see also: [[Iron overdose]] > [!important] Key Points > - **risk_dose**:: 100 mcg/dL (4.8 micromol/L) > - **Antidote**:: EDTA, DMSA (sucimer) > - **key_points**:: a/w encephalopathy, cerebral oedema, death. neonatal/childhood development concerns. notifiable disease - Immigrant and refugee children are at much greater risk for lead poisoning - Children and pregnant women absorb almost four times the amount of ingested lead than other adults. - Once absorbed, lead is bound to red bloods cells and slowly distributes to the soft tissues where it is eventually stored, primarily in bone. # Sources - lead dust - pain in old homes - parent's occupation - fishing weights - old home remodelling construction dust - battery recycling, repair, manufacturing - firing range instructors - car mechanics and car remodelling - ceramics - retained lead bullets # Risk assessment - acute or sub-acute severe lead intoxication occurs from ingestion or inhalational *occupational exposures* | blood lead level | effects | | ---- | ---- | | < 10 mcg/dL | minor dose-dependent reduction in IQ in lung children | | 10-30 | subtle developmental, learning, motor, abnormalities | | 30-100 | non-specific sx eg abdo pain, headaches, insomnia. subclinical impairment in peripheral nerve condiction. renal injury eg chronic interstitial nephritis or fanconi's syndrome. decreased fertility | | >100 | severe GI sx, encephalopathy, seizures, and coma | # Toxic Mechanism - interference with intracellular functions, haem synthesis, neurotransmiter systems, steroid production - lead toxicity affects nervous system, kidney, and reporoductive and haematopoetic systems - can be ingested or inhaled - also shotgun pellets can be a source # Clinical features **Acute** - abdo pain, nausea, vomiting, haemolytic anaemia, heptatitis - cerebral oedema, encephalopathy, [[Seizures]], and coma are pre-terminal conditions **chronic** - vague - impaired concentration, anorexia, vague abdo pain, emotional lability, weight loss, arthralgia, impaired coordination - subclinical impairment of higher center functions, including intelligence # investigations - whole blood lead level -- most useful indicator of lead exposure - FBC - normochromic, normocytic anaemia with **basophilic stippling** classic but rare - free erythrocyte protoporphyrin (FEP) -- surrogate measure of total body burden of lead. low sensitivity at low levels, elevated in chronic lead intoxication due to inhibition of haemaglobin synthesis - abdo xr -- see any lead foreign bodies - nerve condiction and psychomotor testing in chronic exposures # Treatment - rarely needs acute resus - if cerebral oedema, intubate, mannitol 1g/kg, dexamethasone 10mg (0.15 mg/kg children) - endoscopy if there foreign body above gastro-esophageal junction. if beyond this and pt asymptomatic, commence high-residue diet + oral polyethylene glycol to drink at home - if foreign body still present >72 hours, admit pt for [[Decontamination#Whole bowl irrigation]] with polyethylene glycol - **EDTA** - acute lead-induced encephalopathy or symptomatic pt with blood level >100mcg/dL - NOT to be *confused* with dicobalt editate (cyanide antidote) - **Succimer (DMSA)** - oral chelator, used in symptomatic pts without encephalopathy and asymptomatic pts with blood lead levels >60m cg/dL # Disposition # Mnemonic