Concussions

I. What every physician needs to know.

Concussion is a form of brain injury that may result from a direct blow or from rapid rotation, acceleration and/or deceleration of the brain inside the skull. Concussions differ from other forms of traumatic brain injury in that there is no apparent structural damage to the brain parenchyma, no intracranial hemorrhage, and no skull fracture but there is an alteration of the cellular processes in the brain. These perturbations of cellular function cause the concussive phenomenon.

Concussion can occur without direct impact or loss of consciousness, and can result in physical, cognitive or emotional symptoms that are evident immediately or evolve over hours, days or weeks. There are no studies of concussion in hospitalized patients, so recommendations for concussion evaluation and management are typically adopted from the sports literature.

The 5th International Conference on Concussion in Sport, held in Berlin in 2016, offers a revised consensus statement on concussion in sport, which may help in evaluation of both outpatients and inpatients. In it, concussion is defined as a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces.

Several common features that incorporate clinical, pathologic, and biomechanical injury constructs that may be utilized in defining the nature of a concussive head injury.

Concussion may be caused by either a direct blow to the head, face, or neck or a blow elsewhere on the body with an impulsive force transmitted to the head.
Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously. However, in some cases, signs and symptoms evolve over a number of minutes to hours.
Concussion may result in neuropathological changes, but the acute clinical symptoms largely reflect a functional disturbance rather than structural injury. As such, no abnormality is seen on standard structural neuroimaging studies.
Concussion results in a graded set of clinical syndromes that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course. In a small percentage of cases, however, post-concussive symptoms may be prolonged.
The clinical signs and symptoms cannot be explained by drug, alcohol, or medication use. Other injuries (such as cervical injuries, peripheral vestibular dysfunction, etc.) or other comorbidities (psychological factors or coexisting medical conditions, etc).

Postulated causes for the mechanism of concussion include microscopic axonal injury leading to impaired axonal transport and edema, release of neurotransmitters (acetylcholine, glutamate, aspartate) and cytotoxic edema of white matter tracts.

Grading systems for concussion are no longer utilized for prognosis or decisions regarding return to play. Instead focus should be centered upon identifying a possible concussion as soon as possible. The phases of concussion identification should include the following: removal from physical activity, re-evaluation of neurologic exam, rest, rehabilitation, referral to a specialist if symptoms persist, and gradual return to physical activity. As the patient’s symptoms resolve, they should begin a structured and gradual increase in physical activity. Return to full activity should be permitted once they are asymptomatic.

Second impact syndrome results from acute and sometimes fatal cerebral edema that can occur when a patient sustains a repeated concussion before complete recovery from a previous concussion. This may be due to vascular congestion and increased intracranial pressure, which can occur very rapidly. Similar to risk of concussion in sport, the risk of second-impact syndrome is higher in impact sport.

A concussion can be complicated by a brain contusion that can be associated with localized ischemia, edema, and development of intracranial hemorrhage. Signs of a cortical contusion vary depending on size, number, and location and may delay recovery from concussion.

Concurrent research in adult concussion indicates metabolic and cognitive processes return to a pre-concussed state after 7-10 days in the majority of concussed individuals. Approximately 10% of patients have persistent symptoms of concussion that comprise the post-concussion syndrome.

The Diagnostic and Statistical Manual of Mental Disorders (DSM V) now labels this as mild neurocognitive dysfunction from mild TBI. It states that the neurocognitive disorder must present immediately after the occurrence of the TBI or immediately after recovery of consciousness and persist past the acute post-injury period. It includes cognitive deficits in attention or memory and additional symptoms such as fatigue, insomnia, headache, dizziness, tinnitus, vertigo, irritability, mood disturbance, apathy, or personality changes. These symptoms typically resolve within 3 months after a concussion but can persist in older patients and those with a history of multiple concussions. Prolonged symptoms and worsening symptoms are difficult to distinguish from other diagnoses such as major depression disorder.

