Chronic post-traumatic headache: clinical findings and possible mechanisms

Walking the Tightrope: A Proposed Model of Chronic Pain and Stress

Pain and stress are both phenomena that challenge an individual’s homeostasis and have significant overlap in conceptual and physiological processes. Allostasis is the ability to adapt to pain and stress and maintain homeostasis; however, if either process becomes chronic, it may result in negative long-term outcomes. The negative effects of stress on health outcomes on physiology and behavior, including pain, have been well documented; however, the specific mechanisms of how stress and what quantity of stress contributes to the maintenance and exacerbation of pain have not been identified, and thus pharmacological interventions are lacking. The objective of this brief review is to: 1. identify the gaps in the literature on the impact of acute and chronic stress on chronic pain, 2. highlight future directions for stress and chronic pain research; and 3. introduce the Pain-Stress Model in the context of the current literature on stress and chronic pain. A better understanding of the connection between stress and chronic pain could provide greater insight into the neurobiology of these processes and contribute to individualized treatment for pain rehabilitation and drug development for these often comorbid conditions.

Exploring naturally occurring clinical subgroups of post-traumatic headache

Objective

To explore naturally occurring clinical subgroups of post-traumatic headache.

Background

Persistent post-traumatic headache (PTH) is defined as a headache developing within 7 days of an injury that lasts for greater than 3 months. However, there is no evidence available from the International Classification of Headache Disorders (ICHD) based classification between persistent and acute PTH based on clinical phenotypes.

Methods

We conducted a retrospective study using the Stanford Research Repository Cohort Discovery Tool. We reviewed 500 electronic patient charts between January 2015 to September 2019 using inclusion criteria of adults older than 18 years with a diagnosis of PTH. The following variables were extracted from each patient’s chart: diagnosis of PTH as dependent variable, and predictor variables as age, sex, history of migraine, loss of consciousness during head injury, pre-existing psychological history, duration of PTH and new PTH-associated comorbidities (e.g. new onset vertigo, post-traumatic stress disorder). Logistic regression was employed to identify clinical phenotypes predicting persistent PTH. All predictor variables were tested in one block to determine their predictive capacity while controlling for other predictors in the model. Two-step cluster analysis was conducted to identify naturally occurring PTH subgroups.

Results

A total of 300 patients were included (150 acute, 150 persistent PTH) with a median age of 47 years (IQR 31, 59) and female: male ratio of 2.7:1. Two hundred patients were excluded due to misdiagnoses. Pre-existing psychological history (standardized beta 0.16), history of migraine (0.20), new PTH-associated comorbidities (0.23) and medication overuse (0.37) statistically significantly predicted the presence of persistent PTH (p <  0.0001). Clustering analysis revealed PTH subgrouping comparable to ICHD-based classification: 140 patients in Cluster 1 (76% persistent PTH) and 160 patients in Cluster 2 (83% acute PTH). Four distinct clusters were found within persistent PTH.

Conclusion

Pre-existing psychological history, history of migraine, new PTH-associated comorbidities and medication overuse predicted the occurrence of persistent PTH as well as two naturally occurring PTH clusters correlating to acute and persistent PTH. Management emphasis should focus on these phenotypes.

Update on the prevalence of persistent post-traumatic headache in adult civilian traumatic brain injury: protocol for a systematic review and meta-analysis

INTRODUCTION

Traumatic brain injury (TBI) is a major public health concern. Persistent post-traumatic headache (PTH) is a common consequence of TBI affecting productivity and quality of life. The only review providing information about headache prevalence after TBI was published in 2008, combined data from civilian and military TBI, and was strictly derived from Medline database. Due to recent changes in TBI diagnosis and trauma epidemiology, the aim of the current study is to perform a systematic review and meta-analysis to derive updated prevalence estimates of persistent PTH in adult civilian TBI.

METHODS AND ANALYSIS

The methods have been defined following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies published from 2008 to 2019 will be identified searching the electronic databases Medline, Embase, Cochrane, Google Scholar, Directory of Open Access Journals and Web of Science. Retrieved records will be independently screened by two authors and relevant data will be extracted from studies reporting data on persistent PTH prevalence among civilian TBI individuals (≥16 years). The pooled prevalence estimates of any form of headache will be computed applying random-effects meta-analysis. Heterogeneity will be assessed using the I2 statistic and explored through subgroup analyses considering TBI severity (mild vs moderate/severe). Estimations of risk of bias will be performed using the Risk of Bias Tool for Prevalence Studies.

