Nocturnal enuresis in adolescents with anorexia nervosa: prevalence, potential causes, and pathophysiology

Renal fluid and acid/base balance during refeeding in restrictive eating disorders

BACKGROUND AND OBJECTIVES

Fluid shifts have been ascribed to central diabetes insipidus in patients with anorexia nervosa hospitalized for refeeding. Recent data, however, suggest that vasopressin production is not dysregulated in this population. Our objective was to describe the trajectory of fluid imbalances in relationship to kidney function, electrolyte disturbances, and acid/base balance during refeeding.

METHODS

A retrospective review of daily fluid balance and biochemical values was performed in 70 sequential unique patients admitted to University of California at Los Angeles Hospital Medical Stabilization Program for Eating Disorders from December 2018 to November 2020.

RESULTS

Participants (2 males/68 females) were between 10 and 24 years of age and with a median body mass index of 16.1 (14.3, 18.1) kg/m² . A severe negative fluid balance (>-900 ml/day) was observed in 80% of patients at some point during hospitalization. Serum sodium concentrations were normal on admission and remained stable during refeeding. Serum bicarbonate concentrations were 25 ± 1 mEq/dl on admission and increased above the normal range in 31% of patients. Metabolic alkalosis was inversely associated with the development of a negative fluid balance. Estimated glomerular filtration rate was impaired in 54% of patients, improved with refeeding, and was not associated with the development of a severe negative fluid balance or metabolic alkalosis.

DISCUSSION

Chronic energy deprivation alters the physiology of renal fluid and bicarbonate handling in ways that are independent of vasopressin and glomerular filtration. Further studies are warranted to understand the renal adaptations that occur during energy restriction and subsequent refeeding.

PUBLIC SIGNIFICANCE

Massive urinary fluid losses occur in patients with restrictive eating disorders hospitalized for refeeding. In addition, many patients have impaired renal bicarbonate excretion. These findings suggest that chronic energy deprivation impairs the kidney's ability to handle the shifts in fluid and acid/base balance that occur when appropriate oral nutrition is re-introduced.

Females with Eating Disorders and Urinary Incontinence: A Psychoanalytic Perspective

Eating disorders (EDs) are complicated mental illnesses with significant treatment resistance and dropout rates. For successful treatment, it is important for clinicians to better understand the patients' narrative and their lived experiences. A thorough psychodynamic understanding of patients' childhood attachment and primary relationships, personality traits and mental processes is, therefore, crucial for managing patients with ED. Interestingly, several studies have observed an association between functional urinary symptoms and individuals with ED. EDs such as anorexia nervosa are associated with an increased risk of all urinary symptoms, and functional incontinence was also more common in extreme female athletes with low energy availability and with disordered eating. There is, however, a dearth of literature describing this relationship, and the underlying mechanisms remain remote. In this paper, we present a psychoanalytic approach to the presence of urinary symptoms in females with EDs. We hypothesize that these symptoms are tied to specific traits or characteristics of ED patients, namely the overarching need for control, a pathological strive for perfection and the self-denial of basic bodily urges. This is discussed in relation to psychopathological processes, development and personality factors commonly seen in patients with ED.

Bladder and voiding dysfunction in adolescents with anorexia nervosa: a novel finding and potential causes

PURPOSE

This study aimed to investigate the bladder capacity (BC) and bladder dynamics of adolescents with anorexia nervosa (AN).

METHODS

The participants consisted of 15 adolescents newly diagnosed with AN according to the DSM 5 criteria and in the acute weight loss period who were questioned about the symptoms of lower urinary tract (LUT) dysfunction. Functional bladder capacity (FBC) and voided volume with uroflowmetry were measured for each subject; the larger volume of the two was chosen for the bladder capacity. Uroflowmetry was used to obtain uroflow curves for the participants whose patterns were labeled as pathologic if they were outside the bell-shape.

RESULTS

Fourteen (93.3%) of the patients exhibited at least one of the LUT dysfunction symptoms (pathologic voiding symptom/urinary incontinence/pathologic uroflow pattern). BC was observed to increase in 86.6% (n = 13) of the patients. Eighty% of the patients (n = 12) showed pathological uroflow patterns. In patients with pathological uroflow patterns, which showed insufficiency of bladder contraction, assistance of abdominal muscles was needed during voiding.

