Alterations in electrolyte equilibrium in patients with acute leukemia

Biochemical and Hematologic Profiles in B-Cell Acute Lymphoblastic Leukemia Children

B-cell acute lymphoblastic leukemia is the most common type of leukemia found in children. Timely diagnosis, white blood cell count, age of onset, and sex are considered the most important prognostic factors in childhood leukemia. Hematological and biochemical profiles are crucially important to infer the health of leukemia patient pre-chemotherapy and post-chemotherapy treatment. In the current study 200 cases were taken and evaluated for hematological (complete blood count and white blood differential count) and biochemical parameters (renal function tests, liver function tests, serum electrolytes and serum proteins) by comparison with normal reference values. Most of the cases were male under 5 years of age. Hematology parameters including red blood cells, hemoglobin and platelet levels were relatively low whereas white blood cells level was high in cases as compared with normal reference value. Sex-wise and age-wise comparison of biochemical profile showed significant difference among B-cell acute lymphoblastic leukemia cases whereas hematological profile did not show any visible difference.

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.

Hematological Malignancies and the Kidney

The incidence of hematologic malignancies is on the rise worldwide. Kidney disease is ubiquitous in patients with hematologic malignancies, encompassing a wide spectrum of disorders involving each kidney compartment, including the vasculature, tubules, interstitium, and glomerulus, and there is significant overlap of kidney involvement with each hematologic malignancy. Vascular disorders include both microvascular and macrovascular damage, via thrombotic microangiopathy, hyperleukocytosis, hyperviscosity, and cryoglobulinemia. The tubulointerstitial compartment may be affected by prerenal azotemia and acute tubular injury, but malignant infiltration, tumor lysis syndrome, extramedullary hematopoiesis, cast nephropathy, granulomatous interstitial nephritis, and lysozymuria should be considered in certain populations. Obstructive uropathy may occur due to nephrolithiasis or retroperitoneal fibrosis. Glomerular disorders, including membranoproliferative, membranous, minimal change, and focal segmental glomerulosclerosis, can rarely occur. By understanding how each compartment may be affected, care can best be optimized for these patients. In this review, we summarize the widely varied etiologies of kidney diseases stratified by kidney compartment and hematologic malignancy, focusing on demographics, pathology, pathophysiology, mechanism, and outcomes. We conclude with common electrolyte abnormalities associated with hematologic malignancies.

Development and implementation of an electrolyte replacement protocol in the outpatient oncology infusion centers of a large academic healthcare system

Background

Patients receiving chemotherapy frequently experience electrolyte imbalances. Electrolyte replacement is, therefore, a necessity as patients may experience life-threatening symptoms. Study objective: The objective of this study was to evaluate the occurrence of low serum potassium and magnesium, and identify the rate of replacement for patients with low serum potassium and magnesium levels. Based on our findings, we developed and implemented a nursing-driven electrolyte replacement protocol.

Methods

Preimplementation phase – A retrospective review for serum potassium and magnesium values obtained during infusion clinic visit between 1 August and 31 October 2016 was conducted. Implementation phase – A nursing-driven electrolyte replacement protocol with medication order “smart-set” and order selection intelligence within EPIC Beacon was developed and implemented in May 2017. Postimplementation phase – The postimplementation phase data were collected from 1 August to 30 November 2017 using a similar approach as the preimplementation phase.

Results

Preimplementation phase – During the preimplementation phase of the study, a total of 1495 serum potassium levels and 1193 serum magnesium levels were obtained. Among the 152 patients who needed potassium replacement, 34% ( n = 52) were replaced and among the 118 serum magnesium levels that needed replacement, 30% ( n = 35) were replaced. Postimplementation phase – 3979 serum potassium and 2707 magnesium levels were obtained. Among the 170 patients who needed potassium replacement, 75% ( n = 127) were replaced. Among the 142 patients who needed magnesium replacement, 73% ( n = 104) were replaced.

Conclusion

A 121% increase in potassium replacement and a 143% increase in magnesium replacement were identified after implementing this protocol.

