Concussion

Background: Concussion has many different meanings to patients, families, and physicians. One definition of concussion is a traumatically induced alteration in mental status with or without associated loss of consciousness. Perhaps a better definition of concussion is one that encompasses a broader constellation of symptoms associated with the injury, such as a traumatic alteration in neurological function.

Concussion or mild traumatic brain injury (MTBI) is common among most contact and collision sports. For many physicians, even those who specialize in MTBI, this area is confusing due to the paucity of scientific evidence to support much of the clinical decision-making faced in the office. The inconsiderable amount of good scientific research in the area of MTBI is due to problems with ambiguous definitions of concussion, inconsistent criteria when selecting patients to study, variability of injury mechanisms and locations, and differing means of measuring cognitive function. The purpose of this course is to review the epidemiology, diagnosis (but not necessarily classification), the role of imaging studies, return to play issues, and complications surrounding MTBI.

Frequency:

  • In the US: Incidence of head injury varies with sport and age of participants. Many head injuries are likely unreported due to their supposed mild nature. Mild concussions may go unnoticed by teammates, coaches, and even the patients. Patient's fear of medical disqualification also may lead to underreporting. Recent studies of high school athletes show the rate of concussions per 1000 exposures, as follows: football (0.59 for boys), wrestling (0.25 for boys), soccer (0.18 for boys, 0.23 for girls), field hockey (0.09 for girls), and basketball (0.11 for boys, 0.16 for girls).

    Among National Collegiate Athletic Association (NCAA) soccer players, rate of injury is 0.4-0.6/1000 athlete exposures. Seventy-two percent of these injuries were described as mild and almost always were secondary to direct contact with an opponent. None of the injuries in this group of Atlantic Coast Conference (ACC) soccer players was noted to be a direct result of heading the ball.

    In contrast, boxing is the sport with the highest rate of head injuries and has more deaths than any organized athletic activity. At the professional level, many of the bouts end with a technical knockout (ie, brain injury).

    Sports at high-risk for head injury include boxing, football, ice hockey, wrestling, rugby, and soccer. Physicians and other allied health providers responsible for the medical care of such contact or collision sports should be comfortable in the acute and chronic consequences of an injury to the brain.

Sport Specific Biomechanics: Mechanisms of injury may differ between sports. Possible mechanisms of injury include compressive forces, which may directly injure the brain at the point of contact (coup). Tensile forces produce injury at the point opposite the injury (contrecoup), as the axons and nerves are stretched. Finally, rotational forces may result in a shearing of axons. Therefore, the direct force at the point of contact may not solely be responsible for the severity of injury if a high rotational component with significant shear effect occurs.

 

History:

    • Patients with a MTBI often appear confused with a blank expression or blunted affect. Delayed response to simple questioning may be demonstrated along with emotional lability. The emotional lability may become more evident as the patient attempts to cope with their confusion.
    • Many patients complain of associated headache and dizziness.
    • Both pretraumatic (retrograde) amnesia and posttraumatic (antegrade) amnesia may be present. Usually, the duration of retrograde amnesia is quite brief with a more variable duration of posttraumatic amnesia (seconds to minutes), depending upon the injury.
    • Some authors suggest that the persistence of a longer retrograde amnesia is indicative of a more severe concussion.
    • History of persistent vomiting suggests a significant injury with associated elevated intracranial injury.
    • Other signs of increased intracranial pressure include worsening headache, increasing disorientation, and changing level of consciousness. Possible causes of increasing intracranial pressure include subdural hematomas, epidural hematomas, or some other type of intracranial hemorrhage.
    • A previous history of concussions is important to document. Multiple concussions with prolonged neurological symptoms (eg, headache, hyperacusis, dizziness) suggest postconcussive syndrome and should influence return to play decisions.
  • Assessment tools
    • A Glasgow Coma scale (GCS) is routinely used to assess head injuries in an emergency department.

