Prevalence of hypophosphatemia in sepsis and infection: the role of cytokines

Fluid and electrolyte pathophysiology in common febrile illness in children and the implications for clinical management

Achieving fluid homeostasis and the management of fluid and electrolyte complications are constants in the treatment of seriously ill children worldwide. Consensus on the most appropriate fluid strategy for unwell children has been difficult to achieve and has evolved over the last two decades, most notably in high-income countries where adverse events relating to poor fluid management were identified more readily, and official robust inquiries were possible. However, this has not been the situation in many low-income settings where fluids that are prohibited from use in high-income countries may be all that are available, local guidelines and processes to recognise adverse events are not developed, and there has been limited training on safe fluid management for front-line healthcare workers. This narrative review outlines the fluid and electrolyte pathophysiology of common febrile illnesses in children, describes the evolution of this field and concludes with implications and principles of a fluid management strategy for seriously ill children. This review was prepared as a physiological background paper to support evidence presented to the WHO Guideline Development Group for Fluid Guidelines in Children, Geneva, March 2024.

Differential Serum Phosphate Levels in Pediatric Febrile Syndromes and Their Clinical Significance

BACKGROUND

The potential of hypophosphatemia (HP) to differentiate between febrile syndromes and its clinical significance in children without sepsis were not previously described.

METHODS

Data were retrospectively collected of febrile children aged 3 months to 18 years, hospitalized at general pediatric wards during 2010-2019. Phosphate levels were compared between bacterial infection (BI), viral infection (VI), and Kawasaki disease (KD). Regression analyses were used to evaluate the relationship between HP and outcome.

RESULTS

Of 3963 febrile children, 559 had BI, 3271 had VI, and 133 had KD. In BI compared to VI and KD, HP was more prevalent (49.2%, 19.7%, and 31.6%, respectively; P<0.001) and more severe [median (interquartile range) phosphate standard deviation score: -1.85 (2.08), -0.56 (2.08), and -1.20 (2.28), respectively; P<0.001]. In the BI group, Pi-SDS level was lower among patients with than without bacteremia (-2.33 ± 1.8 vs. -0.79 ± 1.68; P<0.001). Phosphate levels displayed discriminatory potential between bacterial and viral etiologies, with an area under the curve of 0.719 (95% CI, 0.697-0.742). Minimal phosphate standard deviation score values had a negative weak correlation with the maximal C-reactive protein levels and white blood cell count. Univariate and multivariate analyses showed an association of HP with a more severe disease course, manifested by longer hospital stay [+2.10 (95% CI, 0.75-3.46) days; P=0.003] and a higher rate of intensive care unit admission [odds ratio, 2.63 (95% CI, 1.94-3.56); P<0.001).

CONCLUSIONS

Hypophosphatemia rates were highest in bacterial etiology, intermediate in KD, and lowest in viral etiology and were associated with poorer outcomes. Phosphate level may serve as a marker for ruling out a bacterial etiology.

Hypophosphataemia and late-onset sepsis in extremely preterm neonates: A case-control study

AIM

Late-onset sepsis (LOS) is common in extreme prematurity. These infants are at risk of refeeding syndrome-associated hypophosphataemia. Our objective was to investigate whether hypophosphataemia predisposes to LOS in extremely premature neonates.

METHODS

A retrospective case-control study of neonates born before 29 weeks' gestation in an Australian NICU from 2016 to 2020. Cases developed LOS or localised infection. Two controls, matched within 2 gestational weeks and 90 calendar days, were selected per case.

RESULTS

Amongst 48 cases and 93 controls, cases were smaller at birth (767 g vs. 901 g, P = 0.01), but were otherwise comparable. Hypophosphataemia was more common in cases (26% vs. 15%, P = 0.18). Increased intravenous protein intake in the first week was protective against LOS (OR = 0.9, 95% CI 0.76-1.00, P = 0.04); median 2.1 g/kg/day in cases, 2.3 g/kg/day in controls.

CONCLUSIONS

Hypophosphataemia as part of refeeding syndrome is prevalent and under-recognised in extremely premature neonates. We did not find an association between hypophosphataemia and LOS. Low intravenous protein may be an independent risk factor for infection.

Evaluation of a Novel Enteral Phosphorus Therapy with Enteral Nutrition during a National Intravenous Sodium Phosphate Shortage

The purpose of this study was to evaluate the efficacy and safety of intragastric administration of small volumes of sodium enema solution containing phosphorus as phosphorus replacement therapy in critically ill patients with traumatic injuries who required continuous enteral nutrition. Adult patients (>17 years of age) who had a serum phosphorus concentration <3 mg/dL (0.97 mmol/L) were evaluated. Patients with a serum creatinine concentration >1.4 mg/dL (124 µmol/L) were excluded. Patients were given 20 mL of saline enema solution intragastrically, containing 34 mmol of phosphorus and mixed in 240 mL water. A total of 55% and 73% of patients who received one (n = 22) or two doses (n = 11) had an improvement in the serum phosphorus concentration, respectively. The serum phosphorus concentration increased from 2.5 [2.1, 2.8] mg/dL (0.81 [0.69, 0.90] mmol/L) to 2.9 [2.2, 3.0] mg/dL (0.94 [0.71, 0.97 mmol/L) for those who received two doses (p = 0.222). Excluding two patients with a marked decline in serum phosphorus by 1.3 mg/dL (0.32 mmol/L) resulted in an increase in the serum phosphorus concentration from 2.3 [2.0, 2.8] mg/dL (0.74 [0.65, 0.90] mmol/L) to 2.9 [2.5, 3.2] mg/dL (0.94 [0.81, 1.03] mmol/L; n = 9; p = 0.012). No significant adverse effects were noted. Our data indicated that intragastric phosphate administration using a small volume of saline enema solution improved the serum phosphorus concentrations in most patients.

Involvement of Inflammatory Cytokines, Renal NaPi-IIa Cotransporter, and TRAIL Induced-Apoptosis in Experimental Malaria-Associated Acute Kidney Injury

The murine model of experimental cerebral malaria (ECM) induced by Plasmodium berghei ANKA was used to investigate the relationship among pro-inflammatory cytokines, alterations in renal function biomarkers, and the induction of the TRAIL apoptosis pathway during malaria-associated acute kidney injury (AKI). Renal function was evaluated through the measurement of plasma creatinine and blood urea nitrogen (BUN). The mRNA expression of several cytokines and NaPi-IIa was quantified. Kidney sections were examined and cytokine levels were assessed using cytometric bead array (CBA) assays. The presence of glomerular IgG deposits and apoptosis-related proteins were investigated using in situ immunofluorescence assays and quantitative real-time PCR, respectively. NaPi-IIa downregulation in the kidneys provided novel insights into the pathogenesis of hypophosphatemia during CM. Histopathological analysis revealed characteristic features of severe malaria-associated nephritis, including glomerular collapse and tubular alterations. Pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6, were upregulated. The TRAIL apoptosis pathway was significantly activated, implicating its role in renal apoptosis. The observed alterations in renal biomarkers and the downregulation of NaPi-IIa shed light on potential mechanisms contributing to renal dysfunction in ECM. The intricate balance between pro- and anti-inflammatory cytokines, along with the activation of the TRAIL apoptosis pathway, highlights the complexity of malaria-associated AKI and provides new therapeutic targets.

The impact of tubular dysfunction and its relationship with acute kidney injury in children

BACKGROUND

Tubular dysfunction can cause electrolyte disturbances with potentially serious consequences. We studied the epidemiology and outcomes of electrolyte disturbances and tubular dysfunction among critically ill children and evaluated their relationships with acute kidney injury (AKI).

METHODS

We conducted a prospective cohort study recruiting children aged 1 month to ≤ 18 years old admitted to the pediatric intensive care unit (PICU) from 6/2020 to 6/2021. The serum levels of sodium, potassium, calcium, phosphate, and magnesium were reviewed and simultaneous urinary investigations for tubular function were performed among children with electrolyte disturbances.

RESULTS

Altogether there were 253 episodes of admission. The median (interquartile) age was 4.9 (1.3-11.0) years and 58.1% were male. The median number of electrolyte disorders was 3 (2-4) types. Hypophosphatemia (74.2%), hypocalcemia (70.3%) and hypermagnesemia (52.9%) were the three commonest types of disturbances. Urinary electrolyte wasting was commonly observed among children with hypomagnesemia (70.6%), hypophosphatemia (67.4%) and hypokalemia (28.6%). Tubular dysfunction was detected in 82.6% of patients and urinary β2-microglobulin level significantly correlated with the severity of tubular dysfunction (p < 0.001). The development of tubular dysfunction was independent of AKI status. Tubular dysfunction was associated with mortality (p < 0.001) and was an independent predictor of PICU length of stay (LOS) (p < 0.001). The incorporation of the tubular dysfunction severity into the AKI staging system improved the prediction of PICU LOS.

CONCLUSIONS

Tubular dysfunction was associated with both morbidity and mortality in critically ill children and its assessment may help to capture a more comprehensive picture of acute kidney insult.

Effect of early serum phosphate disorder on in-hospital and 28-day mortality in sepsis patients: a retrospective study based on MIMIC-IV database

BACKGROUND

This study aims to assess the influence of early serum phosphate fluctuation on the short-term prognosis of sepsis patients.

