CT Scan is Absolutely Required
Yes, a CT scan is mandatory for this elderly female on Plavix (clopidogrel) with head injury, regardless of the absence of loss of consciousness or the 12-hour delay since injury. 1, 2
Anticoagulation Supersedes All Other Clinical Decision Rules
Clopidogrel therapy is an absolute indication for head CT imaging that bypasses the need to assess any other clinical criteria. 2 This recommendation comes directly from the American College of Emergency Physicians and supersedes standard clinical decision rules like the Canadian CT Head Rule and New Orleans Criteria, which were specifically designed for non-anticoagulated patients. 2
Why Antiplatelet Therapy Changes Everything
- Patients on antiplatelet agents like clopidogrel have a significantly elevated risk of intracranial hemorrhage (3.9%) compared to non-anticoagulated patients (1.5%). 2
- Dual antiplatelet therapy (aspirin + clopidogrel) increases the relative risk of significant intracranial injury by 2.88-fold. 1
- The critical pitfall to avoid: Do not rely on clinical decision rules designed for non-anticoagulated patients, as anticoagulation fundamentally changes risk stratification and mandates imaging independent of these tools. 2
Age Compounds the Risk
- Age ≥65 years is independently a high-risk criterion for neurosurgical intervention according to the Canadian CT Head Rule. 2
- The American College of Radiology recommends obtaining a noncontrast head CT in elderly patients (≥60-65 years) who sustain head trauma if they have anticoagulant or antiplatelet therapy (excluding aspirin alone). 1
- The combination of anticoagulation and elderly age creates a particularly high-risk scenario that absolutely warrants immediate CT imaging. 2
Loss of Consciousness is NOT Required
Both the Canadian CT Head Rule and New Orleans Criteria use loss of consciousness or amnesia as entry criteria, and neither applies to patients on anticoagulants—meaning these decision rules cannot be used to exclude the need for imaging in this population. 3
The ACR Appropriateness Criteria explicitly state that patients on anticoagulant or antiplatelet therapy require head CT imaging regardless of symptom severity. 1
The 12-Hour Delay Does Not Eliminate Risk
- Delayed intracranial hemorrhage can occur in anticoagulated patients, with one study showing delayed traumatic intracranial hemorrhage occurring up to 5 days post-injury in a patient on warfarin. 3
- Optimal detection of lesions occurs when CT is performed ≥5 hours post-trauma, making the 12-hour timeframe actually within the ideal imaging window. 1
- Patients on anticoagulants have a 3-fold increased risk of hemorrhage progression (26% vs 9%) if initial CT shows intracranial hemorrhage, underscoring the importance of initial imaging. 1
Post-CT Management
If the CT is negative:
- Provide detailed discharge instructions about warning signs requiring immediate return: worsening headache, vomiting, confusion, increased sleepiness, focal deficits, or abnormal behavior. 2
- Important caveat: The evidence supporting safe discharge after negative CT in mild traumatic brain injury specifically excludes patients on anticoagulation therapy, requiring individualized assessment for this population. 4, 2
If the CT shows intracranial hemorrhage: