Hypophosphataemia in anorexia nervosa

Adherence to Dutch Guideline in Hospitalized Anorexia Nervosa Adolescents

Background. The Dutch guideline Eating Disorders defines admission criteria for children with anorexia nervosa (AN) in need for medical stabilization and advices close monitoring to detect refeeding syndrome (RFS) in an early stage. Methods. Admission criteria, recommendations at admission, and during first week of hospitalization were evaluated in accordance to the guideline. RFS was defined as decreased electrolyte concentrations and/or clinical features. Results. 22 patients were included with a total of 50 admissions. We observed that 62% of the admitted patients met one of the admission criteria, 190/300 (63%) recommended admission examinations were performed. During admission adherence decreased, in particular daily weighing and physical examination (12% and 6%, respectively). The guideline was not fully followed in any of the patients. None of the hospitalized patients met the RFS criteria. Conclusion. Guideline adherence was moderate and can be improved by a few adaptations, which may limit unnecessary laboratory testing.

Vitamin D and hypophosphatemia in patients with anorexia nervosa and avoidant/restrictive food intake disorder: a case control study

BACKGROUND

Refeeding hypophosphatemia (RH) is a common complication of nutritional restoration in malnourished individuals, yet clear risk stratification remains elusive. Individuals with anorexia nervosa (AN) and avoidant/restrictive food intake disorder (ARFID) may be deficient in vitamin D, an important component of dietary phosphorus absorption in the gut. The relationship between vitamin D and RH in AN and ARFID is unknown. Therefore, the aims of this study were to (1) report rates of low serum 25-hydroxy vitamin D and RH in AN and ARFID; (2) describe associations between phosphorus and variables associated with RH identified in extant literature; (3) examine the relationship between 25-hydroxy vitamin D and RH and (4) investigate moderation by vitamin D between variables of interest and phosphorus level.

METHOD

Analyses included retrospective chart review of 307 individuals admitted to the ACUTE Center for Eating Disorders and Severe Malnutrition with a diagnosis of AN or ARFID. Variables of interest included admission laboratory values (vitamin D level, comprehensive metabolic panel, hemoglobin, point-of-care blood glucose), anthropometric measures (weight, body mass index [BMI], % ideal body weight [IBW]), age, duration of illness, length of stay, feeding method, and serum phosphorus nadir. Pearson and Spearman rank correlation, one-way ANOVA, and regression analyses were used to determine the relationship between variables and serum phosphorus.

RESULTS

Over 1/3 of the sample (35.3%) had serum phosphorus levels ≤ 2.9 mg/dL. There were no significant differences between groups in phosphorus nadir (p = .17, η2 = 0.12) or hypophosphatemia (p = .16, ϕc = 0.11). Thirty-five (35%) of individuals with ARFID were either deficient or insufficient in vitamin D, compared to 29% of individuals with AN. Individuals with AN had significantly higher mean vitamin D levels compared to those with ARFID (p = .03; η2 = 0.015). Nadir phosphorus showed a positive association with weight, BMI, %IBW, potassium, and calcium on admission, and a negative association with length of stay, hemoglobin, and total number of tube-fed days. Higher levels of 25-hydroxy vitamin D moderated the relationship between serum phosphorus nadir and weight on admission (p = .0004).

CONCLUSION

Individuals diagnosed with ARFID are as nutritionally fragile as those with AN regarding vitamin D and RH. The negative feedback loop involving vitamin D that maintains phosphorus homeostasis may play a role in the development of RH in AN and ARFID.

