What is the treatment for arsenic poisoning?

Treatment for Arsenic Poisoning

The recommended treatment for arsenic poisoning is chelation therapy with dimercaptosuccinic acid (DMSA), dimercaptopropanesulfonate (DMPS), or British Anti-Lewisite (BAL/dimercaptopropanol), with DMPS being the preferred agent for most cases. 1

Diagnosis of Arsenic Poisoning

Clinical Presentation

• Acute poisoning:

  • Severe nausea and vomiting
  • Colicky abdominal pain
  • Profuse diarrhea
  • Lethargy and altered mental status 2, 3

• Chronic exposure:

  • Skin pigmentation changes
  • Palmar and plantar hyperkeratosis
  • Peripheral neuropathy
  • Peculiar hand posturing (early sign) 2, 4
  • Sensorineural hearing loss (in some cases) 3

Diagnostic Testing

• Quantitative measurement of 24-hour urinary arsenic excretion (most reliable test) 2
  • Normal level: <15 μg/g creatinine
  • Toxic level: >50 μg/g creatinine
• Blood arsenic levels (less reliable due to rapid clearance)

Treatment Algorithm

1. Initial Management

• Ensure airway patency, respiratory status, and hemodynamic stability 2
• Nothing by mouth unless specifically advised by poison control 2
• Remove patient from exposure source
• Decontamination measures for recent ingestions

2. Chelation Therapy

• First-line agents:

  • DMPS (dimercaptopropanesulfonate) - preferred for most cases 1
  • DMSA (dimercaptosuccinic acid) - oral administration, effective for mild-moderate cases 5, 1
  • BAL (dimercaptopropanol) - for severe acute poisoning, especially when oral administration is not possible 1

• Dosing considerations:

  • For acute severe poisoning: Consider initial treatment with BAL combined with DMPS 1
  • For subacute and chronic poisoning: DMPS or DMSA are preferred 1

3. Supportive Care

• Fluid and electrolyte management
• Monitoring of liver and kidney function
• Management of specific organ toxicities (cardiovascular, neurological, etc.)

Special Populations

Pregnancy

• Chelation therapy must be carefully considered
• Lower threshold for ECTR (extracorporeal treatment) may be preferred to reduce exposure to chelating agents 6

Chronic Exposure Cases

• Extended chelation therapy may be necessary
• Rehabilitation for neurological sequelae 7
• Psychological support for patients with chronic invalidism 7

Source Identification and Prevention

• Common sources of arsenic exposure:

  • Contaminated drinking water (especially well water)
  • Foods (rice, seafood)
  • Insecticides and pesticides
  • Chinese herbal medicines 3
  • Ant killers 4

• Prevention strategies:

  • Testing drinking water sources
  • Using alternative water sources in high-risk areas
  • Reducing consumption of high-arsenic foods
  • Maintaining good folate status to support arsenic elimination 2

Monitoring and Follow-up

• Regular monitoring of urinary arsenic levels until normalization
• Assessment of organ function (liver, kidney, neurological)
• Long-term monitoring for potential development of cancers (lung, bladder, skin) in chronic exposure cases 2

Pitfalls and Caveats

1. Arsenic poisoning is often misdiagnosed due to its non-specific symptoms 4
2. Common household water filters do not effectively remove arsenic 2
3. Seafood consumption can cause elevated organic arsenic levels in urine, which are less toxic than inorganic forms
4. Delayed diagnosis can lead to irreversible neurological damage and multi-organ failure 3
5. Patients with celiac disease on rice-based diets may be at higher risk for arsenic exposure 5