Comparison of fractional excretion of electrolytes in patients at different stages of chronic kidney disease: A cross-sectional study

Utility of fractional excretion of magnesium in diagnosing renal magnesium wasting in pediatric nephrology practice

BACKGROUND

Fractional excretion of magnesium (FEMg) is commonly used to diagnose of renal magnesium (Mg) wasting, but it can be affected by serum Mg (SMg) and serum creatinine concentration (SCr). We investigated the sensitivity and specificity of FEMg to diagnose Mg wasting in subgroups with different SMg and eGFR (estimated glomerular filtration rate) in pediatric nephrology practice.

METHODS

One hundred and nineteen patients (59 males and 60 females, median 15 years) seen in our pediatric clinic were investigated for FEMg, SMg, eGFR, and urine Mg-to-creatinine ratio (Mg/Cr). Normal eGFR was defined as ≥ 90 ml/min/1.73 m2 or for infants SCr < chronic kidney disease stage 2. Urine Mg/Cr was compared with age-specific reference values.

RESULTS

Sixteen of all patients (13 %) had hypomagnesemia. All had FEMg greater than the cut-off value of 2 %. Only 4 patients had elevated urine Mg/Cr. Of 65 patients with normal SMg and eGFR, 19 had FEMg above the cut-off value of 4 %. Of these, 13 patients had elevated urine Mg/Cr i.e. Mg wasting (sensitivity and specificity of FEMg, 93 % and 88 %, respectively). Among 38 patients with normal SMg and low eGFR, 30 had FEMg > 4 %, but only 6 had elevated urine Mg/Cr (sensitivity 100 % and specificity 25 %). Overall, hypomagnesemic patients and normomagnesemic patients with elevated urine Mg/Cr were diagnosed with Mg wasting (36/119, 30 %).

CONCLUSIONS

FEMg has variable sensitivity and specificity depending on SMg and eGFR in the diagnosis of Mg wasting. Mg wasting is not uncommon in pediatric nephrology practice.

Electrolyte disorders related emergencies in children

This article provides a comprehensive overview of electrolyte and water homeostasis in pediatric patients, focusing on some of the common serum electrolyte abnormalities encountered in clinical practice. Understanding pathophysiology, taking a detailed history, performing comprehensive physical examinations, and ordering basic laboratory investigations are essential for the timely proper management of these conditions. We will discuss the pathophysiology, clinical manifestations, diagnostic approaches, and treatment strategies for each electrolyte disorder. This article aims to enhance the clinical approach to pediatric patients with electrolyte imbalance-related emergencies, ultimately improving patient outcomes.Trial registration This manuscript does not include a clinical trial; instead, it provides an updated review of literature.

Rebound hyperkalemia in a dog with albuterol toxicosis after cessation of potassium supplementation

OBJECTIVE

To describe the presentation of rebound hyperkalemia as a delayed side effect of albuterol toxicity in a dog.

CASE SUMMARY

A 3-year-old female neutered mixed-breed dog was presented for albuterol toxicosis that led to a severe hypokalemia, hyperlactatemia, and hyperglycemia. The dog also experienced sinus tachycardia and generalized weakness. Treatment was instituted with intravenous fluid therapy and potassium supplementation, and the dog was monitored with a continuous electrocardiogram. Resolution of hypokalemia was documented 12 hours after initial presentation, at which time fluid therapy and potassium supplementation were discontinued. There were no further periods of sinus tachycardia, but instead the dog developed ventricular ectopy with rapid couplets (instantaneous rates of 300/min). An echocardiogram revealed normal cardiac size and function. Twenty-four hours after presentation, the patient developed severe hyperkalemia, despite discontinuation of fluids and potassium supplementation for 12 hours. Serial venous and urinary electrolytes were performed for determination of the fractional excretion of electrolytes. These data confirmed rebound hyperkalemia (7.0 mmol/L), consistent with a markedly increased fractional excretion of potassium, and secondary to the release of potassium from inside the cells. Fluid therapy with dextrose supplementation was provided until 36 hours postpresentation. The hyperkalemia resolved, and the dog was discharged after 44 hours of hospitalization.

NEW OR UNIQUE INFORMATION PROVIDED

This case documents rebound hyperkalemia following treatment of albuterol toxicosis in a dog. This case highlights the importance of understanding the distribution of total body potassium when treating serum hypokalemia. Transcellular shifts of potassium, as in the case of albuterol toxicosis, can lead to rebound hyperkalemia even after discontinuation of potassium supplementation. This case further explores the utility of fractional excretion of electrolytes in elucidating the etiology and management of electrolyte disturbances.