      • This 15-point scale is used to assess eye (spontaneous opening=4 to no response=1), motor (obeys commands=6 to no response=1), and verbal responses (oriented=5 to no response=1) in an attempt to quantify level of consciousness.

      • Unfortunately, this tool is not sensitive enough to evaluate more mild injuries, especially on the field as it relates to playability.
    • McCrea has developed a sideline evaluation to help the practitioner evaluate the more subtle injured brain. A 30-point scale is used to look at orientation, concentration, immediate memory, and delayed recall. Preseason testing must be done if a practitioner is hoping to use this tool as a supplement to their neurological and mental status exam; if the baseline status of an individual is not known, assessment for change after a head injury is useless. The sideline evaluation uses months of the year in reverse after a study by Young showed lack of reliability of serial 7s in the baseline evaluation even in non–head-injured patients. This study is further support for the importance of a baseline evaluation being helpful when attempting to evaluate the injured patient.
  • Classification
    • Many different classification schemes have been proposed over the last 15 years.
    • No one classification system is necessarily better than another classification system.
    • In addition, no scientific basis for any of the classification systems exists.
    • Cantu's guidelines, Omaya and Generalli's guidelines, and the Colorado guidelines all have been proposed to aid in the evaluation of a concussion.
    • The most recent guidelines published in 1997 are as follows:

       

      Grade 1(Mild)

      Grade 2 (Moderate)

      Grade 3 (Severe)

      Symptoms

       Transient confusion
      Symptoms<15 min

      Transient confusion
      Symptoms >15 min

      LOC

      Return to play

      Examine q5min
      May return if no
      symptoms within 5 min

      Remove from game

      Transport (possible)

    • Although neurology guidelines may be more accepted because they were developed by a larger group of neurological specialists and sports medicine physicians, they often are difficult to adhere to when facing return to play decisions for those with grade 2 or grade 3 injuries.

    • Recent studies suggest that loss of consciousness may not be a great predictor of short-term or long-term neurological functioning, which makes the guidelines more controversial.

    • Regardless of which classification scheme or guideline is used, the ultimate recommendation is to not allow return to play until the patient is completely asymptomatic. The patient must be free of headache, dizziness, amnesia, blunted affect, and delayed verbal or ocular responses.

Physical:

  • Perform a thorough organized evaluation to better define the degree of injury when a player is brought to the sidelines or emergency department for evaluation.

  • Initial evaluation should focus on airway, breathing, and circulation for any unconscious patient. Assume all unconscious or mentally impaired patients have sustained an injury to their cervical spine until proven otherwise.
  • For conscious patients, the remainder of the examination should be performed in a quiet place, on the sidelines, in the locker room, or in a private room in an emergency department because of the emotional lability and confusion experienced by the patient.
  • Initial clinical examination should include a careful inspection of the patient's general appearance.
  • Palpating the head and neck is important when looking for associated skull or cervical injury.
  • Palpate the facial bones and the periorbital, mandibular, and maxillary areas after any head trauma.
  • Opening and closing the mouth helps evaluate possible temporomandibular joint (TMJ) pain, malocclusion, or mandible fracture.
  • Inspection of the nose for deformity and tenderness may indicate a possible nasal fracture.
  • Persistent rhinorrhea or otorrhea (clear) indicates a possible associated skull fracture.
  • Perform a careful detailed neurological examination to include examinations of visual fields, extraocular movements, pupillary reflexes and level of the eyes.
  • Assess upper extremity and lower extremity strength and sensation.
  • Assess coordination and balance. Concussed patients often have difficulty with the finger-nose-finger test, using slow purposeful movements to complete the task.
  • Significant sway in Romberg testing may indicate persistent injury.
  • Repeat examination every 15 minutes until clear when examining on the sideline.
  • The patient should not be allowed to return to competition if symptoms or physical examination do not return to normal after 15 minutes.

Causes:

  • A previous concussion is a significant risk factor for sustaining a concussion.
  • One study reported that risk of sustaining a concussion was 4-5 times higher in patients who had at least 1 concussion in the past.
  • Other risk factors for sustaining a concussion that have been suggested but not proven include not wearing mouth guards, poor fitting helmets, and genetic predisposition. Research in all of these areas continues today.



