations of serum free light chain concentrations in light chain myelomas with survival, estimated glomerular filtration rate (eGFR) and other clinical and pathological parameters.

METHODS

Records of patients with light chain multiple myelomas were reviewed. Highest concentration of serum free light chains for each patient were plotted to ascertain an inflection/change point. Survival, eGFR, and other clinical and pathological parameters were compared between the low and high light chain concentration groups.

RESULTS

Plotting serum free light chain concentrations revealed an inflection point at a concentration of 455 mg/L apportioning patients in to 2 subgroups: 39 patients with low light chain concentrations and 26 patients with high concentrations. The high concentration group had more unfavorable pathology in bone marrow examination in terms of higher neoplastic plasma cell burden and high-risk cytogenetics. The survival rate and eGFR in the high concentration group were significantly worse than in the low concentration group.

CONCLUSIONS

As noted for light chain predominant multiple myeloma, high serum free light chain concentration in light chain multiple myelomas are associated with higher renal disease burden and shorter survival. Monitoring of serum free light chain concentrations and customizing treatments to address this parameter are warranted.

Choosing a CRRT machine and modality

Expanded use and steady improvements in continuous renal replacement techniques (CRRT) have enhanced the safety of the application of kidney replacement therapy (KRT) to hemodynamically unstable intensive care unit (ICU) patients. The longer duration of therapy and the personalized prescription provided by continuous therapies are associated with greater hemodynamic stability and a modestly higher likelihood of kidney recovery than standard intermittent hemodialysis (IHD). Studies designed to evaluate the effect on mortality over intermittent therapies lack evidence of benefit. A lack of standardization and considerable variation in how CRRT is performed leads to wide variation in how the technique is prescribed, delivered, and optimized. Technology has progressed in critical care nephrology, and more progress is coming. New CRRT machines are equipped with a friendly user interface that allows easy performance and monitoring, permitting outcome measurements and improved patient quality control. This review discusses the key concepts necessary to guide nephrologists to prescribe and deliver KRT to critically ill ICU patients.

Acute kidney injury in cancer patients

OBJECTIVE

We want to know the causes of AKI in oncology patients, including disease-related complications and the nephrotoxicity of chemotherapy drugs, in order to provide more useful clinical information.

METHODS

In this review, an electronic search of the English language literature was performed in the database PubMed, with the results enriched by manual searches and citation mining, factors investigated in the selected articles included acute kidney injury, oncology, chemotherapy, anticancer drug, antitumor drug.

RESULTS

According to the searched articles, we summarized the causes (including pre-renal, intrinsic renal, and post-renal lesion) of AKI in cancer patients and the corresponding management measures. Among the pre-renal factors we mainly described hypercalcemia, hematopoietic cell transplantation, post-renal factors we mainly described hemorrhagic cystitis, and intrinsic renal factors we mainly described thrombotic microangiopathy, chemotherapeutics, tumor lysis syndrome, cast nephropathy, in which the emphasis was on chemotherapy drug associated AKI and its treatment.

CONCLUSIONS

AKI is not uncommon in cancer patients, and has diverse causes and negative outcomes. Both nephrologists and oncologists need to be aware of the unique reasons of AKI in this population and its optimal management.

Light Chain-Predominant Multiple Myeloma Subgroup: Impaired Renal Function Correlates with Decreased Survival

OBJECTIVE

Patients with light chain-predominant multiple myeloma have been shown to exhibit shorter survival. Retrospective comparison of clinical and laboratory data was undertaken to ascertain the likely cause(s) of this observation.

METHODS

Records of patients with multiple myeloma seen at 1 institution revealed 316 patients with conventional and 71 patients with light chain-predominant multiple myelomas with secretion of intact immunoglobulins. Laboratory and clinical findings in the 2 groups were compared.

RESULTS

Patients with light chain-predominant multiple myeloma had a significantly higher death rate, a higher rate of chronic dialysis, a lower estimated glomerular filtration rate and serum albumin, a significantly higher urine protein concentration, and a significantly higher prevalence of hypertension and blood transfusion requirements. Other clinical and laboratory parameters surveyed were not significantly different between the 2 groups.

CONCLUSION

The shorter survival of patients with light chain-predominant multiple myeloma is clearly associated with renal damage caused by excess free immunoglobulin light chains. Renal damage may be ameliorated by early aggressive treatment with chemotherapy, plasmapheresis, and dialysis; a multi-institutional prospective controlled trial would be needed to test this hypothesis.

