Concussion is defined as a closed head injury associated with transient alteration in mental status or neurologic function, which may or may not involve loss of consciousness (LOC). In the pediatric population, the etiology of concussion is variable and is influenced by age. Young infants and children commonly suffer concussion after a fall from a height. Older children and adolescents may suffer concussion as a result of sports activity. Child abuse should always be considered in the differential diagnosis of head injury, especially in children younger than 2 years of age who are at risk for both shaken baby syndrome and blunt head trauma.

A complete and detailed history, with emphasis on the mechanism of injury and the presence and duration of LOC, is an important part of the head injury and concussion evaluation. For fall injuries, the height of the fall and the composition of the surface that the head strikes are two major factors in determining the degree of force generated by a fall. The degree of force is an important factor in assessing risk for serious injury. For example, a 4-foot fall onto concrete may generate more force than an 8-foot fall onto wood chips. An inconsistent or implausible history should raise the suspicion of inflicted injury.

The most common immediate symptoms of concussion are confusion and amnesia, although a variety of other neurologic deficits may be seen. These include, but are not limited to, headache, dizziness, vomiting, slowing, poor coordination, LOC, and emotional lability. Following the injury, children may develop postconcussive symptoms (PCS), which may persist for days, weeks, or even months. These symptoms may manifest as somatic complaints, emotional or behavioral changes, or cognitive problems. A thorough history and age-appropriate neurologic exam, with emphasis on mental status, should elicit any evidence of ongoing central nervous system dysfunction. If the exam is normal, the diagnosis of concussion or PCS can be made on the basis of the history. Several tools exist for the assessment of both immediate, on-site symptoms, and PCS, and these are reviewed in the references.