Is CT imaging needed for a 69-year-old male on anticoagulant (blood thinner) therapy after an unwitnessed fall with loss of consciousness (LOC)?

From the Guidelines

CT imaging is necessary for a 69-year-old male on anticoagulant therapy after an unwitnessed fall with loss of consciousness to rule out intracranial hemorrhage, given the high risk of bleeding associated with anticoagulant use and the potential for delayed intracranial bleeding. This recommendation is based on the most recent and highest quality study available, which emphasizes the importance of liberal use of neuroimaging in patients on anticoagulants or antiplatelet agents after minor head trauma due to the increased risk of intracranial hemorrhage 1. The study highlights that the risk of spontaneous intracranial hemorrhage in association with anticoagulation is well described, and the threshold for initial imaging after minor head trauma in patients on either anticoagulants or antiplatelet agents is very low because of the consequences of potentially missing an early hemorrhage.

Key factors supporting the need for CT imaging in this case include:

• Advanced age (over 65), which increases the risk of significant intracranial injuries after blunt head trauma
• Use of anticoagulants, which impairs normal clotting mechanisms and can lead to larger hematomas if bleeding occurs
• Loss of consciousness, indicating potential significant head trauma
• The unwitnessed nature of the fall, which adds uncertainty about the mechanism and severity of the injury

The study by Nishijima et al., a Class II study, found that delayed intracranial hemorrhage after a negative initial head CT scan is very rare in patients on warfarin or clopidogrel, and these patients do not warrant admission for observation or immediate reversal of anticoagulation 1. However, given the potential for up to approximately 5% of these patients to develop delayed intracranial hemorrhage, clear discharge instructions with return precautions are warranted.

In terms of management, the CT scan should be performed without contrast as soon as possible, and the patient should be monitored closely for any neurological changes while awaiting imaging and results. Depending on findings, anticoagulation reversal may be necessary if bleeding is detected. The decision to withhold anticoagulant or antiplatelet medication after the injury should be made on a case-by-case basis, weighing the risk of repeat trauma or lack of good social support for home observation against the low incidence of delayed intracranial hemorrhage.

From the Research

CT Imaging for a 69-year-old Male on Anticoagulant Therapy after an Unwitnessed Fall with LOC

• The need for CT imaging in a 69-year-old male on anticoagulant therapy after an unwitnessed fall with loss of consciousness (LOC) is a critical consideration in emergency medicine.
• According to a study published in 2005 2, patients with head injury, normal Glasgow Coma Scale (GCS) scores, and no focal neurologic deficits who are receiving anticoagulants may not necessarily require emergency CT.
• However, another study from 2012 3 suggests that a protocol of 24-hour observation followed by a second CT scan may be necessary to identify delayed intracranial hemorrhage in patients receiving warfarin who experience minor head injury.

Risk of Delayed Intracranial Hemorrhage

• A systematic review and meta-analysis published in 2016 4 found that the pooled estimate of the incidence of intracranial hemorrhage on the second CT scan 24 hours later was 0.60% (95% CI 0-1.2%) in patients with a normal initial CT scan.
• The study suggests that a repeat CT scan in the emergency department 24 hours later may not be necessary if the first CT scan is normal, unless the patient has a serious mechanism of injury, shows signs of neurologic deterioration, or has excessive anticoagulation or receives antiplatelet co-medication.

Relevance of Emergency Head CT Scan

• A retrospective analysis published in 2020 5 found that the systematic indication of an emergency head CT scan for fall in elderly patients presents a low diagnostic and therapeutic yield and is not relevant.
• The study identified male sex, consciousness impairment, focal neurological deficit, past history of post-traumatic brain injury, and time-interval between head trauma and CT as statistically related to the presence of lesions.

Cost-Effectiveness of Repeat Head CT

• A study published in 2021 6 found that routine repeat head computed tomography imaging in patients with a negative scan on admission is not cost-effective, with an estimated total direct cost of $926,247 for negative head CT scans.
• The study suggests that clinically significant delayed intracranial hemorrhage is rare in trauma patients on antithrombotic therapy with an initial negative head CT, and that repeat imaging may not be necessary in the absence of clinical change in neurologic status.