Epidemiology and classification of post-traumatic headache: what do we know and how do we move forward? Comment on Lucas et al., "Prevalence and characterization of headache following mild TBI"

Clinical Trajectories of Comorbidity Associated With Military-Sustained Mild Traumatic Brain Injury: Pre- and Post-Injury

BACKGROUND AND OBJECTIVE

In the US military, traumatic brain injury (TBI) is of distinct importance, at home and in the deployed setting, and is considered a "signature injury of the wars in Afghanistan and Iraq." Since 2000, an estimated 468 424 service members (SMs) have been diagnosed with at least one TBI. We examined the clinical trajectories of a group of 18 comorbidities before and after a military-sustained mild TBI (mTBI).

METHODS

Without making assumptions on causality, a group of 18 conditions often co-occurring with mTBI were identified through literature review and TBI subject matter workgroup consensus. Using data from Military Health System Data Repository, we identified SMs whose first lifetime military mTBI occurred between October 1, 2016, and October 30, 2019. Correlation analyses were used to determine the linear relationship between comorbidities prior to and after mTBI diagnosis. Changes in the period prevalence of comorbidities was calculated.

RESULTS

We identified 42 018 SMs with a first lifetime military mTBI, of which 77.6% had at least one comorbidity. Identified SMs were mostly young (46.1% ages 18-24 years), male (81.4%), and White (64.1%). Up to 180 days prior to an mTBI, the most frequently identified conditions were sleep-related conditions (21.7%), headaches (19.4%), posttraumatic stress disorders (PTSDs) (17.8%), anxiety disorders (11.3%), and cervicogenic disorders (eg, cervicalgia) (10.9%). In the period following mTBI diagnosis, the prevalence of diagnosed conditions increased, especially for visual disturbances (327.2%), cognitive conditions (313.9%), vestibular conditions (192.6%), those related to headache (152.2%), and hearing (72.9%). Sleep-related conditions showed moderate positive correlation with a group of co-occurring conditions, led by cognitive conditions (ϕc = 0.50), anxiety disorders (ϕc = 0.42), PTSDs (ϕc =0.43), and headaches and related conditions (ϕc = 0.38).

CONCLUSION

Results indicate that caring for SMs with mild TBI requires a holistic approach, one that considers the complex nature of SM conditions, prior to sustaining their mTBI, as well as after injury. We found a complex correlation of conditions that suggest SMs with mTBI are undergoing a multifaceted experience, one that may require the development of a targeted multidimensional clinical practice recommendation and practice.

Staying in service with posttraumatic headache

Objective:

To predict the probability of a military outcome (medical discharge/retirement) in patients with mild traumatic brain injury from a clinical analysis of predetermined patient and headache characteristics.

Methods:

This retrospective cohort study sampled all new patients referred for headache evaluation at the Brain Injury Clinic of the Womack Army Medical Center, Ft. Bragg, NC (August 2008–January 2010). Headache characteristics were extracted and analyzed. Multivariable binary logistic regressions were conducted to predict probability of medical discharge/retirement.

Results:

Ninety-five soldiers (age 31.3 ± 7.4 years, male 93.7%) reported 166 headaches. The most common injury cited was a blast (53.7%). Patients with a continuous headache have almost 4 times the odds of a medically related discharge/retirement compared to patients without such a headache (continuous headache regression coefficient estimate: p < 0.042, odds ratio 3.98, 95% Wald confidence interval 1.05–15.07). Results suggest that, compared to service members who did not have a continuous headache, patients with headache histories with severe holocephalic pain who medicate to keep functioning had the highest probability of medical discharge/retirement.

Conclusions:

Certain headache characteristics may be predictive of military outcomes after mild traumatic brain injury, and we propose a profile that may be useful in that prediction. These data could be useful in future attempts to assess and treat patients with posttraumatic headache and to advise longer-term planning for return to duty or discharge.

The Frequent Unusual Headache Syndromes: A Proposed Classification Based on Lifetime Prevalence

BACKGROUND

There is no agreement on a single cutoff point or prevalence for regarding a given disease as rare. The concept of what is a rare headache disorder is even less clear and the spectrum from a very frequent, frequent, occasional to rare headache syndrome is yet to be established.