METHODS

This retrospective study used the Medical Information Mart for Intensive Care IV database to analyze serum phosphate levels in sepsis patients within 3 days of ICU admission. According to the absolute value of delta serum phosphate (the maximum value minus the minimum value of serum phosphorus measured within three days), the patients were divided into four groups, 0-1.3, 1.4-2.0, 2.1-3.1, and ≥ 3.2 mg/dl. Meanwhile, the direction of delta serum phosphate was compared. With the serum phosphate change group of 0-1.3 mg/dl as the reference group, the relationship between delta serum phosphate and in-hospital mortality and 28-day mortality was analyzed by multivariate Logistics regression analysis.

RESULTS

The study involved 1375 sepsis patients. Serum phosphate changes (0-1.3, 1.4-2.0, 2.1-3.1, and ≥ 3.2 mg/dl) correlated with in-hospital and 28-day mortality variations (p = 0.005, p = 0.008). Much higher serum phosphate fluctuation elevated in-hospital and 28-day mortality. Compared to the 0-1.3 mg/dl change group, adjusted odds ratios (OR) in other groups for in-hospital mortality were 1.25 (0.86-1.81), 1.28 (0.88-1.86), and 1.63 (1.10-2.43), and for 28-day mortality were 1.21 (0.86-1.72), 1.10 (0.77-1.57), and 1.49 (1.03-2.19). Under the trend of increasing serum phosphate, the ORs of in-hospital mortality and 28-day mortality in ≥ 3.2 mg/dl group were 2.52 and 2.01, respectively.

CONCLUSION

In conclude, the delta serum phosphate ≥ 3.2 mg/dl was associated with in-hospital mortality and 28-day mortality in patients with sepsis.

The m6A reader YTHDF2 alleviates the inflammatory response by inhibiting IL-6R/JAK2/STAT1 pathway-mediated high-mobility group box-1 release

Background

Sepsis is a common severe complication in major burn victims and is characterized by a dysregulated systemic response to inflammation. YTH domain family 2 (YTHDF2), a well-studied N6-methyladenosine (m6A) reader that specifically recognizes and binds to m6A-modified transcripts to mediate their degradation, is connected to pathogenic and physiological processes in eukaryotes, but its effect on sepsis is still unknown. We aimed to discover the effects and mechanisms of YTHDF2 in sepsis.

Methods

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot analyses were used to measure the expression of YTHDF2, the interleukin 6 receptor (IL-6R), high-mobility group box-1 (HMGB1), Janus kinase 2 (JAK2) and signal transducer and activator of transcription 1 (STAT1) under different in vitro conditions. Enzyme-linked immunosorbent assays were utilized to evaluate the expression of HMGB1, IL-6, IL-1β and tumor necrosis factor-α. To confirm that YTHDF2 specifically targets IL-6R mRNA, RNA immunoprecipitation and dual-luciferase reporter assays were performed. Finally, we utilized a mouse model of lipopolysaccharide (LPS)-induced sepsis to verify the effects of YTHDF2 in vivo.

Results

According to our findings, YTHDF2 was expressed at a low level in peripheral blood mononuclear cells from septic mice and patients as well as in LPS-induced RAW264.7 cells. Overexpression of YTHDF2 alleviated the inflammatory response by inhibiting HMGB1 release and JAK2/STAT1 signalling in LPS-stimulated cells. Mechanistically, YTHDF2 suppressed JAK2/STAT1 signalling by directly recognizing the m6A-modified site in IL-6R and decreasing the stability of IL-6R mRNA, thereby inhibiting HMGB1 release. In vivo experiments showed that YTHDF2 played a protective role in septic mice by suppressing the IL-6R/JAK2/STAT1/HMGB1 axis.

Conclusions

In summary, these findings demonstrate that YTHDF2 plays an essential role as an inhibitor of inflammation to reduce the release of HMGB1 by inhibiting the IL-6R/JAK2/STAT1 pathway, indicating that YTHDF2 is a novel target for therapeutic interventions in sepsis.

Hypophosphatemia in infants with severe bronchiolitis and association with length of mechanical ventilation

OBJECTIVES

Electrolyte disorders occurs frequently in children with bronchiolitis. The aim of the present study was to describe the frequency of hypophosphatemia and to evaluate its association with length of mechanical ventilation in infants admitted to a pediatric intensive care unit (PICU) with bronchiolitis.

METHODS

This retrospective cohort study included infants aged between 7 days and 3 months admitted to a PICU between September 2018 and March 2020 and diagnosed with severe acute bronchiolitis requiring respiratory support. Infants with a chronic condition that could potentially be a confounding factor were excluded. The primary outcome was the frequency of hypophosphatemia (<1.55 mmol/L); the secondary outcomes were the frequency of hypophosphatemia during the PICU stay, and the association with length of mechanical ventilation (LOMV).

RESULTS

Among the 319 infants admitted 178 had at least one phosphatemia value and were included in the study. The frequency of hypophosphatemia was 41% at PICU admission (61/148) and 46% during the PICU stay (80/172). The median [IQR] LOMV was significantly longer in children with hypophosphatemia at admission (109 [65-195] h vs. 67 [43-128] h, p = 0.007), and in multivariable linear regression lower phosphatemia at admission was associated with longer LOMV (p < 0.001) after controlling for severity (PELOD2 score) and weight.

CONCLUSION

Hypophosphatemia was frequent in infants with severe bronchiolitis admitted to a PICU and was associated with a longer LOMV.

ICU Delirium Is Associated with Cardiovascular Burden and Higher Mortality in Patients with Severe COVID-19 Pneumonia

BACKGROUND

COVID-19 can lead to functional disorders and complications, e.g., pulmonary, thromboembolic, and neurological. The neuro-invasive potential of SARS-CoV-2 may result in acute brain malfunction, which manifests as delirium as a symptom. Delirium is a risk factor for death among patients hospitalized due to critical illness. Taking the above into consideration, the authors investigated risk factors for delirium in COVID-19 patients and its influence on outcomes.

METHODS

A total of 335 patients hospitalized due to severe forms of COVID-19 were enrolled in the study. Data were collected from medical charts.

RESULTS

Delirium occurred among 21.5% of patients. In the delirium group, mortality was significantly higher compared to non-delirium patients (59.7% vs. 28.5%; p < 0.001). Delirium increased the risk of death, with an OR of 3.71 (95% CI 2.16-6.89; p < 0.001). Age, chronic atrial fibrillation, elevated INR, urea, and procalcitonin, as well as decreased phosphates, appeared to be the independent risk factors for delirium occurrence.

CONCLUSIONS

Delirium occurrence in patients with severe COVID-19 significantly increases the risk of death and is associated with a cardiovascular burden. Hypophosphatemia is a promising reversible factor to reduce mortality in this group of patients. However, larger studies are essential in this area.

[Involvement of inorganic phosphate starvation in Pseudomonas aeruginosa bacterial virulence]

Pseudomonas aeruginosa is a bacterium causing a wide spectrum of nosocomial and opportunistic respiratory infections. As an element essential for bacterial metabolism , phosphorus is incorporated as an inorganic phosphate and regulated by a two-component PhoB-PhoR system. Recently, it has been shown that as a result of overexpression of virulence factors, including the PhoB transcription factor, P. aeruginosa exhibited increased virulence in phosphate-deficient conditions. Exploration of the relationship between phosphate homeostasis and P. aeruginosa virulence could effectively contribute to the development of new, simple and innovative therapeutic strategies.

Postoperative Hypophosphatemia as a Prognostic Factor for Postoperative Pancreatic Fistula: A Systematic Review

Background and Objectives: Postoperative pancreatic fistula (POPF) is one of the most challenging complications after pancreatic resections, associated with prolonged hospital stay and high mortality. Early identification of pancreatic fistula is necessary for the treatment to be effective. Several prognostic factors have been identified, although it is unclear which one is the most crucial. Some studies show that post-pancreatectomy hypophosphatemia may be associated with the development of POPF. The aim of this systematic review was to determine whether postoperative hypophosphatemia can be used as a prognostic factor for postoperative pancreatic fistula. Materials and Methods: The systematic literature review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations (PRISMA) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO). The PubMed, ScienceDirect, and Web of Science databases were systematically searched up to the 31st of January 2022 for studies analyzing postoperative hypophosphatemia as a prognostic factor for POPF. Data including study characteristics, patient characteristics, operation type, definitions of postoperative hypophosphatemia and postoperative pancreatic fistula were extracted. Results: Initially, 149 articles were retrieved. After screening and final assessment, 3 retrospective studies with 2893 patients were included in this review. An association between postoperative hypophosphatemia and POPF was found in all included studies. Patients undergoing distal pancreatectomy were more likely to develop severe hypophosphatemia compared to patients undergoing proximal pancreatectomy. Serum phosphate levels on postoperative day 4 (POD 4) and postoperative day 5 (POD 5) remained significantly lower in patients who developed leak-related complications showing a slower recovery of hypophosphatemia from postoperative day 3 (POD 3) through postoperative day 7 (POD 7). Moreover, body mass index (BMI) higher than 30 kg/m², soft pancreatic tissue, abnormal white blood cell count on postoperative day 3 (POD 3), and shorter surgery time were associated with leak-related complications (LRC) and lower phosphate levels. Conclusions: Early postoperative hypophosphatemia might be used as a prognostic biomarker for early identification of postoperative pancreatic fistula. However, more studies are needed to better identify significant cut-off levels of postoperative hypophosphatemia and development of hypophosphatemia in the postoperative period.

