Arsenic toxicity
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
Acute ingestion
- Garlic smell of breath and tissues
- GI symptoms that can resemble cholera
- Vomiting may be bloody
- "rice water" like diarrhea
- dehydration
- Pulmonary Edema
- Shock
- Rhabdomyolysis
- altered mental status
- Seizure
- coma
- death
- cardiovascular instability
Arsine gas exposure
- hemolysis causing abdominal pain
- hematuria, urine often looks black
- jaundice
- shaking chills
- can lead to altered mental status
- immediately lethal at 250 ppm
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
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
- Aluminum toxicity
- Antimony toxicity
- Arsenic toxicity
- Barium toxicity
- Bismuth toxicity
- Cadmium toxicity
- Chromium toxicity
- Cobalt toxicity
- Copper toxicity
- Gold toxicity
- Iron toxicity
- Lead toxicity
- Lithium toxicity
- Manganese toxicity
- Mercury toxicity
- Nickel toxicity
- Phosphorus toxicity
- Platinum toxicity
- Selenium toxicity
- Silver toxicity
- Thallium toxicity
- Tin toxicity
- Zinc toxicity
Acute diarrhea
Infectious
- Viral (e.g. rotavirus)
- Bacterial
- Campylobacter
- Shigella
- Salmonella (nontyphi)
- Escherichia coli
- E. coli 0157:H7
- Yersinia enterocolitica
- Vibrio cholerae
- Clostridium difficile
- Parasitic
- Toxin
Noninfectious
- GI Bleed
- Appendicitis
- Mesenteric Ischemia
- Diverticulitis
- Adrenal Crisis
- Thyroid Storm
- Toxicologic exposures
- Antibiotic or drug-associated
Watery Diarrhea
- Enterotoxigenic [[E. coli]
- Norovirus (often has prominent vomiting)
- Campylobacter
- Non-typhoidal Salmonella
- Enteroaggregative E. coli (EAEC)
- Enterotoxigenic Bacteroides fragilis
Traveler's Diarrhea
Evaluation
- 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)
- 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
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