Laboratory Studies
No specific diagnostic studies exist for anticholinergic overdoses. Serum drug concentrations are not helpful and results rarely are available to aid in initial management. However, screening for acetaminophen and salicylate is indicated in all intentional poisonings because combination medication preparations and multiple ingestions often occur. In addition, studies that may be helpful include the following:
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Blood and urine cultures in febrile patients
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Serum chemistry and electrolyte analysis, which may provide clues to the intoxicating agents and co-ingestants
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Creatine kinase (CK) level in patients with psychomotor agitation, to rule out associated rhabdomyolysis
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Electrolyte and arterial blood gas (ABG) analysis when bicarbonate therapy has been instituted for agents that also produce type 1A cardiac conduction disturbances; blood pH should be 7.45-7.55
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Urine pregnancy test on all females of childbearing age.
Imaging Studies
Consider a computed tomography (CT) or magnetic resonance imaging (MRI) scan of the brain in patients with altered mental status that is insufficiently explained by the ingested agent or in patients who are unresponsive to appropriate intervention.
Other Tests
Immediately perform an electrocardiogram (ECG) on all patients with suspected toxic ingestions.
Procedures
Consider lumbar puncture (LP) in patients with fever and altered mental status in whom CNS infection is considered as a possible etiology.
