Traumatic Brain Injury (TBI) may result from anywhere between a simple blow to the head to a penetrating injury to the brain. In the United States, around 1.7 million people suffer TBI with older adolescents (ages 15 to 19 years) and older adults (ages 65 years and older) among the most likely to sustain a TBI. Frontal and temporal areas of the brain are the main areas involved. Mild TBI (mTBI), also known as brain concussion, initially considered as a benign event, has galvanized tremendous attention for some of its adverse neuropsychological outcomes in civilians (e.g., athletes who play contact sports) as well as military personnel. Moderate to severe TBI is a primary cause of injury-induced death and disability. In the United States, It has an annual incidence of approximately 500 in 100,000. However, around 80% of all TBI cases are categorized as mild head injuries.
Mild TBI or brain concussion usually results from closed brain injuries, the incident when the head is being struck by an object, such as a bat or a fist during a fight or when the head is affected by a nearby blast or explosion. Such injuries have shown to affect the structural integrity of the neurons.
Male to female ratio is 2:1. A private study of 1084 individuals with traumatic brain injuries revealed that TBI was a high-risk factor not only for post-traumatic stress disorder (PTSD) but also for other psychiatric disorders. Statistically, the Center for Disease Control and Prevention (CDC) has estimated that annually, about 1.5 million Americans survive a traumatic brain injury (TBI). Among these, approximately 230,000 are hospitalized. In 2000, there were 10,958 TBI diagnoses. In 2015, this number jumped to 344,030. Mortality across all TBI severities is approximately 3%, yet morbidity is more difficult to estimate.
Diffuse axonal injury (DAI) underlying mild to moderate TBI potentially results from any shearing, stretching, or twisting injuries to the neuronal axons. This phenomenon is mainly seen at the junction of the gray and white matter where neuronal axons are entering a more dense, fatty (myelinated), and less fluid-filled white matter. Such shearing forces cause the neuronal axon to be stretched, and the subsequent damage to cytoskeleton may lead to axonal swelling, increased permeability, calcium influx, detachment, and axonal death. Diffuse laminar necrosis is typically seen on autopsy. 
The events of posttraumatic accumulation of fluid, (cerebral edema), the disruption of the blood-brain barrier (BBB), and histopathological changes were studied in a mice model studies. Researchers have discovered significant neuronal cell death in some areas of the left hippocampus following a closed-head injury. An immunohistochemistry using multiple antibodies to the amyloid precursor protein and/or amyloid precursor protein-like proteins showed a novel axonal degeneration in the striatum, corpus callosum, and injured cortex. Histological evaluation of injured brains illustrated an expansion of the cortical cavity, enlargement of the lateral ventricles, deformation of the hippocampus, and thalamic calcifications.
In addition to the biomarkers released secondary to the neuronal injury (proteins that leak from astrocytes and neuron when are damaged), researchers have studied the role of cJun N-terminal kinase (JNK) that mediates neuronal death in response to stress and injury in the CNS and peripheral nervous system. Some of the other variables in settings of TBI include interleukin-1beta concentration, aspartate, glutamate in the CSF, and microdialysate lactate, glucose, pyruvate, and glycerol, along with brain tissue partial oxygen pressure and intracranial pressure. Most of these were measured while studying different modalities of therapy like hyperbaric oxygen treatment and hypothermia in TBI.
Unfortunately, many incidents of mild-moderate traumatic brain injuries in our everyday life do not even present to the emergency room or other healthcare settings, especially when they are associated with sports-related or recreation-related settings. Per the Journal of Pediatrics, cases of TBI in children of age 18 and under were believed to be caused mainly by sports and recreation-related concussions. However, the vast majority of service members and veterans experience a TBI in a non-deployed setting (diagnosed in up to 80%) due to the nature of their training or participation in sports and leisure activities.
The American Journal of Psychiatry published a study in 2015 that showed the prevalence of comorbidity of disorders among soldiers classified at T2 (3 months post-deployment) as experiencing major depressive episode, PTSD, generalized anxiety disorder, or suicidality in the past 30 days went up from 12.9% to 16.8% at T3 (9 months post-deployment).
Apart from the obvious physical complaints, neuropsychiatric symptoms noticeably vary out of proportion with the severity of the correspondent TBI. The patients who experience a post-concussion syndrome may have somatic complaints like a headache, dizziness, cognitive impairment, and neuropsychiatric symptoms like anxiety, irritability, depression, and sleep disorders. They may have frontal lobe syndrome with behaviors like labile affect, poor social judgment, and lewd behavior with loss of social graces, aggressiveness, and perseveration. These are common in up to 23% of adult patients with TBI.
Working memory is largely affected among patients with mTBI. They may also abuse drugs and experience PTSD symptoms more than the general population (up to 18% and 22%, respectively).
Psychotic disorder following traumatic brain injury (PDFTBI) occurs in 0.7% to 8.9% of persons who sustain TBI. Psychosis following TBI causes patients to have deficits: brain-injured (primarily executive), and psychotic (executive and semantic). Although infrequent, auditory hallucinations are a debilitating complication of TBI that can manifest itself 4 to 5 years after the occurrence of the TBI. The latency between traumatic brain injury (TBI) and the onset of psychotic symptoms is highly variable but typically characterized by paranoid delusions and auditory hallucinations, with visual hallucinations and negative symptoms being less common. Studies showed that PDFTBI has an additive effect on executive dysfunction among TBI patients. Significant executive dysfunction was evident in patients with PFTBI on all measures.
