Because the definition of a concussion denotes a mechanical injury of the brain without visible structural damage on imaging studies, the physician makes the diagnosis solely on clinical criteria and the findings from the clinical presentation [1] [2] [3] [4]. Head trauma prior to the onset of symptoms is a mandatory step in the development of a concussion and headaches, often accompanied by dizziness, are described as the two most frequent findings in these individuals [1] [2] [3] Nausea, vomiting, and changes in the state of consciousness can be encountered as well [1] [2] [5]. Furthermore, a concussion is known for producing various neurological changes that are primarily related to behavior and cognition - emotional lability, depression, and irritability are main patterns of mood disorders, whereas forgetfulness, memory loss, transient amnesia, reduced reaction times, and deficits in attention might also be present [1] [2] [3] [4] [5]. Visual impairment and a sense of numbness are reported by some studies, whereas altered sleep may eventually appear in the form of insomnia [1] [2] [3] [4]. In rare cases, convulsions and significant motor deficits right after head trauma can constitute the clinical picture of a concussion [1] [2].

• Pain

  As Mayer points out, during the recovery process after a burn “reported symptoms like pain are greatly reduced before the body is finished healing, when the tissue scabs.” [smithsonianmag.com]

  Glasgow Coma Scale Eye Opening Spontaneous 4 To loud voice 3 To pain 2 None 1 Verbal Response Oriented 5 Confused, disoriented 4 Inappropriate words 3 Incomprehensible words 2 None 1 Motor Response Obeys commands 6 Localizes pain 5 Withdraws from pain [medicinenet.com]

  Pain relief Headaches may occur in the days or weeks after a concussion. To manage pain, ask your doctor if it's safe to take a pain reliever such as acetaminophen (Tylenol, others). [mayoclinic.org]

• Fatigue

  Fatigue and sleep problems go hand-in-hand and tend to worsen each other. Fatigue tends to be worse in the evening and makes symptoms more noticeable. Listen to your body and rest when needed. [mayfieldclinic.com]

  The physician must determine the exact events that preceded the onset of complaints and exclude their presence prior to head trauma, as the clinical presentation could be similar to exercise-induced fatigue and consequent headaches or migraines. [symptoma.com]

  A concussion may result in any of the following symptoms: Loss of consciousness Headache Nausea Vomiting Balance problems Dizziness Lightheadedness Fatigue Drowsiness Sensitivity to light or noise Feeling more emotional Numbness or tingling Feeling like [nicklauschildrens.org]

  At the beginning and the end of the study, both groups completed tests to measure symptoms of depression and other concussion symptoms, such as headache, fatigue and problems with sleep, memory and concentration. [sciencedaily.com]

• Unconsciousness

  Some medical experts also argue that a Grade 2 concussion can feature unconsciousness for up to five minutes. [injuryinformation.com]

  A brief unconsciousness is often associated with this, although the latest reports tell us that unconsciousness does not always occur. The unconsciousness often takes a few minutes but never longer than fifteen minutes. [braininjury-explanation.com]

  You may be knocked out (unconscious) or may just feel confused. The skull bone protects your brain. Fluid inside your skull also cushions your brain. [msdmanuals.com]

• Nausea

  Repeated vomiting or nausea. Slurred speech. Look very drowsy or cannot wake up. Have one pupil (the black part in the middle of the eye) larger than the other. Have convulsions or seizures. Cannot recognize people or places. [cdc.gov]

  Typical symptoms include headache, nausea and dizziness; these may remain for a week or two. Some patients may experience transient loss of inability to create new memories or other brief impairment of mental functioning. Treatment is symptomatic. [ncbi.nlm.nih.gov]

  The Academy recommends that athletes whose symptoms -- headaches, nausea, amnesia, blurred vision -- do not clear up within 15 minutes, or who lose consciousness even briefly, be kept out of competition until their symptoms have disappeared completely [medicinenet.com]

  Repeated vomiting or nausea, convulsions or seizures (shaking or twitching). Unusual behavior, increased confusion, restlessness, or agitation. Loss of consciousness (passed out/knocked out). [brainline.org]

• Orthostatic Hypotension

  hypotension, fainting, and postural orthostatic tachycardia syndrome; neurological and sensory disturbances including muscle weakness of lower limbs, deep sensibility impairment, epileptic seizure, cognitive impairment, visual impairment, balance impairment [en.wikipedia.org]

• Blurred Vision

  The Academy recommends that athletes whose symptoms -- headaches, nausea, amnesia, blurred vision -- do not clear up within 15 minutes, or who lose consciousness even briefly, be kept out of competition until their symptoms have disappeared completely [medicinenet.com]

  Partial or total loss of vision Weakness of eye muscles and double vision (diplopia) Blurred vision Problems judging distance Involuntary eye movements (nystagmus) Intolerance of light (photophobia) Hearing: Decrease or loss of hearing Ringing in the [braininjury-explanation.com]

  Go to a hospital emergency room for these symptoms: loss of consciousness (knocked out) severe headache, including a headache that gets worse blurred vision trouble walking confusion and saying things that don't make sense slurred speech unresponsive [kidshealth.org]

