What is the recommended initial work‑up for a suspected eating disorder?

Initial Work-Up for Suspected Eating Disorder

The initial work-up for a suspected eating disorder requires screening during the psychiatric evaluation, followed by a comprehensive assessment including detailed weight and eating behavior history, physical examination with vital signs and orthostatic measurements, and laboratory testing with complete blood count, comprehensive metabolic panel, and electrocardiogram in patients with restrictive eating or severe purging. 1

History and Behavioral Assessment

Weight and Growth Parameters

• Document current height and weight, calculate BMI (or percent median BMI, BMI percentile, or BMI Z-score for children and adolescents) 1
• Obtain maximum and minimum lifetime weights and identify recent weight changes 1
• Review pre-illness weight trajectories and previous growth charts, particularly in children and adolescents 1

Eating Behaviors and Patterns

• Quantify the frequency and intensity of restrictive eating, food avoidance, and binge eating episodes 1
• Assess changes in food repertoire, including narrowing or elimination of entire food groups 1
• Document patterns of rumination, regurgitation, or chewing and spitting behaviors 1
• Determine the percentage of daily time preoccupied with food, weight, and body shape 1

Compensatory and Weight Control Behaviors

• Quantify frequency of purging behaviors: self-induced vomiting, laxative use, diuretic use 1
• Assess compulsive or driven exercise patterns, including intensity and time spent 1
• Document use of medications to manipulate weight 1
• Establish baseline severity by determining total weight loss, percent below ideal body weight, and types and frequency of purging behaviors 1

Psychiatric and Psychosocial Evaluation

• Screen systematically for depression, anxiety, obsessive-compulsive disorder, and suicidal ideation—suicide accounts for 25% of deaths in anorexia nervosa 2, 3
• Assess degree of obsession with food and weight, and the patient's understanding of the diagnosis and willingness to receive help 1
• Evaluate functioning at home, in school, and with friends 1
• Screen for history of physical or sexual abuse, violence, and substance use disorders 1
• Obtain family history of eating disorders, other psychiatric illnesses, obesity, inflammatory bowel disease, and diabetes mellitus 1
• Assess parents' or caregivers' reaction to the illness, as denial or disagreement about treatment may exacerbate the condition 1

Prior Treatment History

• Document all prior treatment for eating disorders and response to those interventions 1
• Identify psychosocial impairment secondary to eating or body image concerns 1

Physical Examination

Vital Signs and Cardiovascular Assessment

• Measure temperature, resting heart rate, blood pressure, orthostatic pulse, and orthostatic blood pressure 1
• Bradycardia and orthostatic hypotension are common findings that indicate cardiovascular compromise 3, 4

Physical Appearance and Signs of Malnutrition or Purging

• Assess for parotid gland enlargement (swollen cheeks or jawline from repeated vomiting) 2
• Look for Russell's sign: calluses or scarring on the dorsum of the hand from self-induced vomiting 2
• Examine for dental enamel erosion, particularly on lingual surfaces of maxillary anterior teeth 2
• Check for lanugo (fine body hair), hair thinning, or skin changes indicating malnutrition 2, 5
• Evaluate for signs of dehydration and general nutritional status 1

Comprehensive Review of Systems

• Conduct a thorough review of systems to identify co-occurring health conditions and medical complications 1

Laboratory and Diagnostic Testing

Essential Initial Laboratory Tests

• Obtain complete blood count to detect anemia, leukopenia, and other hematologic abnormalities 1, 2
• Order comprehensive metabolic panel including electrolytes (sodium, potassium, chloride, bicarbonate), liver enzymes, and renal function tests (BUN, creatinine) to identify hyponatremia, hypokalemia, hypochloremia, metabolic alkalosis, and hepatic or renal dysfunction 1, 2
• Add magnesium and phosphate levels to the metabolic panel when indicated, particularly if refeeding is anticipated 4

Electrocardiogram

• Perform electrocardiogram in all patients with restrictive eating disorders, severe purging behaviors, or those taking QTc-prolonging medications 1, 2
• Monitor for bradycardia, QTc interval prolongation, and other cardiac abnormalities—up to one-third of deaths in anorexia nervosa are cardiac-related 2, 3

Additional Testing Based on Clinical Presentation

• Obtain thyroid function tests (TSH and free T4) in patients with oligomenorrhea or amenorrhea 2
• Consider hormonal workup to assess for hypothyroidism, hypercorticism, and hypogonadotropic hypogonadism, which typically resolve with nutritional rehabilitation 2
• Measure 25-hydroxyvitamin D levels if low bone mineral density or bone stress injury is suspected 2
• Consider DXA scan for patients with prolonged amenorrhea due to long-term risk of osteopenia and osteoporosis 2

Critical Clinical Caveats

Interpretation of Normal Laboratory Values

• Normal laboratory values do not exclude serious illness or medical instability—approximately 60% of anorexia nervosa patients show normal values on routine testing even with severe malnutrition 1, 2
• Test results will be normal in most patients with eating disorders, but this does not rule out the need for aggressive intervention 1

Diagnostic Criteria Considerations

• More than one-half of children and adolescents with eating disorders do not fully meet all DSM criteria for anorexia or bulimia nervosa, but still experience the same medical and psychological consequences and require the same attention and care 1

Coordination of Multidisciplinary Care

• All patients with eating disorders require a coordinated multidisciplinary treatment plan incorporating medical, psychiatric, psychological, and nutritional expertise 1, 2
• Psychiatrists should coordinate the multidisciplinary team to ensure integrated care 2
• Disorder-specific psychotherapy is the cornerstone of treatment for all eating disorders 2

Hospitalization Criteria

• Patients with serious medical complications (severe bradycardia, significant electrolyte abnormalities, acute food refusal, uncontrollable purging) or psychiatric complications (suicidality) should be hospitalized for treatment 3, 4
• Do not delay hospitalization based on patient or family denial of illness severity, as eating disorders are life-threatening conditions requiring aggressive early intervention 2