Do I need to order a computed tomography (CT) scan after a patient falls?

CT Scan Decision-Making After a Fall

CT scanning after a fall should be guided by specific clinical criteria rather than ordered routinely for all patients, with decisions based on mechanism of injury, patient risk factors, and clinical presentation.

Clinical Decision-Making Framework

High-Risk Patients Requiring CT Head

• Patients with Glasgow Coma Scale (GCS) score <13 1
• Patients with signs of basal skull fracture 2
• Age >65 years 2
• Vomiting >2 episodes 2
• Suspected open skull fracture 2
• Failure to reach GCS of 15 within 2 hours 2
• Amnesia before impact >30 minutes 2
• Dangerous mechanism of injury 2

High-Risk Mechanisms Warranting Whole Body CT

• High-velocity (>35 mph) motor vehicle collision 1
• Motor vehicle collision with rollover or passenger ejection 1
• Motorcycle trauma 1
• Bicycle injury 1
• Pedestrian struck by vehicle 1
• Fall from height >15 feet 1

CT Recommendations by Body Region

Head CT

• Non-contrast CT is the first-line imaging test for acute head trauma when indicated 1
• The Canadian CT Head Rule has 100% sensitivity for predicting need for neurosurgical intervention while requiring only 32% of patients to undergo CT 2, 3
• For elderly patients (>60 years), the threshold for CT head should be lower as they are at higher risk for intracranial hemorrhage even after minor falls 4

Cervical Spine CT

• CT cervical spine without IV contrast is recommended for patients meeting NEXUS or Canadian C-Spine Rule criteria 1
• In obtunded patients with normal CT cervical spine, MRI is not routinely needed 1

Thoracic Imaging

• Chest CT detects significant injuries in 51% of elderly patients after falls from standing height, with rib fractures being the most common finding 4
• Many rib fractures visible on CT are missed on conventional radiographs 4

Abdominal/Pelvic Imaging

• Acute abdominal injuries are relatively rare (16%) in elderly patients after falls from standing height 4
• Contrast-enhanced CT has greater sensitivity for detecting visceral organ and vascular injuries 1

Special Considerations

Elderly Patients

• Lower threshold for imaging is warranted as elderly patients:
  • Have higher risk of significant injury even with minor mechanisms 4
  • May have less obvious clinical signs despite serious injury 4
  • Are more likely to have rib fractures and thoracic injuries after falls 4

Hemodynamically Unstable Patients

• Patients with hemorrhagic shock and unidentified bleeding source require immediate investigation 1
• Initial assessment should include chest and pelvic radiographs with ultrasonography 1
• Patients with significant free intra-abdominal fluid and hemodynamic instability require urgent intervention rather than additional imaging 1

Common Pitfalls to Avoid

• Relying solely on plain radiographs can miss up to 15% of cervical injuries 1
• Assuming minor mechanisms (like falls from standing) cannot cause serious injuries, especially in elderly patients 4
• Overuse of CT scanning in low-risk patients increases radiation exposure and healthcare costs 5
• Delaying imaging in patients with high-risk criteria can lead to missed opportunities for intervention 1

Bottom Line

CT scanning decisions should follow validated clinical decision rules rather than being ordered routinely. For falls, consider the patient's age, mechanism of injury, neurological status, and presence of specific risk factors to guide appropriate imaging selection.