Electrolyte and acid-base disorders in cancer patients and its impact on clinical outcomes: evidence from a real-world study in China

Background: This study aims to delineate the incidence of electrolyte and acid-base disorders (EAD) in cancer patients, to figure out the risk factors of EAD, then to assess the impact of EAD on patients' in-hospital clinical outcomes.Methods: Patients with the diagnosis of malignancies hospitalized during 1 October 2014 and 30 September 2015 were recruited in Zhongshan Hospital, Fudan University in Shanghai of China. Demographic characteristics, comorbidities, and clinical data, including survival, length of stay and hospital cost, were extracted from the electronic medical record system. Electrolyte and acid-base data were acquired from the hospital laboratory database.Results: Of 25,881 cancer patients with electrolyte data, 15,000 (58.0%) cases had at least one electrolyte and acid-base abnormity. Hypocalcemia (27.8%) was the most common electrolyte disorder, followed by hypophosphatemia (26.7%), hypochloremia (24.5%) and hyponatremia (22.5%). The incidence of simple metabolic acidosis (MAC) and metabolic alkalosis (MAL) was 12.8% and 22.1% respectively. Patients with mixed metabolic acid-base disorders (MAC + MAL) accounted for 30.2%. Lower BMI score, preexisting hypertension and diabetes, renal dysfunction, receiving surgery/chemotherapy, anemia and hypoalbuminemia were screened out as the major risk factors of EAD. In-hospital mortality in patients with EAD was 2.1% as compared to those with normal electrolytes (0.3%). The risk of death significantly increased among patients with severe EAD. Similarly, the length of stay and hospital cost also tripled as the number and grade of EAD increased.Conclusion: EAD is commonly encountered in cancer patients and associated with an ominous prognosis. Patients with comorbidities, renal/liver dysfunction, and anti-tumor therapy have a higher risk of EAD. Regular monitoring of electrolytes, optimum regimen for intravenous infusion, timely correction of modifiable factors and appropriate management of EAD should not be neglected during anti-tumor treatment.

Hyponatremia in Patients with Hematologic Diseases

Hyponatremia is the most common electrolyte disorder in clinical practice and is associated with increased morbidity and mortality. It is frequently encountered in hematologic patients with either benign or malignant diseases. Several underlying mechanisms, such as hypovolemia, infections, toxins, renal, endocrine, cardiac, and liver disorders, as well as the use of certain drugs appear to be involved in the development or the persistence of hyponatremia. This review describes the pathophysiology of hyponatremia and discusses thoroughly the contributing factors and mechanisms that may be encountered specifically in patients with hematologic disorders. The involvement of the syndrome of inappropriate antidiuretic hormone (SIADH) secretion and renal salt wasting syndrome (RSWS) in the development of hyponatremia in such patients, as well as their differential diagnosis and management, are also presented. Furthermore, the distinction between true hyponatremia and pseudohyponatremia is explained. Finally, a practical algorithm for the evaluation of hyponatremia in hematologic patients, as well as the principles of hyponatremia management, are included in this review.

Serum electrolyte dynamics in multiple myeloma patients undergoing autologous haematopoietic stem cell transplantation

AIM

High-dose melphalan followed by autologous haematopoietic cell transplantation remains the standard-of-care therapy for multiple myeloma (MM). Gastrointestinal toxicity concomitant with electrolyte derangement is a primary cause of morbidity from transplant. Here, we assessed the dynamics of electrolyte imbalances and its role in hematologic counts and engraftment. Ω Patients and Methods One hundred and eighteen MM patients that received transplant were studied.

RESULTS

Engraftment speed (ES) was calculated as the period between the first rise in the absolute neutrophil count (ANC) and full engraftment defined as the first of three consecutive days with ANC > 500 × 10⁶ /L. The defined median ES was 2 days (range 0-5 days) and 40 patients had ES ≤2 days. Engraftment occurred at a median of 10 days. The median time-to-nadir for phosphorus and potassium was 10 and 4.28 days, respectively. The drop in phosphorus and potassium serum level was statistically greater in patients with an ES ≤2 days compared to patients with ES ≥2 days. Magnesium level were not significantly affected and there was no significant difference between the drop in serum phosphorus and potassium based on severity of nausea or oral mucositis.

CONCLUSION

Our results indicate that there is a significant correlation between the magnitude of drop in potassium and phosphorous levels and a steep rise in neutrophil counts around the engraftment period following stem cell transplant. These events indicate a "genesis syndrome" characterized by a rapid, massive transfer of electrolytes into proliferating cells as has been previously described after HCT for certain high-grade lymphomas and leukemias.

