Intrarenal dynamics in the pathogenesis and prevention of acute urate nephropathy

Relapse of Lung Adenocarcinoma Manifested by Spontaneous Tumor Lysis Syndrome

Introduction

Tumor lysis syndrome (TLS) is an oncologic emergency characterized by several metabolic derangements, such as hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia. TLS is typically observed in hematologic malignancies, especially after starting the first administration of antineoplastic therapies. TLS in a solid malignancy is very unusual, and exceedingly rare when occurring spontaneously, in the absence of chemotherapy.

Case Presentation

We report a case of a 76-year-old man with lung adenocarcinoma, which started as a cancer with indolent behavior and small tumor burden but relapsed in 5 months with rapidly proliferating metastatic disease. Spontaneous TLS was the presenting clinical manifestation of the tumor relapse, and it led to the patient's death.

Conclusion

To our knowledge, this is the first case of spontaneous TLS in a relapsed adenocarcinoma of the lung reported in the medical literature. The development of the metabolic derangements of TLS should prompt the consideration of tumor relapse during the follow-up of patients with solid malignancies.

Tumor Lysis Syndrome: An Endless Challenge in Onco-Nephrology

Tumor lysis syndrome (TLS) is a common cause of acute kidney injury in patients with malignancies, and it is a frequent condition for which the nephrologist is consulted in the case of the hospitalized oncological patient. Recognizing the patients at risk of developing TLS is essential, and so is the prophylactic treatment. The initiation of treatment for TLS is a medical emergency that must be addressed in a multidisciplinary team (oncologist, nephrologist, critical care physician) in order to reduce the risk of death and that of chronic renal impairment. TLS can occur spontaneously in the case of high tumor burden or may be caused by the initiation of highly efficient anti-tumor therapies, such as chemotherapy, radiation therapy, dexamethasone, monoclonal antibodies, CAR-T therapy, or hematopoietic stem cell transplantation. It is caused by lysis of tumor cells and the release of cellular components in the circulation, resulting in electrolytes and metabolic disturbances that can lead to organ dysfunction and even death. The aim of this paper is to review the scientific data on the updated definition of TLS, epidemiology, pathogenesis, and recognition of patients at risk of developing TLS, as well as to point out the recent advances in TLS treatment.

Tumor Lysis Syndrome

Tumor lysis syndrome (TLS) is an oncologic emergency due to massive tumor cell lysis with the release of large amounts of potassium, phosphate, and nucleic acids into the systemic circulation. Clinical presentation is characterized by hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia. Acute kidney injury due to tumor lysis is potentiated by the precipitation of uric acid and calcium phosphate as well as renal vasoconstriction. Early recognition of tumor lysis can help prevent cardiac arrhythmias, seizures, and death. Management includes intravenous hydration to maintain urine flow, medications targeting hyperuricemia including rasburicase and allopurinol and in severe cases renal replacement therapy may be required.

Clinical Interventions to Prevent Tumour Lysis Syndrome in Hematologic Malignancy: A Multisite Retrospective Chart Review

BACKGROUND

Tumour lysis syndrome (TLS) occurs when lysis of malignant cells causes electrolyte disturbances and potentially organ dysfunction. Guidelines recommending preventive therapy according to TLS risk are based on low-quality evidence.

OBJECTIVES

The primary objective was to characterize utilization of TLS preventive strategies through comprehensive description of current practice. Secondary objectives were to determine TLS incidence, to compare use of preventive strategies among intermediate- and high-risk patients, and to describe TLS treatment strategies.

METHODS

This retrospective chart review examined data for patients with newly diagnosed hematologic malignancy who were admitted to an oncology centre and/or affiliated intensive care unit between October 2015 and September 2016 in Toronto, Ontario, Canada.

RESULTS

Fifty-eight patients (29 at intermediate risk, 29 at high risk) were eligible for inclusion. Use of preventive allopurinol, IV bicarbonate, and furosemide was similar between groups. Rasburicase was more frequently used for high-risk patients (3% [1/29] of intermediate-risk patients versus 36% [9/25] of high-risk patients; p = 0.003). In 4 (14%) of the intermediate-risk patients and 2 (8%) of the high-risk patients, TLS developed during the admission. TLS was observed in 10% (1/10) of patients who received preventive rasburicase and 11% (5/44) of those who did not (p > 0.99), and in 9% (4/45) of patients who received preventive IV bicarbonate and 25% (2/8) of those who did not (p = 0.22). Treatment strategies included rasburicase, IV bicarbonate, furosemide, and renal replacement therapy.

