A concussion is a traumatic brain injury resulting from a blow to the head or body, causing the brain to move rapidly within the skull. This leads to temporary chemical and metabolic changes that disturb normal brain function. Immediate evaluation is necessary to ensure safety and determine if the person requires emergency care or a formal clinical assessment.
The first step in evaluation is noticing signs that are visible to a bystander immediately following an impact. One of the most recognizable signs is a brief or temporary loss of consciousness, though this is not always present in a diagnosed concussion. An injured person may appear dazed, stunned, or confused about their current location or the recent events leading up to the injury.
A noticeable impairment in communication, such as slurred or incoherent speech, signals a neurological deficit that requires attention. Similarly, a person may have difficulty maintaining balance or coordination, often appearing clumsy or unsteady on their feet. Any observation of these acute signs mandates immediate removal from any activity to prevent further injury.
Red Flags Requiring Emergency Medical Attention
Certain severe symptoms, known as “red flags,” indicate a potential intracranial bleed or serious structural injury, demanding immediate emergency care (911 or the nearest emergency department). A headache that becomes progressively worse is a serious sign of increasing pressure within the skull. Repeated episodes of vomiting or significant nausea are also danger signs.
The appearance of a seizure or convulsions (uncontrolled shaking or twitching) is an automatic trigger for emergency medical services. Inability to wake up, increasing drowsiness, or a significant change in responsiveness also point to a serious complication. Look for new weakness or numbness in the arms or legs, or a noticeable change in pupil size where one pupil appears significantly larger than the other.
Subjective and Delayed Symptoms
Many symptoms of a concussion are subjective, meaning they are experienced internally by the injured person, and others may not manifest until hours or even days after the initial impact. Continuous monitoring is necessary because the full extent of the injury may not be apparent right away. Cognitive symptoms often include a persistent sense of mental fogginess, difficulty concentrating, or problems with short-term memory. The person may report that their thinking feels slowed down or that they are struggling to process information.
Physical symptoms beyond the immediate acute phase can include persistent dizziness or a feeling of lightheadedness. Many people also develop an increased sensitivity to light (photophobia) or noise (phonophobia), which can make being in a normal environment uncomfortable. Emotional changes are also common, presenting as increased irritability, anxiety, or sadness that is uncharacteristic for the individual.
Sleep disturbances frequently follow a concussion and can involve sleeping significantly more or less than usual, or having trouble falling asleep (insomnia). These symptoms reflect the underlying functional disruption in the brain and require a healthcare professional’s guidance for management. Unlike the immediate, observable signs, these delayed symptoms necessitate a formal medical evaluation once they are recognized.
Clinical Assessment and Diagnostic Tools
When a person reaches a healthcare professional, the formal evaluation process begins with a detailed history of the injury and a review of all reported symptoms. Concussion is primarily a clinical diagnosis, meaning it is established based on the presence and persistence of specific symptoms rather than on traditional medical imaging. The clinician will perform a comprehensive neurological examination to assess cognitive function, balance, and coordination.
Specialized tools, such as the Sport Concussion Assessment Tool (SCAT), are often used to standardize the evaluation of memory, concentration, and balance. These tests provide a structured way to measure aspects like immediate recall, attention span, and postural stability, which are frequently impaired after a concussion. The findings from this clinical assessment are crucial for confirming the diagnosis and establishing a baseline against which recovery will be measured.
While a concussion is a functional injury, neuroimaging tools like Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI) are used to rule out more serious structural damage. Imaging is typically performed only if the patient presents with any of the red flag symptoms, such as severe, worsening headache or focal neurological deficits. The primary purpose of these scans is to exclude conditions like skull fractures or intracranial bleeding, which require urgent intervention, rather than to diagnose the concussion itself.