188 Tox icolog y

SPECIFIC POISONS

4 Gain i.v. access and send blood for FBC, U&Es, LFTs and a plasma cholineste-

rase level, which is a marker of exposure, but a poor indicator of severity.

5 Perform an ECG to evaluate cardiac arrhythmias.

6 Request a CXR as aspiration pneumonitis is common.

MANAGEMENT

1 Inst r uc t a l l st a f f to wea r a gow n a nd g loves when remov i ng soi led clot h i ng or

washing the skin.

2 Give oxygen, and call an airway-skilled doctor to pass an endotracheal tube

for severe bronchorrhoea and respiratory failure.

3 Commence a normal saline infusion to manage hypotension and replace

losses.

4 Treat seizures with midazolam 0.05–0.1 mg/kg i.v., diazepam 0.1–0.2 mg/kg

i.v. or lorazepam 0.07 mg/kg up to 4 mg i.v.

5 Give atropine 2 mg i.v. repeated until the skin becomes dry, and bronchial

secretions are minimal.

(i) Massive doses (50–100 mg) may be necessary, but do not rely on

pupillary dilatation and tachycardia as indicative end points, as

they may not reflect adequate atropinization.

6 Give pralidoxime 2 g (30 mg/kg) i.v. over 15 min and then 1 g every 8 h for the

next 48 h, in all moderate-to-severe cases (except for carbamate poisoning).

(i) Monitor serial plasma or red cell cholinesterase levels and look

for signs of clinical improvement before ceasing treatment.

7 Admit the patient to ICU.

Paraquat

DIAGNOSIS

1 Paraquat is a highly toxic herbicide. Significant oral ingestion is associated

with fulminant multi-organ failure. If patients survive this, they develop

progressive pulmonary fibrosis, and may die 4–6 weeks later from hypox-

aemia.

2 Clinical effects depend on the route of exposure:

(i) Skin: localized irritation, erythema, blistering, ulceration.

(ii) Eyes: corneal inflammation, oedema, ulceration.

Warning: staff treating patients exposed to organophosphates may

develop mild headache, eye irritation and pulmonary symptoms secondary

to the hydrocarbon solvent and not the organophosphate itself. These

resolve with simple analgesia and by removing the staff from the exposure

source.

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