Gulf War and Health Volume 9: Long-Term Effects of Blast Exposures (2014) / Chapter Skim
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4 Human Health Outcomes
4 Human Health Outcomes
Pages 85-184
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From page 85... ...
. During the last decade, the incidence of primary blast injury and injury severity increased, and return-to-duty rates decreased.
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From page 86... ...
SOURCE: Created by Linda Noble-Haeusslein for the Committee on Gulf War and Health: Long-Term Effects of Blast Exposures; figure of the human body adapted from www.readengage.com. and specific outcomes, exposure to blast often leads to polytrauma (that is, multiple traumatic injuries)
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From page 87... ...
That knowledge is in contrast with other etiologies of traumatic brain injury (TBI) in which there is physical evidence of neurotrauma (Bazarian et al., 2013; Jorge et al., 2012)
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From page 88... ...
The symptoms last from 3 days to a month after the trauma exposure. If they persist for more than 1 month, the diagnosis of posttraumatic stress disorder (PTSD)
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From page 89... ...
(2011) conducted a longitudinal cohort study of combatdeployed National Guard members to assess the associations between mild TBI and PTSD symptoms reported in theater and longer-term psychosocial outcomes.
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From page 90... ...
; WHO Quality of Life–Brief NOTES: AUDIT = Alcohol Use Disorders Identification Test; CI = confidence interval; DTI = diffusion tensor imaging; LOC = loss of consciousness; MRI = magnetic resonance imaging; OEF = Operation Enduring Freedom; OIF = Operation Iraqi Freedom; OR = odds ratio;
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From page 91... ...
Service members with a history of mild TBI were more likely than those without such symptoms to report postdeployment postconcussive symptoms and poorer psychosocial outcomes. After adjustment for PTSD symptoms, mild TBI was not associated with postdeployment postconcussive symptoms, depression, problematic drinking, nonspecific somatic complaints, social adjustment, or quality of life.
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From page 92... ...
The study is limited, however, in its usefulness in determining the long-term health effects of blast exposure because there was no direct comparison of those who had a blast-related injury with those who had a non-blast injury or no injury at all. Although many of those who reported symptoms of mild TBI, PTSD, or comorbid mild TBI and PTSD had a blast injury (mild TBI, 70%; PTSD, 35.9%; comorbid mild TBI and PTSD, 80%)
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From page 93... ...
. Outcome measures included the reported incidence of mild TBI during deployment on the basis of a modified version of the Brief Traumatic Brain Injury Screen questionnaire and self-reported postconcussive symptoms that occurred in the month before the questionnaire was completed.
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From page 94... ...
. The study suggests that most of the postconcussive symptoms attributed to having previously experienced a blast-related mild TBI might actually be related to posttraumatic stress symptoms.
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From page 95... ...
. Although the study is limited in its usefulness by its report outcomes only out to 3 months and not looking at blast injuries specifically, it adds to the evidence of a relationship between mild TBI and PTSD symptoms.
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From page 96... ...
Acute psychologic and psychiatric outcomes of exposure to blast can include anxiety, depression, addiction, and worsening of existing psychiatric disorders. Two studies, considered primary by the committee, reported an association between exposure to blast and PTSD; this finding has been corroborated by several supportive studies.
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From page 97... ...
The association may be related to direct experience of blast or to indirect exposure, such as witnessing the aftermath of a blast or being part of a community affected by a blast. The committee concludes, on the basis of its evaluation, that there is sufficient evidence of a substantial overlap in the symptoms of mild traumatic brain injury (TBI)
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From page 98... ...
. That schema incorporates the most widely adopted case definition of mild TBI provided by the American Congress of Rehabilitative Medicine (ACRM, 1993)
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From page 99... ...
A detailed summary of studies of TBI (not specifically related to exposure to blast) in veteran populations can be found in Gulf War and Health, Volume 7: Long-Term Consequences of Traumatic Brain Injury (IOM, 2009)
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From page 100... ...
. Damage to the cardiovascular system caused by blast injury can compromise blood supply to the brain and cause generalized cerebral dysfunction, such as altered affect, confusion, disorientation, or focal neurologic signs from stroke, traumatic cerebral vasospasm, arterial air emboli, or arterial dissection (Magnuson et al., 2012; Phillips, 1986)
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From page 101... ...
