Recommended Blood Work for a 15-Year-Old Male with Fatigue and Restrictive Eating
A 15-year-old male presenting with fatigue and restrictive eating requires a complete blood count, comprehensive metabolic panel (including electrolytes, liver enzymes, and renal function), and an electrocardiogram at initial assessment. 1
Initial Laboratory Assessment
The following blood work should be obtained at the time of diagnosis:
- Complete Blood Count (CBC) to detect anemia and leukopenia, which are common manifestations of malnutrition in restrictive eating disorders 1, 2
- Comprehensive Metabolic Panel including:
- Electrocardiogram (ECG) to assess for QTc prolongation, as adolescents with restrictive eating disorders are at risk for sudden cardiac death 1, 2
Additional Considerations for Males with Restrictive Eating
Males with restrictive eating disorders are frequently underdiagnosed and may present with distinct clinical features. 3 The clinical presentation in this 15-year-old male warrants the same comprehensive laboratory evaluation as females, as medical and psychological complications can be equally severe. 3
Common Laboratory Abnormalities to Anticipate
Based on the presentation of fatigue and restrictive eating, the most likely laboratory abnormalities include:
- Hypokalemia - the most critical electrolyte abnormality requiring immediate attention 2, 4
- Leukopenia - associated with malnutrition 2
- Low serum prealbumin and vitamin D - common nutritional deficiencies 5
- Elevated serum bicarbonate - indicating metabolic alkalosis 5
Electrolyte abnormalities may precede the formal diagnosis of an eating disorder by a median of 386 days, making early detection crucial. 4
Frequency of Laboratory Monitoring
The frequency of repeat laboratory testing depends on clinical severity:
- Weekly to biweekly monitoring is required if the patient exhibits severe malnutrition, rapid weight loss (>1 kg per week), or active purging behaviors until medically stabilized 1
- Every 3-6 months for medically stable adolescents in outpatient treatment, with more frequent monitoring if ongoing weight loss, failure to gain weight, or symptoms suggesting electrolyte abnormalities develop 1
Vital Signs Assessment
At every visit, document:
- Weight 1
- Temperature, resting heart rate, and blood pressure 1
- Orthostatic measurements (pulse and blood pressure changes from lying to standing), as significant orthostatic changes indicate cardiovascular instability requiring hospitalization 1, 2
Clinical Context: RED-S Considerations
Given the presentation of fatigue and restrictive eating in a male adolescent athlete (if applicable), consider Relative Energy Deficiency in Sport (RED-S). 6 This syndrome results from low energy availability and can manifest with:
The RED-S Risk Assessment Model should be implemented during the preparticipation health evaluation if the patient is involved in athletics, particularly weight-sensitive or leanness sports. 6
Critical Red Flags Requiring Immediate Intervention
Severe electrolyte abnormalities, particularly hypokalemia, require immediate attention and may necessitate hospitalization. 2 Hypokalemia is associated with a nearly 2-fold increased risk of an underlying eating disorder (adjusted OR 1.98). 4 Other electrolyte abnormalities strongly associated with eating disorders include hyponatremia (adjusted OR 5.26), hypophosphatemia (adjusted OR 2.83), and metabolic alkalosis (adjusted OR 2.60). 4
Multidisciplinary Coordination
Laboratory results should be interpreted within the context of a multidisciplinary team incorporating medical, psychiatric, psychological, and nutritional expertise. 1, 7 Family-based treatment is strongly recommended for adolescents with involved caregivers. 1