ETHICS AND DISSEMINATION

The result of this systematic review will be published in a peer-reviewed journal and disseminated at relevant conferences presentations. Formal ethical approval is not required because we will search and evaluate only existing sources of literature. By focusing on studies conducted in the last decade, this review will provide the most up-to-date information about the global prevalence of persistent PTH after TBI. Considering the economical and social burden of persistent PTH after TBI, accurate estimates of this problematic disorder is of utmost importance for planning, implementing and evaluating prevention interventions.

PROSPERO REGISTRATION NUMBER

CRD42018094138.

Enhanced descending pain facilitation in acute traumatic brain injury

Acute and persistent pain are recognized consequences of TBI that can enhance suffering and significantly impair rehabilitative efforts. Both experimental models and clinical studies suggest that TBI may result in an imbalance between descending pain facilitatory and inhibitory pathways. The aim of this study was to assess the role of enhanced descending serotonin-mediated pain facilitation in a rat TBI model using selective spinal serotonergic fiber depletion with 5, 7-dihydroxytryptamine (DHT). We observed significant hindpaw allodynia in TBI rats that was reduced after DHT but not vehicle treatment. Immunohistochemical studies demonstrated profound spinal serotonin depletion in DHT-treated rats. Furthermore, lumbar intrathecal administration of the 5-HT₃ receptor antagonist ondansetron at 7 days post-injury (DPI), when hindpaw allodynia was maximal, also attenuated nociceptive sensitization. Additional immunohistochemical analyses of the lumbar spinal cord at 7 DPI revealed a robust bilateral microglial response in the superficial dorsal horns that was significantly reduced with DHT treatment. Furthermore, serotonin depletion also prevented the TBI-induced bilateral increase in c-Fos positive cells within the Rexed laminae I and II of the dorsal horns. These results indicate that in the weeks following TBI, pain may be responsive to 5-HT₃ receptor antagonists or other measures which rebalance descending pain modulation.

CGRP-dependent and independent mechanisms of acute and persistent post-traumatic headache following mild traumatic brain injury in mice

Background

Acute and persistent post-traumatic headache are often debilitating consequences of traumatic brain injury. Underlying physiological mechanisms of post-traumatic headache and its persistence remain unknown, and there are currently no approved therapies for these conditions. Post-traumatic headache often presents with a migraine-like phenotype. As calcitonin-gene related peptide promotes migraine headache, we explored the efficacy and timing of intervention with an anti- calcitonin-gene related peptide monoclonal antibody in novel preclinical models of acute post-traumatic headache and persistent post-traumatic headache following a mild traumatic brain injury event in mice.

Methods

Male, C57Bl/6 J mice received a sham procedure or mild traumatic brain injury resulting from a weight drop that allowed free head rotation while under minimal anesthesia. Periorbital and hindpaw tactile stimulation were used to assess mild traumatic brain injury-induced cutaneous allodynia. Two weeks after the injury, mice were challenged with stress, a common aggravator of migraine and post-traumatic headache, by exposure to bright lights (i.e. bright light stress) and cutaneous allodynia was measured hourly for 5 hours. A murine anti- calcitonin-gene related peptide monoclonal antibody was administered after mild traumatic brain injury at different time points to allow evaluation of the consequences of either early and sustained calcitonin-gene related peptide sequestration or late administration only prior to bright light stress.

Results

Mice with mild traumatic brain injury, but not a sham procedure, exhibited both periorbital and hindpaw cutaneous allodynia that resolved by post-injury day 13. Following resolution of injury-induced cutaneous allodynia, exposure to bright light stress re-instated periorbital and hindpaw cutaneous allodynia in injured, but not sham mice. Repeated administration of anti-calcitonin-gene related peptide monoclonal antibody at 2 hours, 7 and 14 days post mild traumatic brain injury significantly attenuated the expression of cutaneous allodynia when evaluated over the 14-day post injury time course and also prevented bright light stress-induced cutaneous allodynia in injured mice. Administration of anti-calcitonin-gene related peptide monoclonal antibody only at 2 hours and 7 days after mild traumatic brain injury blocked injury-induced cutaneous allodynia and partially prevented bright light stress-induced cutaneous allodynia. A single administration of anti-calcitonin-gene related peptide monoclonal antibody after the resolution of the peak injury-induced cutaneous allodynia, but prior to bright light stress challenge, did not prevent bright light stress-induced cutaneous allodynia.