. The committee that prepared Gulf War and Health, Volume 7: LongTerm Consequences of Traumatic Brain Injury (IOM, 2009)
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From page 102... ...
(2012) examined brains from three military personnel who were known to be exposed to blast and found CTE-linked neuropathologic characteristics: perivascular foci of tau-immunoreactive neurofibrillary tangles and glial tangles in the inferior frontal, dorsolateral frontal, parietal, and temporal cortices with a predilection for sulcal depths.
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From page 103... ...
In addition, it was not known whether any of the subjects experienced CDH before blast exposure. Another study, considered tertiary by the committee, found that among 126 Iraq and Afghanistan war veterans who experienced exposure to blast and sustained a mild TBI, nearly two-thirds (80)
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From page 104... ...
The mild TBI with LOC group had greater psychosocial limitations than the other groups, and this relationship persisted even after adjustment for depressive and PTSD symptoms. The relationship between postconcussive symptoms and Axis I psychiatric disorders has been well detailed in previous studies not specific to blast injury.
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From page 105... ...
on 15 US service personnel and veterans of the Iraq and Afghanistan wars who had blast-related mild TBI and compared them with 15 controls who did not have TBI and were not exposed to blast. The subjects who had experienced blast-related mild TBI demonstrated slower fMRI responses and increased symptoms of PTSD, depression, and somatic complaints.
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From page 106... ...
(2012) conducted a retrospective review to assess neurocognitive function in 32 Iraq and Afghanistan–war service members who had blast-related mild TBI and 28 who had nonblastrelated mild TBI about 6 months after injury and did not find significant differences between the groups in any neurocognitive domain.
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From page 107... ...
The injury appeared to be dose dependent inasmuch as greater numbers of blast exposures were associated with a larger number of low voxels when fractional anisotropy was used. Another study of 12 Iraq war veterans who had persistent postconcussive symptoms and healthy community volunteers showed decreased metabolism in the veterans on the basis of fluorodeoxyglucose positron emission tomography in the cerebellum, pons, and medial temporal lobe; those who had mild TBI also had subtle impairments in verbal fluency, cognitive processing speed, attention, and working memory on neuropsychologic testing (Peskind et al., 2011)
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From page 108... ...
(2012) used the JTTR to identify US military personnel of the Iraq and Afghanistan wars from October 2001 through December 2009 who sustained back, spinal column, and spinal cord injuries.
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From page 109... ...
The committee concludes, on the basis of its evaluation, that there is sufficient evidence of an association between severe or moderate blast related traumatic brain injury and endocrine dysfunction (hypopituita rism and growth hormone deficiency)
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From page 110... ...
. Injury to the external ear is possible from secondary, tertiary, and quaternary blast exposure, but primary blast injury to the middle and inner ear is much more common and likely to affect auditory function.
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From page 111... ...
Much less common in the middle ear -- especially after small to medium blasts -- is disruption of the ossicular chain. Patients who have sustained damage to the middle ear from primary blast injury may present with earache and conductive hearing loss, which may be temporary and resolve with the healing of the TM (Jagade et al., 2008; Walsh et al., 1995)
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From page 112... ...
112 GULF WAR AND HEALTH TABLE 4-3 Auditory Outcomes -- Primary Studies Health Outcomes or Reference Study Design Population Outcome Measures Cohen et al., Cohort 17 survivors of a Auditory, vestibular, 2002 suicide terrorist otoneurologic evaluations explosion on bus in Israel, followed for 6 months; 7 males and 10 females; median age 28 years; October 1994–April 1995 Riviere et al., Cohort 103 blast-exposed Pure-tone air conduction 2008 workers at a chemical audiometric test, plant in France, conducted 1 month–3 91.3% men, 39.9 years after blast vs before ± 8.5 years old vs blast 105 "less-exposed" workers (defined by distance ≥ 1,700 m from blast) , 79.1% men, 39.8 ± 8.6 years old; required routine audiometric test since 1990 and before the explosion in September 2001 Shariat et al., Cohort assembled 494 survivors of Long-term physical and 1999 from registry 1995 Oklahoma City emotional outcomes created by bombing, 92% of assessed 1.5–3 years Oklahoma State whom had sustained after blast via telephone Department of physical injuries interview Health and were treated in hospital or received outpatient care
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From page 113... ...
: hearing loss at 2,000 Hz p values in Table 1 not (p < 0.05)
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From page 114... ...