Clinicopathological characteristics of patients with paraproteinemia and renal damage

Background

This study aimed to analyze the clinicopathological characteristics of patients with paraproteinemia and renal damage.

Methods

Ninety-six patients from 2014 to 2018 with paraproteinemia and renal damage were enrolled and the clinical data, renal pathology, treatment and prognosis data were collected.

Results

A total of 96 patients (54 male and 42 female), accounting for 2.7% of all renal biopsies, were enrolled in this study. Among them, 42 were monoclonal gammopathy of renal significance (MGRS), 21 were renal monotypic immunoglobulin alone (renal monoIg), and 19 were monoclonal gammopathy of undetermined significance (MGUS). Individuals with multiple myeloma (MM) accounted for the fewest number of patients (n  =  14). In the MGRS group, the main diseases were amyloidosis (n  =  25) and cryoglobulinemic glomerulonephritis (n  =  7), while in the MM group, the main diseases were cast nephropathy (n  =  9) and light chain deposit disease (n  =  3). In the MGUS group, it was mainly IgA nephropathy (IgAN, n  =  10) and idiopathic membranous nephropathy (n  =  5); while in the renal monoIg group, most of the cases were IgAN (n  =  19). Chemotherapy was mainly administered to patients in the MM group, while immunosuppression therapy was mostly administered to patients in the renal monoIg group. Most patients with renal monoIg exhibited a major response, followed by the patients with MGUS and MGRS, while most of the patients with MM had a partial response but none had a major response. Approximately more than half (57.1%) of the patients with MM progressed to end-stage renal disease (ESRD), followed by MGRS (33.3%); however, the mortality rate was low in both the MGRS and MM groups. The survival analysis reviewed that serum creatinine, hemoglobin levels, and the serum κ/λ ratio were independent risk factors for ESRD in patients with MGRS.

Conclusions

The clinicopathological changes in patients with MGRS were between those in patients with MM and MGUS. The treatment for MGRS and MM was more intensive, and the overall mortality rate was low. Both MGUS and renal monoIg alone exhibited slighter clinicopathological features than MGRS and MM, and the treatment was focused mostly on primary renal diseases.

Clinicopathological features and outcomes of coexistent light chain cast nephropathy and light chain deposition disease in patients with newly diagnosed multiple myeloma

AIMS

A varying proportion of patients with multiple myeloma suffer from more than one type of kidney disease simultaneously, of which the most common pattern is coexistent light chain cast nephropathy and light chain deposition disease (LCCN+LCDD). We investigated clinicopathological characteristics and outcomes of LCCN+LCDD in comparison with pure LCCN and pure LCDD.

METHODS

We retrospectively analysed 45 newly diagnosed multiple myeloma patients with pure LCCN (n=26), LCCN +LCDD (n=9) and pure LCDD (n=10) between 2000 and 2019 at Peking University First Hospital.

RESULTS

Pathologically, patients with LCCN+LCDD were more likely to have λ light chain isotype and presented atypical features of LCDD including less nodular glomerulosclerosis and less deposit distribution than patients with pure LCDD. In clinical characteristics, patients with LCCN +LCDD and patients with pure LCCN shared similar features. The death-censored renal survival in patients with LCCN +LCDD was similar to patients with pure LCCN but worse than patients with pure LCDD, but the overall survival was much better than patients with LCCN alone and similar to patients with pure LCDD. For patients with pure LCCN, the independent predictor of death-censored renal survival was lactate dehydrogenase, and the independent predictors of overall survival were the mean number of casts and serum albumin.

CONCLUSIONS

Patients with LCCN+LCDD had similar renal outcome compared with patients with pure LCCN but the overall survival is much better. Thus, for patients with LCCN, especially those with λ restriction, pathologists should carefully evaluate the kidney specimens to exclude the possibility of combined LCDD.

Kinetics of Renal Function during Induction in Newly Diagnosed Multiple Myeloma: Results of Two Prospective Studies by the German Myeloma Study Group DSMM

Simple Summary

Renal insufficiency is frequently seen in newly diagnosed multiple myeloma and can be due to the disease itself but also caused by medical interventions or infections. Patients with severe renal insufficiency are known to have an adverse prognosis, but recently, it was shown that even moderately impaired kidney function can have long-term sequelae. Achieving quick disease control by effective antimyeloma therapy can lead to the recovery of renal function. We investigated the kidney-specific variables in a large cohort of 770 myeloma patients receiving three different three-drug regimens for initial myeloma treatment to learn more about the differential effects on kidney function in an early disease phase. All regimens had a positive impact on kidney function without a difference in the proportion of patients who reached normal renal function after three cycles. Interestingly, patients who received bortezomib, lenalidomide, and dexamethasone tended to have higher risk for a worse renal function following induction when compared to the initial values.

