A 46-year-old welder develops bradykinesia, rigidity and a stooped posture over several years. MRI brain shows symmetrical T1 hyperintensity in both globi pallidi. Dopamine transporter imaging is normal. Chronic inhalational exposure to which element best explains these findings?

• A Lead
• B Mercury
• C Arsenic
• D Manganese ✓

Explanation

Chronic manganese inhalation in welding, mining and ferromanganese smelting deposits manganese in the basal ganglia, producing 'manganism', a parkinsonian syndrome with globus pallidus T1 hyperintensity. Unlike Parkinson disease, the nigrostriatal dopaminergic terminals are spared, hence the normal dopamine transporter scan and poor response to levodopa, which is the single fact that separates this from idiopathic parkinsonism.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.