The importance of urinary magnesium values in patients with gut failure

ESPEN guideline on chronic intestinal failure in adults - Update 2023

BACKGROUND & AIMS

In 2016, ESPEN published the guideline for Chronic Intestinal Failure (CIF) in adults. An updated version of ESPEN guidelines on CIF due to benign disease in adults was devised in order to incorporate new evidence since the publication of the previous ESPEN guidelines.

METHODS

The grading system of the Scottish Intercollegiate Guidelines Network (SIGN) was used to grade the literature. Recommendations were graded according to the levels of evidence available as A (strong), B (conditional), 0 (weak) and Good practice points (GPP). The recommendations of the 2016 guideline (graded using the GRADE system) which were still valid, because no studies supporting an update were retrieved, were reworded and re-graded accordingly.

RESULTS

The recommendations of the 2016 guideline were reviewed, particularly focusing on definitions, and new chapters were included to devise recommendations on IF centers, chronic enterocutaneous fistulas, costs of IF, caring for CIF patients during pregnancy, transition of patients from pediatric to adult centers. The new guideline consist of 149 recommendations and 16 statements which were voted for consensus by ESPEN members, online in July 2022 and at conference during the annual Congress in September 2022. The Grade of recommendation is GPP for 96 (64.4%) of the recommendations, 0 for 29 (19.5%), B for 19 (12.7%), and A for only five (3.4%). The grade of consensus is "strong consensus" for 148 (99.3%) and "consensus" for one (0.7%) recommendation. The grade of consensus for the statements is "strong consensus" for 14 (87.5%) and "consensus" for two (12.5%).

CONCLUSIONS

It is confirmed that CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for the underlying gastrointestinal disease and to provide HPN support. Most of the recommendations were graded as GPP, but almost all received a strong consensus.

Recent Advances in Biosensor Technologies for Point-of-Care Urinalysis

Human urine samples are non-invasive, readily available, and contain several components that can provide useful indicators of the health status of patients. Hence, urine is a desirable and important template to aid in the diagnosis of common clinical conditions. Conventional methods such as dipstick tests, urine culture, and urine microscopy are commonly used for urinalysis. Among them, the dipstick test is undoubtedly the most popular owing to its ease of use, low cost, and quick response. Despite these advantages, the dipstick test has limitations in terms of sensitivity, selectivity, reusability, and quantitative evaluation of diseases. Various biosensor technologies give it the potential for being developed into point-of-care (POC) applications by overcoming these limitations of the dipstick test. Here, we present a review of the biosensor technologies available to identify urine-based biomarkers that are typically detected by the dipstick test and discuss the present limitations and challenges that future development for their translation into POC applications for urinalysis.

Development of a new method based on gold nanoparticles for determination of uric acid in urine samples

In the current work, we have reported a fast and easy method based on gold nanoparticles for the determination of uric acid in urine samples. In the first stage, gold nanoparticles were synthesized using the chemical reduction method and then applied as a sensor to measure uric acid concentration based on its strong reducing property. The main parameters affecting response signals such as pH, reagent concentration, and time are optimized using the multivariate method. Under the optimum conditions, the calibration graphs were linear in the range of 0.5 - 10.0 mg.L^-1 with limits of detection of 0.2 mg.L^-1 and RSD% of 1.2% These results show that this nano-based method is a very sensitive and simple method for the determination of uric acid in urine samples.

Chronic intestinal failure and short bowel syndrome in Crohn’s disease

Chronic intestinal failure (CIF) is a rare but feared complication of Crohn’s disease. Depending on the remaining length of the small intestine, the affected intestinal segment, and the residual bowel function, CIF can result in a wide spectrum of symptoms, from single micronutrient malabsorption to complete intestinal failure. Management of CIF has improved significantly in recent years. Advances in home-based parenteral nutrition, in particular, have translated into increased survival and improved quality of life. Nevertheless, 60% of patients are permanently reliant on parenteral nutrition. Encouraging results with new drugs such as teduglutide have added a new dimension to CIF therapy. The outcomes of patients with CIF could be greatly improved by more effective prevention, understanding, and treatment. In complex cases, the care of patients with CIF requires a multidisciplinary approach involving not only physicians but also dietitians and nurses to provide optimal intestinal rehabilitation, nutritional support, and an improved quality of life. Here, we summarize current literature on CIF and short bowel syndrome, encompassing epidemiology, pathophysiology, and advances in surgical and medical management, and elucidate advances in the understanding and therapy of CIF-related complications such as catheter-related bloodstream infections and intestinal failure-associated liver disease.

