Which physical exam finding suggests a diagnosis of bulimia nervosa rather than anorexia nervosa?

The presence of dental caries is a significant physical exam finding that suggests a diagnosis of bulimia nervosa. Patients with bulimia often engage in behaviors such as purging (e.g., vomiting, excessive use of laxatives) after episodes of binge eating. This purging can lead to frequent exposure of the teeth to stomach acid, which can result in enamel erosion and increase the risk of dental caries.

In contrast, anorexia nervosa is characterized by restrictive eating behaviors and significant weight loss, but it does not typically involve the binge-eating and purging cycle seen in bulimia. Therefore, patients with anorexia are less likely to present with dental caries, as their behaviors do not produce the same oral complications.

The other choices, such as hypotension, low body mass index, and thinning hair, may be observed in both anorexia nervosa and bulimia nervosa, as both conditions can lead to nutritional deficits and generally impact physical health. Hence, dental caries stands out specifically as an indicator of bulimia, highlighting the distinct nature of the disorder’s behaviors and their consequences.