EM Toxicology 11 - Lead

Question 1

remarks on lead toxicity

Answer 1

Lead is the most common cause of chronic metal poisoning

The combination of abdominal pain or neurologic dysfunction with anemia should raise suspicion for lead toxicity.

Consider the diagnosis in all children presenting with acute encephalopathy

Question 2

delayed cognitive development can occur in infants and children whose blood lead levels are

Answer 2

5 mcg/dL
(0.24 mcmol/L)

Question 3

classic manifestation of motor weakness in lead poisoning

Answer 3

wrist drop

Question 4

encephalopathy due to lead poisoning typically occurs in toddlers age 15-30 months odld with blood lead levels of

Answer 4

> 100 mcg/dL
(4.8 mcmol/L)

Question 5

the definitive diagnosis of lead poisoning rests on

Answer 5

finding an elevated blood lead level

threshold of 5 mcg/dL
(0.24 mcmol/L)

Question 6

remarks regarding chelation therapy with lead poisoning

Answer 6

If lead encephlopathy is suspected, initiate chelation therapy promptly without waiting for the results of a blood lead level (>100 mcg/dL or >4.8 mcmol/L)

Dimercaprol 75 mg/m2 (or 4 mg/kg) IM every 4h for 5 days
and
†Edetate calcium disodium 1500 mg/m2 per day via continuous infusion or in 2-4 divided doses IV for 5 days, max 3 grams/day;
start 4 h after dimercaprol

used to prevent lead from being transported into the brain

†do not confuse with edetate disodium, which is used to treat hypercalcemia

Question 7

What to give in asymptomatic adults whose blood lead levels are 70-100 mcg/dL (3.4-4.8 mcmol/L)?

Answer 7

Succimer, 350 mg/m2 (or 10 mg/kg) PO every 8 h for 5 days, then veery 12 h for 14 days

Succimer is an oral analog of dimercaprol.

“Some toxicologists consider succimer the preferred chelator for lead poisoning in all but the severe cases”

Question 8

What to give in asymptomatic adults whose blood lead levels <70 mcg/dL (<3.4 mcmol/L)?

Answer 8

Routine chelation is not indicated.

Remove patient from source of exposure

Question 9

important side effects of dimercaprol

Answer 9

allergic reaction (diluent includes peanut oil)
hemolysis in G6PD deficient patients

Question 10

chelation therapy in pregnants

Answer 10

Chelation was not associated with any increased risk of birth defects in the few published cases, and pregnant women with elevated blood lead levels should be chelated following the same guidlines

Question 11

What to do if abdominal films demonstrate GI foreign bodies consistent with lead

Answer 11

institute whole-bowel irrigation with a polyethylene glycol electrolyte solution

Larger lead bodies, such as fishing sinkers and jewelry, may require endoscopic or surgical removal

Question 12

remarks with lead encephalopathy

Answer 12

85% of patients who suffer lead encephalopathy develop permanent central neurologic damage, including seizures, mental retardation in children, and cognitive deficits in adults

Question 13

most important action for lead poisoning

Answer 13

removal of the source of lead
patients should not be returned to the home environment until lead decontamination and abatement measures have been addressed

Question 14

hospital admission is recommended for

Answer 14

1) children with symptoms or with a blood lead level of >70 mcg/dL (>3.4 mcmol/L)
2) adults with central neurologic symptoms
3) patients with suspected lead toxicity when returning to the environment is considered dangerous