Intestinal Failure and Rehabilitation

The rendering of proper care for the patient with intestinal failure requires the provider to have a functional understanding of digestion and absorption, nutrient requirements, and intestinal adaptation. Inherent in those concepts is that not only is nutritional absorption compromised, but medication absorption is as well. The principles of the management of home parenteral nutrition must be mastered and then proper and controlled weaning of parenteral nutrition may be commenced by use of dietary and pharmacologic means with appropriate clinical outcome measures followed. This complicated management requires a team experienced in both medical and surgical management of intestinal failure.

Polycystin-1 dysfunction impairs electrolyte and water handling in a renal precystic mouse model for ADPKD

The PKD1 gene encodes polycystin-1 (PC1), a mechanosensor triggering intracellular responses upon urinary flow sensing in kidney tubular cells. Mutations in PKD1 lead to autosomal dominant polycystic kidney disease (ADPKD). The involvement of PC1 in renal electrolyte handling remains unknown since renal electrolyte physiology in ADPKD patients has only been characterized in cystic ADPKD. We thus studied the renal electrolyte handling in inducible kidney-specific Pkd1 knockout (iKsp- Pkd1^-/-) mice manifesting a precystic phenotype. Serum and urinary electrolyte determinations indicated that iKsp- Pkd1^-/- mice display reduced serum levels of magnesium (Mg²⁺), calcium (Ca²⁺), sodium (Na⁺), and phosphate (P_i) compared with control ( Pkd1^+/+) mice and renal Mg²⁺, Ca²⁺, and P_i wasting. In agreement with these electrolyte disturbances, downregulation of key genes for electrolyte reabsorption in the thick ascending limb of Henle's loop (TA;, Cldn16, Kcnj1, and Slc12a1), distal convoluted tubule (DCT; Trpm6 and Slc12a3) and connecting tubule (CNT; Calb1, Slc8a1, and Atp2b4) was observed in kidneys of iKsp- Pkd1^-/- mice compared with controls. Similarly, decreased renal gene expression of markers for TAL ( Umod) and DCT ( Pvalb) was observed in iKsp- Pkd1^-/- mice. Conversely, mRNA expression levels in kidney of genes encoding solute and water transporters in the proximal tubule ( Abcg2 and Slc34a1) and collecting duct ( Aqp2, Scnn1a, and Scnn1b) remained comparable between control and iKsp- Pkd1^-/- mice, although a water reabsorption defect was observed in iKsp- Pkd1^-/- mice. In conclusion, our data indicate that PC1 is involved in renal Mg²⁺, Ca²⁺, and water handling and its dysfunction, resulting in a systemic electrolyte imbalance characterized by low serum electrolyte concentrations.

Genome-Wide Meta-Analysis Unravels Interactions between Magnesium Homeostasis and Metabolic Phenotypes

Magnesium (Mg²⁺) homeostasis is critical for metabolism. However, the genetic determinants of the renal handling of Mg²⁺, which is crucial for Mg²⁺ homeostasis, and the potential influence on metabolic traits in the general population are unknown. We obtained plasma and urine parameters from 9099 individuals from seven cohorts, and conducted a genome-wide meta-analysis of Mg²⁺ homeostasis. We identified two loci associated with urinary magnesium (uMg), rs3824347 (P=4.4×10^-13) near TRPM6, which encodes an epithelial Mg²⁺ channel, and rs35929 (P=2.1×10^-11), a variant of ARL15, which encodes a GTP-binding protein. Together, these loci account for 2.3% of the variation in 24-hour uMg excretion. In human kidney cells, ARL15 regulated TRPM6-mediated currents. In zebrafish, dietary Mg²⁺ regulated the expression of the highly conserved ARL15 ortholog arl15b, and arl15b knockdown resulted in renal Mg²⁺ wasting and metabolic disturbances. Finally, ARL15 rs35929 modified the association of uMg with fasting insulin and fat mass in a general population. In conclusion, this combined observational and experimental approach uncovered a gene-environment interaction linking Mg²⁺ deficiency to insulin resistance and obesity.

A case of osteomalacia due to deranged mineral balance caused by saccharated ferric oxide and short-bowel syndrome: A case report

RATIONALE

Saccharated ferric oxide has been shown to lead to elevation of fibroblast growth factor 23, hypophosphatemia, and, consequently, osteomalacia. Moreover, mineral imbalance is often observed in patients with short-bowel syndrome to some degree.