Conclusions

We used a clinically relevant mild traumatic brain injury event in mice along with a provocative stimulus as novel models of acute post-traumatic headache and persistent post-traumatic headache. Following mild traumatic brain injury, mice demonstrated transient periorbital and hindpaw cutaneous allodynia suggestive of post-traumatic headache-related pain and establishment of central sensitization. Following resolution of injury-induced cutaneous allodynia, exposure to bright light stress re-established cutaneous allodynia, suggestive of persistent post-traumatic headache-related pain. Continuous early sequestration of calcitonin-gene related peptide prevented both acute post-traumatic headache and persistent post-traumatic headache. In contrast, delayed anti-calcitonin-gene related peptide monoclonal antibody treatment following establishment of central sensitization was ineffective in preventing persistent post-traumatic headache. These observations suggest that mechanisms involving calcitonin-gene related peptide underlie the expression of acute post-traumatic headache, and drive the development of central sensitization, increasing vulnerability to headache triggers and promoting persistent post-traumatic headache. Early and continuous calcitonin-gene related peptide blockade following mild traumatic brain injury may represent a viable treatment option for post-traumatic headache and for the prevention of post-traumatic headache persistence.

Abbreviations

CA Cutaneous allodynia CGRP Calcitonin gene-related peptide mTBI Mild traumatic brain injury PTH Post-traumatic headache APTH Acute post-traumatic headache PPTH Persistent post-traumatic headache

Practice Current: How do you diagnose and treat post-concussive headache?

A common complaint after concussion is the development of new or worsening headaches which can make it difficult or even impossible for patients to work or function in their day-to-day lives. Uncertainties associated with the complaints and a wide variety of approaches exist regarding the appropriate work-up and management of these patients. Areas of ongoing debate include the need for neuroimaging; optimal, acute, and preventative treatment; and proper counseling and expectation management. Given the wide variety of potential approaches and the lack of consensus, we sought expert opinion from around the globe on how to evaluate and manage patients with headache following concussion. Similar questions were posed to the rest of our readership in an online survey (links.lww.com/CPJ/A96), the results of which are also presented.

Chronic Central Pain Among Community-Dwelling Survivors of Moderate-to-Severe Traumatic Brain Injury: A Quantitative Sensory Testing Study

Background:

Central pain associated with changes in sensory thresholds is one of the most enduring consequences of major trauma. Yet it remains sparsely studied among community-dwelling survivors of moderate-to-severe traumatic brain injury (TBI).

Purpose:

To describe and compare thermal and mechanical sensory thresholds in home-based patients with and without central pain after moderate-to-severe TBI with a cohort of healthy controls.

Design:

Cross-sectional.

Method:

Thresholds for cold/heat detection, thermal pain, touch, and distorted sensation were gathered using quantitative sensory testing (QST). QST was performed on the painful and contralateral pain-free body regions in TBI participants with pain (TBI-P) and on both forearms in TBI participants without pain (TBI-NP) and healthy controls (HC). Central pain was characterized using the Brief Pain Inventory–Short Form.

Results:

We tested 16 TBI-P patients, 17 TBI-NP patients, and 16 HC. Mean time since injury for TBI patients was 24 ± 15 months. TBI-P and TBI-NP patients showed significant loss in innocuous mechanical sensitivity compared to HC ( F = 18.929; Bonferroni-adjusted p ≤ .001). Right–left differences in cold pain sensations were significantly larger in TBI-P than in TBI-NP and HC participants ( F = 14.352; Bonferroni-adjusted p ≤ .001). Elevated heat sensitivity thresholds were also observed in TBI-P participants but remained within normal range.

Conclusion:

Damage to cutaneous mechanoreceptors is a necessary, but not sufficient, condition for the development of chronic central pain following TBI. Damage or incomplete recovery of cutaneous thermoreceptors may be a contributing factor to chronic pain after TBI.

A qualitative study of LoveYourBrain Yoga: a group-based yoga with psychoeducation intervention to facilitate community integration for people with traumatic brain injury and their caregivers