Other Problems to be Considered:

Epidural hematoma
Intracerebral hematoma
Subdural hematoma
Repetitive Head Injury Syndrome
Subarachnoid bleed
Trauma-induced migraine
Trauma-induced headache


WORKUP

Imaging Studies:

  • CT scan
    • In an emergency department based study, the percent of abnormal CT scans in adult patients went from 13% for patients with a perfect GCS to 37% for those with a GCS of 13. In a different study looking at patients with loss of consciousness (LOC) or amnesia and a perfect GCS, the rate of abnormal CT scans was 9%, with less than 1% requiring surgical intervention.
    • Indications for ordering a CT scan include focal neurological examination findings, signs or symptoms of increased intracranial pressure, GCS <15, and seizures related to trauma. Some authors suggest that any patient with loss of consciousness (Grade 3 concussion) should have a CT scan obtained. This area is controversial. Patients with brief loss of consciousness are at no higher risk for long-term neurological sequelae and indications for imaging should not differ from above.
    • CT scan continues to be the study of choice in evaluating acute head injury. Better imaging of an acute bleed, speed of the study, and improved ability to monitor the patient are the reasons for using CT scan over MRI.
  • MRI
    • MRI is the study of choice for patients with prolonged symptoms (greater than 7 days) or for late change in neurological signs or symptoms.
    • MRI offers a more detailed examination and possibly detects more subtle findings.
    • Delayed or slowly developing bleeds may be easier to detect on MRI.
  • Neuropsychological testing
    • Detailed neuropsychological testing is employed more often at the professional level and in research for patients with MTBI.
    • When evaluating an patient's performance on the neuropsychological tests, it is best to compare results with the patient's previous tests.
    • Both the National Hockey League (NHL) and National Football League (NFL), along with many college teams, are now utilizing limited neuropsychological testing to document possible prolonged effects of presumed minor head injuries and to assist the clinician in determining possible retirement issues.
  • Although positron emission tomography (PET) scan and functional MRI scan may be used, their clinical application in most cases of MTBI is uncertain.

    TREATMENT

    Acute Phase:

    • Medical Issues/Complications: Most of the complications listed below probably already existed when the patient sustained the initial head injury; in other words, they are not caused by a MTBI. These conditions may be associated with what was thought of as a MTBI. Therefore, the reader should not think of these conditions as a complication of a mild traumatic head injury but rather other conditions they must consider when evaluating an patient with a head injury.

      • Subdural hematoma is a rare injury in the patient presenting with a presumed concussion. Classic presentation is acute and persistent LOC associated with the initial injury.

      • No association between epidural hematoma and brain injury exists. This condition classically presents with a brief period of unconsciousness, followed by a lucid period and subsequent deterioration over 15-30 minutes. Tearing of the middle meningeal artery secondary to an associated temporal skull fracture is the usual cause of epidural hematoma.

      • Subarachnoid bleeding also may occur with a head injury of any sort. Worsening headache and other signs of increasing intracranial pressure will gradually increase after the initial event.

      • Second impact syndrome has been described in many review articles. In this condition, fatal brain swelling occurs after minor head trauma in individuals who still have symptoms following minor head trauma from a prior injury. Thus far, all cases of second impact syndrome have been described in relatively young patients (younger than 20 years). Significant controversy exists over the etiology of this condition, although it is thought to be secondary to loss of autoregulation of cerebral blood flow in an already injured brain. More recently, authors have questioned the validity of this condition due to problems with documentation of the initial event, documentation of persistent symptoms, and documentation of severity of second impact. Despite these problems, practitioners should be aware of this possible complication, especially when treating the relatively immature brain of a young patient. Treatment of second impact syndrome requires immediate recognition and immediate treatment with hyperventilation and
        osmotics. Surgical treatment for this condition is ineffective. The overall prognosis is usually grim.

