A 16-year-old girl is evaluated in the outpatient clinic for primary amenorrhea. She has never had a menstrual period. Over the past year, she has become increasingly focused on maintaining a 'clean' lifestyle, strictly eliminating fats and carbohydrates from her diet, and exercising for at least two hours daily. Her mother reports that the patient often complains of feeling cold and fatigued but continues to excel academically. The patient takes no medications and denies sexual activity. Her temperature is 35.8°C (96.4°F), blood pressure is 92/58 mm Hg, and pulse is 48/min. Her BMI is 15.2 kg/m². Physical examination reveals fine, soft hair on her back and abdomen, as well as dry skin. Pelvic examination is normal. Laboratory testing reveals:
| Laboratory Test | Result | Reference Range |
|---|---|---|
| Beta-hCG | Negative | Negative |
| FSH | 3 mIU/mL | 4.0 - 10.0 mIU/mL |
| LH | 1 mIU/mL | 2.0 - 15.0 mIU/mL |
| TSH | 2.1 µU/mL | 0.5 - 5.0 µU/mL |
| Free T4 | 1.1 ng/dL | 0.9 - 1.7 ng/dL |
| Total T3 | 55 ng/dL | 80 - 200 ng/dL |
Which of the following is the most likely diagnosis?
- Anorexia nervosaCevap
- BPrimary hypothyroidism
- CBulimia nervosa
- DPolycystic ovary syndrome
- EConstitutional delay of growth and puberty