PATIENT CONCERNS

A 62-year-old woman with short-bowel syndrome related with multiple resections of small intestines due to Crohn disease received regular intravenous administration of saccharated ferric oxide. Over the course of treatment, she was diagnosed with tetany, which was attributed to hypocalcemia. Additional assessments of the patient revealed not only hypocalcemia, but also hypophosphatemia, hypomagnesemia, osteomalacia, and a high concentration of fibroblast growth factor 23 (314 pg/mL).

DIAGNOSES

We diagnosed her with mineral imbalance-induced osteomalacia due to saccharated ferric oxide and short-bowel syndrome.

INTERVENTIONS

Magnesium replacement therapy and discontinuation of saccharated ferric oxide alone.

OUTCOMES

These treatments were able to normalize her serum mineral levels and increase her bone mineral density.

LESSONS

This case suggests that adequate evaluation of serum minerals, including phosphate and magnesium, during saccharated ferric oxide administration may be necessary, especially in patients with short-bowel syndrome.

ESPEN guidelines on chronic intestinal failure in adults

BACKGROUND & AIMS

Chronic Intestinal Failure (CIF) is the long-lasting reduction of gut function, below the minimum necessary for the absorption of macronutrients and/or water and electrolytes, such that intravenous supplementation is required to maintain health and/or growth. CIF is the rarest organ failure. Home parenteral nutrition (HPN) is the primary treatment for CIF. No guidelines (GLs) have been developed that address the global management of CIF. These GLs have been devised to generate comprehensive recommendations for safe and effective management of adult patients with CIF.

METHODS

The GLs were developed by the Home Artificial Nutrition & Chronic Intestinal Failure Special Interest Group of ESPEN. The GRADE system was used for assigning strength of evidence. Recommendations were discussed, submitted to Delphi rounds, and accepted in an online survey of ESPEN members.

RESULTS

The following topics were addressed: management of HPN; parenteral nutrition formulation; intestinal rehabilitation, medical therapies, and non-transplant surgery, for short bowel syndrome, chronic intestinal pseudo-obstruction, and radiation enteritis; intestinal transplantation; prevention/treatment of CVC-related infection, CVC-related occlusion/thrombosis; intestinal failure-associated liver disease, gallbladder sludge and stones, renal failure and metabolic bone disease. Literature search provided 623 full papers. Only 12% were controlled studies or meta-analyses. A total of 112 recommendations are given: grade of evidence, very low for 51%, low for 39%, moderate for 8%, and high for 2%; strength of recommendation: strong for 63%, weak for 37%.

CONCLUSIONS

CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for both the underlying gastrointestinal disease and to provide HPN support. The rarity of the condition impairs the development of RCTs. As a consequence, most of the recommendations have a low or very low grade of evidence. However, two-thirds of the recommendations are considered strong. Specialized management and organization underpin these recommendations.

Review article: The nutritional and pharmacological consequences of obesity surgery

BACKGROUND

Obesity surgery is acknowledged as a highly effective therapy for morbidly obese patients. Beneficial short-term effects on common comorbidities are practically undisputed, but a growing data pool from long-term follow-up reveals increasing evidence of potentially severe nutritional and pharmacological consequences.

AIMS

To assess the prevalence, causes and symptoms of complications after obesity surgery, to elucidate and compare therapy recommendations for macro- and micronutrient deficiencies, and to explore surgically-induced effects on drug absorption and bioavailability, discussing ramifications for long-term therapy and prophylaxis.

METHODS

PubMed, Embase and MEDLINE were searched using terms including, but not limited to, bariatric surgery, gastric bypass, obesity surgery and Roux-en-Y, coupled with secondary search terms, e.g. anaemia, micronutrients, vitamin deficiency, bacterial overgrowth, drug absorption, pharmacokinetics, undernutrition. All studies in English, French or German published January 1980 through March 2014 were included.

RESULTS

Macro- and micronutrient deficiencies are common after obesity surgery. The most critical, depending on surgical technique, are hypoalbuminemia (3-18%) and deficiencies of vitamins B1 (≤49%), B12 (19-35%) and D (25-73%), iron (17-45%) and zinc (12-91%). Many drugs commonly administered to obese patients (e.g. anti-depressants, anti-microbials, metformin) are subject to post-operative and/or PPI-associated changes affecting bioavailability and absorption.

