Avoidant/Restrictive Food Intake Disorder
"Anorexia Nervosa", "AN"
Lifetime prevalence is 0.3%, but it is 3 times more common in females than males.
There are 2 main types: (1) Restricting, and (2) Binge-eating
BMI < 18.5 kg/m2
Intense fear of weight gain
Distorted views of body weights and shape
Mental illness with the highest associated mortality (5 - 20% of anorexic patients die)
Patients below 20% ideal body weight (for age, gender, development) should be hospitalized for management. Otherwise, patients can be treated on an outpatient basis.
Avoid refeeding syndrome (can lead to: acute gastric dilation, fluid retention, CHF, cardiac arrhythias, rhabdomyolysis, and death)
Associated lab abnormalities:
Elevated liver enzymes
Carotenemia (elevated serum carotenoids of unknown etiology is associated with AN)
Abnormal Hgb and Hct
Obtain bone density scans
The first step in treatment is to establish the patient's cooperation with the treatment plan. Establish a strong therapeutic alliance with the patient.
The treatment itself depends on a multidisciplinary approach.
Cognitive behavioral therapy (CBT) (replace a behavior with a more adaptive one)
Family therapy (involve social supports)
Supervised weight gain programs (nutritional rehabilitation)
Some antidepressants may be used as adjuncts to promote weight gain (e.g. paroxetine, mirtazapine)
Be aware that other antidepressants may promote weight loss
Consider using the antipsychotic olanzapine if there is no response to CBT and nutritional rehab, as it can typically cause weight gain.