Vitamin D and Hypophosphatemia in Patients with Anorexia Nervosa and Avoidant/Restrictive Food Intake Disorder: A Case Control Study

Background

Refeeding hypophosphatemia (RH) is a common complication of nutritional restoration in malnourished individuals, yet clear risk stratification remains elusive. Individuals with anorexia nervosa (AN) and avoidant/restrictive food intake disorder (ARFID) may be deficient in vitamin D, an important component of dietary phosphorus absorption in the gut. The relationship between vitamin D and RH in AN and ARFID is unknown. Therefore, the aims of this of this study were to 1) describe the prevalence of low serum 25-hydroxy vitamin D levels and RH in AN and ARFID 2) report associations between nadir phosphorus level and variables associated with RH in extant literature and 3) examine the relationship between 25-hydroxy vitamin D levels and serum phosphorus nadir in AN and ARFID.

Method

Analyses included retrospective chart review of 307 individuals admitted to the ACUTE Center for Eating Disorders and Severe Malnutrition with a diagnosis of AN or ARFID. Variables of interest included admission laboratory values (vitamin D level, comprehensive metabolic panel, hemoglobin, point-of-care blood glucose), anthropometric measures (weight, body mass index [BMI], % ideal body weight [IBW]), age, duration of illness, length of stay, feeding method, and serum phosphorus nadir. Pearson and Spearman rank correlation, one-way ANOVA, and regression analyses were used to determine the relationship between variables and serum phosphorus.

Results

Over 1/3 of the sample (35.3%) had serum phosphorus levels ≤ 2.9 mg/dL. There were no significant differences between groups in phosphorus nadir (p = .17, η2 = 0.12) or hypophosphatemia (p = .16, ϕc = 0.11); 44% of individuals with ARFID and 33% of individuals with AN had hypophosphatemia. Nadir phosphorus showed a positive association with weight, BMI, %IBW, potassium, and calcium on admission, and a negative association with length of stay, hemoglobin, and total number of tube-fed days. Higher levels of 25-hydroxy vitamin D moderated the relationship between serum phosphorus nadir and weight on admission (p = .0004).

Conclusion

Individuals diagnosed with ARFID are as nutritionally fragile as those with AN regarding vitamin D and RH. The negative feedback loop involving vitamin D that maintains phosphorus homeostasis may play a role in the development of RH in AN and ARFID.

Electrocardiographic QTc as a Surrogate Measure of Cardiac Risk in Children, Adolescents, and Young Adults With Eating Disorders

The study goal was to investigate electrocardiographic findings, including corrected QT interval (QTc), in patients aged 8 to 23 with eating disorders (EDs) at presentation, compared with an age-and sex-matched control population. We retrospectively reviewed 200 ED patients, and 200 controls. Blinded electrocardiograms (ECGs) were interpreted by an expert reader, and QT intervals corrected using the Bazett formula. Eating disorder patients were 89.5% female, with mean age 16.4 years and median percent median body mass index (BMI)-for-age (%mBMI)a of 91.1%. In ED patients, QTc was significantly shorter than controls (399.6 vs 415.0msec, P < .001). After adjusting for height, %mBMI, sex, magnesium level, and bradycardia, mean QTc duration in patients with anorexia nervosa-restricting subtype (AN-R) was significantly shorter than other ED patients (P = .010). Higher %mBMI was associated with shorter QTc duration (P = .041) after adjusting for height, magnesium, bradycardia, and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis. Within the ED group, no significant association was identified between QTc and medications, electrolytes, or inpatient status.

Renal Function in Patients Hospitalized With Anorexia Nervosa Undergoing Refeeding: Findings From the Study of Refeeding to Optimize Inpatient Gains

PURPOSE

Among complications of malnutrition secondary to anorexia nervosa (AN) or atypical anorexia nervosa (AAN), renal impairment remains poorly elucidated. Evaluating renal function in hospitalized pediatric patients with AN and AAN undergoing refeeding will yield important information to guide clinicians in screening and managing renal dysfunction in this population.