CONCLUSIONS

In this retrospective chart review, rasburicase was more commonly used for high-risk patients, whereas the use of other agents was similar between risk groups. This pattern of use is inconsistent with guidelines, which recommend that all high-risk patients receive rasburicase. There was no difference in TLS incidence between patients who did and did not receive preventive rasburicase or IV bicarbonate. Further prospective studies are needed to inform management of patients with malignancies who are at intermediate or high risk of TLS.

Hyperuricemia complicated with acute kidney injury is associated with adverse outcomes in patients with severely decompensated acute heart failure

Background

The relationship between the serum level of uric acid (UA) and the acute kidney injury on admission in patients with acute heart failure (AHF) remain unclear.

Methods and results

A total of 1326 AHF patients were screened, and data for 1047 patients who were admitted to the intensive-care unit were analyzed. The patients were assigned to a low-UA group (UA ≤ 7.0 mg/dl, n = 569) or a high-UA group (UA > 7.0 mg/dl, n = 478) according to their UA level at admission. Acute kidney injury (AKI) at admission was defined based on the ratio of the serum creatinine value recorded on admission to the baseline creatinine value: no-AKI (n = 736) or AKI (n = 311). The patients were therefore assigned to four groups: low-UA/no-AKI (n = 428), high-UA/no-AKI (n = 308), low-UA/AKI (n = 141) and high-UA/AKI (n = 170). The high-UA patients were significantly more frequent in the AKI group than in the non-AKI group among all patients and the non-chronic kidney injury (CKD) cohort. A Kaplan-Meier curve showed a significantly lower 365-day survival rate in the high-UA/AKI group than in the other groups. The multivariate Cox regression model identified only high-UA/AKI as an independent predictor of 365-day mortality (hazard ratio [HR]: 2.511, 95% confidence interval [CI] 1.671–3.772 in all AHF patients, HR: 1.884, 95% CI 1.022–3.473 in non-CKD patients and HR: 3.546, 95% CI 2.136–5.884 in CKD patients).

Conclusion

An elevated serum UA level complicated with AKI was an independent predictor of mortality in patients with severely decompensated AHF.

Tumour lysis syndrome

Tumour lysis syndrome (TLS) is a life-threatening emergency characterised by a massive cytolysis with the release of intracellular electrolytes, nucleic acids, and metabolites into the circulation. TLS comprises laboratory derangements (hyperuricaemia, hyperkalaemia, hyperphosphataemia, and hypocalcaemia) responsible for acute kidney injury. In patients with hematologic malignancies after cytotoxic therapy or spontaneously and also in advanced solid tumours. Assessment of disease specific risk level for TLS in patients receiving anti-tumoural therapy is essential for early diagnosis. Prophylaxis is the mainstay of management of TLS. It is important to routinely initiate a risk-adapted prophylactic strategy to correct metabolic alterations and preserve renal function. High and intermediate risk patients and patients with established TLS should be managed with multidisciplinary medical care in a hospital unit to receive monitoring and medical care. Renal replacement therapy should be considered in patients with refractory TLS.

Spontaneous tumour lysis syndrome in small cell lung cancer: a rare phenomenon

Tumour lysis syndrome (TLS) is an oncological emergency. It is caused by cellular death occurring secondary to cancer therapy or spontaneously in rapidly dividing tumours. More common in haematological malignancies, it has also been reported in solid tumours. Out of 14 cases of small cell lung cancer (SCLC) with TLS, only three cases of spontaneous TLS have been reported in literature to date. Here we report a case of SCLC presenting as a spontaneous TLS.

Acute kidney injury in hematological patients

PURPOSE OF REVIEW

The present article reviews the recent literature on the main aspects of acute kidney injury (AKI) developing in patients with hematological malignancies admitted to ICU.