114 GULF WAR AND HEALTH TABLE 4-3 Continued Health Outcomes or Reference Study Design Population Outcome Measures Van Campen Longitudinal 83 survivors of Pure-tone and EHF et al., 1999a cohort 1995 Oklahoma audiometry, otoscopic City bombing; mean inspection, immittance age 43 years, 45% and speech audiometry female and 55% male, evaluated 4 times over 1 year vs 10 healthy subjects, 50% female and 50% male, mean age 26.1 years, evaluated twice over 6 months Van Campen Longitudinal 27 survivors of 1995 Balance questionnaire, et al., 1999b cohort Oklahoma City ENG, CDP bombing who had nonrecorded gaze abnormality or one or more episodes of vertigo or continuing imbalance, mean age 43 years, 50% female and 50% male, evaluated quarterly over 1 year
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From page 115... ...
pSPL. 1 year after blast, 76% reported tinnitus, 64% loudness sensitivity, 57% otalgia; averaged across quarters, 76% had mostly sensorineural hearing loss at one or more frequencies; 63% of them were male.
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From page 116... ...
; ENG = electronystagmography; kPa = kilopascal; LOC = loss of consciousness; MHL = mixed hearing loss; NS = nonsignificant; OEF = Operation Enduring Freedom; OIF = Operation Iraqi Freedom; OR = odds ratio; PTA = pure tone audiometry; SNHL = sensorineural hearing loss; SOT = sensory organization test; TBI = traumatic brain injury.
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From page 117... ...
psychologic trauma or Alpha error rate set at Primary blast exposure associated TBI and deployment p < 0.01 for multiple with hearing loss (OR = 2.32; 95% related factors comparisons.
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From page 118... ...
(1999a) conducted a longitudinal cohort study of survivors of the Oklahoma City bombing to examine long-term changes
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From page 119... ...
(1999b) reported vestibular and balance outcomes in 30 survivors of the Oklahoma City bombing.
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From page 120... ...
. Hearing loss was common; hearing in only one ear was normal immediately after the blast.
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From page 121... ...
were included in the study. ORs were calculated to assess the association between current health status and deployment-related factors, such as physical injuries, exposure to potentially traumatic deployment experiences, combat, blast exposure, and mild TBI.
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From page 122... ...
primary blast exposure only)
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From page 123... ...
For example, given the presence of TBI, what is the effect of blast exposure? Additional Long-Term Effects of Blast Injury on Auditory Function Hearing loss as measured by increased pure-tone thresholds is an immediate and long-term effect of blast exposure and is probably due to blast-related damage to the auditory periphery (middle-ear and inner-ear structures)
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From page 124... ...
Moreover, there is only sparse evidence on auditory effects of multiple blast exposures, medication use, and comorbid conditions, such as mild TBI and other brain injuries, PTSD, multisensory impairments, and cognitive losses related to attention and memory. Conclusions Blast can injure the auditory system both acutely and over the long term.
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From page 125... ...
However, more serious outcomes from closed globe injuries are possible too -- mainly from blunt trauma and primary blast injury (PBI) -- and include hyphema, vitreous hemorrhage, commotio retinae, retinal detachment, macular holes, traumatic cataract, optic nerve damage, and orbital fracture (Alam et al., 2012; Morley et al., 2010)
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From page 126... ...
. Similar visual symptoms can occur following a mild TBI.
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From page 127... ...
The patients evaluated in the PRC were seen for inpatient care and had moderate to severe TBI. Those evaluated in the PNS clinic were seen on an outpatient basis, had no life-threatening injuries, and had screened positive for mild TBI.
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From page 128... ...
(2011) examined 36,426 patient records in the Defense Manpower Data Center to determine the prevalence of self-reported auditory, visual, and dual sensory impairment in Afghanistan and Iraq war veterans who were evaluated for TBI.
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From page 129... ...
(2012) examined the occurrence of visual dysfunction in 20 subjects who received care at WRAMC and had suffered blast-induced mild TBI within the preceding 45 days (median time between blast exposure and evaluation, 30.5 days; range, 16–45 days)
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From page 130... ...
compared with one of the seven who wore eye protection. Although the study did not compare ocular outcomes by mechanism of injury, explosive blast injuries occurred in 54 of the 63 (86%)
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From page 131... ...