Refeeding syndrome in hematological cancer patients - current approach

Introduction: According to estimates based on the GLOBOCAN database of the International Agency for Research on Cancer, in 2018 alone, 18 100 000 cancers were globally diagnosed. Importantly, the majority of cancer patients experience unintended weight loss that leads to many adverse clinical consequences, including malnutrition and cancer cachexia. At the same time, each nutritional intervention must be carried out individually, as it can lead to critical complications, resulting in a threat to the health and life of the cachectic patient. An example of this type of risk is refeeding syndrome.Areas covered: Three factors seem to be crucial in this case: early identification of patients at risk of malnutrition, the introduction of an individualized diet regimen and constant monitoring of nutritional intervention. It seems equally important to spread awareness about the possibility of refeeding syndrome and knowledge about its patomechanisms and consequences among medical staff. This should lead to minimizing the risk of refeeding syndrome.Expert opinion: It should be noted that current guidelines on the pathogenesis, risk factors and methods of prevention and treatment of refeeding syndrome require further modifications, that would harmonize the management regimen in both prevention and therapy of refeeding syndrome.

Selective and sensitive detection of lysozyme based on plasmon resonance light-scattering of hydrolyzed peptidoglycan stabilized-gold nanoparticles

The simple, economic, rapid, and sensitive detection of lysozyme has an important significance for disease diagnosis since it is a potential biomarker. In this work, a new detection strategy for lysozyme was developed based on the change of the plasmon resonance light scattering (PRLS) signal of peptidoglycan stabilized gold nanoparticles (PGN-AuNPs). Peptidoglycan (PGN) was employed as a stabilizer to prepare PGN-AuNPs which have the properties of a uniform particle size, good stability, and a specific biological function. Due to the specific cleavage of lysozyme to PGN, a very simple specific and sensitive detection method for lysozyme was developed based on the PRLS signal of PGN-AuNPs after mixing with lysozyme for 1.5 h. The enhanced PRLS signals (ΔI_PRLS, at 560 nm) increased linearly with increasing lysozyme in the range 5 nM to 1600 nM with the detection limit down to 2.32 nM (ΔI_PRLS = 41.6397 + 0.5332c, R = 0.9961). When the PGN-AuNP based method was applied to assay lysozyme in authentic human serum samples, the recovery efficiency was 106.76-119.32% with the relative standard deviations in the range of 0.14-3.11%, showing good feasibility. The PGN-AuNP based method for lysozyme assay developed here is simple, rapid, selective, and sensitive, which is expected to provide a feasible new method for the diagnosis or prognosis of lysozyme-related diseases in a clinical setting.

Tumour genesis syndrome: severe hypophosphatemia and hypokalemia may be ominous presenting findings in childhood acute myeloid leukaemia

We report a 16-year-old girl who was diagnosed with acute leukaemia and a marked leucocytosis >200 × 10⁹/L. She presented with marked hypophosphatemia, hypokalemia, acute renal failure and acute respiratory failure. These electrolytes disturbances may indicate rapid tumour genesis. These ominous findings required urgent treatment to halt the crises of rapid leukemic cell proliferation.

CONCLUSION

Mark hypophosphatemia and hypokalemia may be presenting electrolyte abnormalities in a patient with acute leukaemia, and these may be indicators of aggressive tumour genesis. What is known: • Mild electrolyte disturbances are common in oncology patients • Tumour lysis syndrome is well recognized by paediatriaticians What is new: • Life-threatening hypophosphatemia is an uncommon presentation • These electrolytes disorders may indicate an aggressive tumour genesis process even at presentation and require urgent treatment.

Health effects of desalinated water: Role of electrolyte disturbance in cancer development

This review contends that "healthy" water in terms of electrolyte balance is as important as "pure" water in promoting public health. It considers the growing use of desalination (demineralization) technologies in drinking water treatment which often results in tap water with very low concentrations of sodium, potassium, magnesium and calcium. Ingestion of such water can lead to electrolyte abnormalities marked by hyponatremia, hypokalemia, hypomagnesemia and hypocalcemia which are among the most common and recognizable features in cancer patients. The causal relationships between exposure to demineralized water and malignancies are poorly understood. This review highlights some of the epidemiological and in vivo evidence that link dysregulated electrolyte metabolism with carcinogenesis and the development of cancer hallmarks. It discusses how ingestion of demineralized water can have a procarcinogenic effect through mediating some of the critical pathways and processes in the cancer microenvironment such as angiogenesis, genomic instability, resistance to programmed cell death, sustained proliferative signaling, cell immortalization and tumorigenic inflammation. Evidence that hypoosmotic stress-response processes can upregulate a number of potential oncogenes is well supported by a number studies. In view of the rising production and consumption of demineralized water in most parts of the world, there is a strong need for further research on the biological importance and protean roles of electrolyte abnormalities in promoting, antagonizing or otherwise enabling the development of cancer. The countries of the Gulf Cooperative Council (GCC) where most people consume desalinated water would be a logical place to start this research.