RECENT FINDINGS

Up to two thirds of critically ill patients with hematological malignancies develop AKI. Current mortality rates range from 40 to 60% for most patients with hematological malignancies, except for recipients of allogeneic hematopoietic stem cell transplantation in whom outcomes remain very poor. Renal function recovery occurs in most patients with AKI, but is dependent on the underlying causes. AKI is usually multifactorial, resulting from causes common to other ICU patients and related to the underlying malignancy or its treatment. New targeted therapies and treatment strategies are potentially associated with AKI. Management of these patients requires a high degree of suspicion, close monitoring of metabolic parameters, and use of preventive strategies to limit risk of AKI or to mitigate its severity.

SUMMARY

AKI is a frequent and severe complication in critically ill patients with hematological malignancies. As the clinical management is complex, close collaboration with hematologists is paramount.

Acute Renal Failure in Critically Ill Patients

Acute renal failure is an important cause of morbidity in critically ill patients. Acute renal failure results from pre renal and postrenal causes and, most importantly, acute tubular necrosis (ATN). Although it is known that renal toxins and renal ischemia are the most common causes of ATN in hospitalized patients, the exact pathogenesis of this entity is still not fully understood. Patients in the intensive care unit are at high risk for ATN because of hemodynamic instability, the administration of neph rotoxic antibiotics or chemotherapeutic agents, and ex posure to radiographic contrast agents. The acquired immunodeficiency syndrome is also associated with an increased risk of renal failure development, either from complications of the disease itself or from its treatment. Many consequences of acute renal failure such as vol ume overload, acidosis, hyperkalemia, and serositis can be managed adequately with peritoneal dialysis, hemo dialysis, or a newer technique, continuous arteriove nous hemofiltration. Despite improvements in treat ment, however, the mortality of ATN remains high. In this review, we recommend measures to prevent ATN in certain clinical situations that commonly occur among critically ill patients. We also review therapeutic options for treating patients in whom acute renal failure devel ops and discuss newer developments that may begin to reduce the excessive morbidity associated with ATN.

Heat Stress Nephropathy From Exercise-Induced Uric Acid Crystalluria: A Perspective on Mesoamerican Nephropathy

Mesoamerican nephropathy (MeN), an epidemic in Central America, is a chronic kidney disease of unknown cause. In this article, we argue that MeN may be a uric acid disorder. Individuals at risk for developing the disease are primarily male workers exposed to heat stress and physical exertion that predisposes to recurrent water and volume depletion, often accompanied by urinary concentration and acidification. Uric acid is generated during heat stress, in part consequent to nucleotide release from muscles. We hypothesize that working in the sugarcane fields may result in cyclic uricosuria in which uric acid concentrations exceed solubility, leading to the formation of dihydrate urate crystals and local injury. Consistent with this hypothesis, we present pilot data documenting the common presence of urate crystals in the urine of sugarcane workers from El Salvador. High end-of-workday urinary uric acid concentrations were common in a pilot study, particularly if urine pH was corrected to 7. Hyperuricemia may induce glomerular hypertension, whereas the increased urinary uric acid may directly injure renal tubules. Thus, MeN may result from exercise and heat stress associated with dehydration-induced hyperuricemia and uricosuria. Increased hydration with water and salt, urinary alkalinization, reduction in sugary beverage intake, and inhibitors of uric acid synthesis should be tested for disease prevention.

Admission hyperuricemia increases the risk of acute kidney injury in hospitalized patients(.)

Background

The association between elevated admission serum uric acid (SUA) and risk of in-hospital acute kidney injury (AKI) is limited. The aim of this study was to assess the risk of developing AKI in all hospitalized patients with various admission SUA levels.

Methods

This is a single-center retrospective study conducted at a tertiary referral hospital. All hospitalized adult patients who had admission SUA available from January 2011 through December 2013 were analyzed in this study. Admission SUA was categorized based on its distribution into six groups (<3.4, 3.4–4.5, 4.5–5.8, 5.8–7.6, 7.6–9.4 and >9.4 mg/dL). The primary outcome was in-hospital AKI occurring after hospital admission. Logistic regression analysis was performed to obtain the odds ratio (OR) of AKI of various admission SUA levels using the most common SUA level range (5.8–7.6 mg/dL) as the reference group.

