Rosh Emergency Medicine Practice Test

What finding would be consistent with the suspected diagnosis of an eating disorder in a female patient with electrolyte abnormalities?

1. Amenorrhea

2. Callused knuckles

3. Lanugo

4. Low thyroid-stimulating hormone

The correct answer is: Callused knuckles

In the context of an eating disorder, particularly anorexia nervosa or bulimia nervosa, callused knuckles are a classic finding associated with the behavior of self-induced vomiting. The calluses, known as Russell's sign, occur as a result of repeated friction and abrasion from the knuckles against the teeth during the act of vomiting. This physical manifestation serves as a potential indicator of bulimic behavior, where individuals purge after eating. Amenorrhea can indeed be present in individuals with eating disorders, particularly in cases of severe caloric restriction and weight loss. However, it is not as specific or direct an indicator of eating disorder behavior as the presence of callused knuckles. Lanugo, which is fine hair that can develop in response to malnutrition or weight loss, may also be present in individuals with anorexia. While it provides evidence of the body's response to starvation, it doesn't directly indicate behaviors associated with purging. Low thyroid-stimulating hormone (TSH) levels may also be observed in patients with eating disorders, primarily due to the metabolic changes associated with significant weight loss. However, low TSH is a biochemical finding that does not serve as a direct indicator of disordered eating patterns. Therefore, the presence of callused