Arsenic toxicity

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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

Differential Diagnosis

Background

Heavy metal toxicity results from exposure to metals like lead, mercury, arsenic, or cadmium, which interfere with cellular function. Exposure may occur occupationally, environmentally, through ingestion, or from alternative medicines. Chronic toxicity can present insidiously, while acute toxicity may mimic sepsis or encephalopathy. Diagnosis is often delayed due to nonspecific symptoms.

Clinical Features

Symptoms depend on the metal and exposure duration but may include:

Neurologic: Peripheral neuropathy, confusion, tremor, encephalopathy

GI: Abdominal pain, nausea, vomiting, diarrhea, anorexia

Heme: Anemia (especially microcytic or hemolytic), basophilic stippling (lead)

Renal: Tubular dysfunction, proteinuria, Fanconi syndrome

Dermatologic: Mees’ lines (arsenic), hyperpigmentation, hair loss

Others: Fatigue, weight loss, hypertension (cadmium), immunosuppression

Differential Diagnosis

Sepsis or systemic inflammatory response

Drug toxicity or overdose

Metabolic disorders (e.g., porphyria, uremia)

Psychiatric illness (if symptoms are vague or bizarre)

Neurologic diseases (e.g., Guillain-Barré, MS, Parkinson’s)

Vitamin deficiencies (e.g., B12, thiamine)

Evaluation

Workup

History: Occupational exposures, home remedies, hobbies (e.g., jewelry making, battery recycling), diet, water source, imported goods

Labs:

  • CBC, CMP, urinalysis
  • Blood lead level, serum/urine arsenic, mercury, or cadmium (based on suspicion)
  • Urine heavy metal screen (note: spot testing may require creatinine correction)

Imaging: Abdominal X-ray (radiopaque material in GI tract, especially with lead)

EKG: Evaluate for QT prolongation or arrhythmias in severe cases

Diagnosis

Confirmed by elevated blood or urine levels of the specific metal in the context of clinical findings. Hair and nail testing are unreliable for acute toxicity. Interpret results with toxicologist input if possible.

Management

Remove the source of exposure (e.g., occupational control, GI decontamination if recent ingestion)

Supportive care: IV fluids, seizure control, electrolyte repletion

Chelation therapy (in consultation with toxicology or Poison Control):

Lead: EDTA, dimercaprol (BAL), succimer

Mercury/arsenic: Dimercaprol or DMSA

Cadmium: No effective chelation—focus on supportive care

Notify local public health authorities if exposure source is environmental or occupational

Disposition

Admit if symptomatic, unstable, or requiring chelation

Discharge may be appropriate for asymptomatic patients with low-level exposure and outpatient follow-up

Arrange toxicology or environmental medicine follow-up for source control and serial testing

See Also

Acute diarrhea

Infectious

Noninfectious

Watery Diarrhea

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

Admission

  • Admit patient to intensive care setting if symptomatic from acute exposure

Discharge

  • Asymptomatic/mildly symptomatic patients or those with suspected chronic exposures may be discharged w/ outpatient follow-up after initial ED observation.

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.
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