Traumatic brain injury in older adults

Clinical question

What can I implement in my practice to help me identify and manage the effects of traumatic brain injury (TBI) in older adult patients?

Bottom line

The definition of TBI continues to evolve but can be understood as neuropathic damage and dysfunction of the brain resulting from a direct or indirect force transmitted to the head or body.¹ Traumatic brain injury is a clinical diagnosis based on symptoms, signs, the temporal relation between the timing of the trauma and the presenting symptoms, and the findings of diagnostic imaging when indicated. Symptoms of TBI are physical, cognitive, behavioural, and affective. When assessing an older person for TBI, one must also ask why the trauma occurred in the first place.

Evidence

• Falls are the number one cause of TBI in the elderly. Approximately 50% of people over the age of 65 will experience at least 1 fall-related injury annually, and up to 60% of falls in the elderly result in TBI.²

• Falls assessment and prevention can help reduce the risk of falls and TBI.³

• Traumatic brain injury is not only an acute event; TBI also has implications for long-term risk of dementia. A single episode of moderate to severe TBI can lead to earlier onset of dementia due to Alzheimer disease by 2 to 8 years,⁴ increase the risk of Parkinson disease, and hasten the onset of frontotemporal dementia.⁵ Evidence suggests mild TBI can also increase dementia risk.⁶

Approach

Injuries to the brain have primary and secondary components. Primary injury is the direct result from mechanical force applied to the brain and can include axonal injury, contusion, or hemorrhage. Secondary injuries develop over time at the cellular level; these include electrolyte imbalance, mitochondrial dysfunction, neuroinflammation, hypoxia-ischemia, apoptosis, and hypometabolism. These in turn result in cerebral edema, raised intracranial pressure, and axonal swelling.⁷ These processes can be categorized further as focal, if affecting localized areas of the brain, or diffuse, if affecting multiple areas.

Patients may not report striking their head with a fall due to amnesia caused by the event; clinicians should have a degree of suspicion for possible concussion or brain injury. Traumatic brain injury can be graded using the Glasgow Coma Scale, with scores of 13 to 15, 9 to 12, and 8 or less indicating, respectively, mild, moderate, and severe injury. It is relatively easy to diagnose moderate to severe TBI with clear physical or imaging evidence of brain trauma accompanied by symptoms or an impaired level of consciousness. Recognizing and diagnosing mild TBI can be more challenging.¹ Box 1 provides a summary of TBI symptoms.¹

While mild TBI does not require imaging in every case, the Canadian CT/Head Injury Trauma Rule suggests that for those 65 and older with a minor head injury, a computed tomography scan could be indicated.⁸ If there are neurologic deficits or a change in level of consciousness, imaging should be done. A computed tomography scan of the head is the most commonly used imaging method; magnetic resonance imaging is more sensitive at picking up changes associated with TBI but is not always accessible. Magnetic resonance imaging can show small contusions, petechial hemorrhages, axonal injury, and small extra-axial hematomas in mild TBI.¹

It is important to take a full history (including collateral history) following any head trauma to identify evolving neurologic emergencies, such as intracranial hemorrhages and hematomas. Once the patient is past the urgent phase of care, emphasis should be placed on recognizing and managing neurologic sequelae such as seizures and mood disorders, and decreasing risks for future TBI. For mild TBI or concussion, clinicians should recommend physical and cognitive rest for a maximum of 1 or 2 days following injury to promote recovery.

Cognitive screening and assessment should be part of management, since we know that symptoms of TBI can evolve with time and both mild TBI and moderate to severe TBI are risk factors for dementia. Neuropsychological testing is the criterion standard for assessing baseline cognition once TBI has stabilized. However, it is time consuming and costly, and access to psychology services is limited. Other shorter standardized tests in the acute phase are available, but their main purpose is to assess if the patient is still in a confused state. The Montreal Cognitive Assessment is a reasonable test⁹ to use for cognition screening and is familiar to most family physicians.

Implementation

Box 1 summarizes symptoms to assess for when seeing patients after a recent fall or head injury.¹ As noted, patients might not report a head injury, but the presence of symptoms or evidence of a head injury, such as bruising or laceration, might highlight a TBI. Patients might lack insight into their injuries due to the brain injury or pre-existing cognitive changes, or might choose not to seek medical attention because their symptoms are mild and transient.

The symptoms of TBI vary among patients because injuries to different parts of the brain create different effects. For example, focal injury to the frontal lobe might lead to disinhibition, labile mood, and executive impairments (eg, difficulties with attention, information-processing speed, and even awareness), whereas injury to the parietal lobe might lead to disturbed visuospatial perception. It is important to recognize common post-TBI syndromes, such as postconcussion syndrome (part of the mild TBI spectrum), and deficits seen with moderate to severe TBI (eg, executive dysfunction syndrome, epilepsy, neurologic impairments such as hemiparesis or ataxia).

Fall prevention strategies focus on looking for reversible conditions such as orthostatic hypotension (https://www.posturalhypotension.com), medications, and environmental factors. For falls resources, see the Canadian Fall Prevention Curriculum website (https://canadianfallprevention.ca). Lin and Marshall provide detailed information on TBI in older adults in a 2018 Canadian Geriatric Society Journal of CME article.¹⁰