What are the best initial screens for a pediatric patient with an unspecified eating disorder, Autism Spectrum Disorder (ASD), and an anxiety disorder?

Initial Screening for Pediatric Patient with Eating Disorder, ASD, and Anxiety

For this complex pediatric patient, begin with comprehensive eating disorder screening including vital signs, weight/height history, and detailed eating behavior assessment, followed by genetic testing (chromosomal microarray and Fragile X) for the ASD, and systematic psychiatric evaluation for co-occurring conditions including the anxiety disorder. 1

Eating Disorder Screening (Priority #1)

Physical Assessment

• Measure and document vital signs including temperature, heart rate, blood pressure, and orthostatic changes 1
• Weigh the patient and calculate BMI percentile; obtain maximum and minimum weight history with recent weight changes 1
• Perform Wood's lamp examination to screen for tuberous sclerosis 1

Eating Behavior Assessment

• Quantify restrictive eating patterns, food avoidance behaviors, and any binge eating episodes (frequency and intensity) 1
• Document food repertoire changes, particularly narrowing or elimination of food groups—critical in ASD patients who commonly have selective eating 1, 2
• Assess for compensatory behaviors: purging, laxative use, self-induced vomiting, and compulsive exercise patterns 1
• Determine percentage of time preoccupied with food, weight, and body shape 1

Laboratory Screening

• Obtain complete blood count and comprehensive metabolic panel to detect electrolyte abnormalities, anemia, and organ dysfunction 3
• Perform electrocardiogram for any patient with restrictive eating or purging behaviors to assess for QTc prolongation 3

ASD Genetic Evaluation (Priority #2)

First-Tier Genetic Testing

• Order chromosomal microarray (CMA) as the standard first-line genetic test—this has a 24% diagnostic yield in ASD patients 1
• Order Fragile X testing for all patients with unexplained ASD 1

Additional Genetic Considerations

• If the patient is female, consider MECP2 sequencing and deletion/duplication analysis 1
• Perform G-banded karyotype if CMA is unavailable, though this has lower yield (2.5%) 1
• Refer to clinical genetics if first-tier testing is unrevealing or if family history suggests X-linked disorder 1

Psychiatric Co-Morbidity Assessment (Priority #3)

Anxiety Disorder Screening

• Systematically identify all co-occurring psychiatric disorders as part of the initial evaluation 1
• Document how anxiety symptoms interact with eating disorder behaviors and ASD features 1
• Assess for other common comorbidities including depression, obsessive-compulsive symptoms, and attention problems 1

Comprehensive Review

• Obtain detailed family history of eating disorders, psychiatric illnesses, obesity, inflammatory bowel disease, and diabetes 1
• Document prior treatment history and response to interventions for all three conditions 1
• Assess psychosocial impairment secondary to eating concerns, ASD symptoms, and anxiety 1

Additional Medical Screening

Hearing and Developmental Assessment

• Perform hearing screen as part of the standard ASD medical assessment 1
• Conduct psychological assessment including cognitive ability and adaptive skills measurements for treatment planning 1

Specialized Testing When Indicated

• Order EEG if there is history of regression or staring spells to rule out Landau-Kleffner syndrome 1
• Consider metabolic testing if clinical features suggest specific metabolic disorders 1
• Obtain neuroimaging consultation if dysmorphology or unusual neurological features are present 1

Critical Pitfalls to Avoid

• Do not rely solely on broadband developmental screening tools for ASD detection—the M-CHAT has significantly higher sensitivity than general developmental screens like PEDS, which miss approximately 75% of ASD cases 1
• Do not overlook the interaction between ASD-related food selectivity and eating disorder pathology—these can be difficult to distinguish and may coexist 2
• Do not delay genetic testing while waiting for specialty referrals—CMA and Fragile X can be ordered by primary care providers 1
• Do not prescribe rigid supplement regimens that may reinforce obsessive behaviors in this patient with both eating disorder and ASD 3
• Do not fail to coordinate care across multiple specialists (psychiatry, genetics, nutrition, psychology) as this patient requires multidisciplinary management 3, 4

Immediate Referral Considerations

• Refer to specialized eating disorder treatment team if medical instability is present (severe bradycardia, hypotension, electrolyte abnormalities) 4
• Refer to clinical genetics for counseling if genetic testing reveals abnormalities or variants of uncertain significance 1
• Ensure access to eating disorder-focused cognitive behavioral therapy, which is the evidence-based treatment for most eating disorders 3