Purpose: To explore participants' experiences in a group-based yoga with psychoeducation intervention designed to facilitate community integration for people with traumatic brain injury and their caregivers.Materials and methods: We conducted semi-structured interviews with 13 people with traumatic brain injury and three caregivers who had completed LoveYourBrain Yoga, a 6-session, manualized, group-based yoga intervention that incorporates breathing exercises, yoga, meditation, and psychoeducation. Interviews were analyzed using content analysis.Results: We identified seven themes: ease of participation, belonging, sustaining community connection, physical health, self-regulation, self-efficacy, and resilience. All participants valued the community-based yoga studio environment and multifaceted structure of the program. Participants reported improvements in strength, balance, flexibility, and attention control, and a greater sense of belonging, community connection, and ability to move forward with their lives. Participants reported ongoing use of tools (e.g., breathing exercises) to cope with negative emotions and stress. About half of participants sustained relationships built during LoveYourBrain Yoga and felt more capable of accessing other activities in their community.Conclusions: LoveYourBrain Yoga successfully promoted community integration for people with traumatic brain injury. It also facilitated diverse and meaningful physical, psychological, and social health benefits, which suggest that it may be an effective mode of community-based rehabilitation.Implications for rehabilitationTraumatic brain injury survivors often struggle to participate in their community, the ultimate goal of rehabilitationYoga is a holistic therapy with many benefits, yet is not accessible to the traumatic brain injury population at the community levelParticipants in a community-based yoga with psychoeducation intervention in six states experienced diverse and meaningful physical, psychological, and social health benefitsGroup-based yoga with psychoeducation may be an effective mode of community integration and community-based rehabilitation for traumatic brain injury survivors.

Pain with traumatic brain injury and psychological disorders

Traumatic brain injury (TBI) is the cause for long-term disability in more than 3 million patients in the US alone, with chronic pain being the most frequently reported complain. To date, predisposing mechanisms for chronic pain in TBI patients are largely unknown. Psychological disorders, including post-traumatic stress disorder, depression and anxiety following TBI are commonly reported comorbidities to post-traumatic pain. Long term consequences can be debilitating and affect quality of life even when the injury is mild. In this review, we present the most commonly reported chronic pain conditions across the spectrum of severity of TBI, mainly focusing on mild TBI. We discuss chronic post- traumatic headaches, widespread pain as well as post-traumatic central pain. We discuss pain in the context of injury severity and military versus civilian populations. We are only starting to understand the biological mechanisms behind post-traumatic pain and associated psychological distress following TBI, with genetic, biochemical and imaging studies pointing to the dopaminergic, neurotrophic factors and the role of Apolipoprotein. Physiological and neurological mechanisms are proposed to partially explain this interaction between post-traumatic pain and psychological distress. Nevertheless, the evidence for the role of structural brain damage remains incomplete and to a large extent debatable, as it is still difficult to establish clear causality between brain trauma and chronic pain. Finally, general aspects of management of chronic pain post-TBI are addressed.

Narrative Review of the Pathophysiology of Headaches and Photosensitivity in Mild Traumatic Brain Injury and Concussion

The most common symptom of post-concussive syndrome (PCS) is post-traumatic headache (PTH) accompanied by photophobia. Post-traumatic headache is currently categorized as a secondary headache disorder with a clinical phenotype described by its main features and resembling one of the primary headache disorders: tension, migraine, migraine-like cluster. Although PTH is often treated with medication used for primary headache disorders, the underlying mechanism for PTH has yet to be elucidated. The goal of this narrative literature review is to determine the current level of knowledge of these PTHs and photophobia in mild traumatic brain injury (mTBI) in order to guide further research and attempt to discover the underlying mechanism to both symptoms. The ultimate purpose is to better understand the pathophysiology of these symptoms in order to provide better and more targeted care to afflicted patients. A review of the literature was conducted using the databases CINAHL, EMBASE, PubMed. All papers were screened for sections on pathophysiology of PTH or photophobia in mTBI patients. Our paper summarizes current hypotheses. Although the exact pathophysiology of PTH and photophobia in mTBI remains to be determined, we highlight several interesting findings and avenues for future research, including central and peripheral explanations for PTH, neuroinflammation, cortical spreading depolarization and the role of glutamate excitotoxicity. We discuss the possible neuroanatomical pathways for photophobia and hypothesize a possible common pathophysiological basis between PTH and photophobia.

Lifestyle modifications as therapy for medication refractory post-traumatic headache (PTHA) in the military population of Okinawa

Objective

Our aim was 1) to reduce disability, as characterized by headache frequency, duration and severity in patients with post-traumatic headache (PTHA), 2) to reduce the number of medical boards and work limitations in patients with post traumatic headache, and 3) to reduce use of medical resources and clinic visits related to headache or migraine.

Background

Modifiable risk factors for PTHA include stressful life event, sleep disturbances, and medication overuse. Cognitive-behavioral strategies, biofeedback, and relaxation therapy may have an important role in treatment and preventing progression to chronic post-traumatic headache (CPTHA). There is limited literature and a known practice gap for implementation of these techniques.

Design/methods

An IRB approved project focused on patients who were seen for PTHA and CPTHA. 1) Intervention consisted of lifestyle teaching, cognitive-behavioral therapy and biofeedback, supplemented by decreasing polypharmacy. 2) Patients were followed for 2 years and a retrospective review was conducted for 2 years prior to presentation. 3) Outcome measures included reduction in migraine intensity or frequency, improved quality of life, duty status, and decreased utilization of clinic visits.

