Overview
Manganese is an essential trace element obtained from dietary, occupational, and environmental sources. In the human body, it is required in very small amounts for normal physiological processes, while excessive accumulation can be toxic. Laboratory testing measures bivalently bound manganese in its dissolved form and is primarily used to assess exposure, toxicity, and related systemic effects. Although manganese deficiency in humans is rare, excess manganese is a well-established neurotoxin with significant clinical implications.
Symptoms
Abnormal manganese levels mainly affect the nervous system. Excess manganese exposure may cause tremors, muscle spasms, reduced hand-eye coordination, impaired balance, hearing loss, headaches, and mood changes such as depression. With prolonged exposure, individuals may develop manganism, a neurodegenerative condition characterized by Parkinsonian-like symptoms due to damage to dopaminergic neurons in the basal ganglia. Continued exposure can also lead to pulmonary, hepatic, and renal involvement, reflecting the systemic nature of manganese toxicity.
Causes
Elevated manganese levels commonly result from occupational exposure in mining, welding, and industrial settings, as well as from excessive nutritional intake or environmental contamination. Medical conditions such as acute or chronic kidney disease reduce manganese excretion and contribute to accumulation. Other recognized causes include malnutrition, alcoholism, hypothyroidism, cortico-adrenal insufficiency, and the use of certain medications such as proton pump inhibitors. Manganese is primarily eliminated through bile and urine, and impaired clearance leads to rising body levels. Low manganese levels are uncommon but may occur due to inadequate intake or altered metabolism.
Risk Factors
Individuals at higher risk include workers handling manganese compounds, patients receiving total parenteral nutrition, and those with chronic liver or kidney disease. Long term environmental exposure, poor nutritional status, and alcoholism further increase susceptibility to toxicity. Improper sample collection, recent exposure to contrast media, intake of mineral supplements, or interference from iodine may affect laboratory results. Because manganese levels can vary depending on the biological sample used, interpretation requires correlation with exposure history and clinical findings.
Prevention
Prevention focuses on minimizing unnecessary exposure and ensuring early detection in high-risk populations. Occupational safety measures, environmental control, and avoidance of excessive supplementation are essential preventive strategies. Prior to testing, non-essential nutritional supplements and interfering medications should be discontinued when possible. Proper sample collection, timely separation, and appropriate storage are critical for accurate measurement. Monitoring manganese levels in exposed individuals allows early intervention, helping prevent neurological damage and long-term systemic complications associated with manganese toxicity.
