Mnemonic

Collateral History

A memory aid for when and how to take a collateral history.

Expansion

Essential whenever the patient cannot give a reliable account

Expansion

When it is essential

  • Confusion, delirium or dementia
  • Collapse, seizure or syncope, where the patient cannot describe the event
  • Reduced consciousness, intoxication
  • Children, and patients with communication difficulty
  • Suspected non-accidental injury or safeguarding concerns
  • Psychiatric presentations, particularly regarding risk

What to ask

  • Baseline: what was the patient like a week ago, a month ago, a year ago. This establishes both the premorbid state and the timescale of change
  • Function: activities of daily living, mobility, continence, cognition, who does the shopping and the finances
  • Sequence of events, from a witness
  • Medication, including compliance and recent changes; ask to see the boxes
  • Alcohol and substance use
  • Social circumstances: who lives at home, package of care, next of kin

For a collapse, the witness account is diagnostic: pallor and rapid recovery suggest syncope; tongue biting, incontinence and prolonged post-ictal confusion suggest seizure.

Consent and confidentiality still apply. Where the patient lacks capacity, information can be gathered in their best interests, but disclosure to relatives should still be limited to what is necessary.