Electrolyte disorders associated with the use of anticancer drugs

The use of anticancer drugs is beneficial for patients with malignancies but is frequently associated with the occurrence of electrolyte disorders, which can be hazardous and in many cases fatal. The review presents the electrolyte abnormalities that can occur with the use of anticancer drugs and provides the related mechanisms. Platinum-containing anticancer drugs induce hypomagnesemia, hypokalemia and hypocalcemia. Moreover, platinum-containing drugs are associated with hyponatremia, especially when combined with large volumes of hypotonic fluids aiming to prevent nephrotoxicity. Alkylating agents have been linked with the occurrence of hyponatremia [due to syndrome of inappropriate antidiuretic hormone secretion (SIADH)] and Fanconi's syndrome (hypophosphatemia, aminoaciduria, hypouricemia and/or glucosuria). Vinca alkaloids are associated with hyponatremia due to SIADH. Epidermal growth factor receptor monoclonal antibody inhibitors induce hypomagnesemia, hypokalemia and hypocalcemia. Other, monoclonal antibodies, such as cixutumumab, cause hyponatremia due to SIADH. Tyrosine kinase inhibitors are linked to hyponatremia and hypophosphatemia. Mammalian target of rapamycin inhibitors induce hyponatremia (due to aldosterone resistance), hypokalemia and hypophosphatemia. Other drugs such as immunomodulators or methotrexate have been also associated with hyponatremia. The administration of estrogens at high doses, streptozocin, azacitidine and suramin may induce hypophosphatemia. Finally, the drug-related tumor lysis syndrome is associated with hyperphosphatemia, hyperkalemia and hypocalcemia. The prevention of electrolyte derangements may lead to reduction of adverse events during the administration of anticancer drugs.

Kidney involvement in leukemia and lymphoma

Leukemia and lymphoma are hematologic malignancies that can affect any age group. Disease can be aggressive or indolent, often with multiorgan system involvement. Kidney involvement in leukemia and lymphoma can be quite extensive. Acute kidney injury (AKI) is quite prevalent in these patients, with prerenal and acute tubular necrosis being the most common etiologies. However other prerenal, intrinsic, and obstructive etiologies are possible. AKI can be a direct effect of the malignancy, a complication of the malignancy, or the consequence or side effect of chemotherapy. Nephrotic syndrome and glomerulonephritis, often presenting without overt kidney failure, have also been seen in all forms of leukemia and lymphoma. Lastly, the direct effects of the malignancy and complications from the tumor often result in numerous electrolyte disturbances and acid-base disorders, with life-threatening consequences if left untreated.

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.

Hyponatremia in patients with heart failure

The present review analyses the mechanisms relating heart failure and hyponatremia, describes the association of hyponatremia with the progress of disease and morbidity/mortality in heart failure patients and presents treatment options focusing on the role of arginine vasopressin (AVP)-receptor antagonists. Hyponatremia is the most common electrolyte disorder in the clinical setting and in hospitalized patients. Patients with hyponatremia may have neurologic symptoms since low sodium concentration produces brain edema, but the rapid correction of hyponatremia is also associated with major neurologic complications. Patients with heart failure often develop hyponatremia owing to the activation of many neurohormonal systems leading to decrease of sodium levels. A large number of clinical studies have associated hyponatremia with increased morbidity and mortality in patients hospitalized for heart failure or outpatients with chronic heart failure. Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy. AVP-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia. However, the effects of AVP-receptor antagonists on hard outcomes in patients with heart failure and hyponatremia have not been thoroughly examined.

Adrenal crisis in a patient with acute myeloid leukaemia

Adrenal crisis is a group of clinical manifestation predominantly with hypotensive shock, electrolyte imbalance in a patient with adrenal insufficiency or in a patient who was abruptly withdrawn from glucocorticoid treatment acute myeloid leukaemia (AML) is one of the most common acute leukaemia in adults. Though the above diseases are commonly seen in individual patients, the coexistence of both conditions in the same patient is rare. We reported a 64-year-old African-American man with a history of bilateral deep vein thrombosis, who presented initially with fatigue, neutropenia and macrocytic anaemia. The patient developed a small bowel obstruction during his first hospital course, which resolved spontaneously with conservative management after an exploratory laparotomy. While waiting for his bone marrow biopsy, the patient developed hypotension, hyponatraemia and hyperkalaemia for which adrenal crisis was suspected. Later on, laboratory studies confirmed the diagnosis of primary adrenal insufficiency and the bone marrow was conclusive for AML.