. Blast injury to the cardiovascular system can be caused by the blast wave, penetrating projectiles, and blunt trauma (primary, secondary, tertiary, and quaternary blast injury)
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From page 132... ...
The recognition that those vascular lesions can be occult has clear implications for long-term outcomes because they would be expected to be severe if vascular lesions are not immediately identified. Direct cardiac injury to the thorax can be primary, secondary, tertiary, and quaternary blast injury and can cause myocardial contusions, arterial air emboli, valvular and cardiac-chamber rupture, pericardial injury and tamponade, conduction abnormalities, and cardiac rhythm irregularities (arrythmias)
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From page 133... ...
Of the 99 patients included in the study, although 82% had primary blast- or explosion-related injuries, there was no comparison of blast-exposed with non-blast-exposed patients. In addition, possible delayed effects of the combat-related extremity wounds were evaluated 2–14 days after injury, so the usefulness of this study in understanding long-term cardiovascular outcomes is limited.
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From page 134... ...
cardiovascular outcomes after mild TBI and found that mild-TBI patients had less cardiovagal modulation and baroreflex sensitivity while supine than did a health control group. On standing, the mild-TBI patients still had reduced baroreflex sensitivity and did not withdraw parasympathetic or augment sympathetic modulation adequately.
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From page 135... ...
Acute Effects Blast lung injury (BLI) is the second most frequent injury in blast survivors and the most common fatal primary blast injury in initial survivors of an explosion (Finlay et al., 2012; IOM, 2009)
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From page 136... ...
. Beyond the traditional enumeration of blast injuries, blast lung and other severe blast injuries necessitate critical care.
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From page 137... ...
Two other studies provided further information on possible long-term respiratory outcomes of a blast explosion. In a retrospective cohort study, Krzywiecki et al.
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From page 138... ...
Followup after 6 months and 1 year showed reduced measures of lung function, but the mechanism of injury was not blast exposure (in 80%, it was motor vehicle collisions) , and the study was unable to differentiate between outcomes of chest trauma and outcomes of other injuries.
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From page 139... ...
The committee concludes, on the basis of its evaluation, that there is inadequate/insufficient evidence of long-term effects after acute blast lung injury. DIGESTIVE SYSTEM OUTCOMES Primary blast injuries of the abdomen can cause severe damage to internal organs, typically in the absence of visible external signs of injury (Scekic et al., 1991)
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From page 140... ...
None met enough of the inclusion guidelines to be considered primary. This section details supportive studies of long-term gastrointestinal health outcomes of blast exposure.
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From page 141... ...
(2012) met the guidelines only for a tertiary study but is worth mentioning because it provided longterm data on military personnel who were exposed to blast injuries.
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From page 142... ...
. The literature on GU blast injuries almost exclusively describes injury to males.
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From page 143... ...
The increase presumably is due in part to the nature of combat operations in Afghanistan, where terrain necessitates more patrolling on foot by dismounted troops, who are at particular risk for being injured by blast explosions from IEDs without the protection of an armored vehicle. The authors also discuss the effects of better surgical and trauma care on the battlefield, which has resulted in a greater number of survivors who have complex blast injuries, including multiple-extremity amputation patients.
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From page 144... ...
(2012) examined 26 service members who had mild TBI caused by a blast and compared them with a control group of 59 veterans who had similar deployment history but no history of blast injury or head trauma and normal cognitive testing.
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From page 145... ...
Four of the 19 patients in the blast-TBI group had hypogonadism secondary to direct blast injury to the testicles and perineum; these 4 had normal anterior pituitary function. The five patients in the blast-TBI group who had hypogonadism are examples of how direct blast injury and hypopituitarism as a result of blast affect testosterone production; all five will need lifelong testosterone replacement therapy.
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From page 146... ...
For example, if a soldier has an acute blast injury and loss of both testicles and trauma to the penis that results in damage to the corporal bodies and urethra, he will have permanent, long-term problems with hypogonadism, infertility, voiding dysfunction, and ED. The answer to the clinical question, How much does a partial injury to a GU organ contribute to long-term consequences from blast injuries?
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From page 147... ...
as the original blast injury and initially consisted of multiple tiny burn injuries. The skin condition improved markedly with topical glucocorticoid and hydroxyzine use.
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From page 148... ...
. Musculoskeletal primary blast injuries caused by the blast wave or wind usually occur in proximity to the explosion and result primarily in traumatic amputation.
