Recognizing, managing medical consequences of eating disorders in primary care

MEDICAL COMPLICATIONS OF STARVATION

Cardiovascular effects of starvation

Malnutrition and starvation have multiple adverse effects on the heart.

Electrophysiologic effects. Sinus bradycardia (< 60 bpm) and hypotension are common cardiac manifestations of starvation.¹³ Bradycardia has been attributed to an adaptive increase in parasympathetic vagal tone.¹⁴ QTc prolongation is also seen in patients with malnutrition.¹⁵

Together, these electrocardiographic abnormalities predispose the patient to ventricular arrhythmia and sudden cardiac death.¹⁶ The risk of ventricular arrhythmia is particularly relevant when treating psychiatric symptoms, since antipsychotics and tricyclic antidepressants are among several drug classes that can cause further QTc prolongation (Table 1).^17,18

In patients with QTc prolongation, bradycardia, or both, the standard of care involves acute hospitalization for refeeding using continuous telemetric monitoring until normal rhythm is restored and the heart rate is above 40 at night and 50 by day.^4,19

Structural changes. Starvation also causes structural changes in the heart. Loss of lean body mass can reduce cardiac muscle mass, compromise cardiac output, and lead to mitral valve prolapse.²⁰ These changes are fully reversible with restored nutrition and regaining of heart mass.^21,22

Effects of starvation on the brain

Starvation can affect brain structure and cognitive function. Undernourished patients have reduced volumes of white and gray matter, a change that can occur within months. Cortical volumes may increase with weight gain, but a reduction in gray matter volume may not be completely reversible.²³

Furthermore, starvation impairs cognitive functions that are needed to stop eating-disorder behaviors; namely, decision-making, emotional control, regulation of appetite, and reward path-ways. Therefore, undernourished patients may not have sufficient insight into the disease to be able to make the best choices for recovery. This finding lends support for using the Maudsley method in adolescents, in which parents take control of their child’s eating until the child can maintain a healthy weight.²⁴

Gastrointestinal consequences of starvation

Patients with malnutrition have prolonged gastric emptying and colonic transit time with solid foods.²⁵ They often complain of early satiety, abdominal pain, bloating, and constipation, all symptoms that complicate the refeeding process. A prokinetic such as metoclopramide (Reglan), given 1 hour before meals and at bedtime, may provide some relief from gastrointestinal symptoms.²⁶

Patients may also experience transient lactose or fructose intolerance after prolonged starvation. Taking a lactase supplement (eg, Lactaid 1–10 tabs) before consuming dairy products and dextrose (contained in candies such as Smarties) before eating fruit or fructose-containing foods can sometimes partially relieve symptoms. In general, gastrointestinal function returns over time as nutritional status improves.

Patients with severe or prolonged starvation can develop steatosis accompanied by elevated levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). In reports of starvation-induced steatosis, liver enzyme levels rapidly normalize with nutritional rehabilitation.²⁷

Endocrine consequences of starvation

Amenorrhea. Dysregulation of the hypothalamic-pituitary-gonadal axis is a major endocrine complication of nutritional in-sufficiency. Weight loss disrupts the normal pulsatile secretion of gonadotropin-releasing hormone, reduces secretion of luteinizing hormone and follicle-stimulating hormone, and decreases estrogen levels.²⁸ Leptin deficiency likely plays a role in suppressing gonadotropin secretion with subsequent development of amenorrhea. With weight gain, levels of leptin and gonadotropins normalize and menstruation eventually returns.^29,30

Hypothyroidism. Starvation can also lead to dysregulation of the hypothalamic-pituitary-thyroid axis. Typically, the concentration of triiodothyronine (T3) is reduced, the ratio of thyroxine (T4) to T3 is elevated, and thyroid-stimulating hormone (TSH) is close to or within the normal range, creating a euthyroid sick syndrome. In eating disorders, this thyroid disturbance is a result of starvation and resolves with weight restoration. Therefore, thyroid hormone replacement therapy is not medically indicated.²⁸

Osteoporosis. Amenorrhea resulting from low estrogen levels in undernourished patients can raise the risk of osteoporosis and fractures, particularly in patients with a low body mass index. Osteopenia results from a negative balance between bone deposition and resorption.

Lack of bone deposition can be especially problematic when disordered eating occurs during peak bone mass development, ie, ages 11 to 14 for girls, and ages 15 to 17 for boys.^31,32 Even a 5% to 10% decrease in bone deposition can result in significant risk of osteopenia.³³ However, after age 30, bone resorption is a greater contributor.³⁴

Does hormone therapy correct bone loss? Given the association between estrogen deficiency and bone loss, estrogen supplementation was expected to be an effective treatment for bone loss in patients with eating disorders.³⁵ Also, the restoration of menses through hormone replacement may give underweight patients a false sense of achieving a “healthy” weight.³⁶

Golden et al³⁷ prospectively studied 50 adolescents and found no significant difference in bone mineral density at 1 year of follow-up between patients treated with estrogen and those who received only standard nutritional therapy. However, increased bone mineral density was achieved in adolescents with anorexia nervosa treated with transdermally administered estrogen dosed to mimic physiologic pubertal levels.³⁸

Klibanski et al³⁹ found that hormone therapy resulted in a 4% gain in bone density in an extremely low-weight subset of women with anorexia nervosa (< 70% of ideal body weight), whereas similar patients in the control group lost 20%. However, in all groups, only weight gain correlated with bone gain in women who were within 70% of their ideal body weight.

Divasta et al⁴⁰ evaluated 60 girls and women ages 13 to 27 with anorexia nervosa, randomized to receive either placebo or dehydroepiandrosterone combined with an estrogen-progestin oral contraceptive, and followed for 18 months. As in the study by Klibanski et al,³⁹ bone loss was prevented in the treatment group, but significant bone gain occurred only in the context of weight gain.

The bottom line is that only weight gain has resulted in significant increases in bone density in patients with anorexia nervosa, and hormone therapy without weight gain has not been shown to increase bone density effectively in this population. Although calcium and vitamin D in oral therapeutic doses through foods or through supplementation are required for bone gain, the combination is not enough to augment bone density in the absence of weight gain.³⁷ Although not curative, weight gain is currently the best option for treating bone loss, and no single pharmacologic treatment is effective.