CONCLUSIONS

Complications are associated with pre-operative and/or post-operative malnutrition or procedure-related changes in intake, absorption and drug bioavailability. The high prevalence of nutrient deficiencies after obesity surgery makes life-long nutritional monitoring and supplementation essential. Post-operative changes to drug absorption and bioavailability in bariatric patients cast doubt on the validity of standard drug dosage and administration recommendations.

Systematic review: hypomagnesaemia induced by proton pump inhibition

BACKGROUND

Proton pump inhibitors (PPIs) are a mainstay therapy for all gastric acid-related diseases. Clinical concerns arise from a small but growing number of case reports presenting PPI-induced hypomagnesaemia (PPIH) as a consequence of long-term PPI use. Current opinion is that reduced intestinal magnesium absorption might be involved, but nothing is known on the molecular mechanism underlying PPIH.

AIM

To investigate whether or not PPIH is a true, long-term drug-class effect of all PPIs and to scrutinise a possible role of comorbidity in its aetiology. Therefore, the primary objective in particular was to investigate serum magnesium dynamics in trials drug withdrawal and re-challenge. The secondary objective was to profile the 'patient at risk'.

METHODS

We reviewed systematically all currently available case reports on the subject and performed a statistical analysis on extracted data.

RESULTS

Proton pump inhibitor-induced hypomagnesaemia PPIH is a drug-class effect and occurred after 5.5 years (median) of PPI use, onset was broad and ranged from 14 days to 13 years. Discontinuation of PPIs resulted in fast recovery from PPIH in 4 days and re-challenge led to reoccurrence within 4 days. Histamine-2-receptor antagonists were the preferable replacement therapy in PPIH and prevented reoccurrence of hypomagnesaemia. In PPIH no specific risk profile was identified that was linked to the hypomagnesaemia.

CONCLUSIONS

The cases of PPIH show severe symptoms of magnesium depletion and identification of its causation was only possible through withdrawal of the PPI. Clinical awareness of PPIH is key to avoid putting patients at risk.

Necrolytic acral erythema as a cutaneous marker of hepatitis C: report of two cases and review

Necrolytic acral erythema (NAE) is a member of the necrolytic erythemas, which include necrolytic migratory erythema (NME), acrodermatitis enteropathica, and various dermopathies secondary to nutritional deficiencies. NAE is distinct from the other necrolytic erythemas by virtue of its consistent association with hepatitis C (HCV) together with the acral distribution of its lesions, in particular, dorsal hands and feet. Although its etiology is unknown, NAE has been reported to respond to zinc replacement, suggesting a causal relationship. Two patients with HCV infection presented with scaly acral plaques and histopathologic features consistent with NAE while also demonstrating atypical palmoplantar accentuation of lesions. Both patients were found to have zinc deficiency, and their lesions responded to zinc supplementation. Awareness of NAE as a unique cutaneous marker for HCV infection is important not only for accurate dermatologic diagnosis but also for appropriate management of associated morbidity and prompt detection of potentially undiagnosed underlying HCV.

ESPEN Guidelines on Parenteral Nutrition: gastroenterology

Undernutrition as well as specific nutrient deficiencies has been described in patients with Crohn's disease (CD), ulcerative colitis (UC) and short bowel syndrome. In the latter, water and electrolytes disturbances may be a major problem. The present guidelines provide evidence-based recommendations for the indications, application and type of parenteral formula to be used in acute and chronic phases of illness. Parenteral nutrition is not recommended as a primary treatment in CD and UC. The use of parenteral nutrition is however reliable when oral/enteral feeding is not possible. There is a lack of data supporting specific nutrients in these conditions. Parenteral nutrition is mandatory in case of intestinal failure, at least in the acute period. In patients with short bowel, specific attention should be paid to water and electrolyte supplementation. Currently, the use of growth hormone, glutamine and GLP-2 cannot be recommended in patients with short bowel.

Dietary and medical management of short bowel syndrome in adult patients

Resection of the small bowel can lead to malabsorption of fluid, electrolytes, minerals, and other essential nutrients, resulting in malnutrition and dehydration. Individualized and tailored nutritional management for patients with short bowel syndrome (SBS) helps to optimize intestinal absorption, leading to nutritional independence such that a patient can resume as normal a lifestyle as possible. Parenteral nutrition (PN), used to supply the required nutrients following resection, is associated with a number of complications affecting patient morbidity and mortality. Attempts should be made to wean patients from PN to an oral diet as soon as possible. Dietary management is complex and needs to be individualized for each patient on the basis of his or her specific gastrointestinal anatomy, underlying disease, and lifestyle. In addition to nutrient intake, management of SBS also requires appropriate oral rehydration, vitamin and mineral supplementation, and pharmacotherapy. Several medications provide a useful adjunctive function to dietary intervention, including antidiarrheal agents, H2 antagonists and proton pump inhibitors, pancreatic enzymes, somatostatin analogs, antimicrobials, and trophic factors.