Abstract

Background: Preservation of kidney function in newly diagnosed (ND) multiple myeloma (MM) helps to prevent excess toxicity. Patients (pts) from two prospective trials were analyzed, provided postinduction (PInd) restaging was performed. Pts received three cycles with bortezomib (btz), cyclophosphamide, and dexamethasone (dex; VCD) or btz, lenalidomide (len), and dex (VRd) or len, adriamycin, and dex (RAD). The minimum required estimated glomerular filtration rate (eGFR) was >30 mL/min. We analyzed the percent change of the renal function using the International Myeloma Working Group (IMWG) criteria and Kidney Disease: Improving Global Outcomes (KDIGO)-defined categories. Results: Seven hundred and seventy-two patients were eligible. Three hundred and fifty-six received VCD, 214 VRd, and 202 RAD. VCD patients had the best baseline eGFR. The proportion of pts with eGFR <45 mL/min decreased from 7.3% at baseline to 1.9% PInd (p < 0.0001). Thirty-seven point one percent of VCD versus 49% of VRd patients had a decrease of GFR (p = 0.0872). IMWG-defined “renal complete response (CRrenal)” was achieved in 17/25 (68%) pts after VCD, 12/19 (63%) after RAD, and 14/27 (52%) after VRd (p = 0.4747). Conclusions: Analyzing a large and representative newly diagnosed myeloma (NDMM) group, we found no difference in CRrenal that occurred independently from the myeloma response across the three regimens. A trend towards deterioration of the renal function with VRd versus VCD may be explained by a better pretreatment “renal fitness” in the latter group.

Onconephrology

Current advances in cancer chemotherapeutics have remarkably helped in rapid and definitive treatment options. However, these potent chemotherapeutics have been associated with severe renal toxicities that later impact treatment options. Acute kidney injury is common in patients with cancer. In hospitalized patients with cancer, acute kidney injury is associated with increased morbidity, mortality, length of stay, and costs. This article provides an overview of acute kidney injury caused by cancer or its treatment, including prerenal, tubular, glomerular diseases, infiltrative disease, tumor lysis syndrome, anticancer drug nephrotoxicity, hematopoietic stem cell transplantation-related acute kidney injury, and cancer-associated thrombotic microangiopathy.

Preventive strategies for acute kidney injury in cancer patients

Acute kidney injury (AKI) is a common complication of cancer that occurs in up to 50% of neoplastic patients during the natural history of their disease; furthermore, it has a huge impact on key outcomes such as overall prognosis, length of hospitalization and costs. AKI in cancer patients has different causes, either patient-, tumour- or treatment-related. Patient-related risk factors for AKI are the same as in the general population, whereas tumour-related risk factors are represented by compression, obstruction, direct kidney infiltration from the tumour as well by precipitation, aggregation, crystallization or misfolding of paraprotein (as in the case of multiple myeloma). Finally, treatment-related risk factors are the most common observed in clinical practice and may present also with the feature of tumour lysis syndrome or thrombotic microangiopathies. In the absence of validated biomarkers, a multidisciplinary clinical approach that incorporates adequate assessment, use of appropriate preventive measures and early intervention is essential to reduce the incidence of this life-threatening condition in cancer patients.

Development of a clinical diagnostic tool to differentiate multiple myeloma from bone metastasis in patients with destructive bone lesions (MM-BM DDx)

BACKGROUND

Most patients with destructive bone lesions undergo a comprehensive diagnostic procedure to ensure that proper treatment decisions are pursued. For patients with multiple myeloma, this can lead to delays in diagnosis and treatment initiation. This study was conducted to develop a diagnostic rule that could serve as a tool for early identification of multiple myeloma and promote timely referral of patients to haematologists.

METHODS

The clinical prediction rule was developed using a retrospective case-series of patients with multiple myeloma (MM) and those with bone metastasis (BM) at Chiang Mai University Hospital from 2012 to 2015. Multivariable fractional polynomial logistic regression was used to derive a diagnostic model to differentiate between MM and BM patients (MM-BM DDx).

RESULTS

A total of 586 patients (136 MM patients and 450 BM patients) were included. Serum creatinine, serum globulin, and serum alkaline phosphatase were identified as significant indicators for the differentiation of MM and BM patients. The MM-BM DDx model showed excellent discriminative ability [AuROC of 0.90 (95%CI 0.86 to 0.93)] and good calibration.

