Transcript IRON and STINGS

IRON and STINGS
Rob Hall
Dr. M. Yarema
June 20th, 2002
GOALS
• IRON
– recognize dx
– explain
pathophysiology
– know how, when and
why to treat
• STINGS
– know the basic
management of
bee/wasp/fire ant stings
– know the approach to
management of marine
bites, stings, and
nematocysts
envenomations
She got into my pills……..
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3yo female - 10 kg
5 pills of Ferrrous sulphate 325 mg gone
Presents early vomiting blood
Are you worried?
What if it was 10 pills?
Toxic Ingestions
• Depends on ELEMENTAL IRON
• Look up % elemental iron in ingested tab
• Ferrous sulphate (20% elemental Fe + 10kg
child)
– 325 mg X 0.20 = 65 mg elemental Fe
– 65 mg X 5 pills = 325 mg ----> 32 mg/kg
– 65 mg X 10 pills = 650 mg ----> 65 mg/kg
TOXICITY
• Elemental Fe
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< 20 mg/kg
20 - 40 mg/kg
40 - 60 mg/kg
> 60 mg/kg
Peak []
< 30 umol/L
30 - 60
60 - 90
> 90 umol/L
Toxicity
none
mild
mod
severe
LOCAL TOXICITY
• Direct GI corrosive/irritant
• Nausea, vomiting, abdominal pain, diarrhea,
hematemasis, melena, hematochezia
• Must consider on ddx of gastroenteritis, GI
bleed in peds
SYSTEMIC TOXICITY
• Coagulopathy (inhibits thrombin formation)
• Liver toxicity (periportal necrosis)
• Increased Anion Gap Metabolic Acidosis
– Inhibits oxidative phosphylation ---> lactate
– Direct negative ionotropy ---> lactate
– Direct vasodilation ---> lactate
• MUST be on ddx of SHOCK and AGMA
NYD
What causes the increased
AGMA in Fe overdose?
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Fe 2+ ----------------> Fe 3+ and Hydrogen
Anerobic metabolism ---------> lactate
Hypovolemia from V/D --------> lactate
Hypovolemia from GIB ---------> lactate
-ve Ionotropy ---------------> lactate
Vasodilation ----------------> lactate
FIVE STAGES
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STAGE I (< 6hrs): GI signs symptoms
STAGE II (6 - 24hrs): Latent period
STAGE III (variable): Systemic toxicity
STAGE IV (2-3 days): Liver failure
STAGE V (weeks): Gastric outlet
obstruction
Complications
• Yersinsia enterocolitica
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Noted increased rates of infection
Iron as a growth factor
Increases with deferoxamine use
Abdo pain, fever, diarrhea, sepsis
LABS
• ? WBC > 15 and Glucose > 7.5
– may be a bad sign but not reliable
• Increased AGMA
– remember ddx: AMUDPILECAT
• TIBC
– theoretical reassurance if Fe level less than
TIBC b/c enough transferrin around to bind
– NOT reliable; DO NOT USE or MEASURE
IRON LEVELS
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Measure at 2 - 6 hrs (Peak 4hrs usually)
Repeat levels to catch peak (?)