Early hypophosphatemia in critically ill children and the effect of parenteral nutrition: A secondary analysis of the PEPaNIC RCT

BACKGROUND & AIMS

Hypophosphatemia during critical illness has been associated with adverse outcome. The reintroduction of enteral or parenteral nutrition, leading to refeeding hypophosphatemia (RFH), has been presented as potential risk factor. We investigated the occurrence of early RFH, its association with clinical outcome, and the impact of early parenteral nutrition (PN) on the development of early RFH in pediatric critical illness.

METHODS

This is a secondary analysis of the PEPaNIC randomized controlled trial (N = 1440), which showed that withholding supplemental parenteral nutrition (PN) for 1 week (late-PN) in the pediatric intensive care unit (PICU) accelerated recovery and reduced new infections compared to early-PN (<24 h). Patients with renal replacement therapy or unavailable phosphate concentrations were excluded from this analysis. Early RFH was defined as serum/plasma phosphate <0.65 mmol/L and a drop of >0.16 mmol/L within 3 days of admission to the PICU. The association between baseline characteristics and early RFH, and the association of early RFH with clinical outcome were investigated using logistic and linear regression models, both uncorrected and corrected for possible confounders. To examine the impact of nutritional intake on phosphate concentrations, structural nested mean models with propensity score and censoring models were used.

RESULTS

A total of 1247 patients were eligible (618 early-PN, 629 late-PN). Early RFH occurred in 40 patients (3%) in total, significantly more in the early-PN group (n = 31, within-group occurrence 5%) than in the late-PN-group (n = 9, within-group occurrence 1%, p < 0.001). Patients who were older (OR 1.14 (95% CI 1.08; 1.21) per year added, p < 0.001) and who had a higher Pediatric Risk of Mortality (PIM3) score had a higher risk of developing early RFH (OR 1.36 (95% CI 1.15; 1.59) per unit added, p < 0.001), whereas patients in the late-PN group had a lower risk of early RFH (OR 0.24 (95% CI 0.10; 0.49), p < 0.001). Early RFH was significantly associated with a 56% longer PICU stay (p = 0.003) and 42% longer hospital stay (p = 0.007), but not with new infections (OR 2.01 (95% CI 0.90; 4.30), p = 0.08) or length of mechanical ventilatory support (OR 1.05 (95% CI -3.92; 6.03), p = 0.68), when adjusted for possible confounders. Increase of parenteral nutrition intake (in % kcal of predicted resting energy expenditure) decreased phosphate concentrations (c = -0.002 (95% CI -0.002; -0.001).

CONCLUSIONS

Early RFH occurred in 3% of critically ill children. Patients randomized to late-PN had a lower chance of developing early RFH, which may be explained by the more gradual build-up of nutrition. As early RFH might impact recovery, it is important to closely monitor phosphate concentrations in patients, especially of those at risk for early RFH.

Outcomes of patients with post-hepatectomy hypophosphatemia: A narrative review

Phosphate is an essential electrolyte for proper mineralisation of bone, buffering of urine, and diverse cellular actions. Hypophosphatemia (HP) is a clinical spectrum which range from asymptomatic to severe complications such as neuromuscular and pulmonary complications, or even death. Post-hepatectomy HP (PHH) has been reported to be 55.5%-100%. Post-hepatectomy, there is rapid uptake of phosphate and increased mitotic counts to aid in regeneration of residual liver. Concurrently, PHH may be due to increased urinary phosphorous from activation of matrix extracellular phosphoglycoprotein in the injured liver, which decreases phosphate influx into hepatocytes to sustain adenosine triphosphate synthesis. A literature review was performed on PubMed till January 2022. We included 8 studies which reported on impact of PHH on post-operative outcomes. In patients with diseased liver, PHH was reported to have either beneficial or deleterious effects on post-hepatectomy liver failure (PHLF), morbidity and/or mortality in various cohorts. In living donor hepatectomy, PHLF was higher in PHH. Benefits of correction of PHH with reduced post-operative complications have been shown. Correction of PHH should be done based on extent of PHH. Existing studies were however heterogenous; further studies should be conducted to assess PHH on post-operative outcomes with standardized phosphate replacement regimes.

Phosphate Metabolic Inhibition Contributes to Irradiation-Induced Myelosuppression through Dampening Hematopoietic Stem Cell Survival

Myelosuppression is a common and intractable side effect of cancer therapies including radiotherapy and chemotherapy, while the underlying mechanism remains incompletely understood. Here, using a mouse model of radiotherapy-induced myelosuppression, we show that inorganic phosphate (Pi) metabolism is acutely inhibited in hematopoietic stem cells (HSCs) during irradiation-induced myelosuppression, and closely correlated with the severity and prognosis of myelosuppression. Mechanistically, the acute Pi metabolic inhibition in HSCs results from extrinsic Pi loss in the bone marrow niche and the intrinsic transcriptional suppression of soluble carrier family 20 member 1 (SLC20A1)-mediated Pi uptake by p53. Meanwhile, Pi metabolic inhibition blunts irradiation-induced Akt hyperactivation in HSCs, thereby weakening its ability to counteract p53-mediated Pi metabolic inhibition and the apoptosis of HSCs and consequently contributing to myelosuppression progression. Conversely, the modulation of the Pi metabolism in HSCs via a high Pi diet or renal Klotho deficiency protects against irradiation-induced myelosuppression. These findings reveal that Pi metabolism and HSC survival are causally linked by the Akt/p53–SLC20A1 axis during myelosuppression and provide valuable insights into the pathogenesis and management of myelosuppression.

Effect of irradiation on cytokine production in cancer patients

BACKGROUND

Irradiation, which affects cytokine secretion, is used to treat cancer patients. Cytokine levels have correlations to disease parameters, serving as biomarkers for patients. We aim to explore the effect of irradiation on cytokine production both in vitro (using lymphocytes from healthy donors) and in vivo (using serum levels of head and neck cancer patients following irradiation) and correlating them to mucositis severity/need for percutaneous endoscopic gastroscopy (PEG) tube installation.

METHODS

Cytokine production by cultured lymphocytes from healthy donors, in vitro, following irradiation of 5 or 10 Gy. In addition, blood from 23 patients with head and neck cancers, irradiated by 60-72G in vivo, were assessed for inflammatory cytokines (tumor necrosis factor (TNF)α, interleukin (IL)-6, IL-8, IL-18), the anti-inflammatory cytokine IL-10, and the general marker sIL-2R. Following radiation, selected patients who were developing mucositis were treated by PEG tube installation. Changes in cytokine levels were studied as predictive biomarkers of response to therapy/PEG tube installation. Cytokine production levels were measured using ELISAs kits.

RESULTS

Irradiation decreased the levels of all tested cytokines, most notably IL-6 and IL-8, proportional to irradiation dose. In patients, increases in cytokine levels, correlated with mucositis severity and potentially the need for PEG tube installation.

CONCLUSIONS

Irradiation decreased the levels of all cytokines of healthy lymphocytes in a dose-dependent manner, especially those of IL-6 and IL-8. This study shows a correlation between high and increasing levels of inflammatory cytokines, sIL-2R, plus radiation toxicity and the need for PEG. The reduction of cytokine levels after radiotherapy predicts that PEG will not be required. Thus, our study shows that cytokine changes are predictive biomarkers in head and neck cancer patients.

Profiling vitamin D, its mediators and proinflammatory cytokines in rheumatoid arthritis: A case-control study

INTRODUCTION

The active form of vitamin D has immunomodulatory and anti-inflammatory effect. Vitamin D is implicated in pathogenesis of rheumatoid arthritis (RA) and its deficiency leads to increased inflammation. Moreover, its production is dependent on concentration of calcium, phosphorus, and parathyroid hormone (PTH). Cytokines mediates inflammation in RA synovium. This study evaluated vitamin D, its mediators and proinflammatory cytokines among RA patients.

METHODS

In a case-control study, 78 RA patients from Komfo Anokye Teaching Hospital rheumatology clinic and 60 healthy blood donors were recruited. Chemistry analyzer and enzyme-linked immunosorbent assay kits were used to measure biochemical parameters and cytokines.

RESULTS

We found significantly higher levels of interleukin (IL)-1β, interferon gamma (IFN-γ), and tumor necrosis factor-α (TNF-α) in RA patients compared with controls (p < .05). There was a significant positive correlation between intact parathyroid hormone (iPTH) and IL-10 (r = .30, p < .05) and a negative correlation between IL-6 (r = -0.28, p > .05), IL-1β (r = -0.25, p > .05), TNF-α (r = -0.26, p > .05), IFN-γ (r = -0.24, p > .05), and iPTH. There was a significant negative correlation between IL-1β (r = -0.33, p < .05), IFN- γ (r = -0.29, p < .05), and calcium.

CONCLUSION

Reduced PTH, calcium, and phosphorus is associated with higher levels of proinflammatory cytokines which may worsen RA disease condition. Vitamin D is therefore not an independent regulator of proinflammatory cytokines in RA.

