arsenic poisoning

Etiology

• ingestion of arsenical salts often as insect poison
• case presentation as chronic ingestion of well water

Epidemiology

• worldwide, the greatest threat to public health from arsenic is through contaminated groundwater

Pathology

• reversible interaction with multiple sulfhydryl-containing proteins
• arsine gas is the most toxic form of arsenic
  • can cause intravascular hemolysis & acute renal failure
  • > 30 ppm of arsine gas may be fatal
• a fatal dose of arsenic trioxide is 120 mg
• exposure to inorganic arsenic during infancy can adversely affect some developmental outcomes
• infants eating rice have higher urinary levels of arsenic than infants who eat no rice

Clinical manifestations

• toxicity generally manifested within 1 hours of ingestion
  • toxicity from chronic exposure also occurs
• most commonly presents with gastrointestinal symptoms
  • dry mouth
  • dysphagia
  • nausea/vomiting
  • abdominal pain
  • diarrhea, watery or bloody
  • hematemesis[2]
• odor of garlic on the breath
• metallic taste
• cardiovascular manifestations
  • hypotension
  • tachycardia
  • ventricular arrhythmias
• oliguria, acute renal failure
• pulmonary edema
• headache
• vertigo
• increased fatigability
• paralysis of extremities
• mental impairment
• painful sensory polyneuropathy
  • occurs late, 1-2 weeks after ingestion
  • NO upper motor neuron signs
• mottled brown pigmentation of skin
  • patchy hyperpigmentation is a pathologic hallmark of chronic exposure
  • may be found anywhere on the body
  • occurs particularly on the eyelids, temples, neck, nipples, axillae, & groin
  • in severe cases, chest, back, & abdomen
• hyperkeratosis on palms & soles (rsenical keratoses)
  • generally multiple
  • typically occur at sites of friction & trauma, especially on palms & soles, dorsum of hands, arms & legs
  • nontender, horny, hard, yellowish, 0.2-1.0 cm papules
  • lesions may coalesce into larger verrucous papules or plaques
  • benign arsenical keratoses may progress to malignancy
• edema of cutis
• transverse striate leukonychia; Mees lines
• perforation of nasal septum
• edema of eyelids
• rhinitis
• decreased deep tendon reflexes

Laboratory

• urinalysis
  • hematuria
  • hemoglobinuria
• arsenic in urine > 50 ug/L
• arsenic in hair, arsenic in nails
• arsenic in serum/plasma
• complete blood count: macrocytic anemia
• arterial blood gas

Diagnostic procedures

• electrocardiogram

Radiology

• chest X-ray
• abdominal X-ray

Complications

• increased risk of several cancers
  • basal cell carcinoma
  • Bowen disease
  • Merkel cell carcinoma
  • liver cancer
  • bladder cancer
  • lung cancer

Management

• gastric lavage
• irrigate exposed areas, IV hydration as needed
• dimercaprol combines with arsenic through sulfhdryl groups to produce water soluble complexes
• 2,3-dithioerythritol may be less toxic than dimercaprol
• hemodialysis may be used to remove dimercaprol-arsenic complexes
• remove from toxic source
  • limit infant rice consumption

Notes

• FDA proposes limit for inorganic arsenic in infant rice cereal of 100 ppb (parts per billion)*

* inorganic arsenic levels are higher in rice than in other foods

* ~50% of infant rice cereals tested in 2014 were < 100 ppb

More general terms

• heavy metal toxicity

Additional terms

• arsenic in urine
• arsenic [As]
• leukonychia; achromia unguium; canities unguium; leukopathia unguis; white nails