Duration and Course of Post-Concussive Symptoms

Discussion

To our knowledge, this is the first report to describe the precise duration of individual symptoms after pediatric concussion. Previous studies have demonstrated that post-concussive symptoms can be broadly categorized into physical, emotional, and cognitive clusters, with a high degree of overlap between them,^19–22 but neither the incidence of these symptoms nor their relative burden throughout the recovery period have been well described in children.^23,24 Here we show that although the majority of children initially present to care after a concussion with symptoms of headache, dizziness, and fatigue, new symptoms often develop during the recovery course, particularly those that have a substantial emotional component. Whether this secondary symptom development is attributable to the underlying pathophysiology of mTBI or the psychosocial consequences of the concussion and the restrictions placed on children during their recovery is not known. Understanding the recovery course for children after concussion is important for caregivers and families who will be managing symptoms, as well as for academic and athletic accommodations.

For the majority of patients in our study, symptoms resolved within 2 weeks of the injury. During that recovery period, however, patients experienced a large symptom burden and significant impact on subjective functioning. One week after the injury, more than two-thirds of the patients still had a headache; a majority complained of poor concentration, dizziness, fatigue, and taking longer to think; and >40% struggled with forgetfulness, light sensitivity, and noise sensitivity. Few patients had returned to full cognitive activity or sports participation 1 week after the injury, although we cannot say whether these limitations were attributable to symptoms or to clinician advice to rest. Taken together, these findings show that although concussion symptoms often resolve quickly, they can be debilitating in the short term for many patients.

Our study adds to previous investigations that have demonstrated that headache is the most commonly reported post-concussive symptom,^{5,6,8,25–28} present in 85.1% of children in our cohort on presentation to the ED and in 88.9% of patients at any point during the follow-up period. We found that the median duration of headache was 13 days, with 5.3% still having headache at 3 months, notably less than the 43% reported by Blume and colleagues in a previous pediatric mTBI cohort.⁸ We believe differing survey methodology explains these discrepant findings, as participants in Dr Blume’s study were asked to rate their pain on a scale of 0 to 10, with any score ≥1 considered positive for presence of headache. In our study, on the other hand, we considered a patient to have ongoing headache only if they indicated that their pain was greater than their pre-injury baseline on the RPSQ.

After headache, fatigue was the second most common presenting symptom in our study, reported by 64.2% of patients on initial evaluation. Notably, an additional 15.4% of children who did not initially report fatigue subsequently developed this symptom. A substantial number of children (21.6%) also developed sleep disturbance after their initial evaluation. This finding suggests that children who have a concussion should be warned about the possibility of developing fatigue and sleep issues, and these symptoms should be specifically assessed during follow-up evaluation. Moreover, despite being characterized as somatic symptoms, both sleep issues and fatigue may have a significant emotional component, so careful attention should be paid to coincident emotional symptoms in children who have these complaints.²¹

The emotional symptoms of concussion (frustration, depression, irritability, and restlessness) were not commonly reported on presentation, but did develop in large numbers of patients during follow-up and were among the symptoms that lasted the longest. An exception to this was depression, which developed in only 8.6% of patients who did not report it initially. It is unclear whether this reflects the fact that depression itself did not develop as frequently as other complaints, or that patients were reticent to endorse depression owing to the stigma associated with this symptom. Pediatricians and specialists in concussion care should continue to carefully evaluate patients for the emotional symptoms of concussions attributable to both the physical injury and the psychosocial sequelae that often follow these head injuries.

Cognitive symptoms were particularly burdensome in our cohort, as they were present in substantial percentages initially, still went on to develop in many additional patients, and had greater than average duration of symptoms, with the exception of forgetfulness, which resolved on average within 11 days. These findings support the importance of academic accommodations for children after concussion.

Allowing for overlap between domains and some notable exceptions outlined above, our study shows that the physical symptoms of concussion present early and resolve early after the injury, emotional symptoms develop later than the other domains, and cognitive symptoms impair many patients both immediately after their head trauma and long into the recovery period. Understanding this expected progression of symptoms has several potential benefits. For patients, it may help to normalize the experience of recovery from concussion, preventing the additional stress that comes from worrying that symptoms are unusual or excessive. For families and school personnel, this knowledge may help them better prepare the home and school environment for expected obstacles to recovery and return to normal academic and athletic participation. For health care providers, it may help reduce unnecessary testing and referrals owing to concern that a patient’s course is atypical, better target post-concussive evaluations to expected symptoms, and better inform the anticipatory guidance given to patients and their families.

There are several limitations to our study. We did not include a control group, so we cannot conclude with certainty that the symptoms experienced by patients in our cohort are attributable to the head injury and not part of the recovery from injury in general, the psychosocial consequences of illness, or malingering. A wide body of literature, however, has established that post-concussive symptoms are more frequent in mTBI patients than in other injured patients, and that post-concussion syndrome should be recognized as a unique and valid diagnosis apart from other forms of recovery from trauma.^7,29–31

An additional limitation is that we studied only self-reported symptoms, and patient reports may have been influenced by a desire to either expedite or, conversely, avoid return to school or sports. Furthermore, although we surveyed patients frequently during the study period, our primary focus was on pinpointing the date on which all symptoms resolved, not individual symptoms. As a result, we defined the duration of a symptom as the time from which a patient first reported the symptom until the time that the patient first reported that the symptom was no longer present. This number may have been shorter or longer than the actual symptom duration, depending on the timing of the questionnaire being filled out. However, because we surveyed patients frequently during the follow-up period, we believe these estimates are likely to more closely approximate symptom duration than a single follow-up questionnaire administered at 1 given time point after the injury. Another limitation may come from the small number of patients who were enrolled after their ED visit, and whose initial questionnaire may therefore reflect the symptoms present in the hours to days after the initial injury, rather than those present at the time of their ED evaluation. Given the small number of patients in this category and the short time window in which they were required to fill out the questionnaire after the head injury, we think this effect is likely to be small.

There were differences between our study population and the group that was lost to follow-up in terms of race, ethnicity, and presence of attention-deficit/hyperactivity disorder, although there were no differences in other factors that have been shown to influence concussion outcome, such as age, gender, loss of consciousness, previous concussion, or initial symptom burden. Finally, our study population consisted of children and adolescents referred to a tertiary care pediatric ED. This group likely represents a more severely injured subset of concussion patients than those who are treated on the field, in an outpatient clinic, or in a community ED, as patients may be treated initially in these latter settings and then be referred to a pediatric ED owing to severity of symptoms or need for imaging, subspecialty consultation, or admission. As a result, these results may not be generalizable to all children and adolescents after a concussion.

Despite these limitations, our study had several strengths, including a large sample size and prospective methodology. We enrolled a high percentage of eligible patients and a majority of patients continued participation until symptom resolution. Finally, unlike previous studies that focused on particular subgroups of patients, such as participants in a particular sport, our study examined all eligible patients who presented to a tertiary care ED.