Both hypophosphatemia and hyperphosphatemia are associated with increased mortality in septic patients

Objective

This study was intended to explore the relationship between level of serum phosphate and prognosis in septic patients.

Methods

Data were obtained from the public database, which were divided into 2 subgroups according to whether they were complicated with chronic kidney disease. Initial values of serum phosphate were extracted from patients on admission to hospital. Propensity score-matched analysis was performed. The relationship between hypophosphatemia, hyperphosphatemia and the severity of the disease in septic patients was explored separately. The lowess smoothing technique and the Kaplan-Meier method were utilized for a preliminary analysis of serum phosphate levels in relation to in-hospital mortality and 28-day survival. The initial values of serum phosphate were graded as level 1 (<1.5 mg/dL), level 2 (1.5-2.7 mg/dL), level 3 (2.7-4.5 mg/dL), level 4 (4.5-5.5 mg/dL), level 5 (5.5-6.5 mg/dL), level 6 (6.5-7.5 mg/dL) and level 7 (> 7.5 mg/dL). Multivariate logistic regression and cox regression was used to analyse the relationship between serum phosphate levels and mortality.

Results

There were 4059 cases (17.4%) combined with chronic kidney disease, including 419 cases (10.3%) with hypophosphatemia and 1091 cases (26.8%) with hyperphosphatemia. There were 19224 cases (82.6%) not combined with chronic kidney disease, including 3769 cases (19.6%) hypophosphatemia and 2158 cases (11.2%) hyperphosphatemia. After propensity score-matched, in-hospital mortality, 28-day mortality, risk of septic shock was significantly higher in the 2 subgroups of hypophosphatemia patients than in normophosphatemia patients. In-hospital mortality, 28-day mortality, risk of septic shock, occurrence of renal replacement therapy, occurrence of acute renal failure, and maximum clinical score were all significantly higher in the 2 subgroups of patients with hyperphosphatemia than in patients with normophosphatemia. Multivariate logistic regression was consistent with cox regression results. In septic patients without chronic kidney disease, hypophosphatemia was an independent risk factor for death. When serum phosphate was lower, the risk of death was higher. In all septic patients, hyperphosphatemia was an independent risk factor for death. When serum phosphate was higher, the risk of death was greater.

Conclusions

Both hypophosphatemia and hyperphosphatemia are associated with increased mortality in septic patients and are independent risk factors for death.

Phosphate Ions Alter the Binding of Daptomycin to Living Bacterial Cell Surfaces

Advancements in antibiotic drug design are often hindered by missing information on how these small molecules interact with living cells. The antibiotic, daptomycin, has found clinical success and an emerging resistance, but a comprehensive picture of its mechanism of action has remained elusive. Using a surface-specific spectroscopy technique, second harmonic generation, we are able to quantitatively assess the binding of daptomycin to living cell membranes without the addition of exogenous labels. Our results reveal similar binding affinities for both Gram-positive and Gram-negative bacteria studied, including Escherichia coli. More importantly, we show that the presence of phosphate ions influences the binding of daptomycin to the Gram-positive bacterium Enterococcus faecalis. The role of environmental phosphate has not previously been considered in any proposed mechanism, and its implications are expected to be important in vivo.

Hypophosphatemia Is More Common and Is Prognostic of Poorer Outcomes in Severe Alcoholic Pancreatitis

OBJECTIVES

The aim of this study was to determine if hypophosphatemia is more common in patients with severe alcohol-induced acute pancreatitis (AAP).

METHODS

This is a retrospective, single institution, cohort study that analyzed 147 patients admitted to the hospital for AAP. Multivariate logistic regression was used to determine if hypophosphatemia would be related to clinical outcomes of disease severity.

RESULTS

Hypophosphatemia was more common in patients with severe AAP at admission; in addition, all patients with severe AAP (100%) eventually developed hypophosphatemia during admission, relative to those with mild (43%) and moderately severe (54%) AAP. The magnitude of the lowest phosphate measurement obtained during admission was lower in patients with severe AAP (mean, 1.5 mg/dL, standard deviation [SD], 0.5 mg/dL) relative to those with mild (mean, 2.6 mg/dL; SD, 0.9 mg/dL) and moderately severe (mean, 2.3 mg/dL; SD, 0.9 mg/dL) AAP (P < 0.001). Finally, patients who developed hypophosphatemia during admission were more likely to require intensive care unit admission (P < 0.001), vasopressors (P = 0.01), or intubation (P = 0.003).

CONCLUSIONS

Hypophosphatemia is more common and of greater magnitude in patients admitted to the hospital with severe AAP. In addition, patients with severe AAP who develop hypophosphatemia during admission are more likely to have poorer clinical outcomes.

Hypophosphatemia in critically ill pediatric patients receiving enteral and oral nutrition

BACKGROUND

Hypophosphatemia(HP) is related to several comorbidities in pediatric intensive care units (PICUs). This study aimed to evaluate the incidence of HP in severely ill pediatric patients receiving oral and/or enteral nutrition. The secondary objectives were to investigate the association between HP and the inflammatory state, PICU length of stay, severity, mortality, nutrition status, and protein, energy, calcium, vitamin D, and phosphate intake.

METHODS

A prospective, observational cohort study was conducted in a PICU of a quaternary hospital. Participants aged between 28 days and 14 years were included. Anthropometric and laboratory assessments were performed ≤72 h after PICU admission and repeated after 7 days for three consecutive times. Energy, protein, calcium, phosphate, and vitamin D intake per day of hospitalization were recorded individually. The Pediatric Index of Mortality 2 (PIM2) was used to determine each patient's severity score.

RESULTS

A total of 103 participants were included in the study. Hypophosphatemic events ranged from 27.2% to 37.5% among the assessments. HP was associated with high C-reactive protein levels (P = .012) and lower energy adequacy (P = .037). Serum phosphorus was inversely correlated (weak correlation) with PIM2 (P = .017).

CONCLUSION

HP is common in critically ill pediatric patients, even when they are not receiving parenteral nutrition. It is necessary to monitor serum phosphorus levels and consider the possibility of early replacement, especially in patients showing high levels of inflammation. In addition to inflammation itself, low energy intake and illness severity were related to HP.

Association between phosphate disturbances and mortality among critically ill patients with sepsis or septic shock

Objective

The aim of this study is to examine the association of hypophosphatemia and hyperphosphatemia on the first day of ICU admission with mortality in septic critically ill patients.

Methods

In this retrospective cohort study, all adult patients who were admitted to the medical-surgical ICUs between 2014 and 2017 with sepsis or septic shock were categorized as having hypophosphatemia, normophosphatemia and hyperphosphatemia based on day 1 serum phosphate values. We compared the clinical characteristics and outcomes between the three groups. We used multivariate analysis to examine the association of hypophosphatemia and hyperphosphatemia with these outcomes.

Results

Of the 1422 patients enrolled in the study, 188 (13%) had hypophosphatemia, 865 (61%) normophosphatemia and 369 (26%) had hyperphosphatemia. The patients in the hyperphosphatemia group had significantly lower GCS, higher APACHE II scores, higher serum creatinine, increased use of vasopressors, and required more mechanical ventilation with lower PaO2/FiO2 ratio compared with the other two groups. In addition, the hyperphosphatemia group showed significantly higher ICU and hospital mortality in comparison with the other two groups.

Conclusion

Hyperphosphatemia and not hypophosphatemia on the first ICU admission day was associated with an increase in the ICU and hospital mortality in septic critically ill patients.

Association of Phosphate Containing Solutions with Incident Hypophosphatemia in Critically Ill Patients Requiring Continuous Renal Replacement Therapy

BACKGROUND

Hypophosphatemia in critically ill patients is a common electrolyte disturbance associated with a myriad of adverse effects. Critically ill patients requiring continuous renal replacement therapy (CRRT) are at high risk of hypophosphatemia and often require phosphate supplementation during therapy. The aim of this study was to evaluate the association of phosphate versus non-phosphate containing CRRT solutions with incident hypophosphatemia in critically ill patients requiring CRRT.

MATERIALS AND METHODS

This is a single-center, retrospective, cohort study at a tertiary academic medical center of 1,396 adult patients requiring CRRT during their intensive care unit stay comprising 7,529 (phosphate containing) and 4,821 (non-phosphate containing) cumulative days of CRRT. Multivariable logistic regression was used to model the primary outcome of hypophosphatemia during CRRT according to exposure to phosphate versus non-phosphate containing CRRT solutions.

RESULTS

Incident hypophosphatemia during CRRT, serum phosphate <2.5 mg/dL or 0.81 mmol/L, was significantly higher in the non-phosphate versus phosphate containing solution group: 304/489 (62%) versus 175/853 (21%) (p < 0.001). Cumulative phosphate supplementation was also significantly higher in the non-phosphate versus phosphate containing solution group: 79 (IQR: 0-320) versus 0 (0-16) mmol (p < 0.001). Non-phosphate solutions were associated with an 8-fold increase in the incidence of hypophosphatemia (adjusted OR 8.05; 95% CI 5.77, 11.26; p < 0.001).

DISCUSSION/CONCLUSIONS

The use of phosphate containing CRRT solutions was independently associated with reduced risk of incident hypophosphatemia and decreased phosphate supplementation during CRRT. Interventional studies to confirm these findings are needed.