Hyperosmotic stress strongly potentiates serum response factor (SRF)-dependent transcriptional activity in Ehrlich Lettré Ascites cells through a mechanism involving p38 mitogen-activated protein kinase

Long-term osmotic stress results in altered gene transcription, however, with the exception of the TonE/TonEBP system, the underlying mechanisms are poorly understood. We previously showed that upon osmotic shrinkage of Ehrlich Lettré Ascites (ELA) fibroblasts, the MEK1-ERK1/2 pathway is transiently inhibited while p38 MAPK is activated, in turn impacting on cell survival (Pedersen et al., 2007, Cell Physiol Biochem 20: 735-750). Here, we show that downstream of these kinases, two transcription factors with major roles in control of cell proliferation and death, serum response factor (SRF) and cAMP response element-binding protein (CREB) are differentially regulated in ELA cells. SRF Ser(103) phosphorylation and SRF-dependent transcriptional activity were strongly augmented 5-30 min and 24 h, respectively, after hyperosmotic stress (50% increase in extracellular ionic strength), in a p38 MAPK-dependent manner. In contrast, CREB Ser(133) was transiently dephosphorylated upon osmotic shrinkage. The ERK1/2 effector ribosomal S kinase (RSK) and the ERK1/2- and p38 MAPK effector mitogen- stress-activated protein kinase 1 (MSK1) both phosphorylate CREB at Ser(133) . RSK and MSK1 were dephosphorylated within 5 min of shrinkage. MSK1 phosphorylation recovered within 30 min in a p38-MAPK-dependent manner. CREB was transiently dephosphorylated after shrinkage in a manner exacerbated by p38 MAPK inhibition or MSK1 knockdown, but unaffected by inhibition of RSK. In conclusion, in ELA cells, hyperosmotic stress activates SRF in a p38 MAPK-dependent manner and transiently inactivates CREB, likely due to MSK1 inactivation. We suggest that these events contribute to shrinkage-induced changes in gene transcription and death/survival balance.

Electrolyte disturbances and acute kidney injury in patients with cancer

The interrelation between kidney disease and cancer is complex and reciprocal. Among the most frequent cancer-associated kidney diseases are the electrolyte and acid-base disturbances, which occur frequently and often are associated with an ominous prognosis, and acute kidney injury. Tumor lysis syndrome is a potentially life-threatening condition that frequently occurs in patients with a high tumor burden and high cellular turnover after cytotoxic therapy (including steroids in steroid-sensitive hematologic malignancies). Electrolyte and acid-base disturbances are the consequence of neoplastic spread, anticancer treatment, or, more rarely, paraneoplastic phenomena of all types of tumors. This article reviews hyponatremia and hypernatremia, hypokalemia and hyperkalemia, hypomagnesemia, hypercalcemia and hypocalcemia, hypophosphatemia, and the most important disturbances in acid-base balance in cancer patients. Acute kidney injury (AKI) is a frequent occurrence in cancer patients and has the potential to substantially alter the outcome of patients with cancer and jeopardize their chances of receiving optimal cancer treatment and a potential cure. As in many other circumstances, the etiology of AKI in cancer patients is multifactorial. Initiation and/or continuation of dialysis in the AKI cancer patient should be based on the general clinical condition and overall life expectancy and the personal patient expectations on quality of life after eventual recovery.

High Serum and Urine Lysozyme Levels in a Dog with Acute Myeloid Leukemia

A 2-year-old, female German Shepherd Dog with facial nerve paralysis was diagnosed with acute myelomonocytic leukemia based on clinical, cytologic, and immunologic findings. Proteinuria (urine protein:creatinine ratio = 1.5) occurred in the absence of renal failure. Qualitative assessment of proteinuria by sodium dodecyl sulfate–agarose gel electrophoresis revealed a broad band with a molecular weight of approximately 15 kDa that was compatible with lysozyme (LZM). A diagnosis of tubular proteinuria was made, and a chemical evaluation of LZM in serum and urine samples was performed using a turbidimetric assay. The LZM concentrations were 24.5 mg/l (reference interval: 2.5–8.0 mg/l) and 274.5 mg/l (reference interval: <2 mg/l) in serum and urine, respectively.