Normal is 14 - 32 umol/L
Goes down town; turn around in 2hrs but
must notify lab of STAT order
• Levels used to help guide therapy
• Falsely lowered in presence of
deferoxamine thus must do before
AXR
• Radiopaque
• Ddx of radiopaque ingestant
– C
ca carbonate, chloral hydrate
• Liquids and
– H
heavy metals (iron, zinc, ba,
chewables are
Li, bisthmus)
NOT radiopaque
– I
iron
– P
KCl, Play-doh
• Absence on AXR
– P
phenothiazines
does NOT r/o
– E
enteric coated pills
ingestion
– D
dental amalgan
DECONTAMINATION
• NO ipecac
• Doesn’t bind charcoal
• Gastric Lavage
– Indicated if visible in stomach on AXR
– Water or saline NOT bicarb, phosphosoda, Mg
• Whole Bowel Irrigation
– Indicated if visible past stomach on AXR
DEFEROXAMINE
• Specific iron chelator
• Derived from Streptomyces pilosus
• Ferric iron + deferoxamine ----------------->
ferrioxamine (colors urine red/brown)
• Chelates free iron in blood and intracellular
DEFEROXAMINE
• Administration
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iv > im > po
iv indicated
goal is 15 mg/kg/hr
start at ? 5 mg/kg/hr and increase to target
DEFEROXAMINE
• Adverse Effects
– Hypotension with rapid administration
– ARDS (more common with higher doses,
longer administrations > 24hrs)
– Increased Yersinsia infections
– Ocular and Ototoxicity have been reported with
chronic administration
– Deferoxamine is NOT contraindicated in
pregnancy
DEFEROXAMINE
CHALLENGE
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90 mg/kg im and see if urine color changes
+ve = urine color change -----------> tx
-ve = no urine color change --------->no tx
Problems
– shown to be UNRELIABLE
– DO NOT use as sole determinant for basis of
treatment
Vin Rose’
DEFEROXAMINE
• Indications for use
– Ingestion of > 60 mg/kg
– Iron level > 90 umol/L
– Systemic toxicity: hypotension, coma, AGMA,
seizures
• Discontinuation (generally at 24hrs)
– Clinically well
– AGMA resolved
– No further urine color change
OTHER Mx
• Deferiprone
– Oral active iron chelator
– Used in chronic setting; being looked at with
acute ingestions
• CAVH
– Infuse deferoxamine on arterial side; dog
studies
– Essentially experimental at this point
DISPOSITION
• Asymptomatic after 6 - 8 hrs rules out
significant ingestion and d/c home
• Management of moderate to severe
ingestions depends on …….
– Clinical assessment: hx, physical, labs
– Amount ingested: > 60 mg/kg is bad
– Iron level: > 90 umol/L is bad
APPROACH
History
Physical
Labs
Determine Severity
MILD
< 20 mg/kg
asymptomatic
MODERATE
20 - 60 mg/kg
unknown amount
"mild" GI s/s
SEVERE
> 60 mg/kg
"severe" GI s/s
AGMA or Shock
MILD
• < 20 mg/kg and asymptomatic
• Management
– Observe 6-8 hrs
– D/C if asymptomatic
– No iron levels necessary
MODERATE
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20 - 60 mg/kg or unknown + “mild”GI s/s
Order AXR and Fe level (2-6hr)
Consider Gastric lavage or WBI
Fe level < 60 or 60 - 90 and asymptomatic
-------> observe 6 - 8 hours and d/c if well
• Fe level > 90 or 60 - 90 and symptomatic
-------> treat as severe
SEVERE
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> 60 mg/kg, severe GI s/s, AGMA, shock
AXR, Fe level, baseline urine
Gastric lavage or WBI based on AXR
Start Deferoxamine: target is 15 mg/kg/hr
Discontinue Deferoxamine when……
– Clinically well
– AGMA resolved
– No further urine color change
The GOODs on IRON
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LOCAL and SYSTEMIC toxicity: 5 stages
Asymptomatic at 6hrs r/o sign. ingestion
Consider with gastro, GIB, AGMA, shock
Absence of pills on AXR does NOT r/o
Rx based on clinical status, amount
ingested, and iron levels
• Don’t wait for iron level if toxic
HYMENOPTERA
• Nasty arthropods: bee, wasp, hornet, yellow
jacket, fire ants
• 2nd most common cause of anaphylactic
deaths
• Killer Bees: “normal” bees with a mean
streak (not more toxic, just more
aggressive)
HYMENOPTERA REACTIONS
• Local
– pain, erythema, edema, swelling, itching
– lasts hours to days; looks like infection
• Toxic
– N/V/D, lightheaded, syncope, H/A, fever,
muscle spasms (NO urticaria or bronchospasm)
– Due to toxic nature of venom NOT anaphylaxis
– Lasts few hours to 2-3 days
HYMENOPTERA REACTIONS
• Allergic/Anaphylactic
– Urticarial rash ------------> full anaphylaxis
• Delayed Reaction
– Serum sickness at 10 - 14 days: fever, malaise,
H/A, lymphadenopathy, polyarthritis, urticaria
– Often not associated with sting by patient
• Usual Reactions
– Encephalitis, GBS, neuritis, vasculitis
HYMENOPTERA - Mx
• First Aid
– Ice bag to site, remove stinger, epipen prn
• Local Wound care in ED
– Ice, remove stinger, tourniquet, limb down, can
inject 0.1 ml of 1:1000 epi into site
• Further Mx will depend on severity
– Local reaction, allergic reaction, anaphylactic
reaction
ED Management
• Local Reaction
– Local wound care, benadryl po, ibuprofen po
– Observe 1hr, d/c if well
• Urticarial Reaction
– Local wound care, benadryl po, ibuprofen po
– Observe 2-3 hrs, d/c if well
– Educate, bracelet, Epipen Rx, allergist referral,
Rx with benadryl +/- steroid
ED Management
• Anaphylaxis
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Epinephrine sc, im, iv
Benadryl iv
IV fluids
Ranitidine +/- Cimetidine
Ventolin +/- Racemic epi neb
Methylprednisone
Local wound care
Admit
MARINE ENVENOMATIONS
• 2000 species of venemous marine animals
• General Mx
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Remove from water: drowning MCC of death
Local wound care
? Specific antivenom
Be prepared to manage anaphylaxis
Three Mechanisms of
Envenomation
Oh, Look at the cute little fishy!