[Immunity and tubular dysfunction in case of systemic disease]

The immune renal tubular diseases are known since five decades, but their prevalence remains to be defined. They are caused by humoral and cellular effectors of innate and adaptative immunities on several targets of the renal tubule: protein channels, co or counter transporters, luminal or cytosolic enzymes, tight junctions. Genetic or epigenetic variations are also involved. Clinical manifestations are various and make the diagnosis difficult. They can precede the causal affection and they worsen the prognosis. The classical model consists in hypokalemic tubular distal acidosis observed in Sjögren's syndrome which illustrates the auto-immune epithelitis concept. Cellular immunity can act through other ways, like tertiary lymphoid neogenesis in systemic lupus. Humoral immunity through autoantibodies targets several membrane, cytosolic or nuclear proteins, causing specific tubular dysfonctions. It is also implied in the epithelial-mesenchymal transition of tubular cells. Innate immunity through cytokines may be involved. Treatment consists in electrolytic disorders correction and immunosupppressive medication: the choice should be guided at best by physiopathology.

Hypophosphatemia in Dogs With Presumptive Sepsis: A Retrospective Study (2008-2018)

Background: In humans with sepsis, hypophosphatemia is a marker of illness severity and a negative prognostic indicator. Hypophosphatemia has not been previously investigated in dogs with sepsis, however. This study aimed to estimate the prevalence of hypophosphatemia in dogs, the prevalence of presumptive sepsis in dogs with hypophosphatemia, the prevalence of hypophosphatemia in dogs with presumptive sepsis and the association between outcome and hypophosphatemia in dogs with presumptive sepsis. Methods: Electronic medical records of the Cornell University Hospital for Animals from 2008-2018 were queried to identify all dogs with hypophosphatemia and all dogs with presumptive sepsis. Hypophosphatemia was defined as a serum phosphate concentration <2.7 mg/dL. Sepsis was presumed where ≥2 of 4 systemic inflammatory response syndrome (SIRS) criteria were satisfied associated with a documented or highly suspected infection. Variables were assessed for normality using the D'Agostino-Pearson test. Continuous variables were compared between groups using the Mann-Whitney U test. Differences in frequency between categorical variables were analyzed using contingency tables, calculation of Fisher's exact test or Chi² and estimation of odds ratios. Results: In the study period, 47,992 phosphate concentration measurements from 23,752 unique dogs were identified. After eliminating repeat analyses, the period prevalence of hypophosphatemia on a per dog basis over the 11-year study period was 10.6% (2,515/23,752). The prevalence of presumptive sepsis within dogs with hypophosphatemia was 10.7% (268/2,515). During the 11-year study period, 4,406 dogs with an infection were identified, of which 1,233 were diagnosed with presumptive sepsis and had a contemporaneous phosphate concentration. Hypophosphatemia was more prevalent in dogs with presumptive sepsis than in dogs without 21.7 vs. 10.2%; OR 2.44 [95% CI 2.12-2.81]; P < 0.0001. The mortality rate was greater in dogs with hypophosphatemia and presumptive sepsis than in dogs with hypophosphatemia without presumptive sepsis (15.3 vs. 3.1%; OR 5.70 [95% CI 3.76-8.52]; P < 0.0001), however hypophosphatemia was not associated with outcome in dogs with presumptive sepsis OR 0.87 [95% CI 0.60-1.26]; P = 0.518. Conclusions: In dogs with hypophosphatemia, a presumed diagnosis of sepsis was associated with increased mortality compared to other associated disease processes. In dogs with presumptive sepsis, hypophosphatemia was not associated with outcome.

Role of PstS in the Pathogenesis of Acinetobacter baumannii Under Microaerobiosis and Normoxia

Acinetobacter baumannii is a successful pathogen responsible for infections with high mortality rate. During the course of infection it can be found in microaerobic environments, which influences virulence factor expression. From a previous transcriptomic analysis of A. baumannii ATCC 17978 under microaerobiosis, we know the gene pstS is overexpressed under microaerobiosis. Here, we studied its role in A. baumannii virulence. pstS loss significantly decreased bacterial adherence and invasion into A549 cells and increased A549 cell viability. pstS loss also reduced motility and biofilm-forming ability of A. baumannii. In a peritoneal sepsis murine model, the minimum lethal dose required by A. baumannii ATCC 17978 ΔpstS was lower compared to the wild type (4.3 vs 3.2 log colony forming units/mL, respectively), and the bacterial burden in tissues and fluids was lower. Thus, the loss of the phosphate sensor PstS produced a decrease in A. baumannii pathogenesis, supporting its role as a virulence factor.

DeepAISE - An interpretable and recurrent neural survival model for early prediction of sepsis

Sepsis, a dysregulated immune system response to infection, is among the leading causes of morbidity, mortality, and cost overruns in the Intensive Care Unit (ICU). Early prediction of sepsis can improve situational awareness among clinicians and facilitate timely, protective interventions. While the application of predictive analytics in ICU patients has shown early promising results, much of the work has been encumbered by high false-alarm rates and lack of trust by the end-users due to the 'black box' nature of these models. Here, we present DeepAISE (Deep Artificial Intelligence Sepsis Expert), a recurrent neural survival model for the early prediction of sepsis. DeepAISE automatically learns predictive features related to higher-order interactions and temporal patterns among clinical risk factors that maximize the data likelihood of observed time to septic events. A comparative study of four baseline models on data from hospitalized patients at three different healthcare systems indicates that DeepAISE produces the most accurate predictions (AUCs between 0.87 and 0.90) at the lowest false alarm rates (FARs between 0.20 and 0.25) while simultaneously producing interpretable representations of the clinical time series and risk factors.

Correcting hypophosphataemia in a paediatric patient with Sanjad-Sakati syndrome through a single oral dose of potassium phosphate intravenous solution

Sanjad–Sakati syndrome is an autosomal recessive disorder that is quite common in Kuwait. Among a wide range of complications in Sanjad–Sakati syndrome patients is the vulnerability to infections and subsequent hypophosphataemia. Hypophosphataemia is a metabolic alteration that contributes to numerous consequences such as cardiac arrhythmia. Therefore, if hypophosphataemia is left unresolved, it may culminate in death. A 20-month-old boy of 2.5 kg body weight diagnosed with Sanjad–Sakati syndrome was initially admitted to the paediatric intensive care unit after recovering from COVID-19, and then shifted to the general ward. He was diagnosed with recurrent pneumonia and urinary tract infection. After 9 days, the patient showed severe hypophosphataemia with serum phosphate concentration reaching 0.33 mmol/L. Despite the availability of potassium phosphate intravenous solution, it was difficult to administer potassium phosphate intravenously because of the small body size and low body weight of the patient. Therefore, 0.6 mL potassium phosphate containing 2.4 mEq of potassium and 5.3 mEq of phosphate was administered through a nasogastric tube. The patient showed rapid response after a single dose through the nasogastric tube. Such an intervention in Sanjad–Sakati syndrome patients shows possible advantages of shifting drug administration from intravenous to oral route that includes a convenient route of administration, whether in the intensive care unit or in the general ward. Moreover, shifting drug administration from the intravenous to oral route overcomes the risk of cannula-induced infection and reduces nurses’ workload.

Effect of Regional Citrate Anticoagulation vs Systemic Heparin Anticoagulation During Continuous Kidney Replacement Therapy on Dialysis Filter Life Span and Mortality Among Critically Ill Patients With Acute Kidney Injury: A Randomized Clinical Trial

IMPORTANCE

Although current guidelines suggest the use of regional citrate anticoagulation (which involves the addition of a citrate solution to the blood before the filter of the extracorporeal dialysis circuit) as first-line treatment for continuous kidney replacement therapy in critically ill patients, the evidence for this recommendation is based on few clinical trials and meta-analyses.

OBJECTIVE

To determine the effect of regional citrate anticoagulation, compared with systemic heparin anticoagulation, on filter life span and mortality.

DESIGN, SETTING, AND PARTICIPANTS

A parallel-group, randomized multicenter clinical trial in 26 centers across Germany was conducted between March 2016 and December 2018 (final date of follow-up, January 21, 2020). The trial was terminated early after 596 critically ill patients with severe acute kidney injury or clinical indications for initiation of kidney replacement therapy had been enrolled.

INTERVENTIONS

Patients were randomized to receive either regional citrate anticoagulation (n = 300), which consisted of a target ionized calcium level of 1.0 to 1.40 mg/dL, or systemic heparin anticoagulation (n = 296), which consisted of a target activated partial thromboplastin time of 45 to 60 seconds, for continuous kidney replacement therapy.

MAIN OUTCOMES AND MEASURES

Coprimary outcomes were filter life span and 90-day mortality. Secondary end points included bleeding complications and new infections.