Results

Over the course of one year, 221 patients were treated for migraines in the Naval Okinawa Neurology Clinic. Of these, 22 active duty service members and 3 Dependents suffered a mild TBI prior to onset. After intervention, there was a 36% decrease in PTHA frequency, 56% decrease in headache severity and 60% of patients had improved quality of life as compared to the 2 years prior to intervention. Twenty-four percent had reduction in polypharmacy. Appointment frequency for migraine decreased from an average of 6.8 to 2.6 per year.

Conclusions

An implemented program geared towards reducing polypharmacy was shown to improve safety, quality of life and reduce hospitalizations from the burden of migraines. Our systematic approach resulted in quality of life improvements and decreased use of medical resources.

Trial registration

Authors received the approval of NAVMED West, Okinawa Naval Hospital Institutional Review Board on January 13th, 2016. QI.2016.0021.

Chronic Upregulation of Cleaved-Caspase-3 Associated with Chronic Myelin Pathology and Microvascular Reorganization in the Thalamus after Traumatic Brain Injury in Rats

Traumatic brain injury (TBI) is associated with long-term disabilities and devastating chronic neurological complications including problems with cognition, motor function, sensory processing, as well as behavioral deficits and mental health problems such as anxiety, depression, personality change and social unsuitability. Clinical data suggest that disruption of the thalamo-cortical system including anatomical and metabolic changes in the thalamus following TBI might be responsible for some chronic neurological deficits following brain trauma. Detailed mechanisms of these pathological processes are not completely understood. The goal of this study was to evaluate changes in the thalamus following TBI focusing on cleaved-caspase-3, a specific effector of caspase pathway activation and myelin and microvascular pathologies using immuno- and histochemistry at different time points from 24 h to 3 months after controlled cortical impact (CCI) in adult Sprague-Dawley rats. Significant increases in cleaved-caspase-3 immunoreactivity in the thalamus were observed starting one month and persisting for at least three months following experimental TBI. Further, the study demonstrated an association of cleaved-caspase-3 with the demyelination of neuronal processes and tissue degeneration in the gray matter in the thalamus, as reflected in alterations of myelinated fiber integrity (luxol fast blue) and decreases in myelin basic protein (MBP) immunoreactivity. The immunofluorescent counterstaining of cleaved-caspase-3 with endothelial barrier antigen (EBA), a marker of blood-brain barrier, revealed limited direct and indirect associations of cleaved caspase-3 with blood-brain barrier damage. These results demonstrate for the first time a significant chronic upregulation of cleaved-caspase-3 in selected thalamic regions associated with cortical regions directly affected by CCI injury. Further, our study is also the first to report that significant upregulation of cleaved-caspase-3 in selected ipsilateral thalamic regions is associated with microvascular reorganization reflected in the significant increases in the number of microvessels with blood-brain barrier alterations detected by EBA staining. These findings provide new insights into potential mechanisms of TBI cell death involving chronic activation of caspase-3 associated with disrupted cortico-thalamic and thalamo-cortical connectivity. Moreover, this study offers the initial evidence that this upregulation of activated caspase-3, delayed degeneration of myelinated nerve fibers and microvascular reorganization with impaired blood-brain barrier integrity in the thalamus might represent reciprocal pathological processes affecting neuronal networks and brain function at the chronic stages of TBI.

Sleep, Sleep Disorders, and Circadian Health following Mild Traumatic Brain Injury in Adults: Review and Research Agenda

A rapidly expanding scientific literature supports the frequent co-occurrence of sleep and circadian disturbances following mild traumatic brain injury (mTBI). Although many questions remain unanswered, the preponderance of evidence suggests that sleep and circadian disorders can result from mTBI. Among those with mTBI, sleep disturbances and clinical sleep and circadian disorders contribute to the morbidity and long-term sequelae across domains of functional outcomes and quality of life. Specifically, along with deterioration of neurocognitive performance, insufficient and disturbed sleep can precede, exacerbate, or perpetuate many of the other common sequelae of mTBI, including depression, post-traumatic stress disorder, and chronic pain. Further, sleep and mTBI share neurophysiologic and neuroanatomic mechanisms that likely bear directly on success of rehabilitation following mTBI. For these reasons, focus on disturbed sleep as a modifiable treatment target has high likelihood of improving outcomes in mTBI. Here, we review relevant literature and present a research agenda to 1) advance understanding of the reciprocal relationships between sleep and circadian factors and mTBI sequelae and 2) advance rapidly the development of sleep-related treatments in this population.

