A 40-year-old presents with alopecia, transverse white bands on fingernails (Mees' lines), peripheral neuropathy, and hyper-pigmentation of palms. Urine turns brown on adding 5% AgNO3. The MOST likely toxin is:
- A Lead
- B Mercury
- C Thallium
- D Arsenic ✓
Explanation
The constellation of Mees' lines (transverse white bands on nails appearing 4–6 weeks after acute exposure), rain-drop hyperpigmentation of the skin, diffuse alopecia, and peripheral neuropathy is classic chronic arsenic poisoning. The Reinsch test (silver nitrate on urine turning brown) is positive for arsenic and antimony. Lead causes basophilic stippling and Burton's lines on gums, not Mees' lines. Thallium also causes alopecia but not the skin pigmentation or Mees' lines. Mercury classically produces tremor and neuropsychiatric symptoms (erethism) rather than this dermatological picture.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.