CONCLUSIONS

This MM-BM DDx model could potentially allow for early myeloma diagnosis and improvement of overall prognosis. A prospective validation study is needed to confirm the accuracy of the MM-BM DDx model prior to its application in clinical practice.

Acute Kidney Injury in Patients Receiving Systemic Treatment for Cancer: A Population-Based Cohort Study

BACKGROUND

Patients undergoing treatment for cancer are at increased risk of acute kidney injury (AKI). There are few data on AKI incidence and risk factors in the current era of cancer treatment.

METHODS

We conducted a population-based study of all patients initiating systemic therapy (chemotherapy or targeted agents) for a new cancer diagnosis in Ontario, Canada (2007-2014). The primary outcome was hospitalization with AKI or acute dialysis. We estimated the cumulative incidence of AKI and fitted Fine and Gray models, adjusting for demographics, cancer characteristics, comorbidities, and coprescriptions. We modeled exposure to systemic therapy (the 90-day period following treatments) as a time-varying covariate. We also assessed temporal trends in annual AKI incidence.

RESULTS

We identified 163 071 patients initiating systemic therapy of whom 10 880 experienced AKI. The rate of AKI was 27 per 1000 person-years, with overall cumulative incidence of 9.3% (95% CI = 9.1% to 9.6%). Malignancies with the highest 5-year AKI incidence were myeloma (26.0%, 95% CI = 24.4% to 27.7%), bladder (19.0%, 95% CI = 17.6% to 20.5%), and leukemia (15.4%, 95% CI = 14.3% to 16.5%). Advanced cancer stage, chronic kidney disease, and diabetes were associated with increased risk of AKI (adjusted hazard ratios [aHR] = 1.41, 95% CI = 1.28 to 1.54; 1.80, 95% CI = 1.67 to 1.93; and 1.43, 95% CI = 1.37 to 1.50, respectively). In patients aged 66 years or older with universal drug benefits, diuretic, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker coprescription was associated with higher AKI risk (aHR = 1.20, 95% CI = 1.14 to 1.28; 1.30, 95% CI = 1.23 to 1.38). AKI risk was further accentuated during the 90-day period following systemic therapy (aHR = 2.34, 95% CI = 2.24 to 2.45). The annual incidence of AKI increased from 18 to 52 per 1000 person-years between 2007 and 2014.

CONCLUSION

Cancer-related AKI is common and associated with advanced stage, chronic kidney disease, diabetes, and concomitant receipt of diuretics or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Risk is heightened in the 90 days after systemic therapy. Preventive strategies are needed to address the increasing burden of AKI in this population.

Clinicopathologic predictors of renal outcomes in light chain cast nephropathy: a multicenter retrospective study

Light chain cast nephropathy (LCCN) in multiple myeloma often leads to severe and poorly reversible acute kidney injury. Severe renal impairment influences the allocation of chemotherapy and its tolerability; it also affects patient survival. Whether renal biopsy findings add to the clinical assessment in predicting renal and patient outcomes in LCCN is uncertain. We retrospectively reviewed clinical presentation, chemotherapy regimens, hematologic response, and renal and patient outcomes in 178 patients with biopsy-proven LCCN from 10 centers in Europe and North America. A detailed pathology review, including assessment of the extent of cast formation, was performed to study correlations with initial presentation and outcomes. Patients presented with a mean estimated glomerular filtration rate (eGFR) of 13 ± 11 mL/min/1.73 m2, and 82% had stage 3 acute kidney injury. The mean number of casts was 3.2/mm2 in the cortex. Tubulointerstitial lesions were frequent: acute tubular injury (94%), tubulitis (82%), tubular rupture (62%), giant cell reaction (60%), and cortical and medullary inflammation (95% and 75%, respectively). Medullary inflammation, giant cell reaction, and the extent of cast formation correlated with eGFR value at LCCN diagnosis. During a median follow-up of 22 months, mean eGFR increased to 43 ± 30 mL/min/1.73 m2. Age, β2-microglobulin, best hematologic response, number of cortical casts per square millimeter, and degree of interstitial fibrosis/tubular atrophy (IFTA) were independently associated with a higher eGFR during follow-up. This eGFR value correlated with overall survival, independently of the hematologic response. This study shows that extent of cast formation and IFTA in LCCN predicts the quality of renal response, which, in turn, is associated with overall survival.