METHODS

This is a secondary analysis of data from the Study of Refeeding to Optimize Inpatient Gains trial, a multicenter randomized clinical trial comparing higher calorie refeeding versus lower calorie refeeding in 120 adolescents and young adults hospitalized with medical instability secondary to AN or AAN. Baseline disease characteristics were obtained. Vital sign measurements, weight, electrolytes, and fluid status were evaluated daily to ascertain medical stability. Renal function on admission and throughout hospitalization was quantified using daily creatinine measurement and calculation of the estimated glomerular filtration rate (eGFR) using the modified Schwartz equation. Regression analysis and mixed linear models were utilized to evaluate factors associated with eGFR.

RESULTS

Of the 111 participants who completed treatment protocol, 33% had a baseline eGFR less than 90, suggesting renal impairment. Patients who experienced more rapid weight loss and more severe bradycardia were more likely to have low admission eGFR. While eGFR improved during refeeding, eGFR change by day based on refeeding treatment assignment did not reach statistical significance (95% confidence interval, -1.61, 0.15]; p = .095).

DISCUSSION

Renal impairment is evident on admission in a significant number of adolescents and young adults hospitalized with AN and AAN. We demonstrate that short-term medical refeeding yields improvement in renal function.

Factors associated with refeeding hypophosphatemia in adolescents and young adults hospitalized with anorexia nervosa

BACKGROUND

Refeeding hypophosphatemia (RH) in individuals with anorexia nervosa (AN) is a potentially fatal complication of nutrition restoration; yet, little is known about risk. This retrospective cohort study examined factors found in hospitalized youth with AN that may contribute to RH.

METHODS

We reviewed medical records of 300 individuals diagnosed with AN admitted between the years of 2010 and 2016. Logistic regression examined factors associated with RH. Multivariate regression examined factors associated with phosphorus nadir.

RESULTS

For 300 participants, the mean (SD) age was 15.5 (2.5) years, 88.3% were White, and 88.3% were female. Participants lost an average of 11.3 (9.7) kg of body weight and were 82% (12.1) of median body mass index (BMI). Age (P = .022), nasogastric (NG) tube feeding (P = .054), weight gain (P = .003), potassium level (P = .001), and magnesium level (P = .024) were contributors to RH. Odds of RH were 13.7 times higher for each unit reduction in magnesium, 9.2 times higher for each unit reduction in potassium, three times higher in those who received NG feeding, 1.5 times higher for each kg of weight gain, and 1.2 times higher for each year of age. Regarding phosphorus nadir, serum magnesium level (P < .001) and admission BMI (P = .002) contributed significantly.

CONCLUSION

The results indicate that age, NG feeding, weight gain, electrolyte abnormalities, and BMI on admission are potential indicators of the development of RH in youth. This study identifies clinical risk factors associated with RH and may guide further investigation.

[Anorexia nervosa: Abnormalities in hematological and biochemical parameters]

Abnormalities of hematological and biochemical parameters are various and frequent during anorexia nervosa, and are mainly related to malnutrition, weight loss, and compensatory purgative behaviors. They are most often moderate and reversible through appropriate nutritional and weight rehabilitation, as well as well-conducted symptomatic treatment. Severe abnormalities are rarer, but are potentially serious or even fatal. Isolated moderate anemia and leukopenia are frequently noted, with thrombocytopenia being less frequent. Severe, bi-cytopenic, pancytopenic, and spinal cord injury are less common. They can be explained by the gelatinous transformation of the bone marrow caused by malnutrition. Biochemical abnormalities are typically hydroelectrolytic disorders (hypokalemia, hyponatremia, metabolic alkalosis), acute or chronic renal failure, elevated transaminases, risk of potentially severe hypoglycemia, and elevated lipid parameters. During the refeeding syndrome, hypophosphatemia is characteristic and may be associated with hypomagnesemia and hypocalcemia, and thiamine deficiency. Malnutrition can also lead to alterations in hormone status, including hypothyroidism, hypercorticism and hypogonadism, which may be involved in the development of serious bone conditions such as osteoporosis. These abnormalities should be routinely investigated, monitored, and corrected during anorexia nervosa. Early and multidisciplinary management of this eating disorder is essential to prevent chronicity of the disorder and the potential severity of these abnormalities.

