Psychiatric disturbance leading to potassium depletion, sodium depletion, raised plasma-renin concentration, and secondary hyperaldosteronism

Machine Learning to Identify Genetic Salt-Losing Tubulopathies in Hypokalemic Patients

Introduction

Clinically distinguishing patients with the inherited salt-losing tubulopathies (SLTs), Gitelman or Bartter syndrome (GS or BS) from other causes of hypokalemia (LK) patients is difficult, and genotyping is costly. We decided to identify clinical characteristics that differentiate SLTs from LK.

Methods

A total of 66 hypokalemic patients with possible SLTs were recruited to a prospective observational cohort study at the University College London Renal Tubular Clinic, London. All patients were genotyped for pathogenic variants in genes which cause SLTs; 39 patients had pathogenic variants in genes causing SLTs. We obtained similar data sets from cohorts in Taipei and Kobe, as follows: the combined data set comprised 419 patients; 291 had genetically confirmed SLT. London and Taipei data sets were combined to train machine learning (ML) algorithms, which were then tested on the Kobe data set.

Results

Single biochemical variables (e.g., plasma renin) were significantly, but inconsistently, different between SLTs and LK in all cohorts. A decision table algorithm using serum bicarbonate and urinary sodium excretion (FE_Na) achieved a classification accuracy of 74%. This was superior to all the single biochemical variables identified previously.

Conclusion

ML algorithms can differentiate true SLT in the context of a specialist clinic with some accuracy. However, based on routine biochemistry, the accuracy is insufficient to make genotyping redundant.

Effective medical treatment strategies to help cessation of purging behaviors

OBJECTIVE

Herein we review the major medical issues involved in the "detoxing" of patients who engage in purging behaviors and the pathophysiology of why they occur.

METHODS

Given a limited evidence base of randomized controlled trials, we conducted a thorough qualitative review to identify salient literature with regard to the medical issues involved in "detoxing" patients from their purging behaviors.

RESULTS

Pseudo Bartter's Syndrome is the root cause of much of the medical difficulties which can arise when purging behaviors are abruptly discontinued. However, this is imminently treatable and even preventable with a judicious medical treatment plan which targets the increased serum aldosterone levels which would otherwise promote salt and water retention and a propensity towards severe edema formation. Effective recommendations are provided which can make this process much less vexing for patients attempting to cease their purging behaviors.

CONCLUSIONS

"Detoxing" from purging behaviors can be fraught with medical complications which frustrate these patients and can lead to unsuccessful outcomes. Medical providers should become familiar with the pathophysiology which is the basis for Pseudo Bartter's Syndrome and the effective medical treatments which can lead to a successful outcome.

Laxative abuse, eating disorders, and kidney stones: a case report and review of the literature

Kidney stones are listed among the complications of eating disorders; however, very few cases have been reported. We present an additional case of nephrolithiasis associated with laxative abuse, including detailed results of the patient's urine metabolic profiles, in a patient with idiopathic hypercalciuria. We review the literature and provide an explanation for the paucity of cases of nephrolithiasis associated with these disorders. Despite low urine volumes resulting from extracellular fluid volume depletion and hypocitraturia resulting from hypokalemia, both of which would tend to favor the formation of kidney stones, most patients with eating disorders are likely to be protected from stone formation by the hypocalciuric effect of extracellular fluid volume depletion and increased proximal tubular sodium reabsorption. However, patients with underlying idiopathic hypercalciuria who develop eating disorders may be at increased risk of stone formation in the setting of low urine volume and therefore high supersaturation of calcium oxalate and phosphate.

PseudoBartter syndrome in eating disorders

OBJECTIVE

PseudoBartter's syndrome, a complex pattern of seemingly unrelated metabolic abnormalities, is frequently seen in patients with eating disorders, particularly those who indulge in purging behaviors. We present two cases that, despite divergent background histories and clinical presentations, possess the unifying pathophysiology that ultimately leads to this syndrome.

METHOD

Case report and review of literature pertaining to Bartter's and PseudoBartter's syndromes.

