Differentials
Viral infection
SIGNS / SYMPTOMS
Determine from the history whether the nausea, vomiting, diarrhoea may be due to a viral infection such as influenza or food poisoning.
INVESTIGATIONS
Stool testing, if clinically indicated, may help in diagnosis.
Alcohol intoxication
SIGNS / SYMPTOMS
Concurrent carbon monoxide exposure in intoxicated patients cannot be excluded.
INVESTIGATIONS
Blood ethanol level.
Migraine
SIGNS / SYMPTOMS
Determine from the history and examination whether the headache is associated with photophobia, phonophobia, aura, activity, and/or certain triggers.[38] There may be a personal or family history of migraine.
INVESTIGATIONS
Normal blood tests and imaging.
Sedative hypnotic overdose
SIGNS / SYMPTOMS
Concurrent carbon monoxide exposure in intoxicated patients cannot be excluded.
INVESTIGATIONS
Urine toxicological screen specific for the agent. However, this should be interpreted with caution as urine toxicology screens only document a recent exposure and not necessarily toxicity; these tests are often only qualitative and may lead to erroneous assumptions of causation.
Cyanide and hydrogen sulfide poisoning
SIGNS / SYMPTOMS
Rapid onset of symptoms and progression to fatal events is a clinical clue.[39]
INVESTIGATIONS
Increased levels of serum cyanide and erythrocyte cyanide. Laboratory analysis is non-specific for hydrogen sulfide.
Toluene poisoning
SIGNS / SYMPTOMS
Solvent and aromatic odours, paint on hands and face are clinical clues.[39] Diagnosis of toluene poisoning is a clinical one.
INVESTIGATIONS
Electrolytes should be measured for associated derangements.
Central nervous system infection
SIGNS / SYMPTOMS
History and examination may show features such as neck stiffness, fever, and headache.
INVESTIGATIONS
Abnormalities of cerebral spinal fluid and positive blood cultures. Elevated inflammatory markers.
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