  Any of these could be a sign of traumatic brain injury: confusion or feeling dazed clumsiness slurred speech nausea or vomiting headache balance problems or dizziness blurred vision sensitivity to light sensitivity to noise sluggishness ringing in ears [webmd.com]

• Ganser Syndrome

  심인성 귀머거리(Psychogenic deafness) F44.7 혼합형 해리[전환] 장애(Mixed dissociative [conversion] disorders)(F44.0-F44.6에 분류된 장애의 복합) F44.8 기타 해리[전환]장애(Other dissociative [conversion] disorders) 간저 증후군(Ganser's syndrome) 다중 인격증(Multiple personality) 심인성 혼돈(Psychogenic [dic.impact.pe.kr]

• Headache

  A headache, cognitive deficits, emotional instability, sleep disturbances, and an overall change in mental state after trauma are highly suggestive signs of a concussion. [symptoma.com]

  Up to 86% of athletes that suffer a concussion will experience Post-Traumatic Migraine or some other type of headache pain. [protectthebrain.org]

  No drugs have been shown to improve recovery from concussion, but specific symptoms can be treated with appropriate drugs (eg, acetaminophen or NSAIDs for headache). [merckmanuals.com]

  Some concussions will develop into “Post-concussion syndrome” which is a complex disorder in which a number of post-concussion symptoms — such as headaches and dizziness — last for weeks and sometimes months after the injury that caused the initial injury [nicklauschildrens.org]

  Sometimes symptoms such as headaches, dizziness, etc. will linger for some weeks. Recovery may take longer for those who have had a previous head injury, the elderly, and those with substance abuse problems. [brainfoundation.org.au]

• Confusion

  For example, in the first few minutes after the injury, someone might be just slightly confused or appear a little bit dazed. But an hour later, he or she might become confused or unable to recall what was going on before the injury. [utswmed.org]

  Immediately after the accident, the person may be confused, not remember what happened or have nausea, blurry vision, or dizziness. The person may appear fine at first but show symptoms hours or days later. [mayfieldclinic.com]

  Symptoms include loss of consciousness, confusion, memory difficulties, and other signs of brain dysfunction. Diagnosis is clinical with neuroimaging done as needed. [merckmanuals.com]

  A traumatic brain injury (TBI) can be classified as mild if loss of consciousness and/or confusion and disorientation is shorter than 30 minutes. [traumaticbraininjury.com]

• Dizziness

  Some concussions will develop into “Post-concussion syndrome” which is a complex disorder in which a number of post-concussion symptoms — such as headaches and dizziness — last for weeks and sometimes months after the injury that caused the initial injury [nicklauschildrens.org]

  Sometimes symptoms such as headaches, dizziness, etc. will linger for some weeks. Recovery may take longer for those who have had a previous head injury, the elderly, and those with substance abuse problems. [brainfoundation.org.au]

  To make a diagnosis, professionals look at many variables that might indicate trauma, ranging from changes in balance to memory lapses and dizziness. [brainline.org]

  Typical symptoms include headache, nausea and dizziness; these may remain for a week or two. Some patients may experience transient loss of inability to create new memories or other brief impairment of mental functioning. Treatment is symptomatic. [ncbi.nlm.nih.gov]

• Irritability

  In a mild concussion may be that the person in question for some time suffer from residual symptoms such as: Fatigue Headache Dizziness Concentration problems Tinnitus Anxiousness Quickly irritated; irritability, tearfulness or feeling down Sensitive [braininjury-explanation.com]

  Furthermore, a concussion is known for producing various neurological changes that are primarily related to behavior and cognition - emotional lability, depression, and irritability are main patterns of mood disorders, whereas forgetfulness, memory loss [symptoma.com]

  Post-concussion syndrome can include physical, cognitive, and emotional problems, including: Headache Dizziness Difficulty concentrating or completing tasks Irritability The sense that you “just don’t feel like yourself” All of these symptoms can make [concussion.weillcornell.org]

  It is the acceleration and deceleration of the brain against the inside of the skull that can cause the brain to be irritated and interrupt its function. [medicinenet.com]

• Amnesia

  A period of amnesia, or not recalling what has happened, is essential to the diagnosis of concussion. [brainfoundation.org.au]

  There is often a brief period (seconds or minutes) of retrograde amnesia, meaning a loss of memory for the events immediately prior to the concussion. [weillcornellbrainandspine.org]

  Forgets events after hit (anterograde amnesia) Common Signs Reported By Athletes Headache Nausea Balance problems or dizziness Double or fuzzy vision Sensitivity to light or noise Feeling sluggish Feeling "foggy" Change in sleep pattern Concentration [neurosurgery.pitt.edu]

The diagnostic workup of cases in whom a concussion is suspected must encompass a detailed history and a thorough physical examination [1] [2] [4]. The physician must determine the exact events that preceded the onset of complaints and exclude their presence prior to head trauma, as the clinical presentation could be similar to exercise-induced fatigue and consequent headaches or migraines [1] [2]. If the initial injury occurred days or weeks ago, patients should be asked about their sleeping patterns, whether they experience memory loss, or if new-onset epilepsy may have developed [1]. The physical examination is crucial for assessing the level of consciousness and awareness of the patient, but also for evaluating the cognitive status and other neurological insults that might have occurred. Because a concussion is currently classified as a form of traumatic brain injury (although this topic has become a matter of significant discussion) [6], imaging studies need to be employed in order to rule out more serious damage. Apart from the examination of the skull, plain radiography provides little benefit in patients with a suspected concussion, which is why computed tomography (CT) is used as the cornerstone of diagnostics [1] [2] [6]. Magnetic resonance imaging (MRI) and MR spectroscopy are used as even more advanced methods to reveal pathological changes in the brain that are not visible on CT [1] [2] [5].

