lead poisoning

Lead poisoning or plumbism is a multisystem condition due to the way in which lead interferes with the function of virtually every organ system. Plumbism most severely manifests due to its devastating effects on the CNS, but it also has important deleterious consequences on the skeletal, renal, hematopoietic, and reproductive systems.

Epidemiology

This condition usually occurs as a consequence of a toxic environment: prolonged ingestion or inhalation of lead-containing material (e.g. contaminated water, paints, batteries).

Clinical presentation

  • neuropsychiatric
    • amnesia: short term memory
    • poor concentration
    • ataxia
    • dysarthria
    • sensory loss and paresthesia in the extremities
    • fatigue, sleep problems
    • headaches
    • depression
    • stupor
  • GI
  • anemia
  • reproductive system
  • nephropathy
  • impaired childhood development

Pathology

  • bones
    • lead accumulates in the metaphyses of growing bones, which are the most metabolically-active zones
    • lead is an osteoclast-poison, so bone density is increased due to unopposed action of osteoblasts
  • anemia is multifactorial
    • lead antagonises the enzymes porphobilinogen synthase and ferrochelatase, inhibiting the synthesis of heme
    • lead impairs repair of cell membranes leading to increased erythrocyte fragility

Radiographic features

Plain radiograph
  • may show bands of increased density at the metaphyses
  • can affect any metaphysis, but the involvement of the proximal fibula and distal ulnar metaphyses is highly suggestive
  • may show bone-in-bone appearance

Treatment and prognosis

  • chelation therapy
    • dimercaprol
    • dimercaptosuccinic acid (DMSA) (also known as succimer)
    • sodium calcium edetate

Differential diagnosis

  • healed rickets
  • physiological appearances in <3 years' age group

See also

Siehe auch:
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