Adaptation to severe chronic hypokalemia in anorexia nervosa: a plea for conservative management

Hypokalemia in patients with anorexia nervosa during refeeding is associated with binge-purge behavior, lower body mass index, and hypoalbuminemia

BACKGROUND

Hypokalemia is frequently found in patients with anorexia nervosa and sometimes leads to life-threatening conditions. Although their serum potassium levels are considered to further decrease during refeeding, no previous studies have addressed actual changes in the serum potassium levels and potential mechanisms underlying hypokalemia during the refeeding period of patients with anorexia nervosa. In this study, we investigated factors associated with hypokalemia during refeeding of patients with anorexia nervosa.

METHODS

We recruited 52 independent patients from 89 admissions with anorexia nervosa (body mass index, 13.0 ± 3.3) from the psychiatry unit in Ashikaga Red Cross Hospital during the period from April 2003 to March 2018 and analyzed serum potassium levels at admission. Of the 89 admissions, 66 admissions with > 1-week hospitalization were recruited to determine the lowest potassium levels during the refeeding period. We analyzed these levels with multiple linear regression analysis with explanatory variables, including data upon admission and treatment-related indicators.

RESULTS

The initial serum potassium level of 3.6 ± 0.9 mg/dl decreased to 3.1 ± 0.7 mg/dl at nadir hypophosphatemia, which was observed an average of 2.5 days after admission. A lower serum potassium level at admission and a lower nadir potassium level during refeeding were associated with a lower body mass index, hypoalbuminemia, and binge-purge behavior. Similar results were obtained when the analysis included restrictive or binge-purge types as well as the independent patient group.

CONCLUSIONS

Lower body mass index, hypoalbuminemia, and binge-purge behavior might be used as indicators to guide clinical approaches for controlling serum potassium levels in patients with anorexia nervosa during refeeding. Hypokalemia, low levels of serum potassium, in patients with anorexia nervosa sometimes leads to life-threatening conditions. Thus, it is of great importance to predict the risk of hypokalemia in patients with anorexia nervosa during the refeeding period. Our study found that hypokalemia in patients with anorexia nervosa during refeeding is associated with a lower body mass index and hypoalbuminemia (low levels of serum albumin), in addition to binge-purge behavior.

Diagnosing bulimia nervosa with parotid gland swelling

BACKGROUND

The authors describe bulimia nervosa, or BN, and its effect on the parotid gland. The associated asymptomatic bilaterally enlarged parotid glands often present a diagnostic dilemma.

CASE DESCRIPTION

The authors present a case of a 22-year-old woman with BN who had bilateral parotid gland swelling, serum electrolyte alteration and no dental stigmata. Her principal concern was the associated cosmetic deformity.

CLINICAL IMPLICATIONS

Because patients with BN who have parotid gland swelling usually are secretive about their purging, the diagnosis may be confirmed by conducting a clinical examination and a serum electrolyte study. Prompt diagnosis can avoid serious medical complications.

Serum electrolytes in bulimic patients with parotid swellings

OBJECTIVE

The purpose of this study was to determine whether electrolyte levels can be used to diagnose bulimia nervosa (BN).

STUDY DESIGN

Four patients with bilateral parotid swellings and BN or suspected BN were examined. Their serum electrolyte levels were retrospectively reviewed.

RESULTS

In this limited study, hypochloremia, hypokalemia, and metabolic alkalosis were present in 1 patient. One patient showed both hypochloremia and hypokalemia, whereas a third patient had only hypochloremia and a low normal serum potassium. The fourth patient demonstrated suspiciously low serum levels of Cl(-) and K(+).

CONCLUSION

Because BN patients tend to be secretive regarding their disorder, serum electrolyte levels may serve as useful tools in diagnosing parotid swellings initiated by bulimia.

Hyperphosphatemia: an objective marker for bulimia nervosa?

Phosphorus abnormalities among patients suffering from eating disorders, although cited, have received relatively little attention. Studies generally report decreased concentrations of phosphorus for both bulimia and anorexia nervosa. We have recently noted hyperphosphatemia in several consecutive hospitalized bulimic patients who appeared to have normal renal function and calcium levels. Case files of 30 inpatient and outpatient female bulimic patients and 30 sex- and age-matched physically healthy psychiatric inpatients and outpatients were reviewed. Phosphorus and electrolytes related to phosphorus metabolism were compared between the two groups. Twenty-four of 30 bulimic patients (80%) were found to have at least one elevated serum phosphorus concentration, whereas all but one of 30 age-matched controls had values within normal limits. Elevated phosphorus levels were generally in the mild to moderate range. No correlation was found between phosphorus levels and any of the other electrolytes examined in both patients and controls. No correlation was found between phosphorus levels and the reported frequency of bingeing and vomiting or the number of laxatives ingested. Since bulimic patients are generally of normal weight and tend to deny their disturbed eating habits, diagnosis is often delayed. However, bulimia may be suspected from biochemical abnormalities such as hypokalemia, hypochloremia, elevated amylase, and acid-base disturbances. This preliminary study indicates that elevated serum phosphorus levels may serve as an additional objective marker for the presence of bulimia nervosa.