What is the most common physical exam finding in anorexia nervosa, between hyperactive bowel sounds and lanugo?

Physical Examination Findings in Anorexia Nervosa

Lanugo is a more common physical exam finding than hyperactive bowel sounds in anorexia nervosa. Lanugo—fine, downy hair growth on the face and body—is a direct consequence of severe malnutrition and represents the body's attempt to conserve heat in the setting of low body temperature and loss of subcutaneous fat 1.

Key Physical Examination Findings

Most Common Findings Related to Malnutrition

• Lanugo hair growth appears as fine, downy hair on the face, trunk, and extremities, occurring as a physiological response to severe malnutrition and hypothermia 1

• Vital sign abnormalities are nearly universal and include:

  • Bradycardia (resting heart rate often <60 bpm) 2
  • Hypotension 2
  • Hypothermia (low body temperature) 2
  • Orthostatic changes in pulse and blood pressure 2, 1

• Hair and skin changes include alopecia, hair thinning, dry flaky skin, and the characteristic lanugo growth 2, 1

• Signs of purging behaviors when present include Russell's sign (calluses on knuckles), parotid gland enlargement (swollen cheeks/jawline), and dental enamel erosion 2, 1

Gastrointestinal Findings

• Delayed gastric emptying and intestinal transit are well-documented in anorexia nervosa, with reduced gastric acid secretion, pancreatic enzyme secretion, and increased bacterial colonization of the upper gut 2

• Hyperactive bowel sounds are not a characteristic finding in anorexia nervosa; in fact, the literature describes delayed small and large bowel transit, reduced intestinal motility, and potential for mega-duodenum with absent migrating motor complexes in severe cases 2

• Constipation rather than diarrhea is the typical gastrointestinal complaint, reflecting the slowed gut motility 2

Critical Assessment Components

Essential Measurements at Every Visit

• Document temperature, resting heart rate, blood pressure, orthostatic pulse, and orthostatic blood pressure to assess cardiovascular stability 2, 1

• Measure height and weight to calculate BMI (or percent median BMI for children/adolescents) and determine percentage below ideal body weight 2, 1

• Assess for physical signs of severe malnutrition including skeletal muscle wasting, loss of subcutaneous fat, and the presence of lanugo 2, 1

Cardiac Complications Requiring Attention

• Cardiac abnormalities are responsible for 50% of deaths in anorexia nervosa, with at least one-third of all deaths due to cardiac causes including sudden death 3, 4

• Cardiovascular complications occur in up to 80% of cases and include cardiac muscle atrophy, sinus bradycardia, and QTc interval prolongation 5, 4

• An electrocardiogram should be performed in all patients with restrictive eating disorders to assess for QTc prolongation, which predicts risk of sudden cardiac death 2, 1, 5

Common Pitfalls

• Do not dismiss normal laboratory values as excluding serious illness—approximately 60% of anorexia nervosa patients show normal routine laboratory values despite severe malnutrition 5

• Do not confuse peripheral edema with weight gain—edema occurs in up to 20% of adolescent patients with anorexia nervosa due to hypoproteinemia, electrolyte imbalance, hormonal changes, or rapid refeeding, and can be mistaken for true weight gain 6

• Do not overlook cardiovascular instability based on patient appearance alone—cardiac complications can be life-threatening even when other physical findings seem mild 4, 7