Tx for Lead Poisoning

[The kitchen sink]

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Guys, I came across some descrepancy about lead poisoning treatments.

FA states tx for Lead poisoning are:

Adults: Dimercaprol + EDTA
Kids: Succimer

DIT states:

Adults: EDTA + Succimer
Kids: EDTA + Dimercaprol + Succimer (as a 3rd line tx)

Which one is correct?

 

[ijn]

They're probably all correct. Just in different circumstances. The American Academy of Pediatrics Committee on Environmental Health recommendations for lead toxicity treatment are as follows:


BLL less than 10 μg/dL

No action is required

BLL 10-14 μg/dL

Obtain a confirmatory venous lead level within 1 month. If the BLL is still within this range, patient education about lead exposure is needed, and the BLL test should be repeated in 3 months.

BLL 15-19 μg/dL

Obtain a confirmatory venous lead level within 1 month. If the BLL is still within this range, patient education about lead exposure is needed, and the BLL test should be repeated in 2 months.

BLL 20-44 μg/dL

Obtain a confirmatory venous BLL in 1 week, and if the BLL is still within this range, assess complete medical, nutritional, and environmental hazards. Environmental evaluation by the local health department is also needed.

A large-scale study reported no improvement in neurologic and behavioral test scores after succimer chelation of children with BLL in this range.

BLL 45-69 μg/dL

Obtain a confirmatory BLL within 2 days, and if the level is still within this range, the patient should undergo the same complete evaluation as would patients with a BLL of 20-44 μg/dL. At 45-69 μg/dL, chelation therapy is recommended. Treatment should be in a lead-free environment. If this is not possible, hospitalization is necessary.

Chelation can be started with oral succimer, or, if the patient is hospitalized, calcium disodium edetate (calcium EDTA) can be used. These agents have potential toxicities, and monitoring of the CBC count, electrolytes, and liver function test results is necessary.

BLL 70 μg/dL or higher

Hospitalize the patient, obtain a confirmatory venous BLL, and initiate chelation with dimercaprol and calcium EDTA. Because calcium EDTA does not cross the blood-brain barrier, its use as the only agent in this situation is not recommended because of the possibility of lead redistribution from the soft tissues to the central nervous system (CNS). Pretreatment with dimercaprol (which crosses the blood-brain barrier) is recommended.

 

[AndyRSC]

Katzung states:

Oral succimer used in less severe, outpatient setting, and in kids.
Parenteral EDTA + dimercaprol used in severe cases.

 

[Phloston]

As far as I'm aware, dimercaprol and EDTA are the Tx in adults. Succimer is preferred in kids.

I would honestly doubt the USMLE would throw all three answer choices at us, but if they did, I would put dimercaprol first for adults and succimer first for kids.

 

[The kitchen sink]

So FA it is.

Funny how my final source is SDN sometimes.

 

[ijn]

So FA it is.

If it's an on an outpatient basis, then succimer in kids. But if you have a kid with severe lead toxicity succimer would be supplanted by dimercaprol pretreatment followed by calcium EDTA.

 

[aspiringmd1015]

why is succimer used in kids?

 

[Keto]

Hi

Succimer (DMSA) is a water-soluble analog of dimercaprol (BAL). Like dimercaprol and edetate disodium calcium (EDTA), succimer increases the urine excretion of lead. The main advantage is the route of administration: it can be given orally. In addition to that, it has less toxicity (and less urinary loss of essential minerals), than BAL. Succimer may cause elevated LFT's and cause hemolysis in individuals with G6PD deficiency. You have to adjust the dose to weight or body surface: Give 10 mg/kg two times per day. So dosages can be quite high for adults, that's why it is not prefered in adult.

How do you screen for lead poisoning?
Capillary blood levels. If elevated, get venous lead levels. Treat according to the venous lead level.

• 5-14 ug/dL
  Evaluate source, provide education, measure again in 3m
• 15-19 ug/dL
  Evaluate source, provide education, measure again in 2m, refer to health department
  
• 20-44 ug/dL
  Evaluate source, provide education, measure again in 1m, refer to health department
  
• 45-70 ug/dL
  Evaluate source, provide education, measure again in 1m, refer to health department
  Treat: Dimercaprol (BAL) (single dose, IM) or succimer (DMSA) oral (preferred in kids)
• >70 ug/dL
  Treat: Hospitalization + two-drug IV treatment: EDTA + BAL

I think this is more STEP2 and STEP3 stuff, but it might help you see, where which drugs are used.

UpToDate, Kaplan, Katzung.

It can be confusing, but try to keep it simple. You will never use BAL or DMSA in a clinical setting without consulting an toxicologist anyway. If you want to read further http://www.cdc.gov/nceh/lead/ would be a good start!

Have a great sunday!