RESULTS

Purging behaviors commonly result in a state of profound dehydration and chloride depletion that leads to the metabolic abnormalities characteristic of inheritable sodium and chloride renal tubular transport disorders. In the eating disorder patient, these abnormalities lead to a propensity towards marked edema formation.

DISCUSSION

The metabolic and clinical manifestations of PseudoBartter's syndrome are seen more commonly than previously thought. It is important to appreciate that a complex self-perpetuating pathophysiology leads to the hypokalemic metabolic alkalosis characteristic of PseudoBartter syndrome. The metabolic abnormalities characteristic of this phenomenon should therefore be viewed in this context and the resulting predilection towards marked edema formation should be borne in mind.

Is glycyrrhizin sensitivity increased in anorexia nervosa and should licorice be avoided? Case report and review of the literature

OBJECTIVE

Hypokalemia is a potentially life-threatening electrolyte disturbance in anorexia nervosa and is most frequently caused by purging behavior. We report a case of severe hypokalemia in anorexia nervosa induced by daily ingestion of approximately 20 g of licorice.

METHODS

To confirm the diagnosis of licorice-induced pseudohyperaldosteronism, a re-exposure trial was performed.

RESULTS

Cessation of the licorice intake normalized plasma potassium, renin, and aldosterone levels and the urine cortisol/cortisone ratio. Re-exposure confirmed the diagnosis. The pronounced response to a relatively low daily dose of licorice suggests high glycyrrhizin sensitivity.

CONCLUSION

Patients with anorexia nervosa not only have decreased food intake but also selective and sometimes bizarre eating habits that, in association with increased sensitivity to glycyrrhizin, may cause severe hypokalemia.

Colonic potassium handling

Homeostatic control of plasma K+ is a necessary physiological function. The daily dietary K+ intake of approximately 100 mmol is excreted predominantly by the distal tubules of the kidney. About 10% of the ingested K+ is excreted via the intestine. K+ handling in both organs is specifically regulated by hormones and adapts readily to changes in dietary K+ intake, aldosterone and multiple local paracrine agonists. In chronic renal insufficiency, colonic K+ secretion is greatly enhanced and becomes an important accessory K+ excretory pathway. During severe diarrheal diseases of different causes, intestinal K+ losses caused by activated ion secretion may become life threatening. This topical review provides an update of the molecular mechanisms and the regulation of mammalian colonic K+ absorption and secretion. It is motivated by recent results, which have identified the K+ secretory ion channel in the apical membrane of distal colonic enterocytes. The directed focus therefore covers the role of the apical Ca2+ and cAMP-activated BK channel (KCa1.1) as the apparently only secretory K+ channel in the distal colon.

Threading through the mizmaze of Bartter syndrome

The story, described here in detail, started in 1962 with the publication of a seminal paper by Frederic Bartter et al. in the December issue of the American Journal of Medicine. The authors reported two pediatric patients with hitherto undescribed features, namely growth and developmental delay associated with hypokalemic alkalosis and normal blood pressure despite high aldosterone production. It soon became clear that this condition was not so exceptional. The syndrome named after Bartter was actually identified in children as well as in adults, females as well as males and in all five continents. It took almost four decades to clarify the exact nature of the disease. Bartter disease is an autosomal recessive disorder with four genotypes and mainly two phenotypes. Moreover, there are acquired secondary forms of Bartter syndrome as well as pseudo-Bartter syndromes. The history demonstrates the power of genetics but also illustrates the fundamental and irreplaceable contributions from nephrologists and renal physiologists.

The eating disorders medicine cabinet revisited: a clinician's guide to appetite suppressants and diuretics

OBJECTIVE

This article explores the frequencies of use of alternative medications, available products, and their potential toxicities.

METHOD

Survey data were gathered from 39 consecutive patients diagnosed with bulimia nervosa who were seeking treatment. A survey of area outlets (health food stores, pharmacies, grocery stores) was conducted to establish a database of available agents. Putative active ingredients were identified. MEDLINE literature searches, as well as reviews of specialized texts, were performed to identify the potential toxicities of the ingredients.

