Emergency Medicine

Tox i c o l o g y 18 5

SPECIFIC POISONS

3 Give 20% mannitol 0.5–1.0 g/kg (2.5–5 mL/kg) for clinical or radiographic
evidence of cerebral oedema.

4 Refer the patient to a hyperbaric oxygen (HBO) unit if the patient was found
unconscious, has significant neurological symptoms, or is pregnant.
(i) Local referral practices will vary, as the efficacy of HBO is
challenged.

Cyanide

DIAGNOSIS

1 Cyanide is a metabolic poison associated with a high mortality.

2 Features of toxicit y include:
(i) Cardiovascular: initial hypertension followed by profound
hypotension, bradycardia, arrhythmias, cardiovascular collapse
and cardiorespiratory arrest.
(ii) CNS: headache, anxiety, sedation, respiratory depression,
seizures and coma.

3 Gain i.v. access and send blood for a serum lactate level and ABG analysis.

4 A raised anion gap metabolic acidosis and raised lactate level relate closely to
clinical signs of intoxication and the serum cyanide level (which is not avail-
able acutely).

MANAGEMENT

1 A s s e s s a nd s e c u re t he a i r w ay i m me d i at e l y. G i ve 10 0 % ox y ge n a nd c om me nc e
f luid resuscitation.

2 Call for immediate senior ED doctor help, and/or advice from a clinical
toxicologist if time allows. Give the following:
(i) Hydroxocobalamin 70 mg/kg up to 5 g i.v. over 30 min or as a
bolus in critical cases. Although unlicensed, it is preferred to
dicobalt edetate.
(ii) Then 25% sodium thiosulphate 12.5 g (50 mL) i.v. at a rate
of 2–5 mL/min. Do not mix in the same infusion as the
hydroxocobalamin.
(iii) Repeat the above within 15 min, if there is no or only partial
improvement.

3 Refer a patient with significant toxicity to ICU.

Chloroquine

DIAGNOSIS

1 Overdose with quinine, chloroquine and hydroxychloroquine is potentially
fatal with as little as 2.5–5 g ingested, and is associated with significant
morbidity.