Parenteral nutrition-associated metabolic bone disease

The incidence of parenteral nutrition-associated metabolic bone disease is unknown. Initial reports from the early 1980s suggested that both osteoporosis and osteomalacia were quite common in patients who receive long-term parenteral nutrition. The findings described in these early surveys provide a snapshot into the many factors that contribute to the development of metabolic bone disease. More recent evidence suggests that bone loss may not be as great with the initiation of parenteral nutrition as once was thought, and that most of the metabolic bone disease that is noted may be related to the patient's underlying illness. Although this recent information is reassuring, it is of the utmost importance to provide parenteral nutrition that minimizes further bone loss and promotes the formation of new bone. This review will describe the general features of metabolic bone disease and the abnormalities noted with parenteral nutrition-associated metabolic bone disease, highlight the importance of preexisting illness and parenteral nutrition associated factors that contribute to the development of metabolic bone disease, and finally discuss an approach to avoid this debilitating complication of long-term parenteral nutrition.

Risk factors for developing renal stones in inflammatory bowel disease

OBJECTIVE

To correlate renal calculi and other clinical factors with urinary biochemical analytes in patients with inflammatory bowel disease, and to investigate the relative importance of hyperoxaluria (associated with fat malabsorption) or reduced stone inhibitors in the development of calculi in these patients.

PATIENTS, SUBJECTS AND METHODS

Samples were obtained from 25 patients with Crohn's disease (CD), 15 with ulcerative colitis (UC) and 17 normal subjects (controls). Evidence for the presence of renal calculi was obtained from plain films, ultrasonography or intravenous urography. Urine oxalate and citrate were analysed using commercial enzymatic assays; magnesium was measured using atomic absorption and other analytes assayed using standard methods on automated analysers.

RESULTS

Renal calculi were found in two patients with CD and in none with UC. Hyperoxaluria was present in 36% of patients with CD but was absent in those with UC. Analysis of covariance showed an association between low urinary citrate/creatinine ratio and renal stones (P=0.02), and between a combined urinary citrate and magnesium deficit relative to calcium, as expressed in the CMC index ((citratexmagnesium)/calcium), and renal stones (P=0.017). Changes in urinary calcium, oxalate, urate, magnesium or the calcium oxalate index were not associated with the presence of stones. There was no independent relationship between any clinical factor and the presence of stones.

CONCLUSION

Lower urinary concentrations of magnesium and citrate (stone inhibitors), relative to calcium (stone promoter; the CMC index) may be more important in lithogenesis in inflammatory bowel disease than is hyperoxaluria. In patients with a functioning colon, a low CMC index may predict likely stone-formers; this requires a prospective evaluation. Avoiding low urinary levels of magnesium and citrate may aid in preventing and treating renal calculi.

Nutritional management of short bowel syndrome in adults

Short bowel syndrome (SBS) comprises the sequelae of nutrient, fluid, and weight loss that occurs subsequent to greatly reduced functional surface area of the small intestine. Signs and symptoms of SBS include electrolyte disturbances; deficiencies of calcium, magnesium, zinc, iron, vitamin B12, or fat-soluble vitamin deficiency; malabsorption of carbohydrates, lactose, and protein; metabolic acidosis, gastric acid hypersecretion; formation of cholesterol biliary calculi and renal oxalate calculi; and dehydration, steatorrhea, diarrhea, and weight loss. Thorough nutritional management is the key factor in achieving an optimal outcome in SBS. Total parenteral nutrition is necessary in the early stages, as is replacement of excess fluid and electrolyte losses. Nutritional management of SBS has traditionally been divided into three phases: an acute phase when total parenteral nutrition is usually begun, an adaptation phase, and a maintenance phase. Recommendations regarding the need for parenteral nutrition vary depending on the presence or absence of certain factors: the ileocecal valve, jejunum, and functional colon. Patients with residual small bowel length of 100 cm or less usually require the administration of parenteral nutrition at home with good results. The total parenteral nutrition diet should consist of a majority of calories from fat, followed by protein, and the remaining as carbohydrates. Vitamins, minerals, and trace elements should also be added accordingly. Although total parenteral nutrition is initially necessary, treatment goals should focus on early transition to enteral nutrition followed by oral feeds. Other recent advances in the medical management of SBS include pharmacologic treatment and the use of specific nutrients and growth factors to stimulate intestinal absorption and adaptation. Both animal studies and clinical trials in humans have shown much promise in supplementation with growth factors and hormones. This strategy is likely to play a greater role in the treatment of SBS in the future.