Examining the relationship and clinical management between traumatic brain injury and pain in military and civilian populations

In this review, we discuss the comorbidity of traumatic brain injury (TBI) and pain among civilians and military members, the common causes of pain resulting from TBI, and offer insight about the therapeutic management of TBI symptoms and pain. Traumatic brain injury (TBI) is a debilitating health problem and one of the most common post-TBI symptoms is pain, which can contribute to psychological issues such as Post-traumatic stress disorder (PTSD) and depression. Headache pain appears to be the most common type of pain that results from TBI, yet pain can also be more widespread. Managing TBI symptoms and pain simultaneously is difficult because extensive randomized control and clinical studies assessing the effectiveness of therapeutic approaches are lacking. Pharmacological agents such as antidepressants and Triptans and nonpharmacological therapies such as cognitive rehabilitation and physical therapies are commonly used yet it is unknown how effective these therapies are in the long-term. A combination of pharmacological and non-pharmacological therapies is often more effective for managing TBI symptoms and pain than either treatment alone. However, future research is needed to determine the most therapeutic approaches for managing the comorbidity of pain and TBI symptoms in the long term. This review offers suggestions for such future studies.

Conditions Associated with Essential Tremor in Veterans: A Potential Role for Chronic Stress

Background

Increased depression, hearing loss, dementia, alcoholism, and mortality in essential tremor patients remain unexplained. We investigated whether conditions associated with tremor are linked to chronic stress.

Methods

The FY2013 Veterans Affairs database was queried for 38 selected dual diagnosis combinations in 5,854,223 veterans aged 21–95 years.

Results

Post-traumatic stress disorder, anxiety, and depression were the most common psychiatric diagnoses in tremor patients, with the odds ratio exceeding 2 in all 15-year cohorts. Depending on age, patients with essential tremor were more likely than those without to have obsessive–compulsive disorder, bipolar illness, schizophrenia, use tobacco and abuse alcohol, have hypertension, obesity, hyperlipidemia, diabetes, vitamin D deficiency, coronary and cerebrovascular diseases, congestive heart failure, stroke, asthma, hypothyroidism, irritable bowel syndrome, renal insufficiency, alcoholic liver disease, hearing loss, glaucoma, macular degeneration, migraine, epilepsy, idiopathic polyneuropathy, history of head trauma, and ‘Alzheimer’s dementia. In contrast, lung and colorectal cancer, amyotrophic lateral sclerosis, psychostimulant abuse, and rheumatoid arthritis were not more common.

Discussion

Post-traumatic stress disorder, anxiety, and depression, strongly associated with essential tremor, are known risk factors for poor health habits, tobacco use and alcohol abuse; collectively these are risk factors for vascular disease, with further negative health consequences for multiple organ systems. As essential tremor is associated with all these conditions, we propose that chronic stress is not only responsible for the conditions associated with tremor but in some cases itself directly and indirectly induces essential tremor, so that tremor and poor health share a common cause.

Traumatic Brain Injury Disrupts Pain Signaling in the Brainstem and Spinal Cord

Chronic pain is a common consequence of traumatic brain injury (TBI) that can increase the suffering of a patient and pose a significant challenge to rehabilitative efforts. Unfortunately, the mechanisms linking TBI to pain are poorly understood, and specific treatments for TBI-related pain are still lacking. Our laboratory has shown that TBI causes pain sensitization in areas distant to the site of primary injury, and that changes in spinal gene expression may underlie this sensitization. The aim of this study was to examine the roles that pain modulatory pathways descending from the brainstem play in pain after TBI. Deficiencies in one type of descending inhibition, diffuse noxious inhibitory control (DNIC), have been suggested to be responsible for the development of chronic pain by allowing excess and uncontrolled afferent nociceptive inputs. Here we expand our knowledge of pain after TBI in two ways: (1) by outlining the neuropathology in pain-related centers of the brain and spinal cord involved in DNIC using the rat lateral fluid percussion (LFP) model of TBI, and (2) by evaluating the effects of a potent histone acetyl transferase inhibitor, anacardic acid (AA), on LFP-induced pain behaviors and neuropathology when administered for several days after TBI. The results revealed that TBI induces transient mechanical allodynia and a chronic persistent loss of DNIC. Further, while short-term AA treatment can block acute nociceptive sensitization and some early neuropathological changes, this treatment neither prevented the loss of DNIC nor did it alter long-term neuropathological changes in the brain or spinal cord.

