Anorexia nervosa, restricting type, severe

This code signifies a severe form of anorexia nervosa characterized by extreme dietary restriction without regular engagement in binge-eating or purging behaviors. Patients exhibit a significantly low body weight, intense fear of gaining weight, and a distorted body image, with the severity determined by a Body Mass Index (BMI) less than 15 kg/m² or less than the 3rd percentile for children/adolescents.

Apply this code when documentation clearly indicates a diagnosis of anorexia nervosa where the patient primarily restricts food intake, and their current BMI falls into the severe range. This code is appropriate for initial and subsequent encounters when the severe restricting type is the primary focus of treatment. Documentation should specify the type (restricting) and the severity (severe) based on BMI criteria.

• Ensure the medical record explicitly states "restricting type" and provides BMI documentation to support "severe" classification.
• Do not use this code if the patient engages in recurrent binge-eating or purging behaviors; consider F50.02 for the binge-eating/purging type.
• Always sequence this code as the primary diagnosis when it is the reason for the encounter, followed by any associated medical complications.