Level of consciousness (LOC), altered mental status (AMS), post-traumatic amnesia (PTA), and Glasgow coma scale (GCS) are used in the evaluation of the severity of the TBI (see table 1). Moreover, recent studies recommend implementation of the portable cognitive assessment tools at the time of the incidence of the TBI as a potential indicator for the long-term effects. One of the scales used in measuring the severity of deficit in cognitive functioning is Ranchos Los Amigos Scale, as below:
Comprehensive evaluation should include the utilization of the following tools:
CT head and MRI are used to measure changes in anatomical or physiological parameters of TBI. These include hemorrhage, edema, vascular injury, and intracranial pressure. However, for most cases of mild TBI, CT and MRI often show no abnormalities.
Diffusion tensor imaging (DTI) is used to detect axonal injury for mild to moderate TBI.
Functional MRI (fMRI) is often used to differentiate TBI from control groups and has been used to study activation patterns in patients with TBI.
Brain Perfusion Single Photon Emission Computed Tomography (SPECT) is used to measure cerebral blood flow and activity patterns. It is indicated for the evaluation of TBI in the absence of anatomical findings. Some authors suggest that SPECT should be part of a clinical evaluation in the diagnosis and management of TBI. A recent meta-analysis showed that PTSD patients have significant activation of the mid-line retrosplenial cortex and precuneus when presented with trauma-related stimuli. The preliminary data suggest it has a potential role in distinguishing PTSD from TBI. When compared to subjects with TBI, relative increases in perfusion were observed in PTSD in the limbic regions, cingulum, basal ganglia, insula, thalamus, prefrontal cortex, and temporal lobes. These results suggest that TBI is associated with hypoperfusion while PTSD is associated with regional hyperperfusion, providing important insights regarding pathophysiological differences between these disorders. Recent studies are also highly promising in differentiating PTSD from TBI using both region of interest (ROI) and visual readings (VR) analysis (The study was published on July 1, 2015, in PLOS One).
Treatment of psychiatric symptoms following concussion/mTBI should be based on individual factors and the nature and severity of symptom presentation. It may include physiotherapy, psychotherapeutic, and pharmacological treatment modalities.
TBI may result in a decrease in short and long-term global health (physical and behavioral) and put them at an elevated risk for disability, pain, and handicap (i.e., difficulty with a return to work, maintaining peer networks.) Rehabilitation therapies like physical therapy, occupational therapy, speech-language therapy, and assistive devices and technologies may help to strengthen patients to perform their activities of daily living.
General Guidelines for Using Medications:
Other Considerations in Treating PTSD in Patients with mTBI
Management of Sleep Dysfunction
Immediately following TBI, the difficulty in falling asleep and frequent waking is common; whereas, after several years excessive somnolence is more typical.
Hyperbaric Oxygen Therapy (HBO2)
Some researchers discussed the role of oxygen delivered at supraphysiological amounts in the treatment of TBI. A study published in 2010 included closed-head trauma victims with GCS scores of 3 to 8 after resuscitation, without effects from paralytics, sedation, alcohol, and/or street drugs. HBO2 treatment began within 24 hrs post injury admission to hospital with a mild or moderate TBI compared the effect of HBO2 to normobaric oxygen. They found a significant post-treatment effect of HBO2 on cerebral oxidative metabolism due to its ability to produce a brain tissue PO2 greater than or equal to 200 mmHg (higher cerebral blood flow lead to higher PO2, lower levels of lactate by 13% compared to control group, and lower intracranial pressure). However, in severe TBI, it is not an all or nothing phenomenon but represents a graduated effect. Some controversy still surrounds the use of HBO2 due to the limitations of studies such as the lack of blinding to the intervention, cost, time-consuming practice, and the validity of the actual diagnoses of the patients with reported TBI and PTSD who had a subsequent improvement.
Studies have shown some controversy in the practicality of this practice depending on the patient’s characteristics (age, the initial GCS, the presence or absence of pupillary abnormalities, and CT-based classification of the severity of the injury). In general, there has been an increased belief that cooling the body to systemic temperatures around 34 C to 35 C, helps reduce secondary injury and improve behavioral outcomes. Studies have suggested that this occurs because of the ability of hypothermia to suppress post-traumatic inflammatory response, in turn, preserving the blood-brain barrier and reducing the number of cytokines released as well as glutamate.
TBI in general and mTBI, in particular, are heterogeneous pathological processes. Although post-concussion syndrome and personality changes are frequently presenting symptoms, research remains to be done on the unremarkable neuroimaging results in TBI, the life experiences of young TBI patients with co-morbid symptoms that persist well into adulthood, and the characteristics of families that contribute to function or dysfunction following a TBI. Many therapeutic trials were questioned including hormonal therapy with progesterone in the first few hours that aimed to augment myelin regeneration and neural recovery, but results were not encouraging. Interestingly enough, there are still many questions that demand answers. These are prognosis, permanency of symptoms, best acute and long-term treatment strategies, and whether literature in sports-related TBI can be used as a guide. Imaging and therapeutic intervention research are still underway in hopes of delivering better outcomes.
The management of TBI is multidisciplinary. Treatment of psychiatric symptoms following concussion/mTBI should be based on individual factors and the nature and severity of symptom presentation. It may include physiotherapy, psychotherapeutic, and pharmacological treatment modalities. The prognosis of patients with TBI depends on the initial GCS and neurological deficits at presentation. Those patients with a GCS less than 12 usually have a long recovery and many continue to have residual neuro-psychiatric deficits. (Level V)
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