Weight Loss and Illness Severity in Adolescents With Atypical Anorexia Nervosa

BACKGROUND

Lower weight has historically been equated with more severe illness in anorexia nervosa (AN). Reliance on admission weight to guide clinical concern is challenged by the rise in patients with atypical anorexia nervosa (AAN) requiring hospitalization at normal weight.

METHODS

We examined weight history and illness severity in 12- to 24-year-olds with AN (n = 66) and AAN (n = 50) in a randomized clinical trial, the Study of Refeeding to Optimize Inpatient Gains (www.clinicaltrials.gov; NCT02488109). Amount of weight loss was the difference between the highest historical percentage median BMI and admission; rate was the amount divided by duration (months). Unpaired t tests compared AAN and AN; multiple variable regressions examined associations between weight history variables and markers of illness severity at admission. Stepwise regression examined the explanatory value of weight and menstrual history on selected markers.

RESULTS

Participants were 16.5 ± 2.6 years old, and 91% were of female sex. Groups did not differ by weight history or admission heart rate (HR). Eating Disorder Examination Questionnaire global scores were higher in AAN (mean 3.80 [SD 1.66] vs mean 3.00 [SD 1.66]; P = .02). Independent of admission weight, lower HR (β = -0.492 [confidence interval (CI) -0.883 to -0.100]; P = .01) was associated with faster loss; lower serum phosphorus was associated with a greater amount (β = -0.005 [CI -0.010 to 0.000]; P = .04) and longer duration (β = -0.011 [CI -0.017 to 0.005]; P = .001). Weight and menstrual history explained 28% of the variance in HR and 36% of the variance in serum phosphorus.

CONCLUSIONS

Weight history was independently associated with markers of malnutrition in inpatients with restrictive eating disorders across a range of body weights and should be considered when assessing illness severity on hospital admission.

Low serum phosphate as an independent predictor of increased infection-related mortality in dialysis patients: A prospective multicenter cohort study

BACKGROUND

The role of mineral metabolism in mortality among dialysis patients has received increased attention, but some aspects remain unclear. The aim of the present study was to investigate the prognostic value of serum calcium and phosphate levels for all-cause mortality and cause-specific mortality in dialysis patients.

METHODS

Patients on hemodialysis and peritoneal dialysis were enrolled from a multicenter prospective cohort study in Korea (NCT00931970). The patients were divided into low, normal, and high groups according to their baseline serum calcium or phosphate levels. Cox proportional analysis and a proportional hazards model for the subdistribution of a competing risk were used to calculate hazard ratios (HRs) for the association of serum calcium and phosphate levels with all-cause and cause-specific mortality. Time-dependent values of calcium and phosphate were also evaluated to assess the effect of longitudinal change in mineral metabolism parameters on mortality types.

RESULTS

A total of 3,226 dialysis patients were followed up for a mean of 19.8 ± 8.2 months. Infection was the most common cause of death. Low serum phosphate was significantly associated with all-cause and infection-related death using time-dependent values (HR, 1.43 [95% confidence interval (CI), 1.06-1.93], P = 0.02, and HR, 1.66 [95% CI, 1.02-2.70], P = 0.04, respectively). Low serum phosphate was associated with significantly higher infection-related mortality, especially in patients older than 65 years or on dialysis more than one year or with serum albumin lower than 3.9 g/dL (HR, 2.06 [95% CI, 1.13-3.75], P = 0.02, HR, 2.19 [95% CI, 1.20-4.01], P = 0.01, and HR, 1.77 [95% CI, 1.00-3.13], P = 0.05, respectively). Multinomial logistic regression analysis results suggested that low serum albumin, creatinine, and body mass index correlated with low serum phosphate.

CONCLUSIONS

Low serum phosphate in dialysis patients was an independent risk factor for infection-related death, especially in elderly patients. Persistently low serum phosphate might be a nutritional biomarker to predict increased susceptibility to infection and in turn worse outcomes in dialysis patients.