II. Diagnostic Confirmation: Are you sure your patient has concussion?

Concussion is a clinical diagnosis that relies on a history of injury reported by a patient or a witness of an event, and the presence of post-injury physical examination findings and symptoms listed below.

Assessment may be complicated in a patient with dementia, psychiatric disease, physical disabilities or altered mental state at baseline.

Worsening of symptoms or recurrence after resolution can signal a more severe TBI than originally suspected and should prompt more thorough evaluation in a formal medical setting. Computed tomography (CT) and magnetic resonance imaging (MRI) neuroimaging is normal in most concussions, though is indicated in patients suspected of having an intracranial hemorrhage, focal neurological deficits, associated seizure, or prolonged loss of consciousness (see imaging studies in the diagnostic evaluation below).

A. History Part I: Pattern Recognition:

A patient with suspected concussion typically has a history of a trauma or impact that may result in rapid acceleration and deceleration of the patient or head of the patient, such as motor vehicular accident, fall, occupational or recreation accident, sports related injury, or battery. Any of these events followed by a witnessed loss or change in consciousness, seizure, or onset of symptoms described below, should raise suspicion for concussion or another type of brain injury. The majority of concussions are not accompanied by loss of consciousness but often result in self-reported symptoms that may be missed unless specifically evaluated. Concussion should also be suspected in any patient with face, head, or neck injury.

A patient with an acute concussion may report symptoms of headache, neck pain, dizziness, nausea, vomiting, confusion, anterograde or retrograde amnesia, blurred vision, tinnitus, and sensitivity to noise and light. Though many of these symptoms can be transient, headache can persist for hours to months depending on the severity of injury. Over the course of hours or days, the patient may develop additional symptoms. These typically include ongoing memory disturbances, decreased concentration, increased emotionality, sleep disturbances including both insomnia and hypersomnia, mood changes, personality changes, disinhibition, and fatigue. Patients may also report feeling in a fog or slowed down.

For most concussed individuals, symptoms improve or resolve within 7-10 days. Symptoms may worsen or recur after resolution with increased physical exertion, or cognitive or psychological stress. Ongoing symptoms may signal that a patient needs to extend the period of brain rest. If symptoms persist after a month of rest (see treatment below), suspect a more serious injury than originally diagnosed such as mild traumatic brain injury or onset of post-concussion syndrome. Post-concussion syndrome is characterized by fatigue, headaches, equilibrium disturbances or difficulty in concentrating that may persist for weeks to months after the initial injury. A patient with ongoing symptoms two weeks after injury should be referred for neuroimaging and neuropsychological testing.

B. History Part 2: Prevalence:

It is difficult to accurately estimate incidence and prevalence of concussions. Most concussed individuals do not seek medical attention, especially if their symptoms are mild or improve quickly. Estimates of the number of persons with all types of brain injury ranges from 1.5 to 3.6 million, with 80% of injuries considered mild at time of evaluation in the emergency department. According to the Centers for Disease Control and Prevention (CDC), children aged 0 to 4 years, adolescents aged 15 to 19 years, and adults aged 65 years and older are most likely to sustain a traumatic brain injury (TBI). Adults aged 75 years and older have the highest rates of TBI-related hospitalization and death. Men of all age groups sustain more concussions overall than women. However, in sports with comparable rules played by both genders such as soccer and basketball women have about twice the rate of concussion as men.

The highest at-risk groups for concussion include athletes in high-impact sports such as football, ice hockey, soccer, boxing, field hockey, lacrosse, and rugby. In the general population, concussions most frequently result from motor vehicle accidents, falls, cycling-related injuries, and battery. Unfortunately, patients with previous concussions are at increased risk of repeat concussions, and are most susceptible during the post-concussion period. The rates of repeat concussion vary widely, from 5.6% to 36% of the concussion population at large. High contact and collision sports athletes are again at higher risk for repeat concussions. Those with three or more prior concussions are also at an increased risk of developing post-concussion syndrome, as are women, patients over age 40, and those with history of depression.

