Manganese brain deposition can occur at what daily intravenous manganese administration level?

• A. 0.5 mg/day
• B. 1.1 mg/day
• C. 2.0 mg/day
• D. 5 mg/day

Answer: (B)

Brain deposition from intravenous manganese is a dose- and duration-dependent process. Manganese is normally cleared by the biliary system, but with chronic IV exposure the clearance can be overwhelmed and manganese accumulates in the brain, especially in the basal ganglia. This buildup can cause movement abnormalities and is often visible as T1 hyperintensity in the globus pallidus on MRI. Because of this, deposition has been observed around a daily IV dose of roughly 1.1 mg per day in adults. Doses lower than this are less likely to deposit, while higher daily doses, particularly over long periods or with impaired liver function, increase the risk of brain deposition and related neurologic effects.