Why sudden confusion in an older person matters
A change in behaviour over hours or days is delirium until proven otherwise, not dementia getting worse. Delirium is a medical emergency with a cause to find: often an infection, a medicine, dehydration, or urine or stool that is not passing.
What to ask in the history
- How he was before: memory, behaviour, what he could do
- When the change started; does it come and go
- New or changed medicines
- Falls, head injury
- Passing urine, bowels
- Eating and drinking
- Pain
- Fever, cough
- Alcohol
Red flags
- A fall with a head injury, especially on blood thinners
- Fever
- Drowsiness
- Signs on one side of the body
- Not eating or drinking
What to examine
- Observations, glucose
- Hydration
- Bladder (is it full), constipation
- Chest, skin, mouth
- Neurological examination
- A short delirium screening test
First investigations
- Glucose
- Full blood count, CRP
- Sodium, calcium, kidney and liver function
- Urine culture, without relying on a dipstick at his age
- Chest X-ray, ECG
- CT head after a fall or with focal signs or blood thinners
- A review of every medicine
Differential diagnosis of sudden confusion in an older person
Grouped, not ranked. Which one fits this patient is for you to work out in the case.
Causes of delirium
- Infection
- Medicines that act on the brain
- Dehydration
- Low or high sodium, high calcium
- Urinary retention or constipation
- Low oxygen
- Alcohol withdrawal
In the brain
- Subdural haematoma
- Stroke
- Seizure
Not delirium
- Dementia getting worse, only once delirium is excluded
- Depression or psychosis
Common mistakes
- Putting it down to dementia.
- Diagnosing a urine infection from a dipstick.
- Sedating him before looking for the cause.