Amenorrhea Medical Question
A 26 year old woman has had menses once every 4-6 months since age 16. Menarche occurred at age 12 years and she had regular 28 day cycles until she joined the high school track team when she was 16 years old. She now runs 25 to 35 miles per week. She eats a healthy diet. She is 168 cm (5 ft 5 in) tall and weights 59 kg (130 lb); BMI 21 kg/m2. This woman has an increased risk of developing which of the following?
B) Ovarian cancer
C) Anorexia nervosa
E) Vitamin B12 deficiency
– National Board of Medical Examiners
Osteoporosis is common in anorexia nervosa. It places these patients at increased lifetime risk for fractures. Bone loss may never recover completely even once weight is restored. The strongest predictors of osteoporosis include low body weight and amenorrhea. Loss of bone density can occur rapidly and very early in the course of anorexia nervosa. The etiology of bone loss in the patient with anorexia nervosa is multifactorial. In addition to reduced estrogen and progesterone, excess cortisol levels and low levels of insulin growth factor (IGF-1), a correlate for bone formation, are observed. Dual energy x-ray absorptiometry (DEXA) screening is important to assess bone density. Early diagnosis and treatment of anorexia nervosa are paramount to prevent initial weight loss and subsequent loss of bone.