Severe hypophosphataemia during stem cell harvesting in chronic myeloid leukaemia

Summary. Peripheral blood stem cell autografts for the treatment of chronic myeloid leukaemia (CML) are currently under evaluation. A patient with CML received intensive chemotherapy followed by granulocyte colony-stimulating factor prior to the collection of peripheral blood derived stem cells. He developed unusually severe, and fatal, hypophosphataemia and this coincided with the rapid rise of his peripheral blood white cell count. The hypophosphataemia was considered to be due to a combination of severe anorexia, sepsis and the rapid growth factor-stimulated myeloid regeneration in CML.     

Plasma vitamin D metabolites in a patient with sporadic hypophosphataemic osteomalacia (adult-onset type)

Sporadic hypophosphataemic osteomalacia (adult-onset type) was demonstrated in a 40-year-old man on the basis of severe osteomalacia, hypophosphataemia, hyperphosphaturia and glycinuria. Plasma immunoreactive parathyroid hormone (iPTH) concentration was 9.3 ng prot./ml (normal range: 4-8 ng prot./ml). Plasma 25-hydroxy-vitamin D and 24,25-dihydroxy-vitamin D concentrations were 11 and 2.4 ng/ml respectively. Basal 1 alpha,25-dihydroxy-vitamin D concentrations were slightly elevated (116 and 96 pg/ml) and increased to 240 pg/ml after 3 days on a low-phosphorus diet. The patient was put on oral treatment with 25-hydroxycholecalciferol (100 microgram per day) and phosphorus (1500 mg per day). On the 4th month on treatment, a clinical improvement was apparent. Plasma 25(OH)D was 44 ng/ml, plasma 1,25(OH)2D was 256 pg/ml. However, plasma phosphorus remained low (0.77 mmol/l). On the 9th month of treatment a radiological improvement was evident despite a persistent hypophosphataemia (0.68 mmol/l). These facts suggest in our patient the existence of a vitamin D-independent renal phosphorus leak.     

Severe electrolyte disorders following cardiac surgery: a prospective controlled observational study

Introduction

Electrolyte disorders are an important cause of ventricular and supraventricular arrhythmias as well as various other complications in the intensive care unit. Patients undergoing cardiac surgery are at risk for development of tachyarrhythmias, especially in the period during and immediately after surgical intervention. Preventing electrolyte disorders is thus an important goal of therapy in such patients. However, although levels of potassium are usually measured regularly in these patients, other electrolytes such as magnesium, phosphate and calcium are measured far less frequently. We hypothesized that patients undergoing cardiac surgical procedures might be at risk for electrolyte depletion, and we therefore conducted the present study to assess electrolyte levels in such patients.

Methods

Levels of magnesium, phosphate, potassium, calcium and sodium were measured in 500 consecutive patients undergoing various cardiac surgical procedures who required extracorporeal circulation (group 1). A total of 250 patients admitted to the intensive care unit following other major surgical procedures served as control individuals (group 2). Urine electrolyte excretion was measured in a subgroup of 50 patients in both groups.

Results

All cardiac patients received 1 l cardioplegia solution containing 16 mmol potassium and 16 mmol magnesium. In addition, intravenous potassium supplementation was greater in cardiac surgery patients (mean ± standard error: 10.2 ± 4.8 mmol/hour in cardiac surgery patients versus 1.3 ± 1.0 in control individuals; P < 0.01), and most (76% versus 2%; P < 0.01) received one or more doses of magnesium (on average 2.1 g) for clinical reasons, mostly intraoperative arrhythmia. Despite these differences in supplementation, electrolyte levels decreased significantly in cardiac surgery patients, most of whom (88% of cardiac surgery patients versus 20% of control individuals; P < 0.001) met criteria for clinical deficiency in one or more electrolytes. Electrolyte levels were as follows (mmol/l [mean ± standard error]; cardiac patients versus control individuals): phosphate 0.43 ± 0.22 versus 0.92 ± 0.32 (P < 0.001); magnesium 0.62 ± 0.24 versus 0.95 ± 0.27 (P < 0.001); calcium 1.96 ± 0.41 versus 2.12 ± 0.33 (P < 0.001); and potassium 3.6 ± 0.70 versus 3.9 ± 0.63 (P < 0.01). Magnesium levels in patients who had not received supplementation were 0.47 ± 0.16 mmol/l in group 1 and 0.95 ± 0.26 mmol/l in group 2 (P < 0.001). Urinary excretion of potassium, magnesium and phosphate was high in group 1 (data not shown), but this alone could not completely account for the observed electrolyte depletion.

