When should selenium deficiency be suspected in children?

When to Suspect Selenium Deficiency in Children

Suspect selenium deficiency in children receiving long-term parenteral nutrition (PN) without selenium supplementation, those with chronic kidney disease on dialysis, severely malnourished children, and infants on prolonged elemental diets—particularly when you observe growth retardation, alopecia with pseudoalbinism (depigmentation), muscle weakness, or erythrocyte macrocytosis.

High-Risk Clinical Scenarios

Children on Long-Term Parenteral Nutrition

• Any child receiving PN for >2-6 months without selenium supplementation is at significant risk 1, 2
• Selenium deficiency typically manifests within the first 6 months of PN support 2
• Monitor plasma selenium regularly in all children on long-term PN 1

Chronic Kidney Disease and Dialysis Patients

• Low serum selenium levels occur consistently in children with CKD stages 2-5 and those receiving maintenance hemodialysis, despite selenium being normally excreted by the kidney 1
• Selenium-dependent glutathione peroxidase activity decreases progressively with worsening CKD severity 1
• Assess selenium status in all children with CKD stages 2 to 5 and 5D 1
• Monitor selenium status regularly in patients with renal failure 1

Severe Malnutrition States

• Very low plasma selenium concentrations occur in severely malnourished children with biliary atresia and intractable diarrhea 3
• Children with celiac disease, particularly at initial diagnosis or with poor compliance to gluten-free diet, demonstrate low plasma selenium levels 4
• Infants receiving prolonged elemental diets (2-6 months) are at high risk 2

Preterm and Very Low Birth Weight Infants

• Plasma selenium levels decrease during the first weeks of life in VLBW infants 1
• Low selenium status has been associated with bronchopulmonary dysplasia in preterm infants 1
• Preterm babies face high oxidative injury risk (BPD, retinopathy of prematurity, white matter disease) 1

Cardinal Clinical Features

Early and Characteristic Symptoms

• Growth retardation is an early and consistent finding 2
• Alopecia with pseudoalbinism (hair depigmentation) is highly characteristic in infants 1, 2
• Muscle pain and tenderness occur in prolonged deficiency 5
• Muscle weakness may be present 1
• Erythrocyte macrocytosis can be observed 1

Important Clinical Context

The hair symptoms (alopecia and pseudoalbinism) typically resolve within 1-2 months after selenium supplementation, corresponding to normalization of serum selenium levels 2. Rapid improvement in growth occurs once adequate selenite is administered 2.

Laboratory Assessment

When to Check Selenium Status

Measure selenium status when:

• Any child is on long-term PN (>2 months) 1
• Children with CKD stages 2-5 or on dialysis 1
• Severely malnourished children from any cause 3
• Clinical signs of deficiency are present (growth retardation, alopecia, muscle weakness) 2
• Infants on prolonged elemental diets 2

Diagnostic Testing

• Plasma or serum selenium concentration is the primary monitoring tool 1
• Glutathione peroxidase (GSHPx) activity in plasma or red blood cells provides additional assessment 1, 6
• Erythrocyte and platelet GSHPx activity are sensitive indices in PN patients 1

Critical Threshold Values

• Plasma selenium levels <2.0 μg/dL indicate severe deficiency 2
• Levels of 3.2-3.3 μg/dL may still be associated with clinical deficiency symptoms 2
• Plasma selenium levels of 0.3-0.9 μg/100 mL have been reported to produce deficiency symptoms 5
• Normal whole blood selenium range is approximately 10-37 μg/100 mL 5

Important Caveats and Pitfalls

Limitations of GSHPx Activity in Specific Populations

In preterm infants, glutathione peroxidase activity is NOT a useful marker of selenium status because it is affected by immaturity and oxygen exposure 1, 6. Use plasma selenium concentration instead in this population.

Geographic and Dietary Considerations

• Selenium content of food depends on soil selenium content where crops are grown or animals graze 1
• Children in geographic areas with low selenium soil content (endemic areas for Keshan disease, Kwashiorkor) require heightened suspicion 5

Monitoring Frequency

• Monitor selenium status every 4-6 months in children with particularly low dietary intake 1
• More frequent monitoring is warranted in high-risk populations (PN, CKD, severe malnutrition) 1

Don't Miss These Scenarios

• Children on elemental diets: Even without PN, prolonged elemental diet use (2-6 months) can cause deficiency 2
• Steroid treatment effects: In Crohn's disease, selenium levels may appear falsely reassuring during steroid treatment but drop with selenium-deficient elemental diets 3
• Early infancy vulnerability: Five of six reported cases of selenium deficiency occurred before 6 months of age 2