CONCLUSION

The novel findings presented in this study are the increase of BC in adolescents with AN, the presence of at least one type of voiding or bladder dysfunction, and the pathology of uroflow patterns of most patients show that the bladder dynamics is affected in AN. The most important contribution of this study to the literature is that impaired bladder dynamics was determined to be a medical complication of AN.

LEVEL OF EVIDENCE

Case-control analytic study, Level III.

Incontinence and constipation in adolescent patients with anorexia nervosa-Results of a multicenter study from a German web-based registry for children and adolescents with anorexia nervosa

OBJECTIVE

Nocturnal enuresis (NE), daytime urinary incontinence (DUI), and fecal incontinence (FI) are common disorders in childhood and are frequently accompanied by comorbid psychiatric disorders. Despite a high association between urinary and fecal incontinence with psychiatric and neurodevelopmental disorders, research on comorbidity between incontinence and anorexia nervosa (AN) remains scarce. Yet, it is well known that somatic consequences of AN include metabolic and gastrointestinal disorders. The study sought to assess the prevalence of incontinence and constipation in children and adolescents with AN and to examine associations of these two symptoms with body weight at admission and with BMI changes during inpatient treatment.

METHODS

Data collected between 2015 and 2017 by a multicenter German web-based registry for AN were analyzed. Three hundred and forty-eight patients with AN (96.3% female, mean age = 15.1 ± 1.8 years) were assessed regarding AN subtype, psychiatric comorbidity, body weight, incontinence, and constipation.

RESULTS

Overall, 27.6% of patients had constipation, 1.8% had NE and 1.8% DUI. Prevalence of constipation did not significantly differ between AN subtypes. Constipation did not lead to any significant differences in weight/BMI changes during inpatient treatment.

DISCUSSION

This is the largest study of incontinence and constipation in patients with AN, so far. Our results indicate that constipation is highly prevalent in adolescent patients with AN and reflects a clinically relevant condition. Despite, patients with AN do not have an increased prevalence of incontinence compared with the general population. Future studies should include medical examinations like ultrasound and physical examination of the lower abdomen to evaluate the severity of constipation.

Central diabetes insipidus associated with refeeding in anorexia nervosa: A case report

Anorexia nervosa (AN) has been associated with a multitude of hypothalamic pituitary abnormalities, although it is unknown which aberrations reflect disease causation and which are the consequences of severe malnutrition. Among these endocrinopathies, hypothalamic-posterior pituitary aberrations have been described, including disorders of osmoregulation. We report the case of an adolescent female with a history of severe AN, restricting subtype, treated aggressively with multiple hospitalizations. During hospitalization for severe weakness and lethargy, her course of medical stabilization was complicated by significant polyuria, ultimately diagnosed as central diabetes insipidus (DI). This is the first reported case, to our knowledge, of a severely malnourished adolescent with AN-restricting subtype developing central DI during the refeeding process for medical stabilization, thus adding to the small body of existing literature on disordered osmoregulation in this patient population. This case report raises the question as to whether the frequency of central DI during refeeding is greater than that previously recognized. Additional research should focus on how neuroendocrine dysregulation of water balance might impact the clinical course of AN and its treatment.

Renal complications in anorexia nervosa

PURPOSE

Anorexia nervosa is a malady with possible long-lasting physiological consequences. Among these, little is known about the renal effects, which remain rarely investigated.

METHODS

A literature review was conducted using electronic databases and manual search of relevant articles, discussing the renal impacts of anorexia nervosa.

RESULTS

Renal failure has been described in malnourished patients, but the optimal non-invasive tool to assess the glomerular function rate in this population needs to be further evaluated. Significant disruptions in osmolar regulation, even in the absence of potomania, arise from multiple factors: hypothalamic dysfunction, intrinsic renal insufficiency, and use of psychotropic medications. Urinary urgency and nocturnal enuresis are frequent symptoms, rarely reported by patients. Among hydroelectrolytic disorders, hypokalemia is the most frequent, especially in settings of vomiting or medication misuse. Hyponatremia, hypomagnesemia, and hypophosphatemia may also be encountered. Urinary lithiases are relatively frequent as a consequence of dehydration, laxative use, or both.

CONCLUSION

Investigation and follow-up of the renal function are essential in patients with an eating disorder, especially when the illness has been present for a long time.