Secondary intracranial hypertension (pseudotumor cerebri) presenting as post-traumatic headache in mild traumatic brain injury: a case series

BACKGROUND

Cerebral edema peaks 36-72 h after moderate traumatic brain injury but thought to be uncommon after mild traumatic brain injury. Post-traumatic headache can develop 48-72 h post-injury, perhaps reflecting the developing cerebral edema. Pseudotumor cerebri can result from various causes, including cerebral edema, and is characterized by increased intracranial pressure, headache, visual, and other common symptoms. Our objective was to report a phenotypically identifiable post-traumatic headache subtype.

CASE SERIES PRESENTATION

This case series of six pediatric patients with post-traumatic pseudotumor cerebri was assessed at 48-120 h post-primary injury with new or a change in symptoms such as headache, vision, auditory, balance, and cognition. Clinical findings included slight fever, neck/head pain, papilledema or cranial nerve deficit (6th), and lack of coordination. Elevated cerebral spinal fluid pressure was documented by lumbar puncture, with no infection. Symptoms improved with treatment specific to post-traumatic headache subtype (lumbar puncture, topiramate, or acetazolamide).

CONCLUSIONS

Recognition of specific post-traumatic headache subtypes after mild traumatic brain injury will expedite treatment intervention to lower intracranial pressure and resolve symptoms.

Assessing and treating primary headaches and cranio-facial pain in patients undergoing rehabilitation for neurological diseases

BACKGROUND

Pain is a very common condition in patient undergoing rehabilitation for neurological disease; however the presence of primary headaches and other cranio-facial pains, particularly when they are actually or apparently independent from the disability for which patient is undergoing rehabilitation, is often neglected. Diagnostic and therapeutic international and national guidelines, as well as tools for the subjective measure of head pain are available and should also be applied in the neurorehabilitation setting. This calls for searching the presence of head pain, independently from the rehabilitation needs, since pain, either episodic or chronic, interferes with patient performance by affecting physical and emotional status. Pain may also interfere with sleep and therefore hamper recovery.

METHODS

In our role of task force of the Italian Consensus Conference on Pain in Neurorehabilitation (ICCPN), we have elaborated specific recommendations for diagnosing and treating head pains in patients undergoing rehabilitation for neurological diseases.

RESULTS AND CONCLUSION

In this narrative review, we describe the available literature that has been evaluated in order to define the recommendations and outline the needs of epidemiological studies concerning headache and other cranio-facial pain in neurorehabilitation.

Disability from posttraumatic headache is compounded by coexisting posttraumatic stress disorder

BACKGROUND

Posttraumatic headache (PTH) occurs in up to 82% of patients with traumatic brain injury (TBI). Posttraumatic stress disorder (PTSD) occurs in 39% of those with PTH. This study evaluates whether PTSD affects PTH disability.

METHODS

Eighty-six patients with TBI were prospectively evaluated in a secondary care trauma center. Headache disability was assessed using the Headache Impact Test version 6 and signs indicative of PTSD using the PTSD Check List Civilian version.

RESULTS

Increased PTSD-type symptoms were significantly associated with increased headache disability (p<0.001), as were employment status and loss of consciousness (p=0.049 and 0.016, respectively). Age was negatively correlated with headache disability (Spearman's correlation rho=0.361, p=0.001).

CONCLUSION

Increased severity of PTSD-type symptoms is significantly associated with increased headache disability in patients with chronic PTH. Managing PTSD symptoms in patients with chronic PTH may facilitate headache management.

Is Migraine Headache Associated With Concussion in Athletes? A Case-Control Study

OBJECTIVE

The purpose of this study was to investigate the association between migraine headache and concussion in athletes.

DESIGN

Case-control observational study.

SETTING

A university-associated combined sports neurology and orthopedic sports medicine clinic.

PARTICIPANTS

A total of 221 male (n = 140) and female (n = 81) athletes aged 12 to 24 years, including 115 concussion cases (52%) and 106 orthopedic controls (48%), were included in this study.

INTERVENTIONS

Participants completed a one-page questionnaire that recorded their age, sex, reason for visit (concussion vs any other injury), concussion history, and self/immediate family member migraine headache history.

MAIN OUTCOME MEASURES

The odds of having a previous history of migraine headache were compared in the concussion group versus orthopedic controls.

RESULTS

Controlling for between-group differences in age and sex, there was a significant positive association between concussion group status and history of migraine headache [adjusted odds ratio (OR), 1.90; 95% confidence interval (CI), 1.03-3.50. P = 0.039]. However, when including a previous concussion history in the statistical model, this relationship failed to reach significance [adjusted OR, 1.68; 95% CI, 0.89-3.16. P = 0.107].

