Hypocalcemia and hypomagnesemia in cancer patients

Hypermagnesemia is associated with poor outcomes during hospitalization

BACKGROUND

Hypermagnesemia is one of the vital electrolyte disturbances and is associated with such chronic conditions as cardiovascular, endocrinologic, renal diseases, and malignancy.

AIM

This study evaluates the association between hypermagnesemia and clinical course in hospitalized patients.

METHODS

This study was conducted at the University of Health Sciences Haseki Training and Research Hospital Internal Medicine Clinic. We evaluated a total of 3850 patients. 2130 patients have met the inclusion criteria were included in the study. Those who were discharged with healing were evaluated as having a good prognosis. Patients who died or were transferred to the intensive care unit (ICU) were defined as having a poor prognosis. We divided the patients' serum magnesium levels into four quartiles and examined the clinical course/conditions of the patients.

RESULTS

Of 2130 patients, 1013 (51.9%) were female. The mean age of patients with poor prognoses (69.2 ± 14.9) was higher than those with good prognoses (59.7 ± 19.1). Hypermagnesemia (4th quartile) was detected in 61 (33.9%), and hypomagnesemia (1st quartile) was found in 42 (23.3%) patients out of 180 patients with poor clinical outcomes. It was statistically significant that hypermagnesemia was more common in patients with poor prognoses (p: 0.002). Chronic kidney disease (CKD) was diagnosed in 258 (53.3%) of 484 hypermagnesemia patients. Hypermagnesemia was found to be more common in patients with CKD, which was statistically significant (p: 0.003).

CONCLUSIONS

Hypermagnesemia is associated with poor prognosis independent of comorbidities. Besides hypomagnesemia, hypermagnesemia should be considered a critical electrolyte imbalance.

Disorders of Divalent Ions (Magnesium, Calcium, and Phosphorous) in Patients With Cancer

Disorders of the divalent ions (magnesium, calcium, and phosphorous) are frequently encountered in patients with cancer. Of these, hypomagnesemia, hypocalcemia, hypercalcemia, and hypophosphatemia are seen most commonly. These electrolyte disturbances may be related to the underlying malignancy or due to side effects of anticancer therapy. When caused by a paraneoplastic process, these abnormalities may portend a poor prognosis. Importantly, the development of severe electrolyte derangements may be associated with symptoms that negatively impact quality of life, preclude the administration of critical chemotherapeutic agents, or lead to life-threatening complications that require hospitalization and emergent treatment. In accordance, prompt recognition and treatment of these disorders is key to improving outcomes in patients living with cancer. This review will discuss selected derangements of the divalent ions seen in this population, with a focus on paraneoplastic and therapy-associated etiologies.

Electrolyte Disorders Induced by Antineoplastic Drugs

The use of antineoplastic drugs has a central role in treatment of patients affected by cancer but is often associated with numerous electrolyte derangements which, in many cases, could represent life-threatening conditions. In fact, while several anti-cancer agents can interfere with kidney function leading to acute kidney injury, proteinuria, and hypertension, in many cases alterations of electrolyte tubular handling and water balance occur. This review summarizes the mechanisms underlying the disturbances of sodium, potassium, magnesium, calcium, and phosphate metabolism during anti-cancer treatment. Platinum compounds are associated with sodium, potassium, and magnesium derangements while alkylating agents and Vinca alkaloids with hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH). Novel anti-neoplastic agents, such as targeted therapies (monoclonal antibodies, tyrosine kinase inhibitors, immunomodulators, mammalian target of rapamycin), can induce SIADH-related hyponatremia and, less frequently, urinary sodium loss. The blockade of epidermal growth factor receptor (EGFR) by anti-EGFR antibodies can result in clinically significant magnesium and potassium losses. Finally, the tumor lysis syndrome is associated with hyperphosphatemia, hypocalcemia and hyperkalemia, all of which represent serious complications of chemotherapy. Thus, clinicians should be aware of these side effects of antineoplastic drugs, in order to set out preventive measures and start appropriate treatments.