A practical approach to the pathology of renal intratubular casts

The identification and proper characterization of pathologic renal intratubular casts can be an arduous task, especially since they often admixed with non-pathologic casts, obfuscating debris and inflammation. The list of pathologic intratubular casts is long, and they can be easily missed or misdiagnosed without a thorough understanding of their pathophysiology and morphologic variety. Correct characterization of tubular casts is important since each cast type has a unique pathogenic mechanism, with specific treatment and prognostic implications. This review discusses the clinicopathologic characteristics of the six most common pathologic casts: light chain, hemoglobin, myoglobin, red cell, neutrophilic and bile casts. We also discuss hyaline and uromodulin casts, the commonly encountered "benign" cast types that share certain histologic features with pathologic casts. We limit the discussion to proteinaceous and cellular intratubular casts, with crystalline casts discussed in a separate review within the same journal issue. While not exhaustive, this review covers pathogenesis, clinical and prognostic significance, and a practical discussion of the histomorphologic spectrum of each cast type, along with commonly encountered pitfalls.

Multiple Myeloma Mimicking a Small Vessel Vasculitis Presentation

Multiple myeloma can have different clinical manifestations, and not all patients present with classic CRAB component. We describe a 46-year-old woman admitted to our hospital with a complaint of a bluish-to-black discoloration of the second toe that was rapidly progressive and acute kidney injury. We documented a Kappa light chain monoclonal gammopathy, increased presence of plasmacytes in bone marrow aspiration, and multiple lytic bone lesions, which led to a diagnosis of multiple myeloma. Although multiple myeloma presenting with blue finger syndrome is uncommon, it must always be considered as a differential diagnosis with this clinical finding.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

The treatment of paraprotein-related kidney disease

PURPOSE OF REVIEW

Myeloma kidney and amyloid light-chain (AL) amyloidosis remain the principal kidney complications of paraproteins. In this review, we update readers to many of the recent advances which have occurred in the care and outcomes for patients with these presentations.

RECENT FINDINGS

Myeloma kidney has historically caused a severe acute kidney injury with very poor outcomes. The combination of new diagnostic techniques, enabling a rapid diagnosis and novel chemotherapy agents has transformed these poor outcomes for the better. Two multicentre randomized controlled trials have recently evaluated if the removal of free light chains by high cut-off haemodialysis improves renal outcomes beyond effective chemotherapy alone. Although we await the full articles of these studies to be published, abstracts suggested the studies will have contradictory primary results. In the field of AL amyloidosis, there are now novel criteria for the risk stratification of kidney outcomes which can be used in combination with markers of early kidney response to provide clinicians with powerful tools to guide patient discussions.

SUMMARY

Across both AL amyloidosis and myeloma kidney patient outcomes continue to improve. Principally this improvement has been driven by the continuing development of novel chemotherapy agents in this field.

Disease and Symptom Care: A Focus on Specific Needs of Patients With Multiple Myeloma

Patients with multiple myeloma (MM) often deal with short- and long-term side effects of the treatment and disease sequelae. Reasons for inadequately managed symptoms are multifactorial (e.g., the patient may fear treatment interruption, the clinician does not assess or address the symptoms) and can affect patients' ability to remain on the recommended treatment. This article provides background surrounding this supplement's development and describes the importance of symptom assessment and management.
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Evidence-Based Guidelines for Preventing and Managing Side Effects of Multiple Myeloma

OBJECTIVE

To review disease-related symptoms and side effects of treatment in patients with multiple myeloma (MM).

DATA SOURCES

Peer-reviewed articles, research studies, and clinical guidelines.

CONCLUSION

New therapies provide patients with extended survival, but in many cases this benefit is counterbalanced by an increased incidence of side effects. Preservation of organ function, while managing side effects, is essential for the care of patients with MM.

IMPLICATIONS FOR NURSING PRACTICE

Disease- and treatment-related adverse events are prevalent in patients with MM. Patient, family, and health care professional education is essential to monitor and manage these side effects.

Paraprotein-Related Kidney Disease: Attack of the Killer M Proteins

Paraproteins are monoclonal Igs or their components (light or heavy chains) that are produced by a clonal population of mature B cells, most commonly plasma cells. These paraproteins or monoclonal proteins are secreted into the blood and subsequently filtered by the glomerulus before entering into urine, where they can cause various types of kidney disease, including both glomerular and tubulointerstitial injuries. Furthermore, a monoclonal protein that causes a specific glomerular or tubulointerstitial lesion in a human can reproducibly cause the same pathology when injected into an animal, supporting unique paraprotein characteristics. This Moving Points in Nephrology will provide an update for the Clinical Journal of the American Society of Nephrology readership on some of the clinically relevant kidney lesions associated with monoclonal paraprotein production and the pathophysiology underlying these kidney lesions.