Repeat CT Protocol for Epidural Hematoma
For patients with epidural hematoma (EDH), obtain repeat CT at 6-8 hours after initial imaging if managed conservatively, with all repeat imaging completed within 24-36 hours of injury, as EDH expansion occurs in 23-28% of cases and virtually never occurs beyond 36 hours. 1, 2
Initial Risk Stratification
When an EDH is first identified, the following imaging and clinical features determine immediate surgical versus conservative management:
High-Risk Features Requiring Immediate Surgery
- Initial EDH diameter >1.5 cm (mean diameter requiring surgery is significantly larger than those managed conservatively at 1.26 cm) 3
- Midline shift present on initial CT 1, 3
- Arterial bleeding source identified (particularly skull fracture crossing meningeal artery, vein, or major sinus) 1, 4
- Mixed attenuation or lucent areas within the hematoma (suggesting active bleeding) 1, 3
- Spot sign present on initial imaging 1
- Any clinical neurologic dysfunction (decreased GCS, pupillary dilation, hemiparesis) even with small EDH 3
Additional Risk Factors for EDH Expansion
- Concurrent subarachnoid hemorrhage (SAH) is the strongest predictor of EDH enlargement (OR = 2.60) and mandates close monitoring 1
- CT performed within 6 hours of trauma carries 43% risk of subsequent deterioration versus 13% when diagnosis is delayed beyond 6 hours 4
- Skull fracture overlying major vessel or sinus increases deterioration risk to 55% 4
- Combined risk factors (fracture over vessel + early CT) increase surgical need to 71% 4
Conservative Management Protocol
For patients without immediate surgical indications:
Timing of Repeat CT Imaging
- First repeat CT at 6-8 hours after initial scan (mean time to EDH enlargement is 5.3 hours after initial CT and 8 hours after injury) 1, 2
- Second repeat CT at 24 hours if first repeat is stable 5, 6
- All repeat imaging must occur within 36 hours of injury, as EDH enlargement beyond this timeframe is extremely rare (0%) 2
Special Populations Requiring Modified Protocol
Anticoagulated Patients:
- Obtain repeat CT regardless of clinical stability due to 3-fold increased risk of hemorrhage progression (26% vs 9%) 6, 7
- Maintain 24-hour observation period even with negative progression on repeat imaging 6, 8
- Consider anticoagulation reversal (andexanet alfa for apixaban, PCC for warfarin) if any hemorrhage detected 6
Patients with Concurrent SAH:
- Implement more aggressive repeat imaging schedule due to 2.6-fold increased risk of EDH expansion 1
- Consider repeat CT at 4-6 hours rather than 6-8 hours 1
Indications for Immediate Repeat CT (Outside Scheduled Protocol)
Obtain stat repeat CT for any of the following, regardless of time since last scan:
- Any neurological deterioration (decreased GCS, new focal deficit, pupillary changes) 5, 6, 9
- Persistent abnormal neurologic exam after 24 hours despite initially stable imaging 6, 7
- New or worsening headache, vomiting, or altered mental status 6, 9
Discontinuation of Repeat Imaging
Stop serial CT imaging when:
- 36 hours post-injury reached with stable examinations and no EDH enlargement 2
- Patient maintains GCS 15 with no focal deficits and stable repeat CT at 24 hours 6, 3
Common Pitfalls to Avoid
- Delaying initial repeat CT beyond 8 hours in conservatively managed EDH, as mean enlargement occurs at 5.3 hours after initial CT 1, 2
- Discharging patients before 36-hour window without documented stable repeat imaging, as delayed EDH can occur up to 10 days post-injury in rare cases 9
- Failing to obtain repeat imaging in anticoagulated patients even with excellent clinical exam, given their 3-fold hemorrhage progression risk 6, 7
- Missing concurrent SAH on initial CT, which doubles the risk of EDH expansion and requires more aggressive monitoring 1
- Underestimating risk in patients with early CT (<6 hours post-injury) and skull fracture over vascular structures, who have 71% chance of requiring surgery 4