Arsenic toxicity
Background
- infamous historical poison
- heavy metal
- 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
- readily absorbed via GI tract and inhalation, poorly via skin
- 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
Clinical Features
- Acute ingestion
- GI symptoms
- Can be associated with "garlic odor"
- Pulmonary Edema
- Shock
- Rhabdomyolysis
- Seizure
- coma
- death
- cardiovascular instability
- GI symptoms
- Arsine gas exposure
- Subacute or chronic poisoning
- Anemia
- sensory motor neuropathy
- skin changes
- ataxia
- CNS Depression
Differential Diagnosis
Diagnosis
- urine arsenic level (usual normal level is <50mcg/L); both urine spot test and 24h urine collection
- blood arsenic level not helpful (cleared within 2 hrs of exposure)
- ECG to eval for QT Prolongation in acute exposure
- CBC to eval for hemolysis
- BMP, Mg, phos, Ca, LFTs, CK, type and screen
- CXR if respiratory symptoms
Treatment
- supportive care, ABCs, IV, O2, monitor
- removal from exposure
- NO Charcoal - 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 resp distress
- IV fluids
- CHELATION therapy: if severe symptoms present
- Dimercaprol (BAL). 3-5 mg/kg IM Q4-6h
Disposition
- admit pt's with significant symptoms
- ED observation and discharge with follow-up for mildly symptomatic