0071643192.pdf

TOXICOLOGY

■ Phase 1: Gastrointestinal phase
■ N/V/D, gastrointestinal bleeding from corrosive effect
■ No vomiting within 6 hours = no toxicity.
■ Phase 2: Latent phase (6–24 hours postingestion)
■ Clinically stable after resuscitation
■ Patients with mild toxicity will not progress beyond this stage.
■ Phase 3: Systemic toxicity
■ Recurrence of GI symptoms
■ Anaerobic metabolism →shock, lactate production, anion gap meta-
bolic acidosis.
■ Multiorgan involvement with cardiac dysfunction, bleeding, renal
failure
■ Phase 4: Fulminant hepatic failure (2–5 days postingestion) from cellular
oxidative injury
■ Phase 5: Delayed sequelaefrom gastrointestinal scarring

DIFFERENTIAL

■ Most ingested metals cause gastrointestinal effects with large doses such as
mercuric salts, lead, arsenic.

DIAGNOSIS

■ History of ingestion and presence of GI (phase 1) symptoms indicate toxicity.
■ Presence of anion gap metabolic acidosis (primarily lactate) indicating cel-
lular toxicity.
■ Total serum iron level at 4–6 and 6–8 (for SR or EC preparations) hours
postingestion.
■ Level >500 mcg/dL = severe toxicity.
■ Measurement of TIBC has little or no value.
■ Abdominal radiograph: A negative radiograph for radiopaque pills does not
rule out ingestion.

TREATMENT

■ Supportive and symptomatic care
■ Remember, no GI symptoms within 6 hours = no toxicity.
■ Decontamination
■ Activated charcoal does notbind iron.
■ Whole-bowel irrigation: If large amounts of pills visualized on X-ray
and levels rising

Patients without onset of

vomiting 6 hours after iron

exposure will not have

significant systemic toxicity.

TABLE 6.24. The Five Phases of Iron Toxicity

Phase 1: Gastrointestinal phase

Phase 2: Latent phase

Phase 3: Systemic toxicity

Phase 4: Fulminant hepatic failure

Phase 5: Delayed sequelae

Not all iron pills are visible on

abdominal X-ray.