A retrospective analysis of biochemical and haematological parameters in patients with eating disorders

BACKGROUND

The objective of the study was to determine whether levels of biochemical and haematological parameters in patients with eating disorders (EDs) varied from the general population. Whilst dietary restrictions can lead to nutritional deficiencies, specific abnormalities may be relevant to the diagnosis, pathogenesis and treatment of EDs.

METHODS

With ethics approval and informed consent, a retrospective chart audit was conducted of 113 patients with EDs at a general practice in Brisbane, Australia. This was analysed first as a total group (TG) and then in 4 ED subgroups: Anorexia nervosa (AN), Bulimia nervosa (BN), ED Not Otherwise Specified (EDNOS), and AN/BN. Eighteen parameters were assessed at or near first presentation: cholesterol, folate, vitamin B12, magnesium, manganese, zinc, calcium, potassium, urate, sodium, albumin, phosphate, ferritin, vitamin D, white cell count, neutrophils, red cell count and platelets. Results were analysed using IBM SPSS 21 and Microsoft Excel 2013 by two-tailed, one-sample t-tests (TG and 4 subgroups) and chi-square tests (TG only) and compared to the population mean standards. Results for the TG and each subgroup individually were then compared with the known reference interval (RI).

RESULTS

For the total sample, t-tests showed significant differences for all parameters (p < 0.05) except cholesterol. Most parameters gave results below population levels, but folate, phosphate, albumin, calcium and vitamin B12 were above. More patients than expected were below the RI for most parameters in the TG and subgroups.

CONCLUSIONS

At diagnosis, in patients with EDs, there are often significant differences in multiple haematological and biochemical parameters. Early identification of these abnormalities may provide additional avenues of ED treatment through supplementation and dietary guidance, and may be used to reinforce negative impacts on health caused by the ED to the patient, their family and their treatment team (general practitioner, dietitian and mental health professionals). Study data would support routine measurement of a full blood count and electrolytes, phosphate, magnesium, liver function tests, ferritin, vitamin B12, red cell folate, vitamin D, manganese and zinc for all patients at first presentation with an ED.

[Quality management in weight restitution in Anorexia nervosa--pathophysiology, evidence-based practice and prevention of the refeeding syndrome]

During refeeding syndrome-a well-known and dreaded complication of weight-restauration in anorexia nervosa-a shift of electrolytes and fluid can occur in malnourished patients and might therefore lead to-potentially fatal-cardiovascular, respiratory and neurological symptoms. Causes of this are metabolic and hormonal changes during re-establishment of a carbohydrate-rich diet. This syndrome is most commonly associated with hypophosphatemia, which can however be accompanied by other chemical laboratory abnormalities. Standardized guidelines for the prevention and management of the refeeding syndrome have not yet been established. In case and cohort studies different low- and high-calorie diet protocols led to comparable results with similar complication rates. A focus should be placed on prevention of serious complications by careful monitoring. The pathophysiology, the main constituents in the development of the refeeding syndrome, recommendations for risk assessment and treatment, and current evidence are discussed.

Eating disorders should be considered in the differential diagnosis of patients presenting with acute kidney injury and electrolyte derangement

We present a case of a 40-year-old woman with a history of ongoing anorexia nervosa and bulimia nervosa who has required multiple admissions to hospital for management of acute kidney injury (AKI) and electrolyte derangement. This case is of interest as recent studies have highlighted the significant prevalence of disordered eating and the major public health implications this may have. We discuss the unusual finding of hypercalcaemia in this case and address the investigation and management of AKI and electrolyte disturbance in a patient with anorexia and bulimia.

