Chemical and Drug Poisoning-Part Two

Chemical and Drug Poisoning-Part Two
Iron:
It occurs frequently in childhood and rarely results in death. The toxic dose is greater than 60 mg/kg of elemental iron. dose is equal to 10 tablets.
Clinical features
The manifestations pass in 5 phases::
Phase I: Local irritation of gastrointestinal mucosa, the onset is between 30 min – 6 hr after ingestion and usually subside after 6-12 hours, leading to nausea, vomiting, abdominal pain, hematmesis, bloody diarrhea, and severe hypotension.
Phase II: apparent recovery occur between 2-6 hours, where the iron accumulate in mitochondria, and various organs.
Phase III: cellular damage which occur 12 hours after ingestion, and manifested as hypoglycemia, and metabolic acidosis.
Phase IV: severe hepatic necrosis with increase liver enzyme and prolongation of prothrombin time, it occur 2-4 days after ingestion.
phase V: pyloric stenosis due to scarring and stenosis of pyloric area, it occur 2-4 weeks after ingestion.
Diagnosis:
history,
plain X-ray of abdomen,
free iron in the serum which is the best diagnostic tool, and it is done by estimation of total serum iron and iron binding capacity. If total serum iron > iron binding capacity then free iron exist.
Toxicity is considered if there s 50 mg/kg or more of free iron or the total serum iron > 350 mg/kg.
Vomiting has some correlation with high toxicity.
Treatment:
Induced emesis is of little value, and gastric lavage is not helpful. So we use saline cathartics orally which may be helpful.
Activated charcoal does not adsorb iron and should not be used. Whole bowel irrigation may be of benefit. In sever cases we will do endoscopy or emergency gastrotomy to remove the tablets.
Parenteral desferoxamine is indicated if serum iron concentration > 500 ?g/dL, regardless of symptoms, or moderate to sever symptoms regardless of serum iron concentration. It should be administered as a continuous IV infusion and continued until the patient is symptom-free. Prolonged infusion (> 24 hr), has been associated with pulmonary toxicity and Yesinia sepsis.
When chelating is achieved, reddish colored urine appears. Chelating in renal failure require hemodialysis. Supportive care for hypotension, and other problems associated with phase I, and III.