Amelioration of Cyclosporine A-Induced Acute Nephrotoxicity by Cordyceps cicadae Mycelia via Mg+2 Reabsorption and the Inhibition of GRP78-IRE1-CHOP Pathway: In Vivo and In Vitro

Fruiting bodies of Cordyceps cicadae (CC) have been reported to have a therapeutic effect in chronic kidney disease. Due to the rare and expensive resources from natural habitats, artificially cultivated mycelia using submerged liquid cultivation of CC (CCM) have been recently developed as an alternative to scarce sources of CC. However, little is known regarding potential protective effects of CCM against cyclosporine A (CsA)-induced acute nephrotoxicity in vivo and in vitro. In this study, male Sprague-Dawley rats were divided into six groups: control, CCM (40 mg and 400 mg/kg, orally), CsA (10 mg/kg, oral gavage), and CsA + CCM (40 mg and 400 mg/kg, orally). At the end of the study on day 8, all rats were sacrificed, and the blood and kidneys retrieved. CsA-induced acute nephrotoxicity was evident by increased levels of blood urea nitrogen (BUN). Levels of the endoplasmic reticulum (ER) resident chaperone glucose regulated protein 78 (GRP 78) were increased significantly in rats with acute nephrotoxicity. BUN and GRP 78 were significantly ameliorated in synchronous oral groups of CCM (40 or 400 mg/kg) plus CsA. Examination of hematoxylin and eosin stained kidney tissues revealed that the combined treatment of CCM slightly improved vacuolization in renal tubules upon CsA-induced damage. CsA-induced down-regulation of protein expression of magnesium ion channel proteins and transient receptor potential melastatin 6 and 7 were abolished by the combined treatment of CCM. CCM has the potential to protect the kidney against CsA-induced nephrotoxicity by reducing magnesium ion wasting, tubular cell damage, and ER stress demonstrated further by human renal proximal tubular epithelial cell line HK-2. Our results contribute to the in-depth understanding of the role of polysaccharides and nucleobases as the main secondary metabolites of CCM in the defense system of renal functions in CsA-induced acute nephrotoxicity.

Chemical Composition and Chronic Toxicity of Disc-Cultured Antrodia cinnamomea Fruiting Bodies

Antrodia cinnamomea (AC) is a popular fungus for use as folk medicine in health maintenance and disease prevention and treatment. Disc culture is a novel technique for producing AC fruiting bodies. This study aimed to investigate the bioactive components and toxicological properties of disc-cultured AC fruiting body powders (ACP) in rats. The HPLC technique was used to quantify the composition of bioactive triterpenoids in ACP. Toxicological properties were evaluated on male and female Sprague-Dawley rats receiving ACP orally at 200, 600, and 1000 mg/kg body weight for 90 days; the control group received only distilled water. The results show that ACP contained seven important AC index compounds, namely antcins A, B, C, K, and H, dehydrosulphurenic acid, and dehydroeburicoic acid. At the tested doses, oral ACP administration for 90 days caused no mortality, adverse effects on general health, body and organ weights, and food intake. Furthermore, no significant variations were observed in hematological and biochemical parameters among either sex of ACP-treated and control animals. An histopathological examination of vital organs showed no significant structural changes in organs, even in high-dose ACP-treated animals. This study indicated that ACP contained the major bioactive triterpenoids of AC fruiting bodies, and its no-observed-adverse-effect level (NOAEL) was 1000 mg/kg/day, about 20 times the recommended daily intake.

Magnesium—A More Important Role in CKD–MBD than We Thought

Chronic kidney disease (CKD) is associated with different complications, including chronic kidney disease–mineral and bone disorder (CKD–MBD), which represents a systemic disorder that involves the presence of different mineral or bone structure abnormalities (i.e., modification of bone turnover, strength, volume, etc.), including even vascular calcification development. Even if, over the years, different pathophysiological theories have been developed to explain the onset and progression of CKD–MBD, the influence and importance of serum magnesium level on the evolution of CKD have only recently been highlighted. So far, data are inconclusive and conflicting; therefore, further studies are necessary to validate these findings, which could be useful in developing a better, more adequate, and personalized management of CKD patients.

Aptamer-functionalised magnetic particles for highly selective detection of urinary albumin in clinical samples of diabetic nephropathy and other kidney tract disease

We report a new highly selective detection platform for human albumin (HA) in urine based on aptamer-functionalised magnetic particles. Magnetic separation and re-dispersion was utilised to expose the HA-bound particles to a methylene blue solution. A second magnetic collection step was then used to allow the methylene blue supernatant to be reduced at an unmodified screen-printed electrode. Since methylene blue adsorbs to HA, the reduction current fell in proportion to HA concentration. There was no interference from compounds such as dopamine, epinephrine, vanillylmandelic acid, normetanephrine, metanephrine and creatinine in artificial urine at the concentrations at which they would be expected to appear. A calibration equation was derived to allow for the effect of pH on the response. This enabled measurement to be made directly in clinical urine samples of varying pH. After optimisation of experimental parameters, the total assay time was 40 min and the limit of detection was between 0.93 and 1.16 μg mL^-1, depending on the pH used. HA could be detected up to 400 μg mL^-1, covering the range from normoalbuminuria to macroalbuminuria. Analysis of urine samples of patients, with diabatic nephropathy, type I & II diabetes mellitus and chronic kidney disease, from a local hospital showed good agreement with the standard urinary human albumin detection method.