RESULTS

Diet pill use was found in 64% of patients; 18 % reported use in the past month. The survey identified 167 products. Diuretic use was found in 31% of patients; 21% reported use in the past month. Twenty-five diuretic products were identified.

DISCUSSION

Alternative medicines are frequently used in the population of patients seeking treatment for bulimia nervosa. An abundance of products are available with potentially significant toxicities.

Urine electrolytes as markers of bulimia nervosa

OBJECTIVE

The diagnosis of bulimia nervosa (BN) is often delayed because patients are frequently secretive about the illness. Prior work has examined several potential diagnostic markers, none of which has been both highly sensitive and specific. Little is known about the utility of urine electrolytes in detecting BN symptoms.

METHOD

Seventy-seven women with BN and 53 control women participated in the study. Urine and serum electrolytes and urine phenolthalein screens were obtained. Subjects with BN also completed a self-report instrument (the Eating Behaviors IV) regarding vomiting during the week prior to assessment. Receiver operating characteristic analysis was used to examine the predictive abilities of urine and serum electrolytes.

RESULTS

Bulimic and control subjects differed significantly on most electrolyte measures. The ratio of urine sodium to urine chloride was the best predictor of bulimic behavior; selecting individuals with a ratio of >1.16 identified 51.5% of BN subjects with a 5% false-positive rate. Fractional excretion of sodium (FENA), urine anion gap (UAG), and serum potassium values were also predictive of BN but serum hypokalemia was not more common in BN than in control subjects (4.1% vs. 0%; p =.15). Vomiting frequency was correlated with an abnormal UAG (r(2) =.2231) but not FENA, nor serum potassium.

CONCLUSION

The ratio of urine sodium to urine chloride is a useful predictor of bulimic behavior that appears to be more powerful in detecting BN than traditional screening measures such as serum hypokalemia.

Pregnancy complicated with Bartter's syndrome: a case report

Bartter's syndrome is a rare renal disorder, and since there are few case reports of Bartter's syndrome complicating pregnancy are few, the changes of electrolytes and hormonal metabolism during pregnancy are unknown. We describe and discuss the course of pregnancy complicated with Bartter's syndrome.

Vascular responses to angiotensin II in anorexia nervosa

Anorexia nervosa (AN) patients have a tendency to develop renin-angiotensin-aldosterone (RAA) abnormalities caused by abnormal behaviors expressed over long periods of time. Short-term dietary sodium intake is a known modulator of blood pressure response to infused angiotensin II (A II) in normal subjects. Therefore AN patients and normal gender-matched and age-matched controls were studied for vascular responses to exogenous A II. Untreated AN patients needed significantly greater quantities of exogenous A II to raise diastolic blood pressure (DBP) to over 20 mmHg for 30 min compared with controls (12.1 +/- 0.47 versus 7.6 +/- 0.69 ng/kg/min, p < 0.01). The amount of A II required to raise DBP to over 20 mmHg in AN patients in tests before and after completion of treatment (4.2 +/- 0.33 months later) was significantly different (12.1 +/- 0.47 versus 8.1 +/- 0.25 ng/kg/min, p < 0.01). There was no significant difference between AN patients following treatment and controls. Our results indicate that it requires long time before decreased A II responsiveness caused by chronic sodium depletion normalizes in AN patients.

Aldosterone responses to angiotensin II in anorexia nervosa

Patients with anorexia nervosa (AN) tend to have renin-angiotensin-aldosterone (RAA) abnormalities caused by abnormal behaviors such as strict dieting, fasting, vigorous exercise, self-induced vomiting and abuse of laxatives and/or diuretics. Adrenal responsiveness to angiotensin II (A II) was studied in 13 AN patients before and after therapy and in 6 normal sex- and age-matched controls: adrenal responses to postural change (1 h of walking following 1 h in a supine position) and to exogenous A II injection (A II: 10 ng/kg/min intravenous infusion for 30 min). The 24-h urine sodium concentration was significantly lower in AN patients before therapy than after therapy. Plasma aldosterone secretory response to A II was significantly higher in AN patients before therapy in both postural change and exogenous A II injection tests compared with after therapy response and that of controls. On the other hand, there was no significant difference in adrenal response to postural change or to exogenous A II between AN patients after therapy and controls. In conclusion, increased A II sensitivity caused by chronic sodium deficiency in AN patients normalized over time as the patients recovered.