Doxorubicin Loaded Magnesium Oxide Nanoflakes as pH Dependent Carriers for Simultaneous Treatment of Cancer and Hypomagnesemia

Doxorubicin (DOX) is an anticancer drug commonly used in treating cancer; however, it has severe cytotoxicity effects. To overcome both the adverse effects of the drug and mineral deficiency (i.e., hypomagnesemia) experienced by cancer patients, we have developed magnesium oxide (MgO) nanoflakes as drug carriers and loaded them with DOX for use as a targeted drug delivery (TDD) system for potential application in cancer therapy. The synthesis employed herein affords pure, highly porous MgO nanoparticles that are void of the potentially harmful metal contaminants often discussed in the literature. Purposed for dual therapy, the nanoparticles exhibit an impressive 90% drug loading capacity with pH dependent drug releasing rates of 10% at pH 7.2, 50.5% at pH 5.0, and 90.2% at pH 3. Results indicate that therapy is achievable via slow diffusion where MgO nanoflakes degrade (i.e., dissolve) under acidic conditions releasing the drug and magnesium ions to the cancerous region. The TDD system therefore minimizes cytotoxicity to healthy cells while supplying magnesium ions to overcome hypomagnesemia.

Hypomagnesemia Is Prevalent in Patients Undergoing Gynecologic Surgery by a Gynecologic Oncologist

OBJECTIVE

The aim of this study was to assess the incidence of and risk factors for hypomagnesemia in patients undergoing gynecologic surgery by a gynecologic oncologist.

METHODS

A retrospective chart review was performed on all patients undergoing surgery for gynecologic pathology from July 2011 to July 2015 by a single surgeon. Demographic data, surgical indication, surgery performed, preoperative laboratory values, postoperative laboratory values, and medical history were examined. Hypomagnesemia was defined as less than 1.8 mg/dL. Hypermagnesemia was defined as greater than 2.5 mg/dL.

RESULTS

Six hundred sixty-nine patients were identified for analysis. One hundred ninety-seven patients had hypomagnesemia (29.4%). Four hundred sixty-six patients had normal magnesium levels (69.5%), and 6 patients had hypermagnesemia (1%). Among patients with benign disease, 24.9% had preoperative hypomagnesemia compared with 32.7% of patients with a gynecologic malignancy. African American race (P = 0.041), diabetes mellitus (P < 0.001), and malignancy (P = 0.029) were all associated with preoperative hypomagnesemia. Diabetes and major surgery were associated with postoperative hypomagnesemia (P = 0.012 and P = 0.048, respectively). Hypomagnesemia was associated with increased preoperative and postoperative pain (P = 0.049 and P < 0.001, respectively) as well as postoperative hypokalemia (P = 0.001). Age, body mass index, hypertension, cancer type, hematocrit, surgical indication, and length of hospital stay were not associated with hypomagnesemia.

CONCLUSIONS

Perioperative hypomagnesemia is prevalent in patients undergoing gynecologic surgery by a gynecologic oncology, especially in patients who have a gynecologic malignancy. We recommend routine preoperative and postoperative evaluation of serum magnesium in all patients undergoing gynecologic surgery by a gynecologic oncologist.

Magnesium homeostasis and hypomagnesemia in children with malignancy

Hypomagnesemia is not uncommon among children with malignancies. It is especially seen in association with certain medications and can be further complicated by the presence of diarrhea and malnutrition. Severe hypomagnesemia may cause disturbances in the neuromuscular and cardiovascular systems. All patients with hypomagnesemia should be supplemented with the mineral, and urgent treatment is indicated when serum magnesium decreases below 1.0 mg/dl, a level under which symptoms may develop. This review addresses the essentials of magnesium physiology, and pathophysiology of hypomagnesemia, its etiologies, clinical manifestations and ways to treat it, with an emphasis on the child with hematologic/oncologic disorders.

Drug-induced hypomagnesaemia : scope and management

Nearly 50 medications have been implicated as inducing hypomagnesaemia, sometimes based on insufficient data regarding clinical significance and frequency of occurrence. In fact, clinical effects attributed to hypomagnaesemia have been reported in only 17 of these drugs. A considerable amount of literature relating to individual drugs has been published, yet a comprehensive overview of this issue is not available and the hypomagnesaemic effect of a drug could be either overemphasised or under-rated. In addition, there are neither guidelines regarding treatment, prevention and monitoring of drug-induced hypomagnesaemia nor agreement as to what serum level of magnesium may actually be defined as 'hypomagnesaemia'. By compiling data from published papers, electronic databases, textbooks and product information leaflets, we attempted to assess the clinical significance of hypomagnesaemia induced by each drug. A practical approach for managing drug-induced hypomagnesaemia, incorporating both published literature and personal experience of the physician, is proposed. When drugs classified as inducing 'significant' hypomagnesaemia (cisplatin, amphotericin B, ciclosporin) are administered, routine magnesium monitoring is warranted, preventive treatment should be considered and treatment of hypomagnesaemia should be initiated with or without overt clinical manifestations. In drugs belonging to the 'potentially significant' category, among which are amikacin, gentamicin, laxatives, pentamidine, tobramycin, tacrolimus and carboplatin, magnesium monitoring is justified when either of the following occurs: clinical manifestations are apparent; persistent hypokalaemia, hypocalcaemia or alkalosis are present; other precipitating factors for hypomagnesaemia coexist; or treatment is with more than one potentially hypomagnesaemic drug. No preventive treatment is required and treatment should be initiated only if hypomagnesaemia is accompanied by symptoms or clinically significant relevant laboratory findings. In those drugs whose hypomagnesaemic effect is labelled as 'questionable', including furosemide and hydrochlorothiazide, routine monitoring and treatment are not required.

