What are the symptoms of selenium deficiency?

Symptoms of Selenium Deficiency

Selenium deficiency manifests primarily as cardiomyopathy, impaired immune function, and muscle weakness, with the most severe form (Keshan disease) potentially causing fatal heart failure. 1

Clinical Manifestations

Cardiovascular Symptoms

• Acute cardiomyopathy (Keshan disease) 1
• Congestive heart failure 2
• Cardiac arrhythmias 1
• Cardiomegaly and reduced cardiac function 3

Neuromuscular Symptoms

• Muscle weakness and pain 1
• Myopathy affecting skeletal muscles 4
• Paresthesia in severe cases 1

Immune System Effects

• Increased susceptibility to viral infections 1
• Increased virulence of viral infections 1
• Impaired immune function 1

Other Clinical Manifestations

• Delayed wound healing 1
• Hair and nail changes/loss in chronic deficiency 1
• Skin lesions and depigmentation 1
• Erythrocyte macrocytosis 1
• Thyroid dysfunction (due to selenium's role in thyroid hormone metabolism) 1

Laboratory Findings

Diagnostic Markers

• Plasma selenium <0.4 μmol/L (<32 μg/L) indicates definite deficiency requiring immediate supplementation 1, 5
• Reduced glutathione peroxidase (GPX) activity in plasma and red blood cells 1, 5
• Low selenoprotein P levels (accounts for >50% of plasma selenium) 1

Important Considerations for Testing

• Inflammation significantly affects selenium levels - CRP must be measured simultaneously 1, 5
• CRP 10-40 mg/L reduces plasma selenium by 15-25%
• CRP 41-80 mg/L reduces plasma selenium by ~35%
• CRP >80 mg/L reduces plasma selenium by ~50% 5

High-Risk Populations

Selenium deficiency is most commonly seen in:

• Patients on long-term parenteral nutrition without selenium supplementation 1, 3
• Patients on prolonged enteral nutrition with products low in selenium 1
• Individuals with malabsorption syndromes (Crohn's disease, short bowel syndrome) 3
• Patients with severe burns (increased losses) 1
• Patients on continuous renal replacement therapy (increased losses) 1
• Individuals living in selenium-deficient geographical regions (parts of Europe, China) 1

Pathophysiology

Selenium deficiency causes:

• Reduced activity of glutathione peroxidase enzymes 6
• Decreased protection against oxidative damage to cell membranes 2
• Impaired antioxidant defense 1
• Endoplasmic reticulum stress in cardiomyocytes 7
• Increased susceptibility to toxin-induced injury 7

Clinical Pitfalls to Avoid

1. Failure to measure CRP with selenium levels - inflammatory states will artificially lower selenium levels, leading to misinterpretation 5

2. Not considering geographical variations - reference ranges vary by region due to different soil selenium content 5

3. Missing selenium deficiency in patients with unexplained heart failure - especially in those with risk factors like malabsorption or long-term artificial nutrition 2, 3

4. Overlooking selenium supplementation in parenteral nutrition - selenium should be routinely included in all PN formulations lasting more than two weeks 1

5. Inadequate monitoring - patients on long-term PN should have selenium levels checked regularly (at least every 3-6 months) 1