Mild traumatic brain injury (mTBI) makes up 85% to 90% of all traumatic brain injury (TBI) cases. Based on clinical outcomes and formal research, most people with an mTBI will have self-limiting symptoms (<3 months) and follow a predictable course toward good recovery. A small number (<5%) of mTBI patients, however, will go on to have persistent symptoms, placing them in a category described as postconcussion syndrome (PCS). PCS implies both chronicity and a group of signs and symptoms and is a possible sequela of mTBI. Patients with PCS present with slow and/or incomplete recovery, associating them with higher levels of disability and frequent healthcare service utilization.
The etiology of PCS has never been agreed on. It has been well documented that in the early stages after a mTBI, symptoms are largely a result of numerous organic factors occurring within the brain. These can occur at the macroscopic and microscopic levels. Prolongation of symptoms however, such as those seen in patients with PCS, are thought to be perpetuated by early psychological distress, preexisting mental health disorders, and mental health. , Several studies have suggested early psychological factors play an important etiological role in PCS also. Adequately addressing these psychological elements can help toward symptomatic and functional recovery. Premorbid factors, such as biopsychosocial stability of the individual and the complexity of the initial injury, also have been suggested to play a role in etiology. Knowledge regarding etiologies of PCS also provides a basis for the development of a treatment plan.
Diagnostic criteria
There is no universally accepted definition of PCS. It is loosely described as a constellation of symptoms occurring in individuals with mTBI. The onset and duration of symptoms remain vague, although many have suggested symptom duration of at least 3 months. Objective findings including physical examination, radiological evidence, and laboratory findings are largely absent, leaving the diagnosis of PCS based almost entirely on subjective symptoms, which may be problematic.
Currently, two criteria exist for PCS:
- 1.
Diagnostic and Statistical Manual of Mental Disorders , Fourth Edition (DSM-IV, Table 52.1 )
TABLE 52.1
Postconcussional Syndrome (Research Criteria from the DSM-IV)
These criteria must be met for the diagnosis of postconcussional disorder:
- A.
Requires history of head trauma causing significant cerebral concussion
- B.
Objective evidence on neuropsychological testing of decline in some of his or her cognitive abilities, e.g., attention, concentration, learning, or memory
- C.
The person must report three or more subjective symptoms, and these symptoms must be present for at least 3 months:
- 1.
Easily fatigued
- 2.
Disordered sleep
- 3.
Headache
- 4.
Vertigo or dizziness
- 5.
Irritability or aggression on little or no provocation
- 6.
Anxiety, depression, or affective lability
- 7.
Changes in personality (social or sexual inappropriateness)
- 8.
Apathy or lack of spontaneity
- 1.
Disturbance causes significant impairment in social or occupational functioning and represents a significant decline from a previous level of functioning.
DSM-IV , Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition.
- A.
- 2.
International Classification of Diseases 10th edition (ICD-10, Table 52.2 ).
TABLE 52.2
Postconcussional Syndrome (Research Criteria from the ICD-10)
For those undertaking research into this condition, these criteria are recommended:
- A.
The general criteria of F07 must be met. The general criteria for F07, personality and behavioral disorders caused by brain disease, damage, and dysfunction, are as follows: G1. Objective evidence (from physical and neurological examination and laboratory tests) and/or history of cerebral disease, damage, or dysfunction. G2. Absence of clouding of consciousness and of significant memory deficit. G3. Absence of sufficient or suggestive evidence for an alternative causation of the personality or behavior disorder that would justify its placement in section F6 (other mental disorders caused by brain damage and dysfunction and to physical disease).
- B.
History of head trauma with loss of consciousness, preceding the onset of symptoms by a period of up to 4 weeks (objective electroencephalography [EEG], brain imaging, or oculonystagmographic evidence for brain damage may be lacking).
- C.
At least three of these:
- 1.
Complaints of unpleasant sensations and pains, such as headache, dizziness (usually lacking the features of true vertigo), general malaise and excessive fatigue, or noise intolerance
- 2.
Emotional changes, such as irritability, emotional lability—both easily provoked or exacerbated by emotional excitement or stress, or some degree of depression and/or anxiety
- 3.
Subjective complaints of difficulty in concentration and in performing mental tasks and of memory complaints without clear objective evidence (e.g., psychological tests) of marked impairment
- 4.
Insomnia
- 5.
Reduced tolerance to alcohol
- 6.
Preoccupation with aforementioned symptoms and fear of permanent brain damage to the extent of hypochondriacal overvalued ideas and adoption of a sick role
- 1.
ICD-10 , International Classification of Diseases 10th Edition
- A.
The advantage of employing formal criteria is that it provides a basic framework for healthcare providers who may have minimal clinical experience in managing patients with a history of remote mTBI. It also provides a list of commonly reported symptoms that can guide clinicians during the initial history intake and gathering of objective evidence (i.e., physical and neurological examination). It can also provide a working definition for research. The DSM-IV criteria require that “reported disturbances cause significant impairment in social or occupational functioning and represent a significant decline from a previous level of functioning.” The focus on functional decline implies a more recent event. Its presence can help clinicians disentangle chronic premorbid symptoms versus recent symptoms resulting from a new mTBI.
Having mentioned these utilities, limitations when using these criteria exist, and strict adherence to these guidelines is not recommended. The most obvious limitation seen is the emphasis on subjective symptoms over objective findings (e.g., neuropsychological tests). The ICD-10 criteria, for example, do not require objective evidence of cognitive complaints. Tables 52.1 and 52.2 list symptoms that are vague and can be present in patients with a multitude of medical and psychological diagnoses. In fact, the psychological measures used in several studies that looked at PCS, the Hospital Anxiety and Depression Scale or the Impact of Events Scale, were developed to address emotional distress in medical patients and are not specific to mTBI.
On the contrary, the DSM-IV criteria do require a neuropsychological assessment as a measure of cognitive function. They do not, however, provide rigid guidelines regarding when the assessment should be administered. We believe this degree of freedom is in fact appropriate and allows testing to be individualized as opposed to simply being a protocol-driven decision. Furthermore, the cutoff of 3 months for symptom reporting may not always apply to each individual case. The rigid guideline of waiting 3 months before diagnosis of PCS should be reconsidered because of such high variability of patient presentation, risk factor associations, and related lack of relevance to treatment decision making.
As discussed earlier, the ICD-10 and DMS-IV criteria have some major discrepancies between them. Studies comparing prevalence rates using the different criteria show a three to six times higher rate using the DSM-IV. Higher prevalence rates using DMS-IV is likely because of the additional requirements of documented objective evidence of cognitive impairment and impairment in functioning required by the ICD-10.
Clinical assessment
Clinical assessment should include a detailed history and physical, including an evaluation of concomitant medical conditions, injury-related diagnoses, and psychosocial issues.
Fig. 52.1 lists common medical and psychosocial conditions that may influence the reporting of symptoms after most recent mTBI. Diagnosis of depression, posttraumatic stress, anxiety, and certain personality types (high achievers, dependent, or insecure) should be carefully reviewed because they have shown to be predictive of development of PCS. , , Other risk factors that have also been identified are higher symptoms scores acutely, early manifestation of emotional symptoms, migraine headaches, and within a military population history of TBI, both predeployment and deployment psychological distress and loss of consciousness (LOC) with the injury.