RESULTS

Among 638 patients randomized, 596 (93.4%) (mean age, 67.5 years; 183 [30.7%] women) completed the trial. In the regional citrate group vs systemic heparin group, median filter life span was 47 hours (interquartile range [IQR], 19-70 hours) vs 26 hours (IQR, 12-51 hours) (difference, 15 hours [95% CI, 11 to 20 hours]; P < .001). Ninety-day all-cause mortality occurred in 150 of 300 patients vs 156 of 296 patients (Kaplan-Meier estimator percentages, 51.2% vs 53.6%; unadjusted difference, -2.4% [95% CI, -10.5% to 5.8%]; unadjusted hazard ratio, 0.91 [95% CI, 0.72 to 1.13]; unadjusted P = .38; adjusted difference, -6.1% [95% CI, -12.6% to 0.4%]; primary adjusted hazard ratio, 0.79 [95% CI, 0.63 to 1.004]; primary adjusted P = .054). Of 38 prespecified secondary end points, 34 showed no significant difference. Compared with the systemic heparin group, the regional citrate group had significantly fewer bleeding complications (15/300 [5.1%] vs 49/296 [16.9%]; difference, -11.8% [95% CI, -16.8% to -6.8%]; P < .001) and significantly more new infections (204/300 [68.0%] vs 164/296 [55.4%]; difference, 12.6% [95% CI, 4.9% to 20.3%]; P = .002).

CONCLUSIONS AND RELEVANCE

Among critically ill patients with acute kidney injury receiving continuous kidney replacement therapy, anticoagulation with regional citrate, compared with systemic heparin anticoagulation, resulted in significantly longer filter life span. The trial was terminated early and was therefore underpowered to reach conclusions about the effect of anticoagulation strategy on mortality.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02669589.

Implications of Postpancreatectomy Hypophosphatemia

BACKGROUND

Electrolyte abnormalities are commonly found after major abdominal surgery for malignancy. We hypothesized that the severity of hypophosphatemia developed in pancreatectomy patients would be associated with the incidence of complications postoperatively.

METHODS

A retrospective analysis of an institutional database was conducted for all pancreatic resections (2009-2017). Patient charts were reviewed for demographics, clinicopathologic factors, and perioperative outcomes.

RESULTS

In a cohort of 283 pancreatectomy patients, 107 (37.8%) and 134 (47.3%) developed mild (2.0-2.5 mg/dL) and moderate/severe hypophosphatemia (<2.0 mg/dL), respectively. Nadir serum phosphate levels were shown to occur on postoperative day (POD) 2 for patients without complications and POD3 for patients who had at least 1 complication. Patients who developed severe hypophosphatemia were significantly more likely to suffer fistula-related complications (P = .0401).

CONCLUSIONS

Assessing the severity and timing of postpancreatectomy hypophosphatemia presents an opportunity for early detection of impending fistula-related complications.

Clinical and laboratory features associated with serum phosphate concentrations in malaria and other febrile illnesses

Background

Hypophosphatemia is common in severe infections including malaria. Previous studies suggested that serum phosphate concentrations correlate with temperature, but it is unclear whether the type of infection and other factors occurring during infection influence this association. Here relationships were investigated between serum phosphate levels, cause of fever, demographic, clinical and laboratory parameters.

Methods

Anonymized data were analysed from 633 adults with malaria or other febrile illness admitted to Northwick Park Hospital, London, UK. Univariable and multivariable generalized linear model analyses were performed to examine associations with serum phosphate levels. Interaction terms were included to investigate whether cause of fever (malaria vs other illness), malaria parasite species, or malaria severity influenced the association of other variables with phosphate.

Results

Hypophosphatemia was common in subjects with malaria (211/542 (39%)), and in other febrile illnesses (24/91 (26%)), however median phosphate levels did not differ significantly by diagnostic group, parasite species or severity of malaria. In all analyses, there were highly significant negative associations between serum phosphate and axillary temperature, and positive associations between serum phosphate and platelet count. There were no significant interactions between these variables and cause of fever, parasite species or severity of illness. Sodium and potassium concentrations were associated with serum phosphate in subjects with malaria and when data from all subjects was combined.

Conclusion

Serum phosphate is consistently associated with temperature and platelet count in adults with diverse causes of fever. This may be a consequence of phosphate shifts from plasma into cells to support ATP generation for thermogenesis and platelet activation.

Effects of magnesium, phosphate and zinc supplementation in ICU patients-Protocol for a systematic review

BACKGROUND

Depletion of the trace elements magnesium, phosphate and zinc is common in patients admitted to the intensive care unit (ICU). Observational studies have suggested worse outcome in patients with hypomagnesaemia, hypophosphataemia or hypozincaemia, but also inverse associations with worse outcome with too high serum levels. However, it is unclear whether data from randomised clinical trials (RCTs) confirm this. Accordingly, we plan to assess the balance between benefits and harms of supplementation as compared with placebo or no supplementation in adult ICU patients.

METHODS

We will conduct a systematic review of RCTs with meta-analysis and trial sequential analysis in accordance with the Cochrane Handbook for Systematic Reviews of Interventions, the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) approach. We will assess the effects of any supplementation with magnesium, phosphate or zinc vs. placebo or no treatment in adult ICU patients. We will systematically search the Cochrane CENTRAL, Embase, PubMed, and for unpublished trials: ClinicalTrials.gov, the EU clinical Trials Register and the WHO International Clinical Trials Registry Platform. The primary outcomes will be days alive without mechanical ventilation and overall mortality. Secondary outcomes include use for mechanical ventilation, tachy-arrhythmias, use of vasopressors, length of hospital stay and use of renal replacement therapy.

DISCUSSION

The benefits and harms of supplementation therapy with magnesium, phosphate and zinc in general ICU patients are unknown. This outlined systematic review will provide data on the evidence, on which future recommendations for supplementation may be founded.

Hypophosphatemia in critically ill patients with acute kidney injury on renal replacement therapies

Hypophosphatemia is a common but often underestimated electrolyte derangement among intensive care unit (ICU) patients. Low phosphate levels can lead to cellular dysfunction with potentially relevant clinical manifestations (e.g., muscle weakness, respiratory failure, lethargy, confusion, arrhythmias). In critically ill patients with severe acute kidney injury (AKI) renal replacement therapies (RRTs) represent a well-known risk factor for hypophosphatemia, especially if the most intensive and prolonged modalities of RRT, such as continuous RRT or prolonged intermittent RRT, are used. Currently, no evidence-based specific guidelines are available for the treatment of hypophosphatemia in the critically ill; however, considering the potentially negative impact of hypophosphatemia on morbidity and mortality, strategies aimed at reducing its incidence and severity should be timely implemented in the ICUs. In the clinical setting of critically ill patients on RRT, the most appropriate strategy could be to anticipate the onset of RRT-related hypophosphatemia by implementing the use of phosphate-containing solutions for RRT through specifically designed protocols. The present review is aimed at summarizing the most relevant evidence concerning epidemiology, prognostic impact, prevention and treatment of hypophosphatemia in critically ill patients with AKI on RRT, with a specific focus on RRT-induced hypophosphatemia.

Lower phosphate levels following pancreatectomy is associated with postoperative pancreatic fistula formation

BACKGROUND

Whereas hypophosphatemia following hepatectomy is associated with decreased morbidity, hypophosphatemia following pancreatectomy may be associated with increased morbidity, including the development of postoperative pancreatic fistula (POPF). This study aimed to evaluate the relationship between postoperative hypophosphatemia and POPF formation.

METHODS

Patients from our institutional Research Patient Data Registry who underwent pancreatectomy from 2001 to 2017 were included. POPF was defined according to the International Study Group for Pancreatic Fistulas (ISGPF) criteria and according to internal criteria for drain removal. Postoperative serum phosphate levels, demographics, and comorbidities were evaluated. Unadjusted and adjusted analyses were performed.

RESULTS

2342 patients underwent pancreatic resection. Mean age was 63.0 years (SD 14.3), 51.2% were male, and 58.7% had pancreatic cancer. Of all resections, 67.7% were pancreaticoduodenectomies. In unadjusted analysis, phosphate levels were significantly and persistently lower on POD 0 and POD 2-5 in patients who developed POPF's. In adjusted analysis, POD 2 phosphate <1.75 predicted an additional 46% increased odds of POPF (OR 1.46 95% CI 1.06-2.01; p = 0.02). Distal pancreatectomy was independently associated with POPF formation when compared to pancreaticoduodenectomy (OR 1.72 95% CI 1.18-2.51; p = 0.005).

CONCLUSION

Lower phosphate levels in the early post-operative period following both proximal and distal pancreatectomies is associated with increased risk of POPF.

Hypophosphatemia as a Predictor of Organ-Specific Complications Following Gastrointestinal Surgery: Analysis of 8034 Patients

BACKGROUND

Organ-specific complications (OSC) remain serious potential sequela of gastrointestinal surgery. Hypophosphatemia correlates with poor outcomes and may be a harbinger of OSC after gastrointestinal surgery. Our goal was to describe and evaluate the relationship between postoperative phosphate levels and OSC.

METHODS

Consecutive patients who underwent pancreatic, colorectal, or gastric resections were analyzed. OSC were defined as those resulting from the failure of at least one anastomosis performed during the primary resection, manifesting as an anastomotic leak, fistula, and/or intra-abdominal abscess. Postoperative serum phosphate levels and other recognized OSC risk factors were compared among patients who did and did not develop OSC.