Results

Of 1435 patients enrolled, AKI occurred in 263 patients (18%). The incidence of AKI and need for dialysis was increased in patients with higher admission SUA levels. After adjusting for potential confounders, SUA >9.4 mg/dL was associated with an increased risk of developing AKI, with ORs of 1.79 [95% confidence interval (CI) 1.13–2.82]. Conversely, admission SUA <3.4 and 3.4–4.5 mg/dL were associated with a decreased risk of developing AKI, with ORs of 0.38 (95% CI 0.17–0.75) and 0.50 (95% CI 0.28–0.87), respectively.

Conclusions

Elevated admission SUA was associated with an increased risk for in-hospital AKI.

Tumor lysis syndrome in the emergency department: challenges and solutions

Tumor lysis syndrome (TLS) is the most common oncologic emergency. It is caused by rapid tumor cell destruction and the resulting nucleic acid degradation during or days after initiation of cytotoxic therapy. Also, a spontaneous form exists. The metabolic abnormalities associated with this syndrome include hyperkalemia, hyperphosphatemia, hypocalcemia, hyperuricemia, and acute kidney injury. These abnormalities can lead to life-threatening complications, such as heart rhythm abnormalities and neurologic manifestations. The emergency management of overt TLS involves proper fluid resuscitation with crystalloids in order to improve the intravascular volume and the urinary output and to increase the renal excretion of potassium, phosphorus, and uric acid. With this therapeutic strategy, prevention of calcium phosphate and uric acid crystal deposition within renal tubules is achieved. Other measures in the management of overt TLS are prescription of hypouricemic agents, renal replacement therapy, and correction of electrolyte imbalances. Hyperkalemia should be treated quickly and aggressively as its presence is the most hazardous acute complication that can cause sudden death from cardiac arrhythmias. Treatment of hypocalcemia is reserved for patients with electrocardiographic changes or symptoms of neuromuscular irritability. In patients who are refractory to medical management of electrolyte abnormalities or with severe cardiac and neurologic manifestations, early dialysis is recommended.

How Center Volumes Affect Early Outcomes in Acute Myeloid Leukemia

Early mortality (EM) is all too frequent during induction chemotherapy for acute myeloid leukemia. Older patients shoulder an undue amount of this burden as a result of the inherent biology of their disease and increased comorbidities. EM rates in academic centers have seen a sharp decline over the past 20 years; however, data from population-based registries show that EM rates for the general population have significantly lagged behind. In this review, we analyze the data available on EM in academic centers and the general population, explore recent improvements in supportive care and the use of predictive models, and finally investigate the relationship between case volume and complications during chemotherapy.

Tumor lysis syndrome: A clinical review

Tumor lysis syndrome is an oncometabolic emergency resulting from rapid cell death. Tumor lysis syndrome can occur as a consequence of tumor targeted therapy or spontaneously. Clinicians should stratify every hospitalized cancer patient and especially those receiving chemotherapy for the risk of tumor lysis syndrome. Several aspects of prevention include adequate hydration, use of uric acid lowering therapies, use of phosphate binders and minimization of potassium intake. Patients at high risk for the development of tumor lysis syndrome should be monitored in the intensive care unit. Established tumor lysis syndrome should be treated in the intensive care unit by aggressive hydration, possible use of loop diuretics, possible use of phosphate binders, use of uric acid lowering agents and dialysis in refractory cases.

Tumor lysis syndrome: risk factors, diagnosis, and management

Tumor lysis syndrome (TLS) is a potentially fatal complication of induction therapy for several types of malignancies. Electrolyte derangements and even downstream complications may also occur prior to the initial presentation to a medical provider, before an oncologic diagnosis has been established. It is therefore imperative that emergency physicians be familiar with the risk factors for TLS in children as well as the criteria for diagnosis and the strategies for prevention and management. Careful evaluation of serum electrolytes, uric acid, and renal function must occur. Patients at risk for TLS and those who already exhibit laboratory or clinical evidence of TLS require close monitoring, aggressive hydration, and appropriate medical treatment.

Haematological Emergencies

In a hospital setting, it is common to encounter certain haematological emergencies irrespective of whether or not the patient has an underlying haematological condition or if the hospital has a well-established haematology service. This article aims to define and illustrate common and less common haematological emergencies that a physician may encounter on the wards and the appropriate initial management for the patient prior to a formal hematological consult.

