Study: Low iron storage tied to neurally mediated syncope

A recent retrospective study demonstrated that children with neurally mediated syncope often have low iron stores or iron deficiency, with or without mild anemia. A neurology clinic in Pittsburgh enrolled 106 youngsters up to 19 years of age who had experienced syncope. The syncope was neurally mediated in 71 (67%) youngsters and attributable to other causes-neurologic, metabolic, cardiac, and uncertain-in 35 (33%) others.

After taking initial histories and conducting physical examinations, investigators divided the 106 patients into two groups-those with neurally mediated syncope, and those whose syncope had other causes. They then measued serum ferritin, iron, total iron-binding capacity, and hemoglobin.

Patients with neurally mediated syncope were significantly more likely to have reduced iron stores (serum ferritin ≤25 μg/L) than the other-causes group (57% vs 17%), even after controlling for age and sex. The neurally mediated group also had lower mean values of serum ferritin (27 μg/L vs 46 μg/L), transferrin saturation (23% vs 31%), and hemoglobin (13.3 g/dL vs 14 g/dL). (The lowest hemoblobin value in the study was 11.1 g/dL.) Only patients with neurally mediated syncope had iron deficiency (15%), anemia (11%), or iron deficiency with anemia (7%) (Jarjour IT et al: J Pediatr 2008;153:40).

The authors propose that low iron stores, even in the absence of iron deficiency anemia, may cause dysfunction of enzymes involved in synthesis and degradation of catecholamines. Their theory may explain why syncope in pediatrics is most common in adolescent females. Should we begin screening iron status on adolescents being evaluated for syncope?

DR. BURKE, section editor for Journal Club, is chairman of the department of pediatrics at Saint Agnes Hospital, Baltimore. He is a contributing editor for Contemporary Pediatrics. He has nothing to disclose in regard to affiliations with, or financial interests in, any organization that may have an interest in any part of this article.