History and exam
Key diagnostic factors
common
presence of risk factors
Key risk factors include depression, history of illicit drug or alcohol use, history of benzodiazepine use, drug administration error, comorbidity, suicidal ideation or behaviour, and history of polydrug or unknown substance ingestion.
Alcohol potentiates the effects of benzodiazepines and increases the toxicity.[24]
Older patients and those with severe liver disease are at risk of toxicity from lower doses of benzodiazepines.[24]
impaired mental status
Impaired attention or memory, especially the loss of anterograde memory. Ask the patient about recent events since exposure, such as who brought them to hospital and how. More subtle signs of impaired mental status include inappropriate behaviour or judgment, and labile mood.
drowsiness, slurred speech, ataxia
Benzodiazepines cause central nervous system inhibition and patients present with features similar to alcohol intoxication.
uncommon
coma
Large doses can cause coma.
respiratory depression
May occur, especially if benzodiazepine is combined with other agents.
Other diagnostic factors
common
decreased deep tendon reflexes
As a central nervous system sedative, benzodiazepine overdose can produce diminished deep tendon reflexes or, less commonly, hyper-reflexia from paradoxical excitation. Either response can contribute to ataxia, and is useful in assessing the central nervous system.
uncommon
nystagmus
Pathological nystagmus is the result of damage to one or more components of the vestibular system, including the semicircular canal, otolith organs, and the vestibulocerebellum. While benzodiazepines do not specifically impair the vestibular apparatus, they may cause diminished function as a result of generalised central nervous system impairment, including the vestibulocochlear nerve.[29]
paradoxical stimulation
Uncommonly, patients who have hyperactive, aggressive, or other psychiatric disorders may be excessively agitated.
hypothermia
Can occur in severe cases.[24]
rhabdomyolysis
Can occur in severe cases.[24]
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