A 75-year-old man developed delirium after hip surgery, with increased temperature, heart rate, and lethargy. Possible causes of delirium in this post-operative patient include infection, opiate toxicity, electrolyte imbalance, or hypoglycemia. The AEIOU-TIPS mnemonic outlines common medical causes of delirium and associated diagnostic tests to help determine the etiology.

1. Delirium

2. Objectives
• Discuss various causes of delirium
• Review diagnostic tests in the work-up of
delirium

3. Case
• 75 y/o M with DMII, COPD, and obesity is
hospitalized for a hip fracture. Patient was doing
well post-operatively with adequate pain
management and rehabilitation. On POD #3, he
forgets where he is, becomes more lethargic, and
refuses to eat. Patient’s temperature is 38.5, HR
105, RR 12, 90% on 2L NC.
• What are the possible causes of this change in
mental status?

4. Definition of Delirium
• Altered consciousness and cognition with the following
characteristics:
– Poor attention
– Develops over hours to days and fluctuating course during
the day.
– Disturbance is likely from medical condition, substance
intoxication, or medication side effect.
– Unlikely due to preexisting, established, or evolving
dementia.

5. Delirium
• 10-20% of all hospitalized adults
• 30-40% of elderly hospitalized patients
• 60% to 80% of mechanically ventilated
ICU patients
• 50% to 70% of non-ventilated ICU
patients
Delirium in older patients, Francis et al., Journal of the American Geriatrics Society.
1992;40(8):829
Does delirium contribute to poor hospital outcomes? A three-site epidemiologic study.
Inouye SK et al., J Gen Intern Med. 1998;13(4):234.

6. Pointers on Assessment
• ABCs and vitals first! Check GCS.
• Try to obtain collateral information from family or
hospital staff
• Get an understanding of patient’s baseline
mental status
• What were the circumstances around the time
of change in mental status?
• What is the duration of change?
• Has it happened before?
• What does the family think is going on?

7. AEIOU-TIPS mnemonic
Examples Possible Diagnostic Tests
A Alcohol, Ammonia • alcohol intoxication/withdrawal
• elevated ammonia (hepatic
encephalopathy)
• alcohol level
• serum osmolality (toxic
alcohols)
• ammonia
E Electrolytes/
Endocrine
• hypoglycemia
• hypo/hypernatremia
• hypercalcemia
• hypo/hyperthyroidism
• addisonian crisis
• DKA/HHNS
• glucose
• serum osmolality (HHNK)
• serum electrolytes (esp Na, Ca)
• thyroid function tests
• serum cortisol level
I Iatrogenic • steroid psychosis
• anticholinergics in elderly,
• opiates, benzos
• levels of medications
(anticonvulsants, digoxin,
theophylline,etc)
• drug screen (street drugs,
sedatives, narcotics)
O Oxygen, opiates,
obstruction
• pneumonia,
• PE
• carbon monoxide
• opiate narcosis
• oxygen
• ABG
• CXR
U Uremia • BUN

8. AEIOU-TIPS mnemonic
Examples Possible Diagnostic Tests
T Trauma • concussion
• TIA/CVA
• Hematoma
• Head CT/ cervical spine CT
• X-ray of any areas with trauma or deformity
• MRI/MRA if indicated
I Infection • CBC with differential
• Urinalysis and culture (UCG if appropriate)
• Blood cultures and gram stain
• Chest X-ray
• Lumbar puncture (with opening pressure) - CT first if you
suspect increased ICP
P Poisoning • Levels of medications (anticonvulsants, digoxin,
theophylline,etc)
• Drug screen (street drugs, sedatives, narcotics)
• Alcohol level
• Serum osmolality (toxic alcohols)
S Seizures • Check anticonvulsant level
• EEG/ MRI if indicated

9. Case
• Patient could have multiple causes of his
delirium. A few of the possibilities include:
– Infection given patient’s temperature and HR
(common post-op infections such as UTI and PNA)
– Opiate toxicity given RR and O2 sat
– Electrolyte imbalance
– Hypoglycemia is possible if pt is on insulin and has
decreased po intake

10. Summary
• Try to obtain collateral information
• Use mnemonic AEIOU-TIPS to help
determine etiology and useful
diagnostic tests