C. History Part 3: Competing diagnoses that can mimic concussion.

Loss of consciousness in a concussed individual, lasting greater than 5 minutes and Glasgow Coma Scale (GCS) less than 15, can also meet criteria for mild traumatic brain injury, which may result in long-term or permanent cognitive impairment. Similar to concussion, an intracranial hemorrhage can present with history of trauma and symptoms including headache, nausea, dizziness, seizure, and loss of consciousness, but evolves with worsening of symptoms, such as decreased level of consciousness and focal neurologic deficits, and it requires immediate intervention. Care should be taken to rule out cervical spine injury, especially if the patient complains of neck pain, numbness, or weakness. Other conditions that may share features with concussions include migraine, headache, stroke, transient ischemic attack (TIA), seizure, brain contusion, tumor, metabolic encephalopathy, and skull fracture without brain injury.

Migraines and other headaches can only be distinguished from concussion by history, context, and observation over time. Neuroimaging is warranted if cervical spine injury, stroke, TIA, brain contusion, seizure, tumor, or skull fracture is suspected. Seizure foci may or may not be evident on neuroimaging, though all new onset seizures require thorough evaluation. Metabolic encephalopathy from prescribed or self-administered substances, electrolyte derangement, renal and hepatic failure, bacteremia, or other acute illness can result in symptoms similar to those of a concussion but should be suspected particularly if abnormal vital signs are present. As with seizure and syncope, it is sometimes difficult to ascertain the sequence of events that may have led to a fall in an unwitnessed event.

D. Physical Examination Findings.

Red flag symptoms and exam findings include neck pain or tenderness, double vision, weakness or numbness in arms or legs, severe or worsening headache, seizures, loss of consciousness, rapidly deteriorating mental status, vomiting, and increasing agitation or restlessness. These patients require intracranial and/or cervical spine imaging and should be hospitalized for further monitoring.

Common general physical examination findings of an acutely concussed patient can include altered state of consciousness or brief loss of consciousness, seizure, postictal state, confusion, anterograde or retrograde amnesia, inattention, unsteady gait, slurred speech, vacant stare, agitation, or irritability.

A thorough neurologic examination should include a Glasgow Coma Scale, memory and language testing, complex sequence testing, cranial nerve exam, sensory exam including proprioception, motor strength testing, and coordination, gait and balance testing. Some patients may have cortical blindness or blurred vision, may report tinnitus or hearing difficulties. Evaluation may reveal abnormal gait, positive Romberg, and decreased strength or coordination in upper or lower extremities.

Non-verbal patients or those with an altered mental status at baseline should be assessed for listlessness, increased fatigue or hypersomnolence, agitation, vomiting, change in eating habits, increased unsteadiness, or decreased independence with self-care tasks.

If the patient remains in the hospital, nursing staff should be asked to monitor symptoms (see above) every four hours. The patient should also be reassessed by a physician with a repeat physical exam 24 hours after injury.

E. What diagnostic tests should be performed?

Cognitive function assessment is an essential component of assessment of possible concussion. For patients who are able to communicate appropriately at baseline there are a number of available brief neuropsychological test batteries available to aid in screening and diagnosis. While no one tool is sufficient for diagnosis, combining the physical exam and these tools together will increase diagnostic yield. Ideally athletes should have preseason testing done so that in the event of a concussion their performances on these exams can be compared.

In athletic competition settings, the SCAT5 (for patients older than 13) and child SCAT5 (ages <12) are the most well-established and rigorously developed instruments for testing. In a nonathletic setting, the Standardised Assessment of Concussion (SAC) should be utilized. Both tests overlap with assessment of memory with immediate and delayed recall, attention span, registration and concentration, and orientation. For nonmedical personnel, the Concussion Recognition Tool 5 (CRT5) can be used as an effective screening tool to recognize symptoms of concussion that should prompt referral to a healthcare provider. All of these tools are readily available online for free.

