186 Tox icolog y
SPECIFIC POISONS2 Clinical manifestations (‘cinchonism’) are dose related and include:
(i) Mild: flushed and sweaty skin, tinnitus, blurred vision, confusion,
reversible high-frequency hearing loss, abdominal pain, vertigo,
nausea and vomiting.
(ii) Severe: hypotension, deafness, blindness, anaphylactic shock,
cardiac arrhythmias and cardiac arrest.
3 Gain i.v. access and send blood for FBC, U&Es, LFTs, blood sugar level and
-hCG in females. Attach a cardiac monitor and pulse oximeter to the
patient.
4 Perform an ECG. Look for QRS and QT prolongation and ventricular
arrhythmias.MANAGEMENT
1 Assess and secure the airway and give high-f low oxygen. Commence i.v.
f luid resuscitation for hypotension.
2 Give ora l activated charcoa l to patients presenting wit hin 1 h of overdose.
3 Administer 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 to treat seizures and agitation, and to
reduce the tachycardia.
4 Commence an isoprenaline infusion for torsades de pointes, or arrange for
overdrive cardiac pacing for the QT prolongation, because magnesium is
contraindicated.
5 There are no specific treatment modalities to reverse blindness and deafness
in severe toxicity, other than supportive care.
6 Admit the patient to CCU or ICU.Cocaine
DIAGNOSIS
1 Cocaine hydrochloride is a fine white powder, which may be mixed with
baking soda to make ‘crack’ (free base cocaine) and smoked. It rapidly
reaches the cerebral circulation and has a half-life of 90 min.
2 Complications following cocaine abuse include:
(i) Respiratory: dyspnoea, pneumothorax, pneumonitis and thermal
airway injury.
(ii) Cardiovascular: palpitations, hypertension, aortic dissection,
myocardial ischaemia, arrhythmias and cardiac arrest.
(iii) Nervous system: agitation, altered mental state, syncope, seizures,
focal neurological signs, intracranial haemorrhage and coma.
(iv) Hyperthermia.
3 Base the diagnosis on history and clinical suspicion. Monitor the core
temperature for hyperthermia.