Concussion, Sports-related

Persistent
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Diagnosis and reasoning

This young girl has presented with continuing symptoms after losing consciousness following a sports-related head injury. At the time of the incident, she was correctly transported to the emergency department, where computed tomography (CT) of the head and neck ruled out acute intracranial pathology and significant cervical spine injury. Two days later she continues to have a headache, visual disturbances, emotional lability, and other symptoms. However, considering the unremarkable neurologic examination, her age, and relatively low force impact, the likelihood of a bleed or skull fracture is low. Thus, the diagnosis is probably a sports-related concussion, or mild traumatic brain injury (GCS > 13), the presentation of which can include physical symptoms (such as headaches, nausea, dizziness), cognitive symptoms (difficulty concentrating, emotional lability) or sleep disturbance, or any combination thereof. Note that in the absence of focal neurologic findings suggesting a mass effect, or evidence of cervical spine injury, exposure to further radiation via a repeat CT scan is not indicated; neither is there any additional benefit in performing an MRI. Similarly, flexion and extension cervical spine radiographs are unnecessary. Minimal subluxation on flexion which corrects on extension is physiological in adolescent females. Various computer-based options for the neuropsychological evaluation of athletes with a suspected concussion exist; however the diagnosis can be made on clinical grounds alone. In particular, note that this patient's photosensitivity makes a computer-based assessment difficult. Thus, she should be restricted from physical activity until asymptomatic, as another concussion during this period could lead to a prolonged recovery, a more catastrophic injury, and even death. She should also be given instructions for cognitive rest, including a few days off school, limitations to electronic media, and mental breaks throughout the day. The Headaches can be treated with over the counter analgesics such as acetaminophen. Note also that convergence insufficiency and accommodative dysfunction are common manifestations of sports-related concussions; they are generally self-limited, and the benefits of early vision therapy have not been established. As there is no cervical spine injury, C-spine bracing is unnecessary. Instead, the patient may benefit from physical therapy to strengthen the cervical musculature.


Discussion

A concussion is defined as a complex pathophysiological process affecting the brain, which is induced by biomechanical forces. This is most often an accompaniment of direct trauma to the head, face, or neck, but can also occur following impacts to elsewhere in the body, if the resultant force is transmitted to the head. Note that the remainder of this monograph pertains to sports-related concussions, of which between 1.6 to 3.8 million are reported annually in the United States. As might be expected, their reported incidence is higher in men; however, in sports played by both genders with comparable rules, the rate is twice as high in women. Affected individuals present with symptoms involving a variety of clinical domains: somatic, cognitive, affective, and sleep-related. These typically occur immediately after the injury, but can develop or worsen within the first 24 to 72 hours following the initial insult. The most common somatic complaint is a headache; others are dizziness, visual disturbances, nausea, photophobia, and tinnitus. Cognitive symptoms include post-traumatic amnesia, confusion, feeling 'foggy' or slowed down, and difficulty concentrating or remembering. Affective symptoms such as anxiety, depression, emotional lability or personality changes may also be reported. Sleep disturbances may vary over the course of recovery, with symptoms such hypersomnia or insomnia seen depending on the area of the brain affected. Note that loss of consciousness is reported in less than 10% of cases. Examination may reveal deficiencies in postural stability, coordination, and oculomotor function. Importantly, the presence of focal neurologic deficits should prompt evaluation for an intracranial lesion. Sports-related concussions are usually diagnosed clinically, with investigations being unnecessary unless there are findings suggestive of a risk for complications, or severe injury. CT neuroimaging is acceptable in patients with loss of consciousness, post-traumatic amnesia, a persistently altered mental status (GCS<15), focal neurologic deficits, evidence of skull fracture or clinical deterioration. Functional MRI (fMRI) is not part of the routine assessment, but may demonstrate patterns that correlate with symptom severity and recovery. Symptom checklists, sideline assessment tools, postural stability tests, and neuropsychological assessments may also be employed. Note that concussions are no longer graded by severity, as the scales used had fundamental differences and could not be scientifically validated. Athletes with a concussion should not be allowed to return to play on the same day, and should be closely observed for deterioration. They should be allowed physical and cognitive rest until asymptomatic without the use of analgesic medication. A graded return to physical activity protocol should be undertaken before re-engaging in competitive sports. Pharmacologic therapy can be employed to manage specific or prolonged symptoms, or to modify the underlying pathophysiology in an attempt to shorten the duration of symptoms. Analgesics for persistent headaches, anxiolytics and selective serotonin reuptake inhibitors for depressive symptoms may be used in this regard. Cognitive restructuring, a form of brief psychological counseling which includes education, reassurance, and reattributing symptoms, may be helpful to reduce the length of subjective complaints and risk of post-concussion syndrome; the latter is a constellation of symptoms from the physical, cognitive, emotional, and sleep domains which persist longer that the expected time to recovery. Athletes with multiple concussions and persistent, subjective neurobehavioral deficits should be recommended for retirement from contact sports. Between 70% to 90% of these patients recover in 7 to 10 days; however, this may be as long as several weeks. Current evidence suggests that an isolated concussion is most likely fully or almost entirely reversible. Chronic neurodegenerative changes have been linked to repeated concussions, but the evidence at the time of writing is not conclusive. Research is underway to determine the true risk and natural history of repetitive mild traumatic brain injury. Second impact syndrome is quite possibly the most devastating complication, consisting of rapid, diffuse cerebral edema that is often fatal, following a repeated head impact while recovering from a prior concussion. All documented cases have been in athletes under 20 years of age.


Take home messages

  1. The diagnosis of a sports-related concussion can often be established clinically, with neuroimaging only indicated in the presence of serious trauma.
  2. Physical and cognitive rest is the key to management, and concussed athletes should not be allowed to return to sport on the same day.
  3. The long term effects are not completely known, but current evidence suggests that with an isolated concussion, full recovery can be expected.

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