Signs and Symptoms
Signs and symptoms of MTBI generally fall into four categories: physical, cognitive, emotional, and sleep, and may include:

Physical	Cognitive	Emotional	Sleep
• Headache • Nausea • Vomiting • Balance Problems • Dizziness • Visual Problems • Fatigue • Sensitivity to light • Sensitivity to noise • Numbness/Tingling	• Feeling mentally "foggy" • Feeling slowed down • Difficulty concentrating • Difficulty remembering	• Irritability • Sadness • More emotional • Nervousness	• Drowsiness • Sleeping less than usual • Sleeping more than usual • Trouble falling asleep

Diagnosis
Diagnosing MTBIs can be challenging as symptoms of MTBI are often common to those of other medical conditions and the onset and/or recognition of symptoms may occur days or weeks after the initial injury.^11,18 A systematic assessment of the injury and its manifestations is essential to proper management and reduced morbidity. The Acute Concussion Evaluation (ACE) form (see Figure 2) included in the tool kit was developed to assist physicians with the initial evaluation and diagnosis of patients with known or suspected MTBI. The ACE provides a systematic protocol for the assessment of the key components in diagnosing an MTBI - and serves as the basis for management recommendations provided by the ACE Management Plan.

The ACE contains three major components that require evaluation:

• Characteristics of the injury;
• Types and severity of the symptoms; and
• Risk factors that can lead to a protracted period of recovery.

The following summarizes the information contained on the ACE and outlines steps to take when diagnosing a patient with a known or suspected MTBI. Detailed instructions on how to use the ACE are provided on the backside of the form.

Obtain a description of the injury.

1. Ask the patient (or parent, if child) about how the injury occurred, type of force, and location on the head or body where the force (blow) was received. Different biomechanics of injury may result in differential symptom patterns. For example, an injury that occurs to the occipital lobe of the brain may result in visual changes and balance problems. Determining the cause of the injury may also help to determine the force of the hit or blow the patient sustained. The greater the force associated with the injury, the more likely the patient will present with more severe symptoms. Conversely, significant symptoms associated with a relatively light force might indicate an increased vulnerability to concussion (particularly with a history of multiple concussions) or the presence of other psychological factors contributing to symptom exacerbation.

Figure 2. Acute Concussion Evaluation (ACE)




2. Determine whether amnesia has occurred and attempt to determine length of time of memory dysfunction - before (retrograde) and after (anterograde) injury. Recent research indicates that even seconds of amnesia may be predictive of more serious concussion (ref).
3. Inquire whether loss of consciousness (LOC) occurred or was observed and the length of time the patient lost consciousness. Note: Recent research indicates that up to 90% of concussions do not involve LOC (REF).
4. Inquire whether seizures were observed although this is uncommon.

Record the presence of physical, cognitive, emotional, and sleep symptoms since the injury occurred.

1. Use the ACE to record symptoms reported by the patient (or parent, if child). For all symptoms, determine if present (mark Yes/No), and then ask the patient to define the severity of the symptoms ("1" mild to "6" severe) as experienced within the past 24 hours. Since symptoms can be present prior to the injury (e.g., inattention, headaches), it is important to assess any changes from typical symptom presentation. Note: Any presentation of lingering symptoms associated with concussion indicates incomplete recovery and prudent management is indicated, especially pertaining to at risk activities such as work, school, and sports.
2. Inquire whether any symptoms worsen with exertion , that is, physical activity (e.g., running, climbing stairs, bike riding) and/or cognitive (or mental) activity (e.g., academic studies, multi-tasking at work, reading or other tasks requiring focused concentration). Physicians should be aware that symptoms will typically worsen or re-emerge with exertion, indicating incomplete recovery. Recovery may be protracted with over-exertion.
3. Obtain an overall rating from the patient (or parent) regarding their overall perceived change from their pre-injury self. This rating is helpful in summarizing overall impact of the symptoms. Use the 7 point scale with "0" reflecting no change from normal to "6" reflecting a major change.

Identify risk factors that may complicate the recovery process.
Each of the factors below have been identified through empirical research to be associated with a longer period of recovery from an MTBI. In understanding the nature and extent of the patient's injury, and in assisting their recovery, it is important to identify any of these factors.

1. Concussion history: Assess the number and date(s) of prior concussions, the duration of symptoms for each injury, and whether less biomechanical force resulted in re-injury. The effects of multiple MTBI's may be cumulative, especially if there is minimal duration of time between injuries and less biomechanical force results in subsequent concussion (which may indicate incomplete recovery from the initial trauma). Ref-Iverson G, Gaetz M, Lovell MR, Collins MW. Cumulative effects of concussion in amateur athletes. Brain Injury 2004;18(5):433-43.
2. Headache history: Assess prior personal and/or family history of diagnosis and treatment for headaches. Headaches (migraines in particular) can result in protracted recovery from concussion. Ref-Collins MW, Field M, Lovell MR, Iverson GL, Johnston K, Maroon J, Fu F. Relationship between post-concussion headache and neuropsychological test performance in high school athletes. American Journal of Sports Medicine, 31:168-173; 2003. Mihalik J, Stump J, Collins MW, Lovell MR, Field M, Maroon J. Posttraumatic migraine characteristics in athletes following sports-related concussion. Journal of Neurosurgery 2005;102:850-855.
3. Developmental history: Assess history of learning disabilities, Attention-Deficit/ Hyperactivity Disorder or other developmental disorders. Recovery may take longer in patients with these conditions. Ref-Collins MW, Grindel S, Lovell et al. Relationship between concussion and neuropsychological performance in college football players. JAMA.1999;282(10):964-970.
4. Psychiatric history: Assess for history of depression/mood disorder, anxiety, and/or sleep disorder. Guskiewicz reference.recent article.

Signs of Deteriorating Neurological Function
It is important to assess for whether the patient with a concussion exhibits any signs or reports any symptoms that would indicate deteriorating neurological functioning. Patients should be carefully observed over the first 24-48 hours for the serious signs listed below. If a patient reports any of these signs they should be referred to an emergency department for an immediate medical evaluation.

• Headaches that worsen
• Seizures
• Focal neurologic signs
• Looks very drowsy or can't be awakened
• Repeated vomiting
• Slurred speech
• Can't recognize people or places
• Increasing confusion, unusual behavioral change, or irritability
• Weakness or numbness in arms or legs
• Neck pain
• Unusual behavior change
• Significant irritability

Establishing the Diagnosis.
Following the above assessment, the diagnosis of concussion or MTBI using the following ICD-9 codes may be applicable:

850.0 (Concussion, with no loss of consciousness) - Positive Injury Description (A1 on the ACE), i.e., forcible direct/indirect blow to the head; plus evidence of active symptoms (B) of any type and number related to the trauma; no evidence of LOC (A5), skull fracture, internal bleed.

850.1 (Concussion, with brief loss of consciousness < 1 hour) - Positive Injury Description (A1), i.e., forcible direct/indirect blow to the head; plus evidence of active symptoms (B) of any type and number related to the trauma; positive evidence of LOC (A5); no skull fracture, internal bleed..

850.9 (Concussion, unspecified) - Positive Injury Description (A1), i.e., forcible direct/indirect blow to the head; plus evidence of active symptoms (B) of any type and number related to the trauma; unclear or unknown injury details and unclear evidence of LOC (A5); no skull fracture, internal bleed.

It is recommended that the following ICD-9-CM diagnosis - 959.01 Head injury, unspecified - not be used for concussion as this code is both non-specific and also explicitly excludes the above Concussion diagnoses.