Tumor lysis syndrome: new challenges and recent advances

Tumor lysis syndrome (TLS) is an oncologic emergency triggered by the rapid release of intracellular material from lysing malignant cells. Most common in rapidly growing hematologic malignancies, TLS has been reported in virtually every cancer type. Central to its pathogenesis is the rapid accumulation of uric acid derived from the breakdown of nucleic acids, which leads to kidney failure by various mechanisms. Kidney failure then limits the clearance of potassium, phosphorus, and uric acid leading to hyperkalemia, hyperphosphatemia, and secondary hypocalcemia, which can be fatal. Prevention of TLS may be more effective than treatment, and identification of at-risk individuals in whom to target preventative efforts remains a key research area. Herein, we discuss the pathophysiology, epidemiology, and treatment of TLS with an emphasis on the kidney manifestations of the disease.

Tumor lysis syndrome: a systematic review of case series and case reports

Tumor lysis syndrome (TLS) is a clinical condition that is caused by a massive lysis of tumor cells that accumulate very rapidly and disturb hemodynamics. This oncologic emergency requires immediate intervention. Tumor lysis syndrome was first described in the 19th century. Since then, it has become a well-known disease with improved management measures. Tumor lysis syndrome can occur after any type of neoplasm. It is highly associated with rapidly proliferating tumors compared with those that are well demarcated, such as acute lymphoblastic leukemia and high-grade non-Hodgkin lymphoma. Initiation of chemotherapy, radiotherapy, or steroid treatment may trigger TLS, or it may develop spontaneously. The release of massive quantities of intracellular contents may produce hyperkalemia, hyperphosphatemia, secondary hypocalcemia, hyperuricemia, and acute renal failure. Prevention and treatment measures include intravenous hydration, use of allopurinol and rasburicase, management of TLS-associated electrolyte abnormalities, and renal replacement therapy; the use of urine alkalinization remains controversial. In this article, we summarize the findings of case series and case reports published over the past 6 years in an effort to help familiarize clinicians better recognize and manage TLS.

[Therapeutic of respiratory manifestations at the early phase of acute myeloid leukaemia]

The effective management of the respiratory manifestations at the early phase of acute myeloid hemopathies, especially acute myeloid leukaemia, frequently requires a close collaboration between hematologists, pulmonologists and intensivists. Dominated by infectious etiologies, there are however "specific" disease entities that should not be neglected in the diagnostic and therapeutic approach. These include lung leukostasis, leukemic lung infiltration, the cell lysis pneumopathy and the secondary alveolar proteinosis. These were the subject of a review in the Revue des Maladies Respiratoires published in 2010. We wished to review the management of these clinical situations, the severity of which mean patients frequently require intensive care unit admission. We are only able to make proposals for management here as there is little consensus, except in the metabolic care of tumour lysis syndrome. These data must therefore be reinterpreted regularly as new publications become available.

Lowering serum uric acid to prevent acute kidney injury

Epidemiological, experimental and clinical studies support a role for uric acid in acute kidney injury (AKI). We discuss how the conventional role of uric acid in AKI has now evolved from intratubular crystal deposition to pro-inflammatory, anti-angiogenic and immunological function. Data from recent studies are presented to support the hypothesis that uric acid may have a role in AKI via a crystal-independent process in addition to its traditionally accepted role to induce injury via crystal-dependent pathways.

Paradigm shift in the role of uric acid in acute kidney injury

It has been known for decades that uric acid causes acute kidney injury by intratubular crystal precipitation and obstructing the renal tubules. Uric acid crystals stimulate inflammation and elicit immune responses in many disease conditions, including gouty arthritis. More recently, soluble uric acid has been reported to stimulate proliferation of vascular smooth muscle cells, inhibit endothelial function, cause renal vasoconstriction, impair renal blood flow autoregulation, and induce inflammatory response via crystal-independent mechanisms. This article examines the changing role for uric acid in acute kidney injury.

Rasburicase for hyperuricemia in hemolytic uremic syndrome

BACKGROUND

Acute kidney injury (AKI) with elevated serum uric acid (UA) levels has been reported in patients with hemolytic uremic syndrome (HUS). AKI is thought to result from tubular obstruction by UA crystals. Inducing a diuresis may ameliorate the oligoanuria in such patients. We describe a child with HUS in whom reducing UA with fluids and rasburicase appeared to accelerate the recovery of renal function.