    • Consultations: Consultation with a neurologist or primary care sports medicine physician is indicated for patients with prolonged symptoms. Neuropsychological consultation also may be considered to document any deficits that may interfere with return to sport, school, or work.

        MEDICATION

        Overall, no medical therapy treatment usually is prescribed for patients after an acute injury. Pain control usually is achieved with over-the-counter medications, such as acetaminophen. Avoid narcotics so that clouding of the patient’s mental status or neurological examination does not occur.

        Drug Category: Analgesics -- Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties, which are beneficial for patients who have sustained trauma or have sustained injuries.
        Drug Name
        		Acetaminophen (Tylenol, Panadol, Aspirin Free Anacin) -- DOC for pain in patients with documented hypersensitivity to aspirin, NSAIDs, diagnosed with upper GI disease or on oral anticoagulants.
        Adult Dose 325-650 mg PO q4-6h or 1,000 mg tid/qid; not to exceed 4 g/d
        Pediatric Dose <12 years: 10-15 mg/kg/dose PO q4-6h prn; not to exceed 2.6 g/d
        >12 years: 325-650 mg PO q4h; not to exceed 5 doses in 24 h
        Contraindications Documented hypersensitivity
        Interactions Rifampin can reduce analgesic effects of acetaminophen; coadministration with barbiturates, carbamazepine, hydantoins, and isoniazid may increase hepatotoxicity
        Pregnancy B - Usually safe but benefits must outweigh the risks.
        Precautions Hepatotoxicity can occur, in chronic alcoholics, with various dose levels of acetaminophen; severe or recurrent pain or high or continued fever may indicate a serious illness

        FOLLOW-UP

        Return to Play: Return-to-play criteria are controversial. Similar to classification guidelines, several different guidelines regarding return to play have been established. No scientific evidence exists to justify one criterion versus another criterion. The main criteria include complete clearing of all symptoms, complete return of all memory and concentration, and no symptoms after provocative testing. Provocative testing includes jogging, sprinting, sit-ups, or push-ups, in other words, some type of exercise that raises the patient's blood pressure and heart rate. The rules are the same for patients who have a concussion that prohibits return to play during competition. Only after all symptoms have cleared both at rest and with exertion should an patient even consider returning to practice or competition. In addition, the patient has to show complete resolution of any emotional lability, mood disturbance, attention, or concentration difficulty. Relatively minor concussions may have more prolonged neurological
        deficits. Therefore, the most important aspect of all published guidelines is the concept of an patient not being allowed to return to play until completely asymptomatic.

        Complications: See Postconcussive Syndrome in Medical Issues/Complications (Treatment, Acute Phase).

        Prevention: Injury prevention methods currently are being studied. In the past, rule changes barring spearing in football and teaching football players not to lead with their head have significantly reduced the frequency of severe head injuries in American football.

        Equipment and environmental changes also can prevent injury. Soccer goals must be anchored to the ground because many deaths secondary to head injury in soccer have been the direct result of a goal tipping over on a player.

        Controversy regarding possible helmet wearing in soccer recently has been proposed. Although helmets have been shown to clearly reduce the risk of head injury in recreational bicycle riding, no clear evidence exists that the type of headgear proposed for youth soccer will prevent acute or chronic head injury among soccer players. Most concussions in soccer are the result of direct contact rather than heading of the ball.

        Even if helmets are used, no guarantee exists that they will necessarily fit. Studies of football helmet use in high school have demonstrated that only 15% of the helmets fit properly. Further documentation of the possible increase in risk of head injury associated with poor helmet fit has not been completed.

        Although mouth guards have been advocated for injury prevention purposes, no controlled study has proven their usefulness in concussion prevention.

