The postconcussion syndrome (PCS) is a common sequelae of traumatic brain injury (TBI), and it is a symptom complex that includes headache, dizziness, neuropsychiatric symptoms, and cognitive impairment . PCS is most often described in the setting of mild TBI, but it may also occur after moderate and severe TBI, and similar symptoms are described after whiplash injuries as well . Loss of consciousness does not have to occur for PCS to develop.
PCS is controversial, especially in its protracted form . The symptoms are vague, subjective, and common in the general population. The affected patient population is heterogeneous with varying degrees of injury to the head and brain. Individual patient characteristics may alter the expression of the injury. The underlying pathophysiology is undefined. Test results may or may not be abnormal; when present, test abnormalities do not follow a consistently defined pattern.
Mild TBI results after blunt force, nonpenetrating head trauma, and it is most often defined as mild by a Glasgow Coma Scale (GCS) score of 13 to 15, 30 minutes after head injury (table 1). Concussion is a subset of mild TBI, and it is a trauma-induced alteration in mental status that may or may not involve loss of consciousness . This topic will discuss the pathophysiology, clinical features, diagnosis, and management of PCS. The acute presentation and management and other sequelae of concussion and mild TBI are discussed separately. (See "Concussion and mild traumatic brain injury" and "Minor head trauma in infants and children".)
Thirty to 80 percent of patients with mild to moderate brain injury will experience some symptoms of postconcussion syndrome (PCS). This wide range of reported incidence reflects variabilities in the patient population studied and the criteria by which a diagnosis of PCS is made, either using individual symptoms or defined clinical criteria. Two clinical criteria, the International Classification of Diseases, ICD-10 and the DSM-IV, are commonly used and give widely different results, even within the same patient population .
A number of studies have tried to associate the severity of brain injury with PCS among patients with mild traumatic brain injury (TBI) using a variety of measures including the Glasgow Coma Scale (GCS) (table 1), the duration of loss of consciousness or post-traumatic amnesia, and the presence or extent of visualized abnormalities on CT or MRI [2,5-8]. Overall, the severity of injury does not clearly correlate with the risk of PCS. However, at least one study suggests that a history of prior concussion, particularly if recent or multiple, is a risk factor for prolonged symptoms after concussion .