CONCLUSIONS

These results suggest that there is an association between migraine headache and concussion in athletes, but the cause-effect nature of this relationship cannot be determined. Migraine headache should be considered a modifying factor when caring for concussed athletes.

Mild closed head traumatic brain injury-induced changes in monoamine neurotransmitters in the trigeminal subnuclei of a rat model: mechanisms underlying orofacial allodynias and headache

Our recent findings have demonstrated that rodent models of closed head traumatic brain injury exhibit comprehensive evidence of progressive and enduring orofacial allodynias, a hypersensitive pain response induced by non-painful stimulation. These allodynias, tested using thermal hyperalgesia, correlated with changes in several known pain signaling receptors and molecules along the trigeminal pain pathway, especially in the trigeminal nucleus caudalis. This study focused to extend our previous work to investigate the changes in monoamine neurotransmitter immunoreactivity changes in spinal trigeminal nucleus oralis, pars interpolaris and nucleus tractus solitaries following mild to moderate closed head traumatic brain injury, which are related to tactile allodynia, touch-pressure sensitivity, and visceral pain. Our results exhibited significant alterations in the excitatory monoamine, serotonin, in spinal trigeminal nucleus oralis and pars interpolaris which usually modulate tactile and mechanical sensitivity in addition to the thermal sensitivity. Moreover, we also detected a robust alteration in the expression of serotonin, and inhibitory molecule norepinephrine in the nucleus tractus solitaries, which might indicate the possibility of an alteration in visceral pain, and existence of other morbidities related to solitary nucleus dysfunction in this rodent model of mild to moderate closed head traumatic brain injury. Collectively, widespread changes in monoamine neurotransmitter may be related to orofacial allodynhias and headache after traumatic brain injury.

Osteopathic Manipulative Treatment for Somatic Dysfunction After Acute Severe Traumatic Brain Injury

Somatic dysfunction caused by traumatic brain injury (TBI) may be managed by osteopathic manipulative treatment (OMT). In this case report, the authors describe 2 patients with severe TBI who were each treated with OMT in a level-1 regional trauma center. Both patients received OMT beginning in the acute care phase of injury. Somatic dysfunction improved during the course of treatment, and no adverse effects of OMT were noted. More comprehensive research may clarify the efficacy and adverse effects of OMT as part of multimodal acute care of patients with severe TBI.

Diminished supraspinal pain modulation in patients with mild traumatic brain injury

Background

Chronic pain conditions are highly prevalent in patients with mild traumatic brain injury. Supraspinal diffuse axonal injury is known to dissociate brain functional connectivity in these patients. The effect of this dissociated state on supraspinal pain network is largely unknown. A functional magnetic resonance imaging study was conducted to compare the supraspinal pain network in patients with mild traumatic brain injury to the gender and age-matched healthy controls with the hypothesis that the functional connectivities of the medial prefrontal cortices, a supraspinal pain modulatory region to other pain-related sensory discriminatory and affective regions in the mild traumatic brain injury subjects are significantly reduced in comparison to healthy controls.

Results

The mild traumatic brain injury group (N = 15) demonstrated significantly (P < 0.01, cluster threshold > 150 voxels) less activities in the thalamus, pons, anterior cingulate cortex, insula, dorsolateral prefrontal cortex, and medial prefrontal cortices than the healthy control group (N = 15). Granger Causality Analyses (GCA) indicated while the left medial prefrontal cortices of the healthy control group cast a noticeable degree of outward (to affect) causality inference to multiple pain processing related regions, this outward inference pattern was not observed in the mild traumatic brain injury group. On the other hand, only patients’ bilateral anterior cingulate cortex received multiple inward (to be affected) causality inferences from regions including the primary and secondary somatosensory cortices and the inferior parietal lobe. Resting state functional connectivity analyses indicated that the medial prefrontal cortices of the mild traumatic brain injury group demonstrated a significantly (P < 0.01, F = 3.6, cluster size > 150 voxels) higher degree of functional connectivity to the inferior parietal lobe, premotor and secondary somatosensory cortex than the controls. Conversely, the anterior cingulate cortex of the healthy group demonstrated significantly (P < 0.01, F = 3.84, cluster size > 150 voxels) less degree of functional connectivities to the inferior parietal lobe and secondary somatosensory cortex than their mild traumatic brain injury counterparts.

Conclusions

In short, the current study demonstrates that patients with mild traumatic brain injury and headaches appear to have an altered state of supraspinal modulatory and affective functions related to pain perception.