Reversible renal failure due to bilateral renal sarcoma in a patient with acute myeloid leukemia

A 68-year-old male presented with acute myeloid leukemia, renal failure, hypokalemia, and enlarged kidneys on renal ultrasound. Renal biopsy revealed massive leukemic infiltration of the kidney. After systemic chemotherapy, the patient developed tumor lysis syndrome followed by a phase of proximal tubule dysfunction presenting as polyuria and diverse electrolyte abnormalities. In time, renal function returned to normal, as did kidney size. This report shows that renal failure, enlargement of the kidneys, and tubule dysfunction in the course of AML infiltrating the kidneys can be reversed by treatment of the hematological disease.

Acute renal problems in the critically ill cancer patient

PURPOSE OF REVIEW

This review addresses three major topics relevant for the management of renal problems in the critically ill cancer patient; the assessment of kidney function in patients with cancer, serious water and electrolyte metabolism disturbances and acute kidney injury secondary to hematological and nonhematological malignancies.

RECENT FINDINGS

In all cancer patients, renal function (urinalysis for proteinuria or albuminuria and serum creatinine to estimate glomerular filtration rate) should be tested when they first present, at initiation and change of cancer therapy as well as during follow-up. However, the different proposed formulae for estimation of the glomerular filtration rate should be used with caution. Electrolyte abnormalities associated with the refeeding syndrome are common, yet underappreciated, and occur typically in acutely ill, malnourished hospitalized patients who are administered intravenous or enteral nutrition. Currently available data on acute kidney injury and its consequences suggest that acute kidney injury has the potential to substantially alter the outcome of patients with cancer and jeopardize their chances of receiving optimal cancer treatment and a potential cure.

SUMMARY

The complex management of the numerous renal complications of the critically ill cancer patient needs a multidisciplinary approach in which the nephrologist, intensivist and oncologist all play a pivotal role.

Cell volume regulation: physiology and pathophysiology

Cell volume perturbation initiates a wide array of intracellular signalling cascades, leading to protective and adaptive events and, in most cases, activation of volume-regulatory osmolyte transport, water loss, and hence restoration of cell volume and cellular function. Cell volume is challenged not only under physiological conditions, e.g. following accumulation of nutrients, during epithelial absorption/secretion processes, following hormonal/autocrine stimulation, and during induction of apoptosis, but also under pathophysiological conditions, e.g. hypoxia, ischaemia and hyponatremia/hypernatremia. On the other hand, it has recently become clear that an increase or reduction in cell volume can also serve as a specific signal in the regulation of physiological processes such as transepithelial transport, cell migration, proliferation and death. Although the mechanisms by which cell volume perturbations are sensed are still far from clear, significant progress has been made with respect to the nature of the sensors, transducers and effectors that convert a change in cell volume into a physiological response. In the present review, we summarize recent major developments in the field, and emphasize the relationship between cell volume regulation and organism physiology/pathophysiology.

Causes and mechanisms of acid-base and electrolyte abnormalities in cancer patients

Patients with cancer frequently exhibit acid-base and electrolyte disturbances that complicate their management and prolong their hospitalization. The mechanisms encountered for these abnormalities are multifactorial in origin. Both the underlying disease and the therapeutic interventions can contribute to the development of these disturbances. An understanding of the mechanisms involved in their pathogenesis is of paramount importance for their prevention and treatment in cancer patients. This article briefly reviews the causes and the pathophysiology of acid-base and electrolyte abnormalities observed in cancer patients.

Acute lymphoblastic leukemia presenting as acute renal failure

BACKGROUND

A 42-year-old previously healthy man presented with acute-onset headache and facial paralysis. He was treated for Bell's palsy with corticosteroids and valaciclovir. One week later, he developed acute renal failure requiring hospitalization.

INVESTIGATION

Physical examination, laboratory tests, urinalysis, renal ultrasound, renal biopsy, bone marrow biopsy, lumbar puncture, CT of the chest, abdomen and pelvis, MRI of the brain, and whole-body PET scan.

DIAGNOSIS

Acute lymphoblastic leukemia, bilateral renal enlargement secondary to leukemic infiltration, acute renal failure, tumor lysis syndrome, and leukemic involvement of the facial nerve.

MANAGEMENT

The patient was treated with a modified induction chemotherapy regimen. He was given allopurinol for hyperuricemia and hydrated with alkalized intravenous fluids to prevent uric acid precipitation in the renal tubules. The profound tumor lysis that occurred after the cytotoxic chemotherapy required hemodialysis.