Case Report: A Metabolic Disorder Presenting as Pediatric Manganism

Abstract

Manganese is a trace element, essential for physiologic functioning but neurotoxic at high doses. Common exposure sources include dietary intake as well as drinking water in some regions; toxicity is most often associated with inhalation exposures in occupational settings. In this article we describe the investigation of a pediatric case of manganism using both clinical and environmental assessment methods. A previously healthy 6-year-old child presented with severe Mn neurotoxicity, iron deficiency, and elevated cobalt levels. Immediate and selected extended family members had elevated plasma Mn but remained asymptomatic. An exposure assessment identified seasonal ingestion exposures to Mn at the family’s summer cottage; these were common to the four immediate family members. Well water used for drinking and cooking exceeded recommended guidelines, and foods high in Mn predominated in their diet. No inhalation exposures were identified. Only pica was unique to the patient. The combined evidence of the environmental assessment and biomonitoring of blood Mn levels supported a seasonal ingestion exposure source; this alone was insufficient to explain the toxicity because the patient’s 7-year-old sibling was asymptomatic with almost identical exposures (except pica). A metabolic disorder involving divalent metals (Mn, Fe, and Co) interacting with environmental exposures is the most likely explanation. This case report adds to the emerging body of evidence linking neurologic effects to ingestion Mn exposure.