What is the appropriate workup for a 79-year-old patient with increasing confusion over the last 2-3 weeks, refusing medications, and becoming aggressive, with normal urinalysis (urine analysis) results?

Workup for Increasing Confusion in a 79-Year-Old Patient

In a 79-year-old patient with increasing confusion over 2-3 weeks, medication refusal, and increasing aggression, a comprehensive delirium workup is necessary, focusing on reversible causes of altered mental status before considering pharmacological management.

Initial Assessment

• Address reversible causes of confusion, delirium, and agitation first by exploring the patient's concerns, ensuring effective communication, adequate lighting, and explaining to caregivers how they can help 1
• Evaluate for common precipitating factors of delirium including:
  • Infections (beyond UTI, which has been ruled out)
  • Electrolyte disorders
  • Acute kidney injury
  • Dehydration
  • Constipation
  • Medication side effects or interactions 1

Recommended Diagnostic Workup

• Complete metabolic panel to assess for electrolyte abnormalities, renal function, and liver function 1
• Complete blood count to identify potential underlying malignancy or infection 1
• Medication review to identify potentially inappropriate medications that may cause confusion in older adults 2
• Brain imaging (CT or MRI) should be considered in this case as this is:
  • A first episode of altered mental status with increasing aggression
  • Not responding to initial management
  • Showing focal neurological signs (if present) 1
• Consider toxicology screening if medication misuse or substance use is suspected 1

Special Considerations for Elderly Patients

• Use caution when considering pharmacological management in frail elderly patients due to higher risk of adverse effects 1
• Evaluate for alcohol intoxication or withdrawal, which are common causes of altered mental status in older adults 1
• Consider medication side effects, especially from anticholinergics, sedatives, or other central nervous system depressants 3
• Assess for potential drug-drug interactions that may be contributing to confusion 2

Management Approach

• For agitation management while workup is ongoing:
  • Start with non-pharmacological approaches including verbal de-escalation techniques 4
  • If pharmacological management is necessary, consider lower starting doses appropriate for elderly patients 3
  • For severe agitation requiring medication, consider haloperidol 0.5-1mg orally at night and every 2 hours as needed (maximum 5mg daily in elderly patients) 1
  • Use caution with benzodiazepines as they may worsen confusion in elderly patients 1

Cautions and Pitfalls

• Avoid routine measurement of ammonia levels as they are variable within patients and laboratories and may be elevated in non-hepatic encephalopathy conditions 1
• Use caution when prescribing antipsychotics in elderly patients due to increased risk of orthostatic hypotension, extrapyramidal symptoms, and sedation 3
• Patients with Parkinson's Disease or Lewy Body Dementia can experience increased sensitivity to antipsychotics, manifesting as confusion, postural instability, extrapyramidal symptoms, and features consistent with neuroleptic malignant syndrome 3
• Consider that elderly patients are more likely to have decreased renal function, which may affect medication clearance 3

Follow-up Recommendations

• Reassess mental status regularly after addressing potential reversible causes 1
• If confusion persists despite addressing reversible causes, consider referral to neurology or geriatric psychiatry for further evaluation 1
• Monitor for medication side effects closely, especially when initiating new treatments 2