OBJECTIVE

An attempt has been made to estimate the lifetime prevalence of each of the headache subtypes classified in the ICHD-II.

METHOD

Using the ICHD-II, 199 different headache subtypes were identified. The following classification was made according to the estimated lifetime prevalence of each headache disorder: very frequent (prevalence >10%); frequent (between 1 and 10%); occasional (between 0.07 and 1%); and unusual or rare (<0.07%).

RESULTS

One hundred and fifty-four of 199 (77%) were categorized as unusual headache disorders, 7/199 (4%) as very frequent, 9/199 (5%) as frequent, and 29/199 (15%) as occasional forms of headache disorder.

CONCLUSION

The unusual headache syndromes do not appear to be as infrequent in clinical practice as has been generally believed. About three-fourths of the classified headache disorders found in the ICHD-II can be considered as rare. This narrative review article may be regarded as an introduction to the concept of unusual headaches and a proposed classification of all headaches (at least those listed in the ICHD-II).

Demographics and treatment of adolescent posttraumatic headache in a regional concussion clinic

OBJECTIVE

Mild traumatic brain injury affects over one million pediatric patients annually. Minimal data and no guidelines exist regarding treatment of posttraumatic headache (PTH). The current study investigated treatment and outcomes in patients with posttraumatic headache.

METHODS

Medical records of all patients (age 13-18 years of age) seen at a regional concussion program from 2006 to 2011 were reviewed. Statistical analysis using SAS 9.2 was conducted to determine the effectiveness of treatment as well as the association of gender, concussion history, and football participation on the duration of posttraumatic headache.

RESULTS

Four hundred subjects met the inclusion criteria. Females were more likely to report posttraumatic headache than males (90% vs. 79%, P = 0.004), more likely to be prescribed amitriptyline (24% vs. 13%, P = 0.004), and had a significantly longer recovery time (median, 80 days versus 34 days, P < 0.001). Seventeen percent of subjects were prescribed amitriptyline for treatment of posttraumatic headache, of which 82% reported a beneficial effect. There was no difference in the percentage of posttraumatic headache or recovery time in football players versus other male athletes from other sport mechanisms.

CONCLUSION

Females are more likely to report posttraumatic headache than males and also take longer to recover. Amitriptyline appears to be well-tolerated and an effective treatment strategy for patients with posttraumatic headache. Among pediatric patients evaluated in a concussion clinic, there is no difference in the proportion of football players reporting headaches compared with male players of other sports.

Mild closed head injury promotes a selective trigeminal hypernociception: implications for the acute emergence of post-traumatic headache

BACKGROUND

Headache is one of the most common symptoms following traumatic head injury. The mechanisms underlying the emergence of such post-traumatic headache (PTH) remain unknown but may be related to injury of deep cranial tissues or damage to central pain processing pathways, as a result of brain injury.

METHODS

A mild closed head injury in mice combined with the administration of cranial or hindpaw formalin tests was used to examine post-traumatic changes in the nociceptive processing from deep cranial tissues or the hindpaw. Histological analysis was used to examine post-traumatic pro-inflammatory changes in the calvarial periosteum, a deep cranial tissue.

RESULTS

At 48 h after head injury, mice demonstrated enhanced nociceptive responses following injection of formalin into the calvarial periosteum, a deep cranial tissue, but no facilitation of the nociceptive responses following injection of formalin into an extracranial tissue, the hindpaw. Mice also showed an increase in the number of activated periosteal mast cells 48 h following mild head trauma, suggesting an inflammatory response.

CONCLUSION

Our study demonstrates that mild closed head injury is associated with enhanced processing of nociceptive information emanating from trigeminal-innervated deep cranial tissues, but not from non-cranial tissues. Based on these finding as well as the demonstration of head injury-evoked degranulation of calvarial periosteal mast cells, we propose that inflammatory-evoked enhancement of peripheral cranial nociception, rather than changes in supraspinal pain mechanisms play a role in the initial emergence of PTH. Peripheral targeting of nociceptors that innervate the calvaria may be used to ameliorate PTH pain.