Tox i c o l o g y 18 9
Chemical Burns
(iii) Systemic from oral ingestion:
(a) <15 mL of 20% solution: nausea, vomiting and diarrhoea
with reversible pulmonary irritation
(b) >15 mL of 20% solution: pharyngeal ulceration,
hypersalivation, intractable vomiting, haematemesis, severe
abdominal pain and bowel perforation.
3 Gain i.v. access and send blood for FBC, U&Es, LFT, coagulation profile and
blood sugar level. Request a serum paraquat level.
(i) A serum level of >5 mg/L is invariably fatal.
4 A qualitative urine test may be performed by adding 1 mL of 1% sodium
dithionite solution to 10 mL of urine. Paraquat ingestion is confirmed if the
urine turns blue.
5 Perform an ECG.
6 Request a CXR to look for evidence of mediastinitis, aspiration, pulmonary
opacities and abdominal viscus perforation.
MANAGEMENT
1 Early gastrointestinal decontamination is paramount. Give activated
charcoal 50–100 g immediately orally or via a nasogastric tube.
(i) The traditional alternative adsorbing agent 15% aqueous suspension
Fuller’s earth (bentonite) 1000 mL is rarely available now.
2 Administer oxygen only if the SaO 2 is <90%, as otherwise oxygen enhances
pulmonary toxicity.
3 Refer the patient immediately for admission to ICU.
CHEMICAL BURNS
DIAGNOSIS
1 These occur at home, in schools, in laboratories and in industrial accidents.
2 Most agents are strong acids or alkalis, although occasionally phosphorus
and phenol are responsible.
3 Alkali burns are generally more serious than acid as they penetrate deeper.
MANAGEMENT
1 Wear gloves to remove any contaminated clothing. Treat by copious irriga-
tion with running water. Continue irrigating for at least 30 min.
2 Do not attempt to neutralize the chemical, as many resultant reactions produce
heat and will exacerbate the injury, except in the case of hydrof luoric acid.