What are the guidelines for ordering a head computed tomography (CT) scan in an elderly patient with a history of dementia and possible bleeding disorders, who has experienced a fall and may be taking anticoagulant medications such as warfarin (coumarin) or aspirin (acetylsalicylic acid)?

Head CT Guidelines After Falls in Elderly Patients

Obtain a noncontrast head CT immediately for any elderly patient (≥65 years) who falls and is taking warfarin or other anticoagulants, regardless of whether they have symptoms, loss of consciousness, or normal neurological examination. 1, 2, 3

Absolute Indications for Head CT (Any ONE of these requires imaging)

High-Risk Clinical Features

• Glasgow Coma Scale (GCS) < 15 at any point after the fall 4, 1, 2
• Focal neurological deficits (weakness, numbness, speech changes, visual disturbances, abnormal reflexes) 4, 1, 2, 5, 6
• Loss of consciousness or post-traumatic amnesia of any duration 4, 1, 2
• Altered mental status or acute confusion beyond baseline dementia 4, 2, 3
• Vomiting (≥2 episodes increases risk significantly) 4, 1, 2
• Severe or persistent headache 4, 1, 2
• Signs of basilar skull fracture (Battle's sign, raccoon eyes, hemotympanum, CSF otorrhea/rhinorrhea) 2
• Post-traumatic seizure 1, 2

Medication-Related High-Risk Factors

• Warfarin (coumarin) therapy - increases relative risk of significant intracranial injury by 1.88-fold and requires CT regardless of symptoms 1, 7
• Novel oral anticoagulants (NOACs) - carry 2.6% hemorrhage risk and warrant imaging despite lower risk than warfarin 1
• Dual antiplatelet therapy (aspirin + clopidogrel) - increases relative risk by 2.88-fold 1
• Clopidogrel monotherapy - requires head CT 1

Physical Examination Findings

• Visible trauma above the clavicles (scalp hematoma, lacerations, contusions) 1, 2
• Palpable facial bone fractures - present in 85.7% of patients with intracranial hemorrhage 8

Age-Specific Considerations

Age ≥65 years alone is a Level B indication to strongly consider head CT when combined with ANY additional risk factor listed above, even with normal neurological examination 1, 2. The Canadian CT Head Rule specifically includes age ≥65 years as a high-risk criterion 2.

When Head CT May Be Deferred

Head CT is not routinely required if ALL of the following are present: 1, 5, 9

• No loss of consciousness or amnesia
• GCS = 15 and stable
• Normal neurological examination (no focal deficits)
• No severe headache or vomiting
• Not taking anticoagulants (warfarin, NOACs, clopidogrel, or dual antiplatelet therapy)
• Aspirin monotherapy alone does NOT require routine CT (relative risk 1.29, not statistically significant) 1
• No visible trauma above clavicles
• No signs of skull fracture

Critical Timing Considerations

Optimal detection of intracranial lesions occurs when CT is performed ≥5 hours post-trauma, but do not delay imaging if any high-risk features are present 1, 5. The 5-hour window allows time for hemorrhagic lesions to become radiographically apparent.

Special Populations Requiring Extra Caution

Patients with Dementia

• Baseline cognitive impairment makes detection of acute mental status changes challenging 4
• Document baseline mental status carefully and compare to current presentation 3
• Any decline from baseline warrants imaging if other risk factors present 4, 3

Patients with Bleeding Disorders

• Coagulopathy of any etiology (inherited or acquired) is an absolute indication for head CT after head trauma 4, 1
• History of previous intracranial hemorrhage increases risk 7.17-fold 5

Hypertensive Patients

• Hypertension is a major independent risk factor for intracranial hemorrhage 3
• Hypertensive emergency with altered mental status requires immediate CT 4

Clinical Decision Rules

The Canadian CT Head Rule is the most specific validated tool and can reduce unnecessary CT scans by 37% while maintaining high sensitivity 2. It recommends CT for:

• GCS <15 at 2 hours post-injury
• Suspected open or depressed skull fracture
• Signs of basilar skull fracture
• Vomiting ≥2 episodes
• Age ≥65 years
• Amnesia >30 minutes before impact
• Dangerous mechanism of injury 2

Follow-Up Imaging

Repeat head CT is indicated if: 4

• Initial CT shows intracranial hemorrhage in anticoagulated patients (3-fold increased risk of hemorrhage progression: 26% vs 9%)
• Patient on anticoagulation develops neurological deterioration even with initially normal CT
• GCS fails to return to 15 within 24 hours despite normal initial CT 4

Common Pitfalls to Avoid

• Do not assume aspirin monotherapy requires routine CT - it does not significantly increase hemorrhage risk unless combined with other antiplatelet agents 1
• Do not rely solely on mechanism - 76% of falls occur from standing height, but falls on stairs (42% abnormal CT rate) or from height (40% abnormal CT rate) carry higher risk 6
• Do not skip CT in anticoagulated patients with "minor" trauma - even without symptoms, these patients require imaging 1, 3
• Do not order CT for delirium workup without specific trauma history or neurological findings - only 4.7% yield acute findings in delirium without focal deficits or GCS <14 10

Discharge Safety

If CT is deferred, ensure: 1

• Reliable caregiver available for close observation
• Clear written and verbal discharge instructions about warning signs (worsening headache, vomiting, confusion, altered consciousness)
• Anticoagulation risk-benefit evaluation scheduled for outpatient follow-up
• Fall risk assessment arranged