Iron

Question 1

iron is leading cause of fatal poisoning in who

Answer 1

children

Question 2

ferrous sulfate elemental iron

Answer 2

20%

Question 3

ferrous gluconate elemental iron

Answer 3

12%

Question 4

ferrous fumarate elemental iron

Answer 4

33%

Question 5

absorption of iron

Answer 5

absorbed into mucosal cell and oxidized to ferric acid
regulated by the level of body iron stores
intake 10-20mg only 1-2mg is absorbed

Question 6

how is iron distributed

Answer 6

in plasma bound to transferrin which is normally 1/3 saturated, normally none free in the plasma
in tissue iron is stored as ferritin

Question 7

OD effect on absorption

Answer 7

acute corrosive effect of iron on the GIT mucosa enhances absorption
transferrin system may become saturated

Question 8

elimination of iron

Answer 8

no physiologic mechanism
sweat
bile
desquamation of skin and mucosal surfaces

Question 9

toxic dose of iron

Answer 9

10-20mg/kg elemental iron

Question 10

toxicity effects on the gastric intestinal tract

Answer 10

direct corrosive effects on mucosa - ulcer, hemorrhage, edema
actue corrosive effects = perforation and peritonitis which may enhance iron absorption

Question 11

toxicity effects on liver

Answer 11

electron transport abnormalities
lactate production
glycogen depletion
enzymatic dysfunction - metabolic acidosis, hyperglycemia
result of free iron concentrations in the hepatocyte during first absorptive pass
hepatocellular toxicity: hyperbilirubinemia, aminotransferase abnormalities, coagulopathy, diffused tissue necrosis, disruption of normal metabolic pathways

Question 12

toxicity effects on cardiovascular

Answer 12

free iron - venodilation, CV compromise, shock
acute volume loss from GIT - vomiting, hemorrhage
direct cytotoxic effects - capillary leakage, plasma loss

Question 13

toxicity effects on the neurological system

Answer 13

lethargy and weakness

coma

Question 14

stage 1 local toxicity symptoms .5-6hr after

Answer 14

NV
hematemesis
abd pain
diarrhea
severe gastreoenteritis
melena
lethargy 
hypotension
tachycardia

Question 15

stage 2 latent period symptoms 6-24hr after

Answer 15

may recover or go onto stage 3

Question 16

stage 3 systemic toxicity 4-40hr symptoms

Answer 16

pallor cyanosis 
lethargy 
hypotension
disorientation
convulsions
coma
shock
fever
leukocytosis
hyperglycemia
metabolic acidosis

Question 17

stage 4 2-4 days after symptoms

Answer 17

jaundice
hypoglycemia
elevated transaminases
prolonged clotting times
thrombocytopenial
hemorrhage
renal failure
pulmonary edema

Question 18

stage 5 lat complications 2-8 wks after symptoms

Answer 18

GI obstruction
pyloric stenosis
gastric fibrosis
strictures

Question 19

<20mg/kg presents as

Answer 19

asymptomatic

Question 20

20-30mg/kg presents as

Answer 20

self limiting vomiting and diarrhea

Question 21

> 40mg/kg may be

Answer 21

serious

Question 22

> 60mg/kg may be

Answer 22

lethal

Question 23

refer children with a dose_____ to emerg

Answer 23

> 10mg/kg

Question 24

diagnosis of iron toxicity

Answer 24

history of exposure
vomting, diarrhea, hypotension
iron serum level >350mcg/dL (>500 requires action)
abdominal radiograph

Question 25

interventions for iron toxicity

Answer 25

ABC basic life support
gastric emptying
activated charcoal not useful
chelators - severe

Question 26

why is activated charcoal not good for iron OD

Answer 26

metals not absorbed well

agent corrosive so AC will get into the cavity

Question 27

what is deferoxamine mesylate

Answer 27

specific iron binding ligand
very high affinity for iron
chelates free iron and iron of ferritin but NOT ironbound to hemoglobin or cytochromes

Question 28

100mg DFO = ____ iron

Answer 28

9mg

Question 29

iv infusion rate of DFO

Answer 29

15mg/kg/hr
iv removes much more than im
should see change in color of urine

Question 30

when do you discontinue DFO therapu

Answer 30

patient returns to asymptomatic state after latent period has passed
serum iron <150ug/dL
return to normal urine color

Question 31

can DFO be used in pregnant patients

Answer 31

yes

Question 32

DFO adverse effects

Answer 32

histamine release
DFO-iron complex is a growth factor for yersinia enterocolitica that can cause infection
excessive intracellular chelation causes oxidant damage
acute: hypotension, infections, pulmonary toxicity

Question 33

chronic use of DFO causes

Answer 33

auditory/ocular and pulmonary toxicity

infections