CASE-DIAGNOSIS/TREATMENT

A 9-month-old Caucasian male infant presented with 6 days of diarrhea, 3 days of vomiting, and 24 h of oliguria. On admission, hemoglobin was 8.3 g/dL, platelet count 36,000/L, blood urea nitrogen 73 mg/dL, and serum creatinine (SCr) 2.7 mg/dL. Diarrhea-associated HUS was diagnosed. The day after admission, SCr was 2.9 mg/dL and UA 12.3 mg/dL. On hospital day 2, he received a dose of intravenous rasburicase 0.18 mg/kg, and less than 12 h later, the UA had fallen to 0.3 mg/dL. The SCr level also started to fall, and urine output progressively increased without the use of diuretics. Renal function continued to improve, and the UA level remained normal despite ongoing hemolysis requiring a second red blood cell transfusion on hospital day 5. The patient was discharged on hospital day 7 in good physical condition. Two months later, he was in good health, with a SCr level of 0.2 mg/dL and UA of 4.2 mg/dL.

CONCLUSIONS

We postulate that aggressive management of the high serum UA level with rasburicase and fluid hydration accelerated the recovery of our patient. Further studies are needed to determine the role of rasburicase in the treatment of hyperuricemia in patients with HUS.

Risk evaluation, prophylaxis, and treatment of tumor lysis syndrome: consensus of an Italian expert panel

INTRODUCTION

Tumor lysis syndrome (TLS) is a life-threatening complication in patients with hematological disease and/or solid tumors that results from rapid, large-scale tumor necrosis occurring spontaneously, or more commonly, as a result of chemotherapy. TLS is characterized by metabolic and electrolyte imbalances that include hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia. Identification of risk groups as well as early detection of TLS is crucial for the establishment of appropriate strategies of prophylaxis and treatment.

METHODS

A review of the peer-reviewed literature on TLS between 1990 and 2011 was conducted via a systematic search of the PubMed database using the keywords "TLS" [AND] "management," "risk evaluation," "prophylaxis," and "treatment." An expert opinion-based approach was used to review the national and international recommendations and guidelines on the topic.

RESULTS

The PubMed search produced 90 results, all of which were evaluated. These studies, together with a recent international consensus panel provided recommendations for evaluating the risk of TLS and providing prophylaxis. Five algorithms are presented that consider all of the factors when assessing the risk for neoplastic disease in general, and specifically for leukemia and lymphoma.

CONCLUSION

The present report provides clinicians with an easily consultable tool to guide the evidence-based management of this oncohematological emergency.

The clinical management of tumour lysis syndrome in haematological malignancies

Tumour lysis syndrome (TLS) is caused by the disintegration of malignant cells, usually following the instigation of chemotherapy, although it may already be established at the time of initial presentation in a minority of cases. As a direct consequence of malignant cell breakdown, intracellular ions, proteins, nucleic acids and their metabolites are released into the plasma causing the characteristic metabolic abnormalities of TLS; hyperuricaemia, hyperkalaemia, hyperphosphataemia and hypocalcaemia. In many cases the release of large amounts intracellular contents is so abrupt that the normal homeostatic mechanisms are rapidly overwhelmed and without prompt, effective management, the clinical effects of TLS soon become apparent.

[Tumor lysis syndrome in intensive therapy: diagnostic and therapeutic encare]

The tumor lysis syndrome (TLS) is a life-threatening complication caused by the massive release of nucleic acids, potassium and phosphate into the blood. This complication is the result of tumor cell lysis, which may occur due to treatment of drug sensitive and is characterized by rapid capacity of proliferation, that is often hematological origin. Moreover, the TLS can be observed before starting the treatment due to spontaneous tumor cell death, and frequently worsens when chemotherapy is initiated. TLS has high mortality, so that its prevention continues to be the most important therapeutic measure. In the intensive care unit (ICU), physicians should be aware of the clinical characteristics of TLS, which results in severe electrolyte metabolism disorders, especially hyperkalemia, hyperphosphatemia and hypocalcemia, and acute kidney injury which is a major cause of ICU mortality. An adequate strategy for the management of the TLS, combining hydration, urate oxidase, and an early admission to ICU can control this complication in most patients. The aim of this review is to provide diagnostic tools that allow to the ICU physician to recognize the population at high risk for developing the TLS, and outline a proper strategy for treating and preventing this serious complication.

