A 48-year-old man who has worked as a welder for 15 years develops bradykinesia, cogwheel rigidity, postural instability, and cognitive slowing. MRI shows symmetrical signal change in the globus pallidus. His motor symptoms respond poorly to levodopa. Chronic exposure to which element best explains this presentation?
- A Manganese ✓
- B Mercury
- C Arsenic
- D Thallium
Correct answer: A. Manganese
Explanation
Chronic inhalational manganese exposure, seen in welders and miners, causes manganism, a parkinsonian syndrome with preferential deposition in the globus pallidus and a characteristically poor response to levodopa because dopaminergic neurons are not primarily destroyed. Mercury causes tremor with erethism and gingivitis, arsenic causes hyperkeratosis and neuropathy, and thallium causes painful neuropathy with alopecia.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.