Differentials
Non-cocaine sympathomimetic overdose
SIGNS / SYMPTOMS
Difficult to distinguish clinically from cocaine poisoning, but the management is similar.
The onset of effects is slower and the duration of action longer, especially when ingested orally.
Dysrhythmias due to sodium channel effects do not occur.[14]
INVESTIGATIONS
Cocaine urine assay is negative.
Urine immunoassay may identify the presence of phencyclidine or amfetamines.
Gas chromatography-mass spectrometry can identify many individual sympathomimetics.
Alcohol, sedative or hypnotic withdrawal
SIGNS / SYMPTOMS
Social history may elicit the diagnosis.
Alcohol withdrawal becomes more severe as time passes, whereas patients with cocaine toxicity improve as drug is metabolised.
Anticholinergic syndrome
SIGNS / SYMPTOMS
Anticholinergic toxicity can present with tachycardia, hyperthermia, mydriasis, and agitation.
Skin is dry, not diaphoretic; bowel sounds are decreased or absent; and urinary retention is present.
Treatment is similar to that of cocaine toxicity.
INVESTIGATIONS
Urine drug screen will detect the anticholinergic drug.
Thyroid storm
SIGNS / SYMPTOMS
A history of hyperthyroidism suggests the diagnosis.
The onset of symptoms is much more insidious and the duration is much longer.
Hypertension is less frequently seen.
INVESTIGATIONS
Thyroid studies suggest the diagnosis (elevated triiodothyronine, thyroxine, free thyroxine, decreased thyroid-stimulating hormone).
Phaeochromocytoma
SIGNS / SYMPTOMS
Extremely rare.
Usually associated with history of hypertension and attacks are usually accompanied by a headache.
Symptoms are longer lasting and recurrent.
INVESTIGATIONS
Fractionated plasma metanephrine is 97% sensitive and 85% specific for phaeochromocytoma.[35]
Infection
SIGNS / SYMPTOMS
History of exposure to cocaine is absent and a history of infection is usually present.
INVESTIGATIONS
Symptoms respond to empiric treatment of the infection (e.g., antibiotics).
Chest x-ray, urinalysis, or lumbar puncture may reveal the source and cause of the infection.
Hypoglycaemia
SIGNS / SYMPTOMS
Cannot be clinically distinguished from cocaine toxicity as autonomic (adrenergic) features overlap.
INVESTIGATIONS
Bedside serum glucose is diagnostic.
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