Lead, Arsenic & Mercury Poisoning

Key points

• Lead: abdominal pain, constipation, motor neuropathy (wrist drop), blue lines on gums (Burton's lines), basophilic stippling; Mees' lines on nails.
• Arsenic: most toxic heavy metal; acute GI haemorrhage, Mees' lines (white transverse nail bands), garlic breath, 'raindrop' pigmentation; chelation with dimercaprol.
• Mercury: paraesthesia, visual field defects, hearing loss, irritability, renal tubular acidosis; DMSA chelation for acute inorganic poisoning.
• Lead poisoning gives a predominantly MOTOR neuropathy.