Additional tests that will increase diagnostic yield are the timed tandem gait, clinical reaction time test (stick drop), Balance Error Scoring System test (BESS), King-Devick test, and Mobile Universal Lexicon Evaluation System (MULES) test. Unfortunately all rely on pre-injury and post-injury testing to assess for differences in cognitive processing ability and coordination. Timed tandem gait can be performed in any clinical setting. It should be assessed over a constant distance before and after injury, with increasing time required to traverse the distance successfully raising concern for impairment. The BESS is an additional method to test balance but it more involved than the simple timed tandem gait. The clinical reaction time test evaluates hand-eye coordination and reaction time and can be easily performed on the sideline by evaluating how long it takes the patient to react to and catch a falling stick. Distance traveled increases in the setting of concussion. The King-Devick test and the MULES test assess rapid number naming and rapid picture naming, respectively. Each test evaluates the patient’s eye movements, saccades, language recognition, processing ability, and speech. Each test has a set number of cards that are read by the patient. Once again pre-injury and post-injury assessments are required. In the setting of concussion, the time needed to complete the rapid number naming and rapid picture naming increases significantly. The King-Devick test is unfortunately only available for purchase as an iPad app currently. The MULES test was recently validated against the King-Devick test and will be available for clinical use soon.

Should these tests raise concern for concussion, the patient should cease all physical activity and undergo more formal neurologic evaluation. In addition to the physical exam discussed above, the following symptoms should be evaluated and documented (including severity): headache, nausea, vomiting, dizziness, poor balance, blurred or double vision, sensitivity to light, sensitivity to noise, tinnitus, difficulty concentrating, feeling slowed down, fatigue, feeling depressed, agitation or irritability, amnesia (if present, document length and anterograde or retrograde).

1. What laboratory studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?

There are no laboratory tests helpful in evaluation for concussion at this time.

2. What imaging studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?

Concussion is not associated with abnormal findings on neuroimaging. However, it is imperative to evaluate the risk of intracranial hemorrhage in all patients presenting with possible concussion or traumatic brain injury, and to obtain neuroimaging in at-risk patients. The American College of Emergency Physicians (ACEP) and the Centers for Disease Control and Prevention (CDC) formed a panel to evaluate and guide clinical policy on neuroimaging and clinical decision-making in adults presenting to the emergency department with mild traumatic brain injury. Their advice is set put below.

“A non-contrast head CT is indicated in head trauma patients with loss of consciousness or post-traumatic amnesia only if one or more of the following is present: headache, vomiting, age greater than 60 years, drug or alcohol intoxication, deficits in short-term memory, physical evidence of trauma above the clavicle, post-traumatic seizure, GCS score less than 15, focal neurologic deficit, or coagulopathy. A non-contrast head CT should be considered in head trauma patient with no loss of consciousness or post-traumatic amnesia if there is a focal neurologic deficit, vomiting, severe headache, age 65 years or greater, physical signs of basilar skull fracture, GCS score less than 15, coagulopathy, or dangerous mechanism of injury (for example, ejection from a motor vehicle, a pedestrian struck, and fell from a height of more than 3 feet or 5 stairs).”

Other tests such as positron emission tomography, structural MRI, functional MRI, diffusion tensor imaging may provide additional information but are still in the research phase of clinical utility.

F. Over-utilized or “wasted” diagnostic tests associated with this diagnosis.

In patients with no red flag symptoms (discussed above) or risk factors for intracranial lesions, neuroimaging is very unlikely to yield positive findings in in the emergency department setting. However, there are no studies in concussion in hospitalized patients to guide practice.

III. Default Management.

Physical and cognitive rest is key to concussion recovery. The patient should be instructed to avoid strenuous physical and cognitive activities for at least 24 hours or until previous symptoms are completely resolved as such activity can delay recovery. These activities include reading, checking e-mail, watching television, engaging in stressful discussions or decision making.

