146 Iron and Heavy metals Flashcards
(32 cards)
Name the 2 mechanisms of iron toxicity
- direct injury to the GI mucosa
- impaired cellular metabolism (primarily heart liver, CNS)
What amount of elemental iron correlates to asx symptom severity level?
<20mg/kg
What amount of elemental iron correlates to mild to mod symptom severity level?
20-40mg/kg
What amount of elemental iron correlates to severe symptom severity level?
> 60mg/kg
Tell me the steps to calculating the amount of elemental iron ingested.
- determine which iron and its elemental amount (gluconate ~10, sulfate 20, fumarate = 30)
- doseage per tab (ie 360mg) x elemental iron = elemental amount ingested
- multiply this by number of tabs
- divide this mg value by the weight of the patient for mg/kg amount and expected level of sx
What questions on iron overdose are key for history taking
form
timing
quantity
Name the 5 phases of iron toxicity and expected timing post ingestion
- GI 0-6h
- latent 6-24h
- systemic 12-24h
- hepatic *2-5d)
- obstructive (3-6 weeks)
What are the clinical features of iron toxicity stage I GI, and why?
vomit
diarrhea
hematemesis
hematochezia
corrosive effect iron on GI mucosa
What are the clinical features of iron toxicity stage II latent, and why?
resolution GI sx
high HR
acidosis
decreased mental state
cellular toxicity and organ damage
What are the clinical features of iron toxicity stage III systemic sx, and why?
return GI sx
acidosis
wbc high
coagulopathy
renal failure
lethargy or coma
cv collapse
iron gets further into tissues with worsening cellular toxicity
What are the clinical features of iron toxicity stage IV hepatic, and why?
fulminant liver failure (LE elevation, INR up, AMS)
coagulopathy
rapid absorption from portal system –> further oxidate damage
What are the clinical features of iron toxicity stage V Obstructive, and why?
pyloric or bowel scarring
obstruction
healing of injured GI mucosa
Name 5 toxic ingestions that can cause hemorrhagic gastroenteritis
iron
etoh
toxic alcohols
caustics
ibuprofen
colchicine
heavy metals (ar, inorganic mercury)
List 5 initial investigations in iron ingestion evaluation
- serum iron levels 3-5 hours post ingestion
- plan abdo XR
- plasma BG
- serum electrolytes
- VBG
6/ ABG - PT, PTT, INR
- CBC
- type and screen
- asa/apap level
- ecg
When should your measure iron levels?
What if its enteric coated?
why is timing important?
3-5 hours post ingestion
6-8h
iron is rapidly cleared from serum into tissues so could actually look low
What peak level of iron correlates with minimal sx severity in microgram per dL AND Canadian units of micro mol per L
<350
<60
What peak level of iron correlates with MODERATE sx severity in microgram per dL AND Canadian units of micro mol per L
350-500
60-90
What peak level of iron correlates with SEVERE sx severity in microgram per dL AND Canadian units of micro mol per L
> 500
> 90
Why might you not see iron on an abdo xray? list 4 reasons
- didn’t take it
- liquid
- chewable
- completely dissolved
List 5 overdoses that can show radioopaque on abdo XR
CHIPES
caco3, chloral hydrate
heavy metals
iron, iodine
phenothiazines
enteric coated pills
solvents (halogenated hydrocarbons)
Give a general approach to managing iron overdose
- suppportive care with IVF, hemodynamic support and airway protection as needed
- decontam with WBI
- GI endoscopy or surgical gastronomy for lethal dose, bezoar, tablet adherence
- deforoxamine
Is hemodialysis helpful for iron OD?
no
does IV iron have lower likelihood or adverse effects compared to oral?
yes
How do you WBI a patient with iron ingestion
PEG through NG
child 9 mo - 6y: 500ml/hour
6-12 y: 1000ml/hour
> older than 12: 1.5-2L per hour in adolescenets and adults