RESULTS

A total of 8034 patients who underwent pancreatic (n = 397), colorectal (n = 5808), or gastric (n = 1829) resections were included in the study. In each resection group, the majority of patients experienced hypophosphatemia postresection with the nadir on postoperative day (POD) 2, and the subgroups that developed OSC exhibited lower phosphate levels on POD3-7. On multivariate analysis, lower phosphate level on POD3 remained significantly associated with OSC following pancreatic resection [median (interquartile range) mmol/L, 0.65 (0.53-0.76) vs. 0.71 (0.61-0.84), p = 0.045] and colorectal resection [0.71 (0.61-0.87) vs. 0.77 (0.65-0.94), p = 0.006], and lower phosphate level on POD4 remained associated with OSC following gastric resection [0.87 (0.74-1.03) vs. 0.96 (0.81-1.13), p = 0.049].

CONCLUSION

This study identified a consistent trajectory of serum phosphate levels following 3 different gastrointestinal operations and association between early postoperative phosphate levels and OSC. Persistent lower phosphate levels should raise the level of concern for evolving postoperative leak and may lead to earlier radiographic evaluation and treatment.

Endotoxaemia differentially regulates the expression of renal Ca2+ transport proteins in mice

AIM

Alterations in parathyroid hormone (PTH) and/or vitamin D signalling are frequently reported in patients with sepsis. The consequences on renal and intestinal Ca²⁺ and P_i regulatory mechanisms are still unclear. We hypothesized that endotoxaemia alters the expression of important renal and intestinal Ca²⁺ and P_i transport proteins.

METHODS

Male C57BL/6 mice were treated with lipopolysaccharide (LPS; 3 mg/kg; i.p.). The mRNA and protein levels of renal and intestinal Ca²⁺ and P_i transport proteins were measured by RT-qPCR, immunohistochemistry and western blot analysis.

RESULTS

Lipopolysaccharide-induced hypocalcaemia and hyperphosphataemia was paralleled by a decrease in glomerular filtration rate and urinary excretion of Ca²⁺ and P_i . Endotoxaemia augmented plasma levels of PTH and affected the fibroblast growth factor 23 (FGF23)-klotho-vitamin D axis by increasing plasma levels of FGF23 and downregulation of renal klotho expression. Renal expression of CYP27b1 and plasma levels of 1,25-dihydroxyvitamin D₃ were increased in response to LPS. Endotoxaemia augmented the renal expression of TRPV5, TRPV6 and PiT1, whereas the renal expression of calbindin-D_28K , NCX1, NaP_i -2a and NaP_i -2c were decreased. Incubation of primary distal tubule cells with LPS increased TRPV6 mRNA levels. Furthermore, LPS decreased the intestinal expression of TRPV6, calbindin-D_9K and of NaP_i -2b.

CONCLUSION

Our findings indicate that endotoxaemia is associated with hypocalcaemia and hyperphosphataemia and a disturbed FGF23-klotho-vitamin D signaling. Further, LPS-induced acute kidney injury was accompanied by an increased or decreased expression of specific renal and intestinal Ca²⁺ and P_i transporters respectively. It seems unlikely that LPS-induced hypocalcaemia is due to renal loss of Ca²⁺ .

Bone resorption: supporting immunometabolism

Activation of the immune system is associated with an increase in the breakdown of various peripheral tissues, including bone. Despite the widely appreciated role of inflammatory mediators in promoting bone resorption, the functional value behind this process is not completely understood. Recent advances in the field of immunometabolism have highlighted the metabolic reprogramming that takes place in activated immune cells. It is now believed that the breakdown of peripheral tissue provides metabolic substrates to fuel metabolic anabolism in activated immune cells. We argue that phosphate, liberated by bone resorption, plays an indispensable role in sustaining immune cell metabolism. The liberated phosphate is then incorporated into macromolecules such as nucleotides and phospholipids, and is also used for the phosphorylation of metabolites (e.g. glycolytic intermediates). In addition, magnesium, also liberated during the breakdown of bone, is an essential cofactor required by various metabolic enzymes which are upregulated in activated immune cells. Finally, calcium activates various additional molecules involved in immune cell migration. Taken together, these factors suggest a key role for bone resorption during infection.

Incidence and Clinical Outcome of Hypophosphatemia in Pediatric Burn Patients

The objective of this study is to investigate the factors associated with serum phosphate concentrations in severely burned children and whether hypophosphatemia is associated with outcome. Seventy-eight children with a total body surface area of 24% (6.0-68.5) were retrospectively analyzed for serum phosphate concentrations during the first 10 days of stay in the intensive care unit (ICU). The method of generalized estimating equations was used to evaluate the effect of the exposure variables for serum phosphate concentrations during the study period. Outcome variables were the probability of ICU discharge at 30 days and time on mechanical ventilation. Potential explanatory variables for clinical outcome were hypophosphatemia (serum phosphate <3.8 mg/dL for children <2 years and <3.5 mg/dL for older children), age, sex, percent total body surface area burn, inhalation injury, and severe sepsis and/or septic shock. Competing-risk analysis was applied to calculate the probability of ICU discharge at 30 days, and death was assumed as the competing event. The rate of hypophosphatemia was 79.5%. Serum phosphate concentrations were associated with C-reactive protein (coefficient: -0.63; 95% confidence interval [CI]: -0.96 to -0.30; P = .001). Hypophosphatemia was independently associated with a 68% decrease in the probability of ICU discharge at 30 days (subhazard ratio: -0.32; 95% CI: 0.20, 0.53; P = .001) and an increase of 2.9 days in mechanical ventilation (coefficient: 2.91; 95% CI: 1.16, 4.66; P = .001). Serum phosphate concentrations in pediatric burn patients are associated with the magnitude of inflammatory response. Hypophosphatemia is associated with decreased probability of ICU discharge and increased time on mechanical ventilation.

A Novel Distal Enhancer Mediates Inflammation-, PTH-, and Early Onset Murine Kidney Disease-Induced Expression of the Mouse Fgf23 Gene

Fibroblast growth factor 23 (FGF23) production is regulated by both calciotropic hormones and inflammation. Consistent with this, elevated FGF23 levels are associated with inflammatory markers as well as parathyroid hormone (PTH) in various disease states, including chronic kidney disease (CKD). However, the molecular mechanisms underpinning Fgf23 transcription in response to these regulators are largely unknown. We therefore utilized chromatin immunoprecipitation followed by DNA sequencing (ChIP‐seq) data from an osteocyte cell line to identify potential regulatory regions of the Fgf23 gene. Based on ChIP‐seq analysis of enhancer‐associated histone modifications, including H3K4 methylation and H3K9 acetylation, we discovered several potential enhancers for Fgf23, one of which was located 16kb upstream of the gene's transcriptional start site. Deletion of this putative enhancer from the mouse genome using CRISPR‐Cas9 technology led to lower bone, thymus, and spleen expression of Fgf23 mRNA without altering circulating levels of the intact hormone, although as previously reported, only bone displayed significant basal expression. Nevertheless, lack of the −16kb enhancer blunted FGF23 upregulation in a tissue‐specific manner by the acute inflammatory inducers lipopolysaccharide (LPS), interleukin‐1‐beta (IL‐1β), and tumor necrosis factor‐alpha (TNFα) in bone, non‐osseous tissues, and in circulation. Lack of the −16kb enhancer also inhibited PTH‐induced bone Fgf23 mRNA. Moreover, the absence of this Fgf23 enhancer in an oxalate diet‐induced murine CKD model prevented the early onset induction of osseous, renal, and thymic Fgf23 mRNA levels and led to a significant blunting of elevated circulating intact FGF23 levels. These results suggest that −16kb enhancer mediates the induction of Fgf23 by inflammation and PTH and facilitates the increase in FGF23 expression in a murine model of CKD. As exemplified herein, these Fgf23 enhancer‐deleted mice will provide a unique model in which to study the role of FGF23 expression in inflammatory diseases. © 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Anti-aging factor, serum alpha-Klotho, as a marker of acute physiological stress, and a predictor of ICU mortality, in patients with septic shock

PURPOSE

Genetic deletions decreasing serum alpha-Klotho (alpha-KL) have been associated with rapid aging, multi-organ failure and increased mortality in experimental sepsis. We hypothesized that lower alpha-KL obtained at the onset of septic shock correlates with higher mortality.

MATERIALS AND METHODS

Prospective cohort of 104 adult patients with septic shock. Alpha-KL was measured via ELISA on serum collected on the day of enrollment (within 72h from the onset of shock). Relationship between alpha-KL and clinical outcome measures was evaluated in uni- and multi-variable models.

RESULTS

Median (IQR) alpha-KL was 816 (1020.4) pg/mL and demonstrated a bimodal distribution with two distinct populations, Cohort A [n=97, median alpha-KL 789.3 (767.1)] and Cohort B [n=7, median alpha-KL 4365.1(1374.4), >1.5 IQR greater than Cohort A]. Within Cohort A, ICU non-survivors had significantly higher serum alpha-KL compared to survivors as well as significantly higher APACHE II and SOFA scores, rates of mechanical ventilation, and serum BUN, creatinine, calcium, phosphorus and lactate (all p≤0.05). Serum alpha-KL≥1005, the highest tertile, was an independent predictor of ICU mortality when controlling for co-variates (p=0.028, 95% CI 1.143-11.136).

CONCLUSIONS

Elevated serum alpha-KL in patients with septic shock is independently associated with higher mortality. Further studies are needed to corroborate these findings.

