Presentations
Approach to confusion / altered mental status
The same eight steps, every presentation: threats first, then the history and exam that discriminate, one honest sentence, a mechanism-grouped differential, and the tests read in order.
Immediate threats
- Hypoglycemia: glucose at the bedside, immediately
- Hypoxia and hypercapnia
- Intracranial catastrophe with focal signs
- Meningitis and encephalitis
- Overdose and withdrawal syndromes
History that discriminates
- Collateral history is the exam: baseline cognition, tempo of change, fluctuation
- Medications (especially new, anticholinergic, sedating), alcohol
- Preceding symptoms: fever, dysuria, cough, falls, head strike
Examination
- Vitals with glucose and saturation
- Attention testing (months backwards): the delirium hallmark
- Focal neurology, neck stiffness, asterixis
- The bladder scan and the rectal exam that find the retention and impaction everyone forgot
Problem representation
An acute, fluctuating attention deficit in an 81-year-old with a urinary catheter (delirium physiology) versus progressive months-long memory decline (dementia tempo).
Differential, by mechanism
Metabolic
- Hypoglycemia
- Sodium disorders
- Hypercalcemia
- Uremia
- Liver failure
- CO2 narcosis
Infectious
- UTI and pneumonia (in the vulnerable brain)
- Meningitis/encephalitis
- Sepsis
Structural
- Stroke
- Subdural hematoma
- Tumor
- Seizure and post-ictal states
Toxic
- Medications (opioids, benzodiazepines, anticholinergics)
- Alcohol intoxication and withdrawal
Investigations
- Glucose, gas, electrolytes, calcium, ammonia when cirrhotic
- Cultures and urinalysis with a symptom anchor, not reflexively
- CT head for focality, anticoagulation, or trauma
- LP when meningitis is genuinely on the table
- EEG for the non-convulsing seizure question
Interpretation
- Delirium is a syndrome with a cause list, not a diagnosis to stop at
- The attention test separates delirium from dementia faster than any scan
- In the old, the confused organ is often not the sick one: the brain is the monitor, not the lesion
Next steps
- Treat causes, fix the environment (light, hearing aids, reorientation), avoid new sedatives
- Delirium found means delirium documented and handed over: it changes every subsequent assessment
Connected
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