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Flashcards in Iron toxicity Deck (19):
1

Describe the 5 stages of iron toxicity

I

GI (abdo pain, N/V/D, hematemesis, melena, lethargy, shock, met acidosis)

30m-6hrs

II

Quiescent phase (stop vomiting but developing acidosis)

6-24hrs

III

Met acidosis, renal failure, hepatotoxicity, GI symptoms, CNS dysfxnhypovolemic/distributive/cardiogenic shock

6-72hrs

IV

Fulminant hepatic failure: coma, coagulopathy, jaundice

12-96 days

V

GI strictures, gastric outlet obstruction, bowel obstruction

2-8wks

2

What are the toxic levels of Fe

20-60 mg/kg toxic
more than 60 mg/kg serious toxicity

3

what is the pathophys of iron toxicity

disrupts oxidative phosphorylation, decr ionotropy of myocardium, tnhibits thrombin

4

what symptom indicates serious fe toxicity

vomiting, do not give antiemetics until they vomit

5

indications for defuroxime

serum level 60-90umol/L and symptomatic
serum level more than 90
shock
metabolic acidosis
coma

6

what can iron toxicity be treated with

defuroxime until the urine is rose coloured

7

List common Fe preparations and their elemental Fe content

fummarate: 33%
sulfate20%
gluconate12%

8

What causes the coagulation defects seen in iron poisoning?

- Early: Direct effects of vitamin K dependent clotting factors
Late: Hepatic failure and decreased production of clotting factors

9

List 5 occupations that increase risk of lead exposure.

- Lead smelting
- Battery manufacture
- Radiator repair
- Bridge and ship construction or demolition
- Smoldering or welding
- Cable or tin can production
- Stained glass manufacture
- Lead-crystal or crystal pottery making
- Glass production
- Firing range operation
- Lead based pain abatement

10

Describe the anemia that is characteristic of lead poisoning?

- Inhibits heme synthesis
- Normochromic or hypochromic
- Severity of anemia correlates with lead BLL
- smear shows basophilic stippling

11

What diagnostic clue to chronic lead poisoning may be apparent of skeletal x-rays?

- “Lead band/lines” – Increased metaphyseal brightness seen with chronic exposures

12

What are the indications for chelation therapy in lead poisoning?

- BLL >70 mcg/dL (3.38umol/L)
- Protracted GI symptoms
CNS symptoms from acute exposure

13

In seriously lead poisoned patients what chelating agents are used?

- Dimercaptol (British antilewisite; BAL) first chelator
Calcium Disodium ethylenediaminetetraacetic acid (CaNa2-EDTA) given with second dose of BAL

14

What is the pathophysiology of arsenic poisoning?


- Binds sulfhydryl groups, inhibiting critical enzymes in glycolysis
- Disrupts oxidative phosphorylation by replacing phospohorous (arsenolysis)

15

What strategies can limit or remove arsene?

- Exchange transfusions
- Urinary alkalinization

16

List chronic effects of arsenic poisoning.

- Mees’ line on the nails
- Painful sensorimotor neuropathy
- Hyperkeratosis of the soled and palms
Anemia (basophilic stippling), leukocytosis or penia, abn u/a, renal or lfts

17

Which chelators are used in arsenic poisoning?

- Dimercaptol (IM)
- DMSA orally
D-penicillamine

18

Which chelating agents are indicated for clinically significant inorganic mercury toxicity?

- BAL (dimercaptol) used for clinically significant inorganic mercury intox but contraindicated in pts with organomercurial poisoning (increases brain merc levels in pts with mentyl merc poisoning)
- DMSA
- D-penicillamine
- Chelation therapy binds the sulfhydryl group that bind mercury after its absorption

19

Outline your basic approach to heavy metal toxicities:

2. In acute exposures of large amounts:
a. Draw levels, AXR à Fe, Pd, As, Hg are ALL radio-opaque
b. AC not indicated, none bind adequately
c. WBI in acute ingestion
d. Manage ABCs
e. Anticipate and manage CNX, renal, hepatic, toxicities
f. Find the antidote à chelation