If a patient is discharged prior to complete resolution of concussion symptoms, give instruction not to operate machinery, including cars and even bicycles. The patient should also avoid alcohol, benzodiazepines, non-steroidal anti-inflammatory drugs (NSAIDs), and narcotics or other medications that can increase the risk of bleeding, alter mental status, or increase risk of seizure. In the inpatient setting, symptom management should include first-line analgesia with acetaminophen. One time doses of an anti-emetic such as prochlorperazine or metoclopromide may help with the headache as well. Opiates can be used for severe headache. If headache continues to persist, starting a prophylactic medication such as topiramate can be considered. For persistent nausea, ondansetron is typically utilized first line to avoid over sedation. Appropriate acute symptom management may decrease likelihood of post-concussion syndrome.

A. Immediate management.

There are no interventions that can reverse injury or symptoms of concussion. The concussed patient should be advised to rest in a dark room, and to minimize noise and unnecessary interruptions. Headache is the most common symptom of concussion and should be managed with acetaminophen and triptans if possible. Ondansetron may be used for nausea. Avoid medications that lower seizure threshold and are associated with increased bleeding. Medications that alter mental status such as opiates or benzodiazepines can be very useful in an observed setting. Nursing staff should obtain neurological checks every 4 hours during the initial 24 hours after trauma. If the patient has a safe discharge plan, a responsible caregiver needs to assess the patient every 4 hours for the first 24 hours.

B. Physical Examination Tips to Guide Management.

In hospitalized patients, repeat evaluation of symptoms and serial neurological exams as detailed above should be repeated frequently. Nursing neurologic checks should be ordered every 4 hours and formal neurologic exam should be documented 24 hours after initial event. A decline in mental status, new focal neurologic deficits, or worsening symptoms should prompt immediate re-evaluation and consideration for urgent intracranial imaging.

C. Laboratory Tests to Monitor Response To, and Adjustments in, Management.

There are no laboratory tests to evaluate or monitor for concussion at this time.

D. Long-term management.

Patients with concussion should be instructed to remain on cognitive and physical rest for at least 24 hours or until symptoms are completely resolved prior to increasing their level of activity. Once symptom-free, the patient can increase the level of activity to include low-impact physical exertion not requiring agility or balance. If symptoms recur, activity should be immediately discontinued until symptom free for at least another 24 hours. If there are no symptoms with low level of exertion, the patient can increase the level of activity every few days. Any recurrence of symptoms should signal immediate cessation, with rest for at least 24 hours and resumption of previous symptom-free activity. It is important to note that return to full physical activity (especially contact sports) should not be advised until the patient is not requiring medicines for symptom management. The masking of symptoms while returning to full physical activity can lead to repeated concussions and worsening prognosis.

For 90% of patients, the symptoms of concussion resolve after 2 weeks. Ongoing symptoms of headache, fatigue, insomnia, dizziness, irritability, mood disturbance, apathy, or personality changes may signal post-concussion syndrome, which requires further evaluation and management by a neurologist or neuropsychologist. Though there are several modalities including tricyclic antidepressants, neuroepinephrine selective reuptake inhibitors, and anti-epileptic agents in use for this syndrome, there are no clinical trials that show superiority of any of these agents. Patients with new onset seizures within one week of the traumatic event should be started on anti-epileptic medications and weaned several weeks after. This is mainly to prevent status epilepticus.

E. Common Pitfalls and Side-Effects of Management

The most important factors in concussion management is evaluating for other serious injuries including intracranial hemorrhage and more serious traumatic brain injury, educating patients about the importance of rest in recovery, and ensuring proper follow-up options for possible complicated recovery.

IV. Management with Co-Morbidities

The evaluation for concussion may be significantly more difficult in a patient who is severely physically handicapped and unable to participate in tests of balance or coordination.

Evaluation of both symptoms and obtaining an accurate mental status examination will also be more difficult in a patient with altered mental status or cognitive or psychiatric impairment at baseline. Though management would center on physical and cognitive rest, there is a lower threshold to perform neuroimaging and have closer observation after initial injury.

A patient with previous concussions requires close observation, increased length of time on cognitive rest, and slower return to activities to decrease delayed recovery, post-concussion syndrome, and second impact syndrome.