Difference between revisions of "Arsenic toxicity"

(Differential Diagnosis)
 
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==Background==
 
==Background==
 
*[[Heavy metal]]  
 
*[[Heavy metal]]  
*readily absorbed via GI tract and inhalation, poorly via skin  
+
*Readily absorbed via GI tract and inhalation, poorly via skin  
*tasteless and odorless
+
*Tasteless and odorless
*organic trioxide form used as chemotherapeutic agent  
+
*Organic trioxide form used as chemotherapeutic agent  
*trivalent form, As3+, is toxic to over 200 intracellular enzymes  
+
*Trivalent form, As3+, is toxic to over 200 intracellular enzymes  
*known carcinogen: skin, lung, other  
+
*Known carcinogen: skin, lung, other  
*ingestion fatal dose: 100-200mg
+
*Ingestion fatal dose: 100-200mg
  
 
===Sources of Exposure===
 
===Sources of Exposure===
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*GI symptoms that can resemble [[cholera]]
 
*GI symptoms that can resemble [[cholera]]
 
**Vomiting may be bloody
 
**Vomiting may be bloody
**"rice water" like diarrhea
+
**"Rice water" like diarrhea
*dehydration
+
*Dehydration
 
*[[Pulmonary Edema]]  
 
*[[Pulmonary Edema]]  
 
*[[Shock]]  
 
*[[Shock]]  
 
*[[Rhabdomyolysis]]  
 
*[[Rhabdomyolysis]]  
*[[altered mental status]]
+
*[[Altered mental status]]
 
*[[Seizure]]
 
*[[Seizure]]
*[[coma]]  
+
*[[Coma]]  
*death
+
*Death
*cardiovascular instability
+
*Cardiovascular instability
 
[[File:Meeslines.png|thumb|"Mees lines"]]
 
[[File:Meeslines.png|thumb|"Mees lines"]]
 
===Arsine gas exposure===
 
===Arsine gas exposure===
*hemolysis causing abdominal pain
+
*Hemolysis causing abdominal pain
*[[hematuria]], urine often looks black
+
*[[Hematuria]], urine often looks black
*[[jaundice]]
+
*[[Jaundice]]
*shaking chills
+
*Shaking chills
*can lead to [[altered mental status]]
+
*Can lead to [[altered mental status]]
*immediately lethal at 250 ppm
+
*Immediately lethal at 250 ppm
  
 
===Subacute or chronic poisoning===
 
===Subacute or chronic poisoning===
 
*[[Anemia]]  
 
*[[Anemia]]  
*peripheral neuropathy
+
*Peripheral neuropathy
**typically symmetric "glove and stocking" distribution
+
**Typically symmetric "glove and stocking" distribution
*skin changes  
+
*Skin changes  
 
*White lines on the finger nails known as "Mees lines"
 
*White lines on the finger nails known as "Mees lines"
*[[ataxia]]  
+
*[[Ataxia]]  
 
*[[CNS Depression]]
 
*[[CNS Depression]]
  
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*[[ECG]] to eval for [[QT Prolongation]] in acute exposure  
 
*[[ECG]] to eval for [[QT Prolongation]] in acute exposure  
 
*CBC and retic count, expect hemolytic anemia  
 
*CBC and retic count, expect hemolytic anemia  
*BMP, Mg, phos, Ca, LFTs, CK
+
*BMP, Mg, Phos, Ca, LFTs, CK
*type and screen for possible transfusion in arsine gas exposure
+
*Type and screen for possible transfusion in arsine gas exposure
 
*[[CXR]] if respiratory symptoms 
 
*[[CXR]] if respiratory symptoms 
 
*Consider other ingestion labs including acetaminophen and salicylate level in intentional ingestions
 
*Consider other ingestion labs including acetaminophen and salicylate level in intentional ingestions
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==Management==
 
==Management==
*supportive care, ABCs, IV, O2, monitor  
+
*Supportive care, ABCs, IV, O2, monitor  
*removal from exposure  
+
*Removal from exposure  
 
