Part of the ICU Emergencies Hub — browse every related guide in one place.
Acute arsenic poisoning is rare, and that rarity is the danger: it is easy to miss because its first act looks like severe gastroenteritis or sepsis. But arsenic is one of the classic homicidal and industrial poisons, and a patient with unexplained profound GI losses, shock, and a widening QT interval — especially with a suggestive history — may be arsenic-poisoned. The ICU nurse's role is to resuscitate the massive fluid losses, watch the heart for the lethal dysrhythmia arsenic causes, and support the patient through chelation while toxicology confirms the diagnosis.
Arsenic poisons cellular energy production, binding to sulfur-containing groups on enzymes throughout the body and crippling the cell's ability to make ATP. Nearly every organ that depends on high energy turnover suffers: the gut lining sloughs, the heart's electrical system destabilizes, capillaries leak, and later the nerves and marrow fail. Inorganic arsenic (the toxic form) comes from pesticides and rodenticides, some industrial and mining exposures, contaminated well water (usually chronic), certain folk and traditional remedies, and deliberate poisoning.
Acute arsenic poisoning unfolds over hours to weeks, and the ICU nurse may meet it at any stage.
| Phase | What you may see |
|---|---|
| Early (minutes–hours) | Metallic taste, garlicky breath, vomiting, and severe "rice-water" diarrhea; profound volume loss, third-spacing, hypotension and shock |
| Cardiac (hours–days) | QT prolongation, torsades de pointes and other ventricular dysrhythmias, myocardial dysfunction, ongoing hypotension |
| Delayed (days–weeks) | Painful, ascending sensorimotor peripheral neuropathy; encephalopathy; bone-marrow suppression (pancytopenia); hepatic and renal injury; later, Mees' lines on the nails |
The diagnosis is a clinical suspicion confirmed by testing. A 24-hour urine arsenic is the standard for acute inorganic exposure; a random urine or blood level may help early, but blood arsenic clears quickly. An important pitfall: eating seafood loads the urine with harmless organic arsenic (arsenobetaine) and can produce a high total level that does not mean poisoning — speciation or a seafood-free interval sorts this out. Because arsenic is radio-opaque, an abdominal X-ray can sometimes show ingested material. Hair and nail testing document remote or chronic exposure but do not guide acute care.
The first job is aggressive fluid resuscitation for the rice-water losses — these patients can lose liters and go into hypovolemic shock — along with correcting electrolytes and treating dysrhythmias. Chelation is started early in significant poisoning and is toxicology-directed.
| Agent | Route | Note |
|---|---|---|
| Dimercaprol (BAL) | Deep IM | Often first in the acutely ill patient who cannot take oral meds |
| Succimer (DMSA) | Oral | Used once the patient can tolerate oral therapy / for continued chelation |
| DMPS (unithiol) | Oral/IV (availability varies) | Used in some centers/regions for arsenic |
Dimercaprol is a painful deep IM injection in a peanut-oil base (screen for peanut allergy), can cause fever and hypertension, and is avoided in G6PD deficiency. Succimer is oral with GI and hepatic effects and a strong sulfur smell. Chelation courses are guided by repeat urine levels, and therapy continues until the burden falls.
Hemodynamics and strict intake/output for the ongoing GI losses; continuous ECG with QT/QTc surveillance and aggressive K+/Mg2+ repletion; neuro checks for the encephalopathy and the emerging painful neuropathy (which may need long-term rehab and pain management); serial CBCs for marrow suppression; and renal and hepatic function. As with all metal poisonings, the exposure must be identified and stopped, and because deliberate poisoning is on the differential, unexplained cases may involve public health or law enforcement — document carefully and follow your facility's process.
For related metal and toxin exposures and the complications arsenic shares, see lead poisoning, mercury poisoning, and organophosphate poisoning. For the dysrhythmia and kidney threads, see torsades de pointes and acute kidney injury and CRRT.
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