Serum magnesium aberrations in furosemide (frusemide) treated patients with congestive heart failure: pathophysiological correlates and prognostic evaluation

OBJECTIVES

To determine the prevalence of hypomagnesaemia and hypermagnesaemia, to discern various factors associated with abnormal serum magnesium, and to estimate prognostic significance of serum magnesium aberrations in patients with congestive heart failure.

DESIGN

Observational study.

SETTING

Medical department of a university hospital (tertiary referral centre).

PATIENTS

404 consecutive patients admitted with congestive heart failure as one of the diagnoses and previously treated with furosemide (frusemide) for at least three months.

MAIN OUTCOME MEASURES

Clinical, biochemical, and electrocardiographic variables were analysed with respect to serum magnesium aberrations. Following discharge, mortality rates, including sudden death, were registered.

RESULTS

Hypomagnesaemia was found in 50 patients (12.3%) and 20 (4.9%) were hypermagnesaemic. Female sex (p < 0.04), diabetes mellitus (p < 0.006), hypocalcaemia (p = 0.03), hyponatraemia (p < 0.05), malignant disease (p = 0.05), and high fever (p = 0.05) were statistically associated with hypomagnesaemia. Renal failure, severe congestive heart failure, and high dose furosemide treatment (> 80 mg/day) were associated with hypermagnesaemia (p < 0.001, p = 0.05, and p < 0.03, respectively). Hypermagnesaemic patients were older and weighed less. On follow up (median duration 43 months), 169 (41.8%) died, with 22 (13%) sudden deaths. Mortality was highest with hypermagnesaemia, lowest with normomagnesaemia, and intermediate with hypomagnesaemia. After adjustment for renal failure, old age, and severity of congestive heart failure, hypomagnesaemia but not hypermagnesaemia emerged as being significantly associated with shorter survival (p = 0.009). No statistical association was found between sudden death and magnesium concentrations.

CONCLUSIONS

While hypermagnesaemia seems to represent a prognostic marker only, hypomagnesaemia appears to have an adverse pathophysiological effect. The subgroup of patients at risk for hypomagnesaemia requires frequent serum magnesium determinations and magnesium replacement for as long as hypomagnesaemia persists.

Changes in magnesium content and subcellular distribution during retinoic acid-induced differentiation of HL60 cells

Magnesium (Mg) is required for cellular proliferation; however, the differences in subcellular regulation of Mg between proliferating and differentiated cells has not been determined. We used electron probe microanalysis (EPMA) to investigate the subcellular distribution of Mg in HL60 cells (a promyelocytic leukemia cell line) before and after retinoic acid (RA)-induced differentiation. Most intracellular Mg is bound to ATP and the Mg-ATP complex regulates several metabolic enzymes. We also compared alterations in Mg content following differentiation with the changes in ATP and ADP levels. Using atomic absorption spectrophotometry, we observed a significant decrease (-20%) in cellular Mg content in RA-differentiated HL60 cells. To investigate which intracellular compartments were involved in these changes, we analyzed subcellular elemental composition in freeze-dried cryosections of rapidly frozen undifferentiated and differentiated HL60 cells by EPMA. Following differentiation of HL60 cells, we observed an 18% decrease in Mg content in both the cytoplasm (regions of the cell excluding mitochondria and nuclei) and mitochondria. There was also a significant (40%) decrease in cytoplasmic Ca content after RA-induced differentiation. Nuclear Mg concentration was not significantly different between differentiated and undifferentiated HL60 cells, although differentiation was accompanied by a 30% decrease in the nuclear K/Na ratio. After differentiation, cellular ATP and ADP content decreased by 31 and 40%, respectively. We conclude that during exit from the cell cycle, Mg redistributes within cells and that the decrease in cytoplasmic and mitochondrial Mg is accompanied by a decrease in ATP and ADP content.