*NO [[Charcoal]] if co-ingestion is not suspected - adsorbs poorly to arsenic
 
*NO [[Charcoal]] if co-ingestion is not suspected - adsorbs poorly to arsenic
*consider [[Whole Bowel Irrigation]] if large radiopaque material in GI tract on xray
+
*Consider [[Whole Bowel Irrigation]] if large radiopaque material in GI tract on xray
*airway management and mechanical [[ventilation]] if acute inhalation of arsine gas and respiratory distress  
+
*Airway management and mechanical [[ventilation]] if acute inhalation of arsine gas and respiratory distress  
 
*IV fluids  
 
*IV fluids  
 
*CHELATION therapy: if severe symptoms present
 
*CHELATION therapy: if severe symptoms present
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==Disposition==
 
==Disposition==
*admit patient's with significant symptoms  
+
*Admit patient's with significant symptoms  
 
*ED observation and discharge with follow-up for mildly symptomatic
 
*ED observation and discharge with follow-up for mildly symptomatic
  

Latest revision as of 17:43, 14 October 2018

Background

  • Heavy metal
  • Readily absorbed via GI tract and inhalation, poorly via skin
  • Tasteless and odorless
  • Organic trioxide form used as chemotherapeutic agent
  • Trivalent form, As3+, is toxic to over 200 intracellular enzymes
  • Known carcinogen: skin, lung, other
  • Ingestion fatal dose: 100-200mg

Sources of Exposure

  • Poisoning
  • Contaminated drinking water
  • Eruptions
  • Metal and semiconductor industry
  • Wood preservatives
  • seafood arsenic (felt to be organic form which is NONTOXIC and cleared from body in few days)

Clinical Features

Typical rash associated with chronic exposure

Acute ingestion

"Mees lines"

Arsine gas exposure

Subacute or chronic poisoning

  • Anemia
  • Peripheral neuropathy
    • Typically symmetric "glove and stocking" distribution
  • Skin changes
  • White lines on the finger nails known as "Mees lines"
  • Ataxia
  • CNS Depression

Differential Diagnosis

Heavy metal toxicity

Acute diarrhea

Infectious

Noninfectious

Watery Diarrhea

  • Enterotoxigenic E. coli (most common cause of watery diarrhea)[1]
  • Norovirus (often has prominent vomiting)
  • Campylobacter
  • Non-typhoidal Salmonella
  • Enteroaggregative E. coli (EAEC)
  • Enterotoxigenic Bacteroides fragilis

Traveler's Diarrhea

Evaluation

Workup

  • Urine arsenic level
  • ECG to eval for QT Prolongation in acute exposure
  • CBC and retic count, expect hemolytic anemia
  • BMP, Mg, Phos, Ca, LFTs, CK
  • Type and screen for possible transfusion in arsine gas exposure
  • CXR if respiratory symptoms 
  • Consider other ingestion labs including acetaminophen and salicylate level in intentional ingestions

Diagnosis

  • Urine arsenic level (usual normal level is <50mcg/L); both urine spot test and 24h urine collection
    • Lab must differentiate inorganic from organic arsenic (treat for inorganic exposure only)
  • Blood arsenic level not helpful (cleared within 2 hrs of exposure)

Management

  • Supportive care, ABCs, IV, O2, monitor
  • Removal from exposure
  • NO Charcoal if co-ingestion is not suspected - adsorbs poorly to arsenic
  • Consider Whole Bowel Irrigation if large radiopaque material in GI tract on xray
  • Airway management and mechanical ventilation if acute inhalation of arsine gas and respiratory distress
  • IV fluids
  • CHELATION therapy: if severe symptoms present
  • Dimercaprol (BAL). 3-5mg/kg IM Q4-6h

Disposition

  • Admit patient's with significant symptoms
  • ED observation and discharge with follow-up for mildly symptomatic

See Also

References

  1. Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.