Abuse of drugs associated with eating disorders

Concomitant bulimia nervosa and drug abuse are common in women. Drugs used by this group include diuretics, emetics, laxatives, and diet pills, as well as alcohol, cigarettes, and illicit street drugs. This paper applies principles from behavioral pharmacology to the problem of drug use by women with bulimia nervosa. The prevalence of use, primary effects, toxicity, detection, tolerance, withdrawal, and effects on appetite and weight are discussed for drugs used by bulimic women to reduce appetite or weight or to induce purging (e.g., diuretics, emetics, laxatives, and diet aids). Alternatives in the diagnosis and treatment of drug use in women with eating disorders are discussed.

Anorexia nervosa. Fluid-electrolyte and acid-base manifestations

Psychiatric nurses need to know about the biologic, psychologic, and social implications of anorexia nervosa; however, the current nursing literature presents little information regarding the physiologic aspects of the syndrome. The pathophysiologic basis for the clinical manifestations of acid-base and fluid-electrolyte disturbances associated with anorexia nervosa are examined, and, when appropriate, the implications for nursing assessment are discussed.

Bulimia nervosa in the male: a report of nine cases

Nine male patients with bulimia nervosa, accounting for one in 24 bulimic patients attending a clinic for eating disorders, are described. Symptomatology and demographic characteristics were similar in males and females. A history of either anorexia nervosa or obesity was always present, and a chronic course was seen in 6 patients. Five of the men showed atypical sexuality.

Stimulation of PGE2 synthesis and water and electrolyte secretion by senna anthraquinones is inhibited by indomethacin

The effect of dried senna pod extract, containing 10% sennoside B, on colonic electrolyte and fluid transport was examined in the anaesthetized rat in-situ. Oral administration of senna pod extract dose-dependently (17.5-30 mg kg-1, calculated as sennoside B) reversed net absorption of water, sodium and chloride to net secretion and increased potassium secretion. Senna pod extract stimulated the output of prostaglandin E2 into the colonic lumen. Inhibition of prostaglandin biosynthesis by pretreatment of the rats with indomethacin (10 mg kg-1) significantly inhibited the effects of senna pod extract (17.5-30 mg kg-1) both on net fluid transport and on prostaglandin E2 synthesis. The inhibitory effect of indomethacin on net fluid transport induced by senna pod extract (30 mg kg-1) was dose-dependent. It is concluded that anthraquinones exert their laxative action at least partially via stimulation of colonic fluid and electrolyte secretion, and that this secretion is mediated by stimulation of endogenous prostaglandin E2 formation.

Influence of chronic bisacodyl treatment on the effect of acute bisacodyl on water and electrolyte transport in the rat colon

Excessive or unnecessary taking of laxatives leads to a vicious circle with perpetuation of laxative abuse and increase of laxative dosage, accompanied by severe clinically evident disturbances. It was investigated in rats whether chronic administration of bisacodyl reduces the effects of acute bisacodyl administration on net water and electrolyte flux in the rat colon transport in-vivo. After chronic pretreatment with bisacodyl had been given for 21 days (3 mg and 10 mg kg-1 day-1), net water and sodium absorption was found to be decreased whereas potassium secretion was increased. After 21 days of pretreatment, the effect of acute bisacodyl (10 micrograms ml-1 intraluminal) on net water and sodium transport was reduced whereas the effect on potassium secretion remained unchanged. Serum and erythrocyte levels of sodium and potassium remained unchanged in chronically pretreated rats. Serum aldosterone levels were enhanced two fold. It is concluded that under the experimental conditions described, chronically administered bisacodyl leads to elevated serum aldosterone which counteracts the effect of bisacodyl on net water and sodium transport but acts synergistically with bisacodyl on the effect on potassium loss.

