Osteoporotic fractures revealing anorexia nervosa in five females.

Anorexia nervosa affects 0.5% to 1% of female adolescents. The course is chronic in 50% of cases, causing substantial bone loss with osteoporotic fractures after a few years of amenorrhea. This is probably an underestimated problem. The diagnosis of anorexia nervosa is readily missed, as illustrated by five cases reported herein. The five patients were females aged 17 to 44 years who were only slightly underweight (mean weight, 43.6 kg; body mass index < 20 kg/m2). The first fracture occurred seven to 24 years after the onset of anorexia nervosa. Three patients had vertebral crush fractures, and two had peripheral insufficiency fractures. Bone mineral density measured by absorptiometry was very low (mean lumbar z-score, -3.7 SD). Three patients, who were all members of health care professions, knew that they had anorexia nervosa but failed to report this condition. In the other two patients, the amenorrhea had been mistakenly ascribed to other causes (Stein-Leventhal syndrome and psychogenic anovulation). None of the patients was receiving medical follow-up. Anorexia nervosa should be considered routinely in women who are slightly underweight. The patients often deny abnormal menstruation or eating behaviors. The diagnosis rests on determination of the body mass index, a thorough history emphasizing current and past gonadal dysfunction, and evaluation of the diagnostic criteria for anorexia nervosa. Osteoporosis is probably a common but underestimated complication of anorexia nervosa, particularly before the menopause. Enhanced awareness of this condition should allow earlier detection of a greater number of cases.