Refeeding hypophosphatemia in adolescents with anorexia nervosa: a systematic review

The rate of adolescents presenting with anorexia nervosa (AN) is increasing. Medically unstable adolescents are admitted to the hospital for nutrition restoration. A lack of global consensus on appropriate refeeding practices of malnourished patients has resulted in inconsistent refeeding practices. Refeeding hypophosphatemia (RH) is the most common complication associated with refeeding the malnourished patient. This review sought to identify the range of refeeding rates adopted globally and the implication that total energy intake and malnutrition may have on RH while refeeding adolescents with anorexia nervosa. Studies were identified by a systematic electronic search of medical databases from 1980 to September 2012. Seventeen publications were identified, including 6 chart reviews, 1 observational study, and 10 case reports, with a total of 1039 subjects. The average refeeding energy intake was 1186 kcal/d, ranging from 125-1900 kcal/d, with a mean percentage median body mass index (% mBMI) of 78%. The average incidence rate of RH was 14%. A significant correlation between malnutrition (% mBMI) and post-refeeding phosphate was identified (R (2) = 0.6, P = .01). This review highlights the disparity in refeeding rates adopted internationally in treating malnourished adolescents with anorexia nervosa. Based on this review, the severity of malnutrition seems to be a marker for the development of RH more so than total energy intake.

The clinical biochemistry of anorexia nervosa

In anorexia nervosa, under-nutrition and weight regulatory behaviours such as vomiting and laxative abuse can lead to a range of biochemical problems. Hypokalaemia is the most common electrolyte abnormality. Metabolic alkalosis occurs in patients who vomit or abuse diuretics and acidosis in those misusing laxatives. Hyponatraemia is often due to excessive water ingestion, but may also occur in chronic energy deprivation or diuretic misuse. Urea and creatinine are generally low and normal concentrations may mask dehydration or renal dysfunction. Abnormalities of liver enzymes are predominantly characterized by elevation of aminotransferases, which may occur before or during refeeding. The serum albumin is usually normal, even in severely malnourished patients. Amenorrhoea is due to hypogonadotrophic hypogonadism. Reduced concentrations of free T4 and free T3 are frequently reported and T4 is preferentially converted to reverse T3. Cortisol is elevated but the response to adrenocorticotrophic hormone is normal. Hypoglycaemia is common. Hypercholesterolaemia is a common finding but its significance for cardiovascular risk is uncertain. A number of micronutrient deficiencies can occur. Other abnormalities include hyperamylasaemia, hypercarotenaemia and elevated creatine kinase. There is an increased prevalence of eating disorders in type 1 diabetes and the intentional omission of insulin is associated with impaired metabolic control. Refeeding may produce electrolyte abnormalities, hyper- and hypoglycaemia, acute thiamin depletion and fluid balance disturbance; careful biochemical monitoring and thiamin replacement are therefore essential during refeeding. Future research should address the management of electrolyte problems, the role of leptin and micronutrients, and the possible use of biochemical markers in risk stratification.

Teenage Diet: Context and Companions Determine Eating Habits

Objetivo: presentar los significados de la alimentación y las prácticas relacionadas de un grupo de adolescentes escolarizados del colegio Nuestra Señora de Guadalupe, de Cali, Colombia. Método: estudio con abordaje cualitativo de tipo exploratorio, orientado por la hermenéutica dialéctica, utilizando como técnica el análisis de contenido. Se tuvieron en cuenta los espacios familiares, escolares y de la calle, donde los adolescentes interactúan con sus pares o amigos. Participaron 31 adolescentes (17 mujeres y 14 hombres), 10 familiares (6 madres, 2 padres y 2 abuelas), 3 profesores y la administradora de la cafetería. Resultados: de acuerdo con el espacio y la compañía se establecieron subcategorías que determinan e influyen en el tipo de alimentos que consumen los adolescentes, así: en la familia, las tradiciones; en el colegio, la autonomía, la disponibilidad económica, las preferencias del grupo y la oferta de alimentos en la cafetería; en la calle, el género, la amistad y el amor inciden en la elección e ingesta de alimentos. Conclusiones: el espacio y la compañía determinan el tipo y la calidad de los alimentos ingeridos por los adolescentes.