Electrolyte and other physiological abnormalities in patients with bulimia

The frequencies of various forms of eating-related behaviour (such as vomiting and laxative abuse) are reported for a series of non-anorectic bulimia patients seen for evaluation in an eating disorders clinic. The results of serum electrolyte, glucose and other screening tests in these patients are presented. Electrolyte abnormalities were found in 82 of the 168 patients (48.8%) who were diagnosed as having either bulimia or atypical eating disorder. The most common abnormality was metabolic alkalosis (27.4%); hypochloremia (23.8%) and hypokalemia (13.7%) were also commonly seen. No significant blood sugar abnormalities were encountered. An elevated serum amylase level was found to be associated with frequent binge-eating and vomiting behaviour. The pathophysiology of electrolyte abnormalities in this patient group is briefly reviewed.

Case report. Tumoral calcinosis: an unusual complication of the laxative abuse syndrome

A 47-year-old woman who abused laxatives as a means of weight control is described. Her laxative abuse resulted in an episode of tetany for which she was given long-term calcium and vitamin D therapy. This therapy, along with the ingestion of absorbable phosphate and alkali, and large amounts of milk, led to the development of tumoral calcinosis. The failure to fully appreciate the contribution of laxative abuse in her metabolic imbalance resulted in this complication.

Furosemide-induced hyperuricemia, hyperglycemia, hypertension and arterial lesions in nonarteriosclerotic and arteriosclerotic rats

Male and female, Sprague-Dawley rats, with and without arteriosclerosis, were subjected to chronic treatment with furosemide for 4 weeks. Furosemide-treated rats manifested increased adrenal and kidney weights along with an increase in blood pressure; rats with pre-existing arteriosclerosis showed considerable reduction in heart and body weights. Furosemide-treated animals displayed an increase in circulating levels of creatine phosphokinase, lactic dehydrogenase, free fatty acids, glucose, BUN and uric acid. Circulating levels of triglycerides, total cholesterol, and corticosterone were subnormal, whereas aldosterone was distinctly elevated. Despite these metabolic derangements, de novo arterial disease did not appear in virgin rats without pre-existing arterial disease. However, furosemide-treated virgin rats did develop grossly visible apical and left-ventricular foci of myocardial necrosis, i.e., 12% in males, 9% in female virgins. Breeder rats with pre-existing arteriosclerosis manifested exacerbation of their arterial disease, e.g., intimal calcification of the epicardial coronary arteries along with foci of myocardial fibrosis and islet beta-cell granule depletion. Adrenocortical lipid alterations appeared in all animals treated with furosemide. It is suggested that this spectrum of metabolic and histopathologic degenerative changes may have been caused by secondary aldosteronism due to the chronic treatment with furosemide.

Bulimia nervosa: an ominous variant of anorexia nervosa

Thirty patients were selected for a prospective study according to two criteria: (i) an irresistible urge to overeat (bulimia nervosa), followed by self-induced vomiting or purging; (ii) a morbid fear of becoming fat. The majority of the patients had a previous history of true or cryptic anorexia nervosa. Self-induced vomiting and purging are secondary devices used by the patients to counteract the effects of overeating and prevent a gain in weight. These devices are dangerous for they are habit-forming and lead to potassium loss and other physical complications. In common with true anorexia nervosa, the patients were determined to keep their weight below a self-imposed threshold. Its level was set below the patient's healthy weight, defined as the weight reached before the onset of the eating disorder. In contrast with true anorexia nervosa, the patients tended to be heavier, more active sexually, and more likely to menstruate regularly and remain fertile. Depressive symptoms were often severe and distressing and led to a high risk of suicide. A theoretical model is described to emphasize the interdependence of the various symptoms and the role of self-perpetuating mechanisms in the maintenance of the disorder. The main aims of treatment are (i) to interrupt the vicious circle of overeating and self-induced vomiting (or purging), (ii) to persuade the patients to accept a higher weight. Prognosis appears less favourable than in uncomplicated anorexia nervosa.

