Pediatrics · Year 3 · from Pediatrics
Case 2: Anorexia Nervosa
Patient Demographics
- Age: 16-year-old female
- Sex: Female
Chief Complaint
"Her coach is worried about her weight loss."
History of Present Illness
A 16-year-old cross-country runner is brought in by her mother after her coach expressed concern about significant weight loss over the past 4 months. The patient states she has been trying to "eat healthy" to improve her running performance. She has eliminated most carbohydrates, fats, and snacks from her diet, eating mostly salads and fruit. She exercises 2-3 hours daily in addition to team practice. She denies vomiting, laxative use, or binge eating. She reports feeling "fine" and insists she is "not that thin." Her last menstrual period was 4 months ago. She was previously having regular monthly periods. She feels cold frequently and has noticed increased hair on her arms.
History
- Weight history: Current 47 kg; weight 6 months ago was 58 kg (19% weight loss)
- Menstrual history: Menarche age 12; regular periods until 4 months ago; now amenorrheic
- Exercise: Running 8-10 miles daily; added extra workouts without coach's knowledge
- Purging behaviors: Denies vomiting, laxatives, diuretics
- Body image: Feels stomach is "still fat"; wants to lose 5 more pounds
Physical Examination
- Vital Signs: Temperature 35.8C (hypothermic), HR 48 bpm (bradycardic), BP 88/54 mmHg (orthostatic drop of 20 mmHg on standing), RR 14/min
- Height: 165 cm
- Weight: 47 kg
- BMI: 17.3 kg/m2 (severely underweight; <5th percentile)
- General: Thin, ill-appearing adolescent in mild distress from cold
- Skin: Dry skin, lanugo hair on arms and back, yellowish tinge to palms (carotenemia)
- Cardiovascular: Bradycardic, regular rhythm, no murmurs
- Abdomen: Scaphoid, normoactive bowel sounds
- Extremities: Cold, mottled, delayed capillary refill
- Neuropsych: Denies depressed mood; anxious about being weighed
Laboratory Findings
- CBC: WBC 3,200/uL (low), Hemoglobin 11.2 g/dL
- Electrolytes: Na 138, K 3.2 mEq/L (low), HCO3 28
- BUN/Cr: 22/0.9 (elevated BUN suggesting dehydration)
- Glucose: 62 mg/dL (low)
- ECG: Sinus bradycardia, HR 46 bpm, QTc 480 ms (prolonged)
- LH, FSH: Low (hypothalamic suppression)
Diagnosis
Anorexia nervosa, restricting type
Clinical Reasoning
This patient meets DSM-5 criteria for anorexia nervosa: (1) restriction of energy intake leading to significantly low body weight (BMI 17.3, <5th percentile, with 19% weight loss), (2) intense fear of gaining weight despite being underweight, (3) disturbance in body image (feels "stomach is still fat"). The subtype is restricting (no binge-purge behaviors). She has multiple medical complications of starvation: hypothermia, severe bradycardia, orthostatic hypotension, prolonged QTc (risk for arrhythmia), hypoglycemia, and amenorrhea. These findings indicate severe disease requiring hospitalization.
Management
- Hospital admission: Required due to:
- HR <50 bpm
- Orthostatic hypotension
- Prolonged QTc
- Hypoglycemia
- Severe malnutrition
- Cardiac monitoring: Telemetry for arrhythmia risk
- Nutritional rehabilitation: Start low (1,200-1,400 kcal/day) and advance slowly to prevent refeeding syndrome
- Refeeding syndrome prevention:
- Monitor phosphorus, potassium, magnesium twice daily during initial refeeding
- Supplement phosphorus prophylactically
- Slow rate of caloric increase
- Multidisciplinary team: Medical, psychiatry, nutrition, family therapy
- Psychotherapy: Family-based treatment (Maudsley approach) has strongest evidence for adolescent anorexia
- Remove from sports: Until medically and psychologically stable
- Weight restoration goal: Establish target weight with return of menses
Clinical Image
Image Description: Clinical photograph demonstrating lanugo hair on the back of a patient with anorexia nervosa, a physical sign of the body's attempt to maintain temperature in the setting of severe malnutrition.
Source: DermNet NZ URL: https://dermnetnz.org/topics/lanugo License: CC BY-NC-ND 3.0 NZ