Physical Examination Findings in Anorexia Nervosa
Bradycardia (low heart rate) is the most likely physical examination finding in a 16-year-old girl with anorexia nervosa. This finding is consistent with the severe malnutrition and physiological adaptations that occur in this condition.
Common Physical Examination Findings in Anorexia Nervosa
Cardiovascular Findings
- Bradycardia: Heart rate below normal range (often <60 bpm)
- Hypotension
- Orthostatic changes in blood pressure and pulse
- Prolonged QTc interval on ECG
Other Common Physical Findings
- Low body temperature
- Lanugo (fine hair growth on body)
- Muscle wasting
- Loss of subcutaneous fat
- Dry skin
- Brittle hair and nails
Evidence-Based Explanation
The American Psychiatric Association recommends comprehensive physical assessment for patients with eating disorders, with particular attention to vital signs including heart rate 1. Bradycardia is a common physiological adaptation to severe malnutrition and is considered a significant finding that may warrant urgent cardiac evaluation when heart rate drops below 40 bpm 1.
The patient's presentation includes:
- Rapid weight loss over six months
- BMI of 17.8 (below normal range)
- Obsession with weight
- Food avoidance behaviors
These features strongly suggest anorexia nervosa, and the associated physiological changes would likely include bradycardia as the body attempts to conserve energy by slowing metabolic processes.
Differential Diagnosis of Physical Findings
Among the options presented:
Dental erosion: While dental erosion is common in eating disorders, it is primarily associated with purging behaviors in bulimia nervosa or the purging subtype of anorexia nervosa due to exposure of teeth to gastric acid during vomiting 2, 3, 4. The patient's history does not specifically mention purging behaviors, making this less likely to be the primary finding.
Hyperactive bowel sounds: Not typically a characteristic finding in anorexia nervosa.
Hyperhidrosis (excessive sweating): Not a characteristic finding in anorexia nervosa. In fact, patients often have reduced sweating due to adaptive mechanisms to conserve energy.
Bradycardia: Most consistent with the physiological adaptations seen in anorexia nervosa as the body attempts to conserve energy 1, 5.
Tachycardia: Opposite of what would be expected in anorexia nervosa. Tachycardia might suggest other conditions or complications.
Clinical Implications
Bradycardia in anorexia nervosa patients requires careful monitoring as it can lead to serious cardiac complications. The American Psychiatric Association recommends ECG monitoring for patients with restrictive eating disorders, especially those with severe malnutrition 1.
When evaluating adolescents with suspected eating disorders, clinicians should pay particular attention to vital signs, as these can provide objective evidence of physiological compromise even when patients are uncooperative or deny symptoms.