[Causes, consequences and treatment of hypophosphatemia: A systematic review]

CONTEXT

Although hypophosphatemia is usually very seldom, it can reach two to 3% of hospitalized patients and until 28% of intensive care unit patients. Due to the lack of knowledge, clinical practice regarding seeking or treatment of hypophosphatemia is very heterogenous. However its clinical consequences might be heavy. A better knowledge of its causes, physiopathological effects and treatment should lead to a documented and homogenous care of these patients in clinics.

OBJECTIVE

The aim of our study was a systematic review of littérature, seeking for publications about causes, consequences and treatment of hypophosphatemia.

DOCUMENTARY SOURCES (KEYWORDS AND LANGUAGE)

A research has been conducted on the Medline database by using the following keywords "phosphorus supplementation", "hypophosphatemia" and ("physiopathology" or "complications").

RESULTS

Three mains mechanisms might be responsible for hypophosphatemia: a decrease in digestive absorption, a rise in kidney excretion and a transfer of phosphorus to the intracellular compartment. Denutrition, acid base balance troubles, parenteral nutrition or several drugs are capable of provoking or favouring hypophosphatemia. All these situations are frequently encountered in intensive care unit. Consequences of hypophosphatemia might be serious. Best studied and documented are cardiac and respiratory muscle contractility decrease, sometimes leading to acute cardiac and respiratory failure, cardiac rhythm troubles and cardiac arrest. Hypophosphatemia is frequent during sepsis. It could be responsible for leucocyte dysfunction that might favour or increase sepsis. The treatment of hypophosphatemia is usually simple through a supplementation that quickly restores a regular concentration, with few adverse effects when regularly used.

CONCLUSION

During at-risk situations, the systematic search for hypophosphatemia and its treatment may limit the occurrence of serious consequences.

Phosphate replacement in the critically ill: potential implications for military patients

BACKGROUND

Severe hypophosphataemia in the intensive care unit (ICU) setting has been widely associated with adverse clinical outcomes across multiple organ systems, as well as increased mortality. However, the clinical significance of mild or moderate hypophosphataemia remains uncertain. This can lead to heterogeneous phosphate replacement protocols across different institutions. The aim of this study was to assess the significance of mild and moderate hypophosphataemia on clinical outcomes across several organ systems.

METHOD

All patients over a 3-week period in our ICU were retrospectively analysed with admission serum phosphate compared with subsequent clinical outcomes after admission. Low serum phosphate (0.3-1.0 mmol/L), according to local protocol, was compared with normal serum phosphate (>1.0 mmol/L).

RESULTS

Of the 72 patients admitted to intensive therapy unit during this period, 14/72 (19%) had phosphate levels deemed low (<1.0 mmol/L) and received phosphate supplementation. No significant difference was found between groups in terms of cardiac arrhythmias (p=0.55), capillary blood glucose (p=0.08) and serum lactate (p=0.32). Low phosphate (0.3-1.0 mmol/L) was not associated with increased likelihood of requiring ventilation. Platelet count was significantly lower in the low phosphate group (p=0.008).

CONCLUSION

In our study, mild and moderate hypophosphataemia was not associated with adverse clinical outcome across most organ systems analysed. Given the current evidence and results of this study, we would suggest that there is a trend towards over-replacement of phosphate, representing a potential clinical safety issue as well as clear financial implications.

Phosphate disturbance in critically ill children: Incidence, associated risk factors and clinical outcomes

Background

Hypophosphatemia is one of the common disorders that develop in critically ill patients. It has potential complications and is often unrecognized in those patients.

Objective

Determining the incidence of hypophosphatemia in critically ill children, its association with clinical outcomes and the possible risk factors.

Methods

50 patients were enrolled in the study. Levels of serum phosphate were measured on day 1 and day 7 of PICU (Pediatric intensive care unit) stay. The following variables were analyzed: age, gender, diagnosis on admission, malnutrition, phosphorus intake, clinical severity score on admission OFI (Organ Failure Index) and daily scores PELOD (Pediatric Logistic Organ Dysfunction), sepsis, use of dopamine, furosemide and steroids and assessment of nutrition by z scores.

Results

The incidence of hypophosphatemia on admission was 42%. On seventh day of admission incidence of hypophosphatemia was 62%. Malnutrition was present in 24% of patients, serum phosphorus level was significantly lower in malnourished than in well-nourished children (p value = 0.018). Hypophosphatemia was associated with prolonged PICU length of stay (p < 0.001) but was not associated with increased mortality (p = 0.13). Cases on parenteral nutrition and insufficient oral intake while on mechanical ventilator significantly showed hypophosphatemia (p = 0.017). Hypophosphatemia was associated with the use of furosemide, dopamine, steroids and β2 agonist.

Conclusion

Hypophosphatemia was common in the first 7 days of PICU hospitalization and was associated with prolonged PICU stay, Significant association between hypophosphatemia and duration of use of mechanical ventilation, use of furosemide, dopamine, steroids and β2 agonist.

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Hypophosphatemia was common in the first 7 days of pediatric intensive care unit hospitalization.

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Significant association between hypophosphatemia and duration of use of mechanical ventilation.

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Hypophosphatemia was associated with prolonged pediatric intensive care unit length of stay.

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Hypophosphatemia was associated with use of furosemide, dopamine, steroid and β2 agonist.

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Good nutrition of critically ill children has an important role in improving their clinical condition.

Refeeding Syndrome in the Intensive Care Unit

Nutrition Support Consultant features issues pertinent to the clinical aspects of pharmacy nutrition support practice.

Hypophosphatemia after Hepatectomy or Pancreatectomy: Role of the Nicotinamide Phosphoribosyltransferase

BACKGROUND

Postoperative hypophosphatemia is common and is associated with a lower risk of liver failure after hepatectomy, but higher morbidity after pancreatectomy. Whether different physiologic mechanisms underlie the hypophosphatemia associated with these very different clinical outcomes is unclear. This study aims to evaluate the underlying mechanism in postoperative hypophosphatemia.

STUDY DESIGN

We prospectively enrolled 120 patients who underwent major hepatectomy (n = 30), minor hepatectomy (n = 30), pancreatectomy (n = 30), and laparotomy without resection (control group, n = 30). Preoperative and postoperative serum and urinary phosphorus, calcium, and creatinine, as well as phosphaturic factors, including serum nicotinamide phosphoribosyltransferase (NAMPT), fibroblast growth factor-23, and parathyroid hormone were measured. In addition, we evaluated urinary levels of nicotinamide catabolites, N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-3-carboxamide.

RESULTS

We found that significant hypophosphatemia occurred from postoperative day (POD) 1 to POD 2 in all 4 groups and was preceded by hyperphosphaturia from preoperative day to POD 1. Phosphate level alterations were associated with a significant increase in NAMPT levels from preoperative day to POD 2 in all 3 resected groups, but not in the control group. The fibroblast growth factor-23 levels were significantly decreased postoperatively in all 4 groups, and parathyroid hormone levels did not change in any of the 4 groups. Urine levels of N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-3-carboxamide decreased significantly in all 4 groups postoperatively.

CONCLUSIONS

This study demonstrates that the mechanism of hypophosphatemia is the same for both liver and pancreas resections. Postoperative hypophosphatemia is associated with increased NAMPT. The mechanism that upregulates NAMPT and its role on disparate clinical outcomes in postoperative patients warrant additional investigation.

Correlates of thymus size and changes during treatment of children with severe acute malnutrition: a cohort study

Background

The impairment of immune functions associated with malnutrition may be one reason for the high mortality in children with severe acute malnutrition (SAM), and thymus atrophy has been proposed as a marker of this immunodeficiency. The aim of this study was to identify nutritional and clinical correlates of thymus size in children with SAM, and predictors of change in thymus size with nutritional rehabilitation.

Methods

In an observational study among children aged 6–59 months admitted with SAM in Uganda, we measured thymus area by ultrasound on hospital admission to treatment with F75 and F100, on hospital discharge and after 8 weeks of nutritional rehabilitation with ready-to-use therapeutic food, as well as in well-nourished healthy children. We investigated anthropometric, clinical, biochemical and treatment-related correlates of area and growth of the thymus.

Results

Eighty-five children with SAM with a median age of 16.5 months were included. On admission 27% of the children had a thymus undetectable by ultrasound. Median thymus area was 1.3 cm² in malnourished children, and 3.5 cm² in healthy children (p < 0.001). Most anthropometric z-scores, hemoglobin and plasma phosphate correlated positively with thymus area. Thymus area correlated negatively with caretaker-reported severity of illness, plasma α-1 acid glycoprotein, and C-reactive protein >5 mg/L. At follow-up after 8 weeks, median thymus area had increased to 2.5 cm² (p < 0.001). Increase in thymus area during treatment was associated with simultaneous increase in mid-upper-arm circumference, with 0.29 cm² higher increase in thymus area per cm larger increment in MUAC (p = 0.03). Children whose F-75 had partially been replaced by rice porridge during their hospital admission had less increase in thymus area after 8 weeks.

Conclusion

Malnutrition and inflammation are associated with thymus atrophy, and thymus area seems positively associated with plasma phosphate. Substituting therapeutic formula with unfortified rice porridge with the aim of alleviating diarrhea may impair regain of thymus size with nutritional rehabilitation. This calls for research into possible effects of phosphate status on thymus size and other immunological markers.

Trial registration

The study is based on data from the FeedSAM study, ISRCTN55092738.