Predisposing chronic diseases and hypophosphatemia in patients with influenza

Almost half of the hospitalized influenza patients have a chronic disease, which increases the risk for secondary bacterial infections and for adults >65 years influenza is related to high mortality risk. The impact of diabetes mellitus (DM), asthma bronchiale, cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) on the risk of having a low serum phosphatemia (S-P) in addition to influenza is important to investigate as this increases both morbidity and mortality and can be prevented. Hypophosphatemia could be the explanation for reduced chemo-taxis and phagocytosis, which in addition to respiratory function may increase the risk of pneumonia and sepsis. Data for this study was collected from the medical journals retrospectively for 100 patients admitted to the Department of Infectious Diseases during the study period, 1992-94, with the clinical diagnosis influenza out of which seventy-two cases were used in the calculation. Forty-seven percent of the hospitalized influenza patients had a 2.7-fold risk of suffering from DM than of any other chronic disease and an almost significantly doubled risk of having a low S-P level with a chronic disease. The prevalence of hypophosphatemia (S-P<0.70 mmol/l) was high; 13.0% of the women and 15.0% of the men; 34.0% of all patients had S-P<0.82 mmol/l. Men, in contrast to women, showed clinical signs of a secondary bacterial infection more frequently (12/41 and 6/35, respectively). Our study gives indications for an involvement of low S-P with chronic disease.

Staging anorexia nervosa: conceptualizing illness severity

In recent years, there has been increasing attention to the conceptualization of anorexia nervosa (AN) and its diagnostic criteria. While varying levels of severity within the illness category of AN have long been appreciated, neither a precise definition of severity nor an empirical examination of severity in AN has been undertaken. The aim of this article is to review the current state of knowledge on illness severity and to propose a theoretical model for the definition and conceptualization of severity in AN. AN is associated with significant medical morbidity which is related to the 'severity' of presentation on such markers as body mass index, eating and purging behaviours. The development of a functional staging system, based on symptom severity, is indicated for reasons similar to those cited by the cancer lobby. Improving case management and making appropriate treatment recommendations have been the primary purpose of staging in other fields, and might also apply to AN. Such a standardized staging system could potentially ease communication between treatment settings, and increase the specificity and comparability of research findings in the field of AN.

Hypophosphatemia: an update on its etiology and treatment

Phosphate plays a key role in several biological processes. In recent years, new insights have been obtained into the regulation of the phosphate metabolism, including a growing amount of evidence suggesting that factors other than parathyroid hormone (PTH) and vitamin D are involved in maintaining the phosphate balance. A new class of phosphate-regulating factors, the so-called "phosphatonins," have been shown to be important in phosphate-wasting diseases. However, the role of the phosphatonins in the normal human homeostasis remains to be established. The incidence of hypophosphatemia in selected patient series can be more than 20%, with clinical sequelae ranging from mild to life threatening. Only when combined with phosphate depletion does hypophosphatemia become clinically significant. The factors that are involved in the phosphate homeostasis, the pathophysiology, the relevance in patient care, the clinical manifestations, and an appropriate management of phosphate depletion are discussed in this review.

Phosphate depletion is the link between growth, stress and diet in the aetiology of MS

Predisposition to multiple sclerosis (MS) can originate in adolescence, when nutrient requirement is high and not satisfied and because of too little food intake and/or a poor diet. Growth per se increases the need for phosphate, an often neglected mineral in clinical conditions. The combination of marginal nutrition (either under- or malnutrition) with a negative phosphate balance, physical exertion, infections or other types of stress during puberty can disturb metabolism and result in demyelinization. Phosphate depletion (PD) can lead to neurological complications, which have been characterized in experimental and clinical studies. Hypophosphataemia, whether acute or chronic, induced by stress from accident, surgery or burns, by infection and/or undernutrition, is therefore an important etiological factor. Low SP levels have been reported in MS patients and the hypothesis that PD causes MS is presented here.