        Prognosis: Most patients with MTBI are able to return to full competition without complication. Because many patients may not report minor head injuries to the athletic trainer, emergency department, or primary care physician, overall prognosis of many head injuries is unclear. Chronic postconcussive syndrome can be quite severe, with the most dramatic presentation including dementia pugilistica associated with boxing. This Alzheimer-like condition has a reported incidence of 15% among professional boxers. Fortunately, this condition is rare in most other sports. Hopefully, more frequent, detailed neuropsychological testing will decrease the frequency of postconcussive syndrome among elite and professional patients by detecting more subtle injuries earlier.

        Education: Educating allied health professionals, coaches, and families about recognition and acute management of a concussion and the difficulties involved with a concussion is important. All groups mentioned above must recognize the difficulty in managing and treating concussions. Inexperienced health care providers may want to use some type of published guideline when initially managing these injuries. Subtle problems with long-term complications must be recognized by health professionals, coaches, and families in hopes of preventing recurrent problems.

         

        Medical/Legal Pitfalls:

        • Although many classification systems and guidelines exist, many physicians across the country do not necessarily follow the guidelines. Whether this lack of compliance is because physicians and caretakers are not aware of the guidelines or because they do not think the guidelines are valid is unclear. Reasons may differ among different types of primary caregivers and specialists. Although the physician who does not follow the stated guidelines may be sued for malpractice, no clear standard of care for concussions exists because of the many different classification systems and guidelines.

        REFERENCES

        • Boden BP, Kirkendall DT, Garrett WE Jr: Concussion incidence in elite college soccer players. Am J Sports Med 1998 Mar-Apr; 26(2): 238-41
        • Cantu RC: Second Impact Syndrome. 1992; 20: 55-66.
        • Capruso DX, Levin HS: Cognitive impairment following closed head injury. Neurol Clin 1992 Nov; 10(4): 879-93
        • Jeret JS, Mandell M, Anziska B: Clinical predictors of abnormality disclosed by computed tomography after mild head trauma. Neurosurgery 1993 Jan; 32(1): 9-15; discussion 15-6
        • Kelly JP, Nichols JS, Filley CM: Concussion in sports. Guidelines for the prevention of catastrophic outcome. JAMA 1991 Nov 27; 266(20): 2867-9
        • Kelly JP, Rosenberg JH: Diagnosis and management of concussion in sports. Neurology 1997 Mar; 48(3): 575-80
        • Lovell MR, Iverson GL, Collins MW: Does loss of consciousness predict neuropsychological decrements after concussion? Clin J Sport Med 1999 Oct; 9(4): 193-8
        • McCrea M, Kelly JP, Randolph C: Standardized assessment of concussion (SAC): on-site mental status evaluation of the athlete. J Head Trauma Rehabil 1998 Apr; 13(2): 27-35
        • McCrea M, Kelly JP, Kluge J: Standardized assessment of concussion in football players. Neurology 1997 Mar; 48(3): 586-8
        • McCrory PR, Berkovic SF: Second impact syndrome. Neurology 1998 Mar; 50(3): 677-83
        • McGuine T, Nass S: Football Helmet Fitting Errors in Wisconsin High School Players. American Society for Testing and Materials 1996: 83-88.
        • Pieter W, Zemper ED: Head and neck injuries in young taekwondo athletes. J Sports Med Phys Fitness 1999 Jun; 39(2): 147-53
        • Powell JW, Barber-Foss KD: Traumatic brain injury in high school athletes. JAMA 1999 Sep 8; 282(10): 958-63
        • Stein SC, Ross SE: Mild head injury: a plea for routine early CT scanning. J Trauma 1992 Jul; 33(1): 11-3
        • Wojtys EM, Hovda D, Landry G: Current concepts. Concussion in sports. Am J Sports Med 1999 Sep-Oct; 27(5): 676-87
        • Young CC, Jacobs BA, Clavette K: Serial sevens: not the most effective test of mental status in high school athletes. Clin J Sport Med 1997 Jul; 7(3): 196-8
        • Zemper E: Relative Risk of Cerebral Concussion in Football. Presented at: Annual Meeting of the American College of Sports Medicine; 1999.

          MEDCEU Continuing Education Courses CEU for Nurses and Healthcare Professional

           Home Page