Patient characteristics in the US:
(1) Most patients are Caucasian females, although males may be affected.
(2) For women, the onset is usually within 8 years of menarche.
(3) Patients are often from an affluent family.
(4) Energy and activity are often unimpaired.
(5) The person usually maintains his or her appetite.
Criteria:
(1) Refusal to maintain body weight at or above a minimally normal weight for age and height.
(2) An intense fear of gaining weight or becoming fat, even though below ideal body weight
(3) A distorted body image with a disturbance in the perception of own body weight or shape, an undue influence placed on body weight or shape in self-evaluation, and/or denial of the seriousness of current low body weight
(4) In post-menarcheal females, the presence of amenorrhea, with absence of at least 3 consecutive menstrual cycles
where:
• There is no specific cut-off for "minimally normal" body weight.
• Guidelines are (1) < 85% of ideal body weight for height and weight, (2) a body mass index < 17.5 kg per meter squared.
• The amenorrhea usually is related to low serum estrogen levels, and periods may occur after hormone (estrogen) replacement.
Subtypes:
(1) restricting: the patient does not regularly engage in binge-eating followed by purging behavior, with weight loss maintained by dietary restriction and exercise
(2) binge-eating and purging: during episodes of anorexia, the patient regularly is engaged in binge-eating followed by purging behavior, similar to that seen in bulimia nervosa
Complications:
(1) emaciation
(2) hypotension
(3) bradycardia, cardiac arrhythmias
(4) hypothermia
(5) acrocyanosis
(6) carotenemia
(7) dry skin
(8) diffuse growth of lanugo hair
(9) ankle edema (with protein malnutrition)
(10) dehydration or hypokalemia with vomiting, or laxative/diuretic abuse
Differential diagnosis:
(1) underlying disease causing weight loss (malignancy, gastrointestinal tract disease, metabolic disorder)
(2) slender person below mean for height and weight
(3) person maintaining slender physique to participate in profession (gymnastics, dance, modeling, etc.)
