What are the implications of a history of multiple concussions with loss of consciousness (LOC)?

From the Guidelines

A history of multiple concussions with loss of consciousness requires immediate medical evaluation by a neurologist or sports medicine specialist, and these patients should avoid activities that risk further head injury until cleared by a physician. According to the most recent guidelines from the American Heart Association and American Red Cross, published in 2024 1, loss of consciousness is associated with an increased risk of life-threatening brain injury. Treatment typically includes physical and cognitive rest for 24-48 hours after injury, followed by a gradual return to normal activities as symptoms allow. Medications may include acetaminophen for headaches (avoid NSAIDs due to bleeding risk), and in some cases, amitriptyline 10-25mg at bedtime for persistent headaches or sleep disturbances. Patients should monitor for persistent symptoms like headaches, dizziness, memory problems, sensitivity to light or noise, and mood changes. Long-term management involves neuropsychological testing to assess cognitive function and regular follow-ups to monitor for chronic traumatic encephalopathy risk, as suggested by a study published in JCI Insight in 2018 1. Multiple concussions with loss of consciousness are particularly concerning because they indicate more severe brain injury and may lead to cumulative neurological damage, including increased risk of neurodegenerative conditions later in life. Recovery time typically increases with each subsequent concussion.

Some key points to consider in the management of multiple concussions with loss of consciousness include:

• The importance of immediate medical evaluation by a neurologist or sports medicine specialist
• The need for physical and cognitive rest for 24-48 hours after injury
• The gradual return to normal activities as symptoms allow
• The potential use of medications like acetaminophen and amitriptyline for symptom management
• The importance of long-term management, including neuropsychological testing and regular follow-ups to monitor for chronic traumatic encephalopathy risk.

It is also important to note that repeated concussions may lead to long-term difficulties with memory, concentrating, fatigue, headache, and other neurological sequelae, as highlighted in the 2024 American Heart Association and American Red Cross guidelines for first aid 1. Therefore, a thorough and individualized approach to management is necessary to ensure the best possible outcomes for patients with a history of multiple concussions with loss of consciousness.

From the Research

History of Multiple Concussions with Loss of Consciousness

• A history of multiple concussions with loss of consciousness can lead to various symptoms and signs, including headaches, dizziness, fatigue, irritability, anxiety, insomnia, loss of consciousness and memory, and noise sensitivity 2.
• The postconcussion syndrome has been recognized for at least the last few hundred years and has been the subject of intense controversy for more than 100 years 2.
• Studies have shown that approximately half of individuals with a single mild traumatic brain injury (mTBI) demonstrate long-term cognitive impairment 3.
• Advanced imaging techniques, such as diffusion tensor imaging, resting-state functional magnetic resonance imaging, and brain perfusion imaging, can provide insights into concussion-related neuropathology and might be useful for differentiating concussed patients from healthy controls 4.

Risk Factors and Prognosis

• Risk factors for persisting sequelae include age over 40 years; lower educational, intellectual, and socioeconomic level; female gender; alcohol abuse; prior head injury; and multiple trauma 2.
• Persistent symptoms and cognitive deficits are present in a distinct minority of patients for additional months or years 2.
• The majority of concussion symptoms are transient and resolve within 1-2 weeks, but some individuals may experience prolonged recovery 5.
• Understanding the pathophysiology and clinical translation of concussion can move research towards management paradigms that will minimize the risk for prolonged recovery and repeat injury 5.

Diagnostic Challenges

• Concussions are typically "invisible" on diagnostic brain imaging, indicating that the neuropathology associated with concussion lies under the detection threshold of routine imaging 4.
• Neuroimaging, including advanced techniques, can be used to identify concussion-related neuropathology, but its role in clinical practice is still being researched 6, 4.
• The diagnosis of concussion is often based on clinical symptoms, as there are no objective biomarkers or overt pathologic brain changes 5.