What is the appropriate diagnosis and management for an elderly patient with new onset intermittent paranoia, confusion, visual and olfactory hallucinations, depression, and anxiety, with no prior history of mental illness?

Diagnosis: Delirium Until Proven Otherwise

This presentation represents delirium—a medical emergency—until proven otherwise, and requires immediate systematic evaluation for underlying medical causes rather than primary psychiatric diagnosis. 1, 2

Why This is Delirium, Not Primary Psychosis

The combination of intermittent/fluctuating symptoms, confusion, visual AND olfactory hallucinations, paranoia, and new onset in an elderly patient with no psychiatric history creates a clinical picture that screams delirium 1, 2. Here's the critical distinction:

• Visual hallucinations are the strongest indicator of an underlying medical cause rather than primary psychiatric disorder 3
• Olfactory hallucinations are extremely rare in primary psychosis and should immediately trigger investigation for neurological causes (seizures, tumors, infections)
• The intermittent/fluctuating course with lucid intervals is pathognomonic for delirium, not psychosis 1, 3
• Confusion (altered consciousness) distinguishes delirium from psychosis, where consciousness remains intact 1, 2
• Missing this diagnosis doubles mortality 1, 2

Immediate Diagnostic Workup

Step 1: Rule Out Life-Threatening Causes First

Medication review (bring in all bottles):

• Anticholinergic medications are a leading cause 1
• Over-the-counter combinations of pseudoephedrine, dextromethorphan, and caffeine can cause psychosis and hallucinations, especially in elderly patients 4
• Polypharmacy and drug interactions 1
• Recent medication changes or withdrawals (benzodiazepines, alcohol) 2

Laboratory evaluation:

• Complete blood count with differential (infection, anemia) 1
• Comprehensive metabolic panel (electrolytes, glucose, renal/hepatic function) 1
• Urinalysis and culture (urinary tract infection is the most common precipitating factor in elderly delirium) 1
• Thyroid function tests (endocrine disorders cause secondary psychosis) 1, 2

Vital signs and physical examination:

• Fever, tachycardia, blood pressure abnormalities 1
• Signs of infection (pneumonia is second most common cause after UTI) 1
• Neurological examination for focal deficits 1

Step 2: Neuroimaging Decision

Non-contrast head CT is indicated immediately if: 1

• Patient is on anticoagulation or has coagulopathy
• Any focal neurological signs present
• History of recent falls or head trauma
• Rapid progression of symptoms
• Atypical features suggesting structural lesion

The olfactory hallucinations in this case warrant neuroimaging to rule out temporal lobe pathology, seizures, or mass lesions 1, 2.

Step 3: Consider Additional Causes

Two or more coexisting precipitating causes frequently occur together: 1

• Infection + medication side effects
• Dehydration + electrolyte abnormalities + pain
• Constipation + urinary retention (both common and overlooked) 1

Assess for pain systematically (patients with dementia may not report pain effectively) 1

Screen for nutritional deficiencies (B12, thiamine) that cause neuropsychiatric symptoms 1, 2

When to Refer to Specialist

Immediate specialist consultation is warranted for: 1

• Rapidly progressive symptoms (developing over weeks rather than months)
• Prominent olfactory hallucinations (suggests temporal lobe pathology requiring neurology evaluation)
• Fluctuating course with prominent sensorimotor dysfunction
• Symptoms that persist after treating identified medical causes
• Young-onset (under 65) with atypical features

The combination of visual AND olfactory hallucinations with fluctuating confusion requires dementia subspecialist or neurologist evaluation after acute medical causes are addressed 1.

Management Approach

Treat the underlying cause(s)—this is the definitive treatment: 1

• Discontinue offending medications immediately 4
• Treat infections aggressively
• Correct metabolic abnormalities
• Manage pain adequately
• Ensure hydration and nutrition

Non-pharmacological interventions first: 1

• Reorientation strategies
• Optimize sensory function (glasses, hearing aids)
• Maintain sleep-wake cycle
• Familiar caregivers present
• Reduce environmental stimulation

Pharmacological management only when necessary for safety: 1

• CRITICAL WARNING: Antipsychotics carry a black box warning for increased mortality in elderly patients with dementia-related psychosis (1.6-1.7 times increased death risk) 5
• Cerebrovascular events (stroke, TIA) occur at significantly higher rates in elderly dementia patients treated with risperidone 5
• Use lowest effective dose for shortest duration only if patient is danger to self/others

Critical Pitfalls to Avoid

Never attribute this to "just depression with psychotic features" without complete medical workup 3, 2. Up to 46% of patients presenting with psychiatric symptoms have an underlying causative medical disease 3.

Never dismiss the olfactory hallucinations as "bizarre but benign"—they are diagnostically significant and may indicate serious neurological pathology 3.

Never start antipsychotics before ruling out delirium and medical causes—you may mask the underlying process and expose the patient to serious medication risks 5.

Never assume "anxiety and depression" explain the entire picture—these may be prodromal symptoms of an evolving delirium or neurodegenerative process 1.

Document the fluctuating nature, specific types of hallucinations, and level of consciousness meticulously—this documentation is essential for distinguishing delirium from primary psychosis and guides appropriate management 3.