Renal complications in oncologic patients

Acute renal failure (ARF) can be one of the many complications associated with malignancy and, unfortunately, often harbors a worse prognosis for the afflicted patient. Insult to the kidneys can occur for a variety of reasons in the oncologic patient. This article focuses on several of these etiologies, such as tumor lysis syndrome (TLS) and thrombotic microangiopathy (TMA), which are unique threats faced by the oncologic patient.

Tumor lysis syndrome and acute kidney injury: evaluation, prevention, and management

Tumor lysis syndrome (TLS) describes a constellation of biochemical and clinical abnormalities resulting from rapid and massive tumor cell death. TLS is frequently associated with hyperuricemia, hyperkalemia, hyperphosphatemia, and secondary hypocalcemia that may lead to serious clinical complications, including acute kidney injury and cardiac arrest. Identification of tumor- and patient-specific risk factors for TLS and early recognition of laboratory and clinical TLS based on established criteria are essential for preventing TLS and forestalling acute kidney injury. Early collaboration between oncologists and nephrologists will help improve assessment of patients' kidney function and risk factors, paving the way for timely and efficacious interventions.

Diagnosis, treatment and follow-up of 25 patients with melamine-induced kidney stones complicated by acute obstructive renal failure in Beijing Children's Hospital

A total of 25 Chinese patients aged 6 to 36 months hospitalised at Beijing Children's Hospital due to melamine-induced kidney stones complicated by acute obstructive renal failure in 2008 were included in a study in order to diagnose and treat these special cases more effectively. Feeding history, clinical presentation, ultrasound findings, treatments and effects were summarised. Twelve to seventeen months follow-up was reported also. Ultrasound examination showed that calculi were located at the kidney and ureters. Stones were composed of both uric acid and melamine in a molar ratio of 1.2:1 to 2.1:1. Treatments providing liquid plus alkalisation of urine proved to be effective in helping the patients pass the stones. Surgical intervention was needed in severe cases. Renal function returned to normal in all 25 patients after various durations of therapy. Sixty-eight percent of the patients expelled all of the calculi within 3 months, 90% in 6 months and 95% in 9 months, without sequelae till now. Melamine-contaminated milk formula can cause kidney stones in infants, which should be diagnosed by feeding history, clinical symptoms and ultrasound examination. Composition of the stones was not only of melamine but also uric acid. Providing liquid orally or intravenously plus alkalisation of urine proved to promote the removal of the stones. Follow-up of 12 to 17 months after discharge showed no sequelae.

An integrated clinical approach for the identification, prevention, and treatment of tumor lysis syndrome

Tumor lysis syndrome (TLS) is a potentially life-threatening metabolic disorder that occurs when tumor cells undergo rapid decomposition spontaneously or in response to cytoreductive therapy. Delayed recognition of the metabolic imbalances caused by the massive release of tumor cell contents may result in clinical complications such as acute kidney injury, seizures, and cardiac arrhythmias. Prevention, the key principle in TLS management, relies on the identification of patients at risk for developing TLS during chemotherapy or because of disease progression. TLS-related risk factors pertain to tumor type (particularly hematologic malignancies), specific tumor characteristics (e.g. bulky tumor, high cellular proliferation rate, sensitivity to cytoreductive therapy), and other host-related factors. A comprehensive grading system proposed by Cairo and Bishop classifies TLS syndromes into laboratory or clinical TLS, thus facilitating TLS prevention and management. The mainstays of TLS management include monitoring of electrolyte abnormalities, vigorous hydration, prophylactic antihyperuricemic therapy with allopurinol, and rasburicase treatment of patients at high TLS risk or with established hyperuricemia. Urine alkalinization and use of diuretics remain controversial clinical practices. In this review, we describe the incidence of, risk factors for, and diagnostic characteristics of TLS and summarize strategies for the prevention and management of TLS-associated metabolic abnormalities, particularly hyperuricemia. We specifically highlight recently published TLS management guidelines, which focus on the prevention of TLS and hyperuricemia based on a patient's level of risk, and the important role of nephrologists in the prevention and treatment of one of the most serious complications of TLS, acute kidney injury.