Conclusion

Patients undergoing cardiac surgery with extracorporeal circulation are at high risk for electrolyte depletion, despite supplementation of some electrolytes, such as potassium. The probable mechanism is a combination of increased urinary excretion and intracellular shift induced by a combination of extracorporeal circulation and decreased body temperature during surgery (hypothermia induced diuresis). Our findings may partly explain the high risk of tachyarrhythmia in patients who have undergone cardiac surgery. Prophylactic supplementation of potassium, magnesium and phosphate should be seriously considered in all patients undergoing cardiac surgical procedures, both during surgery and in the immediate postoperative period. Levels of these electrolytes should be monitored frequently in such patients.     

Severe hypocalcaemia and hypophosphataemia following intravenous iron and denosumab: a novel drug interaction

We present the case of a 59‐year‐old woman with chronic kidney disease who suffered severe hypocalcaemia and hypophosphataemia after receiving denosumab and intravenous iron. This potentially life‐threatening adverse drug interaction has never been reported before. We propose a mechanism to explain it with reference to the physiological derangements caused by both agents on calcium and phosphate homeostasis.     

High-dose fast infusion of parenteral iron isomaltoside is efficacious in inflammatory bowel disease patients with iron-deficiency anaemia without profound changes in phosphate or fibroblast growth factor 23

Objective: Iron isomaltoside (Monofer^®) is a high-dose intravenous iron preparation with good tolerability and efficacy in inflammatory bowel disease (IBD) patients with iron deficiency anaemia (IDA). This trial evaluates the safety and efficacy, including effect on intact fibroblast growth factor 23 (iFGF23) of a high single dose and cumulative doses of iron isomaltoside in IBD patients with IDA.

Materials and methods: The trial was a prospective, open-label, multi-centre trial conducted in IBD patients with IDA. Based upon haemoglobin (Hb) levels at baseline and weight, the patients received 1500, 2000, 2500 or 3000?mg of iron isomaltoside infused in single doses up to 2000?mg. The outcome measurements included adverse drug reactions (ADRs) and changes in haematology and biochemistry parameters.

Results: Twenty-one IBD patients with IDA were enrolled, receiving 1500 (seven patients), 2000 (eight patients), 2500?mg (four patients) or 3000 (two patients) mg of iron. No serious ADRs were observed. Four patients experienced nine mild to moderate ADRs (hypersensitivity, pyrexia, vomiting, constipation, abdominal pain, dyspepsia (two events) and eye allergy (two events)). In total, 15 (75%) patients had an increase in Hb of ≥2.0?g/dL during the trial, with normalisation of ferritin. No changes in iFGF23 or clinically significant hypophosphataemia were found.

Conclusion: Rapid infusions of high-dose iron isomaltoside, administered as single doses up to 2000?mg and cumulative doses up to 3000?mg, were without safety concerns and were efficacious in increasing Hb levels in IBD patients. Iron isomaltoside did not induce profound phosphate wasting via increased iFGF23 levels.     

Craniosynostosis in X-linked hypophosphataemic rickets

A report of three cases of craniosynostosis in X-linked hypophosphataemic rickets (XLH) is presented. The literature is reviewed, suggesting that craniosynostosis is relatively common in XLH and that boys may be more at risk than girls. It is recommended that radiological screening be offered to all patients with XLH.     

阿德福韦酯致Fanconi综合征6例并文献复习

目的:了解阿德福韦酯导致肾脏损伤的临床特点和预后。方法:报告6例小剂量阿德福韦酯导致Fanconi综合征的患者临床起病和肾损害特点、诊断以及预后。结合文献讨论长期应用阿德福韦酯时肾损害的合理监测和早期诊断。结果:长期小剂量服用阿德福韦酯可以导致Fanconi综合征,临床表现隐袭,容易延误诊断。如果及时停药,肾小管功能可以恢复。结论:应提高对于阿德福韦酯肾脏损害的认识,在患者服药过程中应加强随访,一旦发现肾脏受损应尽早干预。