Marine Envenomation
Mechanisms
Bites
Nematocysts
Stings
Octopi
Seasnakes
Jellyfish
Man-o-war
Sea wasp
Fire corals
Bony Fish
Sea Urchin/starfish
Cone Shells
Stingrays
BITES
• Octopi
– Local wound care: irrigate,
debride, dress, tetanus,
analgesia
– Blue - ringed Octopus can be
lethal (tetrodotoxin like
venom)
BITES
• Seasnakes
– 50 species, all toxic, 7 fatal
– Most bites do not result in
envenomation b/c fangs
short/loose ---> poor
delivery of venom
– Local wound care +
polyvalent sea snake
antivenom
NEMATOCYSTS
• Nematocyst = spring - loaded venom gland
that suddenly everts and delivers venom
• Often located on tentacles
• Remain functional after animals death
• May still be “loaded”when in skin
• Local reaction, allergic reaction, toxic
reaction (N/V/D, CP, cramps, SOB,
paralysis, cardiorespiratory collapse)
NEMATOCYSTS
• General Mx
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Cut off tentacles
Inactivate nematocysts: VINEGAR
Remove nematocyts: credit card scrape
Antihistamine, analgesia
Antivenom only exists for seawasp
NEMATOCYSTS
• Jellyfish
– Usually only local reaction
– Remove tentacle, vinegar,
credit card scrape,
antihistamine, analgesia
NEMATOCYSTS
NEMATOCYSTS
• Box Jellyfish (Seawasp)
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Australia, Indian ocean
MOST deadly of all envenomating marine life
25% fatality rate; more deaths than sharks!
One box can kill 10 humans
Cardioresp arrest within minutes
Mx: ABCs, remove tentacles, VINEGAR,
credit card scrape, ANTIVENOM (Chironex)
NEMATOCYSTS
NEMATOCYTS
• Portuguese Man -o - war
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Southern US coast line
Not a true jellyfish
Usually only local reaction
Potential for full CV collapse
Many deaths reported
Mx: ABCs, remove tentacles, vinegar, credit
card scrape, NO antivenom exists
STINGS
• Stinger = specialized apparatus that
punctures skin and delivers venom
• Mx
– Remove stinger (? Xray to r/o stinger in tissue)
– Irrigate copiously, tetanus, analgesia
– HOT WATER for 30 - 90 min (inactivates the
heat labile venom; hot as possible)
– Antivenom exists for stonefish stings
STINGS
• Starfish
– Most nonvenomous
– Crown - of - thorns: severe
local reaction
STINGS
• Sea Urchins
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Toxic coated spines
Severity depends on species
Usually only local reaction
Imbedded spines problematic
STINGS
• Stingray
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Barbs on tail
Stepped on in shallow water
Tail spines ---> laceration
Stinger: local +/- systemic rxn
(N/V/D, cramps, CP, SOB)
– Remove stinger, irrigate, HOT
water, tetanus, abx to cover
vibrio
STINGS
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Bony fish (Lionfish, Stonefish)
Venomous spins on fins
Stepped on or handled
Will attack b/f swimming away
Severe local rxn: pain, swelling
Systemic rxn: N/V/D, syncope,
SOB, paralysis, CV collapse
• ANTIVENOM exists
The Goods on Marine
Envenomations
Look but DON'T touch
Management
BITES
octopi
seasnakes
NEMATOCYSTS
jellyfish, sea wasp
man - of - war
STINGS
starfish, urchins
stingray, bonyfish
Local wound care
Antivenom for snakes
Remove tentacles
VINEGAR
Credit card scrape
Antivenom for sea wasps
Remove stinger
Irrigate
HOT WATER
Antivenom for stonefish