Management of patients with a short bowel

There are two common types of adult patient with a short bowel, those with jejunum in continuity with a functioning colon and those with a jejunostomy. Both groups have potential problems of undernutrition, but this is a greater problem in those without a colon, as they do not derive energy from anaerobic bacterial fermentation of carbohydrate to short chain fatty acids in the colon. Patients with a jejunostomy have major problems of dehydration, sodium and magnesium depletion all due to a large volume of stomal output. Both types of patient have lost at least 60 cm of terminal ileum and so will become deficient of vitamin B₁₂. Both groups have a high prevalence of gallstones (45%) resulting from periods of biliary stasis. Patients with a retained colon have a 25% chance of developing calcium oxalate renal stones and they may have problems with D (-) lactic acidosis. The survival of patients with a short bowel, even if they need long-term parenteral nutrition, is good.

Severe convulsant hypomagnesaemia and short bowel syndrome

Hypomagnesaemia as a primary cause of a generalized seizure is uncommon. A 60-year-old woman with Crohn's disease, who had had recent small bowel surgery and a total colectomy 10 years previously, was admitted complaining of severe nausea, vomiting, fatigue and thirst. Despite oral magnesium therapy she had a generalized seizure due to severe hypomagnesaemia of 0.09 mmol/l (normal range 0.65 to 1.05 mmol/l). Her serum calcium was 1.91 mmol/l (2.03 to 2.63 mmol/l). Hypomagnesaemia can cause generalized convulsions but is usually associated with hypocalcaemia. This patient had an almost normal serum calcium level, and therefore hypomagnesaemia would seem to have been the direct cause of her seizure. Long-term intravenous magnesium was necessary to prevent further seizures.

Nutritional support for the patient with short-bowel syndrome

Short-bowel syndrome refers to the clinical consequences that follow extensive resection of the small bowel. As a result of resection, malabsorption of macro- and micronutrients occurs. The prognosis after resection depends on the extent and location of resection, the presence of a colon, the function of the residual intestinal mucosa, and the extent of intestinal adaptation. Intestinal adaptation is influenced by the presence of intraluminal nutrients and various trophic peptides and hormones. This article discusses the dietary management of the patient with short-bowel syndrome and the recent literature on growth factors (ie, growth hormone and glutamine) and small-bowel transplantation.

Serum ionized versus total magnesium in patients with intestinal or liver disease

In serum, magnesium exists in three fractions: protein-bound, complex-bound and free ionized form. Only the free ionized fraction is biologically active. Until recently, only the measurement of serum total magnesium has been in clinical use. Now, commercially available instruments using new ion-selective electrodes for Mg++ have made possible the reliable measurement of serum ionized magnesium in clinical practice. For the measurement of serum ionized magnesium we used a magnesium-selective electrode installed in a six-channel electrolyte analyzer. We compared the use of ionized versus total magnesium measurement in 52 patients with intestinal disease, 54 with liver disease, and in 75 healthy control subjects. In the patients with alcoholic liver disease both serum ionized and total magnesium were lower, and in those with inflammatory bowel disease slightly higher than in control subjects. The correlation coefficient between serum ionized and total magnesium was r=0.87 (p<0.001) in the patients, and r=0.75 (p<0.001) in the controls. In the patient group the fraction of ionized magnesium in the total was negatively related to the serum albumin level (r=-0.41, p<0.001). Serum total magnesium was below the reference range in 30 out of 150 measurements, serum ionized magnesium in only 9 out of 150 measurements, respectively. Thus, 21 cases with low total but normal ionized magnesium (two thirds of hypomagnesemia according to serum total magnesium) were false positive. Total magnesium measurement may overestimate the incidence of hypomagnesemia when significant hypoalbuminemia is present. Measurement of serum ionized magnesium instead of total magnesium may therefore be of advantage in evaluating patients with hypoalbuminemia and when hypomagnesemia is expected.

Short bowel syndrome

This article discusses the causes, prognosis, and management of short bowel syndrome. Attempts to enhance intestinal adaptation with trophic factors and surgical treatment options, including small bowel transplantation, are discussed.