[Histopathology of the kidney in pseudo-Bartter's Syndrome induced by chronic abuse of diuretics (author's transl)]

A 38-year-old female patient developed a Pseudo-Bartter's-Syndrome with hypokalemic alkalosis, hyponatremia and hyperrenism as the result of the abuse of diuretics (furosemide, spironolactone, thiabutacide) for a period of more than 10 years. The needle biopsy specimen from the kidney showed a hyperplasia of the juxtaglomerular apparatus and of the mesangium cells as the morphologic basis of hyperrenism, a focal vacuolisation of the proximal tubular epithelium and a focal atrophy of the distal tubules. The pathogenesis of the tubular alterations and their possible relation to hypokalemia, hypoxemia or drug-toxicity is discussed, a satisfactory interpretation, however, cannot be given. The encroachment of proximal tubular epithelium on the parietal layer of Bowman's capsule is another striking pathoanatomical finding, and considered a compensatory mechanism under the continuous loss of water.

Chronic hypokalemic nephropathy: a clinical study

Description of 23 patients (21 women, 2 men) with an average age of 36.6 (19--68) years, who were hypokalemic during 6.5 years on the average (range 1/2--16 years). The cause of the potassium depletion was malnutrition (anorexia nervosa, vomiting) and/or abuse of laxatives and/or diuretics. With increasing duration of potassium depletion renal function deteriorated; in two cases terminal renal failure developed. Histology of the kidneys (9 cases) showed the picture of chronic abacterial interstitial nephritis. Urinalysis was negative or non-specific. The blood pressure levels were normal or low, hypertensive values being exceptional. Aside of hypokalemia a tendency to hyponatriemia, hypochloremia and metabolic alcalosis was observed, the latter turning into hypokalemic normochloremic acidosis with advancing renal insufficiency. Plasma renin activity and aldosterone concentration or excretion frequently were elevated, but no close correlation was found between these parameters or with the blood pressure. Bacterial infection of the urinary tract occured, if at all, in the late phase and seems to be complication rather than the cause of the kidney disease. The discussion of other possible pathogenetic factors leads to the conclusion that the term "chronic kaliopenic nephropathy" is justified. Some diagnostic and therapeutic consequences are mentioned.

A perspective on aldosterone abnormalities

Not all the varied clinical disorders in which aldosterone and the mineralocorticoid hormones are involved have been reviewed. Only those disorders in which the mineralocorticoid hormones and their regulatory factors are the principal cause of the biochemical and clinical abnormalities have been examined. These are many and varied. Appreciation of the extent and magnitude of their involvement in the regulation of blood pressure, body fluids, and electrolyte composition continues to grow. The major direct clinical impact of the mineralocorticoid hormones appears to be in two areas: hypertension and potassium homeostasis. Their part in the mosaic of hypertension is established in primary hyperaldosteronism, but they also appear to affect and modify the hypertensive process in primary or essential hypertension. The probe continues. Hypoaldosteronism is more than the rare occurrence associated with Addison's disease. It may be the clue to the presence of nonaldosterone mineralocorticoid excess syndromes, and is obviously of critical importance in an increasing number of patients with chronic renal failure of varied aetiologies.

Laxative-induced diarrhoea: a continuing clinical problem

Seven women spent an average of 127 days in hospital and were extensively investigated, including a laparotomy, before their complaints of abdominal pain, diarrhoea, and weight loss were shown to be due to excessive taking of laxatives. All denied taking laxatives and in none were the characteristic features of the effects of cathartics on the colon seen on sigmoidoscopy or radiological examination.Hypokalaemia and other electrolyte abnormalities were common and were thought to be due to a combination of severe diarrhoea and vomiting. The rectal mucosa was seen to be abnormal on biopsy only in the three patients who had taken senna preparations. The diagnosis was not easy and was finally established either by analysis of the urine and stools or by searching the patient's ward locker.

Vitamin D intoxication, with hypernatraemia, potassium and water depletion, and mental depression

Two elderly patients suffering from manic-depressive psychosis/depressive reaction had concurrently hypercalcaemia from vitamin D intoxication. They developed hypernatraemia with severe potassium and water depletion. Hypercalcaemia was pronounced, but both patients recovered quickly and their depressive symptoms resolved following water and potassium repletion and corticosteroid therapy.