A specialist should direct treatment and recovery of concussion. [uofmhealth.org]

Concussion Treatment If you suspect that you or a loved one has suffered a concussion, it’s important to seek medical treatment as soon as possible. [spinalcord.com]

UT Southwestern is a leader in brain research to pioneer new evaluations and treatments for brain trauma, and we have one of the nation’s premier treatment centers. [utswmed.org]

frequency of treatment, and frequencies that are best used. [drpawluk.com]

Unfortunately, this creates a gap in rehabilitative services, resulting in incomplete treatment and frustration for the patient, family and treatment team. The vision care professional can play an important role in the rehabilitation effort. [braininjuries.org]

Almost invariably the prognosis of brain concussion is good. [ncbi.nlm.nih.gov]

We know that you have questions about your symptoms and prognosis, and our accomplished team of highly trained specialists is here to provide you with the answers you need. [barrowneuro.org]

Prognosis Most people recover completely, with no lasting problems. Sometimes symptoms such as headaches, dizziness, etc. will linger for some weeks. [brainfoundation.org.au]

The young brain and concussion: imaging as a biomarker for diagnosis and prognosis. Neurosci Biobehav Rev. 2012;36(6):1510-31. Complete Listing of References [sports-health.com]

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. [emedicine.medscape.com]

Similarly, the etiology of post-concussion symptoms is also debatable. [frontiersin.org]

The epidemiology of sport-related concussion. Clin Sports Med 2011;30:1–17, vii. Meehan WP, 3rd, d’Hemecourt P, Comstock RD. High school concussions in the 2008-2009 academic year: mechanism, symptoms, and management. [apsf.org]

Epidemiology of concussion in collegiate and high school football players. [scielo.isciii.es]

WebMD REFERENCES: Boston Children's Hospital: "Head or Brain Injury" eMedicineHealth: "Concussion" Medscape: "Classification and Complications of Traumatic Brain Injury" Medscape: "Skull Fracture" Medscape: "Traumatic Brain Injury (TBI) -- Definition, Epidemiology [onhealth.com]

Epidemiology Frequency United States The incidence of head injury varies with the sport and the age of the participants; many head injuries are likely unreported due to their supposed mild nature; mild concussions may go unnoticed by teammates, coaches [emedicine.medscape.com]

Pathophysiology Pathophysiology explains the affects of a concussion or brain injury to the physical brain. We look at traumatic injuries from macroscopic, microscopic and molecular views. This is my particular speciality area. [xlntbrain.com]

This can be attributed to a greater understanding of the effects of both acute and chronic repeated concussion on brain pathophysiology. [apsf.org]

Pathophysiology is still being clarified, but brain dysfunction is thought to involve excitotoxicity, which is neuronal damage caused by excessive release of excitatory neurotransmitters, particularly glutamate. [merckmanuals.com]

Boston Children's Hospital: "Head or Brain Injury" eMedicineHealth: "Concussion" Medscape: "Classification and Complications of Traumatic Brain Injury" Medscape: "Skull Fracture" Medscape: "Traumatic Brain Injury (TBI) -- Definition, Epidemiology, Pathophysiology [onhealth.com]

The NCAA defines concussion or mild traumatic brain injury as "a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces." [aans.org]

Molecular View Brain trauma causes changes in the neurons, preventing the brain from working normally, including: Inability to regulate electrolytes which prevents the brain cells from operating properly. [xlntbrain.com]

Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/TraumaticBrainInjury/index.html. Updated March 6, 2014. [cancercarewny.com]

Such difficulties are prevented if the athlete is allowed time to recover from a concussion and return to play decisions are carefully made. [neurosurgery.pitt.edu]

Centre for Disease Control and Prevention. [canchild.ca]

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2. Giza CC, Kutcher JS, Ashwal S, et al. Summary of evidence-based guideline update: Evaluation and management of concussion in sports: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2013;80(24):2250-2257.
3. Shaw NA. The neurophysiology of concussion. Prog Neurobiol. 2002;67(4):281-344.
4. Kutcher JS, Giza CC. Sports Concussion Diagnosis and Management. Continuum (Minneap Minn). 2014;20(6 Sports Neurology):1552-1569.
5. Signoretti S, Lazzarino G, Tavazzi B, Vagnozzi R. The pathophysiology of concussion. PM R. 2011;3(10 Suppl 2):S359-368.
6. Sharp DJ, Jenkins PO. Concussion is confusing us all. Pract Neurol. 2015;15(3):172-186.