EMQs in Clinical Medicine.pdf - Peshawar Medical College

234 Miscellaneous
If the salicylate concentration is below 500 mg/l in an adult or 350 mg/l
in a child and there is no acidosis, then observations, fluids and
symptomatic support are usually sufficient.
If salicylate concentration is above 500 mg/l in an adult or 350 mg/l in a
child, alkaline diuresis with intravenous sodium bicarbonate is indicated.
Forced diuresis is no longer used because it can cause cerebral and
pulmonary oedema.
If the overdose is severe (salicylate concentration exceeds 700 mg/l),
haemodialysis is indicated.
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A man says that his depressed partner has taken an overdose. She is
drowsy and hypotensive with signs of respiratory depression. There is
no response to naloxone.
Toxicity is enhanced when benzodiazepines are taken with alcohol or
other drugs.
A 40-year-old depressed man is brought to A&E with dilated pupils,
blurred vision and seizures. On examination he is tachycardic and his
ECG shows wide QRS complexes.
Amitriptyline is a tricyclic antidepressant. Anticholinergic effects are
seen in overdose, e.g. dry mouth, dilated pupils, urinary retention and
tachycardia. The presence of arrhythmias indicates cardiotoxicity but the
use of anti-arrhythmic therapy is often not beneficial. The use of sodium
bicarbonate is indicated to correct any associated acidosis.
A 35-year-old IVDU presents comatose with pin-point pupils and
respiratory depression.
Remember that cocaine, amphetamine and tricyclics dilate the pupil
but heroin constricts it. Heroin overdose is treated with naloxone (a
competitive opioid receptor antagonist).
A 42-year-old man presents with cyanosis and confusion. On
examination he is noted to have the smell of almonds on his breath.
Intravenous dicobalt edetate is the antidote of choice for cyanide poisoning.
Other antidotes include intravenous hydroxycobalamin or combination
treatment with sodium nitrite followed by sodium thiosulphate.
90 Treatment of poisoning and overdose
Answers: F J C H E
F
A 40-year-old drowsy woman is brought to A&E with headache
and vomiting with flushed cherry-pink skin. Carboxyhaemoglobin
(COHb) is 40 per cent.
This is a presentation of severe carbon monoxide poisoning, so
hyperbaric oxygen therapy is indicated.