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From page 149... ...
None of the studies met enough of the inclusion guidelines to be considered primary. This section details supportive studies on musculoskeletal and rehabilitation outcomes of blast exposure.
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From page 150... ...
Mechanism of injury was specifically examined to determine whether heterotopic ossification was associated with one injury type rather than another. Results of the record review showed a relationship between blast injury and development of heterotopic ossification, but the relationship only approached significance (p = 0.06)
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From page 151... ...
(2013) conducted a retrospective review by using data from the Joint Facial and Invasive Neck Trauma Project to assess the numbers and types of facial and penetrating neck injuries sustained by US military personnel serving in Iraq and Afghanistan from January 2003 through May 2011.
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From page 152... ...
Therefore, the study is not useful in understanding whether long-term skin problems in amputees can be attributed specifically to blast injury. Additional information about dermal effects is presented in the preceding section of this chapter.
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From page 153... ...
. Pathogenic bacteria are commonly found in the wounds of military personnel who have blast injuries (Murray, 2008a,b)
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From page 154... ...
4 Pseudomonas aeruginosa (4) 5 Acinetobacter baumannii, Enterobacter cloacae, Proteus mirabilis, Rhodotorula mucilaginosa, Streptococcus salivarius (1 each)
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From page 155... ...
The committee did not identify any studies that met its guidelines for primary studies, but did identify a number of supportive studies: a cohort study that is still going on, a case-control study, five retrospective chart reviews, and several case reports that provide information on acute and chronic complications from infections of wounds caused by blast. Acute Effects Wolf et al.
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From page 156... ...
(2012) used JTTR data to study fungal wound infections in military personnel who had extremity injuries due to blast.
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From page 157... ...
. Pathogens isolated from the Bali burn patients were Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Enterococcus species, MDR Acinetobacter baumannii, Chryseobacterium indologenes, Candida, Enterobacter cloacae, and Diphtheroid bacillus; the other patients were infected with Pseudomonas aeruginosa, Klebsiella pneumoniae, Serrata marcescens, and Bacillus cereus.
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From page 158... ...
(2010) conducted a retrospective chart review to study infections in British service members who had sustained life-threatening and limb-threatening injuries in the Iraq and Afghanistan wars.
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From page 159... ...
On the basis of the committee's expert clinical knowledge, it is plausible that infections related to blast injury can have long-term outcomes, including osteomyelitis, deep-wound infection, amputation, and delayed union. The committee concludes, on the basis of its evaluation, that there is inadequate/insufficient evidence of an association between exposure to blast and long-term effects of infections.
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From page 160... ...
All patients were military personnel in the Iraq and Afghanistan wars. Of the 274 patients, 142 were exposed to blast when they were injured as a result of detonation of an explosive device.
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From page 161... ...
(2006) compared records of military personnel of the Iraq and Afghanistan wars who had burn injuries with records of civilians who had burn injuries treated at the same facility.
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From page 162... ...
BLAST PROTECTION Protective equipment has been developed to protect military personnel from injuries caused by exposure to blast and gun shots: body armor (or vests, which can have add-on equipment, such as groin and deltoid protectors and neck collars) , helmets, eye protection (spectacles and goggles)
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From page 163... ...
Additional information about body armor standards and testing for gunshot and projectile injuries can be found in Chapter 3 of the NRC report mentioned above. Such a comprehensive set of guidelines does not exist for blast injuries.
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From page 164... ...
(2010) reported that the percentage of military personnel killed in action in the Iraq and Afghanistan wars is similar to percentages in previous conflicts despite improvements in personal protective equipment and blast-resistant vehicles.
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From page 165... ...
. Several studies have evaluated the effectiveness of hearing protection in military personnel, although the studies focus on noise in general and not specifically on blast.
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From page 166... ...
A review of 30 GU injuries in the 1991 Gulf War (body armor was worn) found that only 17% of the patients had abdominal GU injuries (Thompson et al., 1998)
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From page 167... ...
The importance of correctly fitting personal protective equipment cannot be overestimated. Anecdotal data indicate that body armor that is too small or too large might increase the injurious effects of a blast via enhancement of the impact-related parenchymal organ damage or via reflection of
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From page 168... ...
The committee concludes, on the basis of its evaluation, that there is sufficient evidence of an association between the use of personal protective equipment, including interceptive body armor and eye protection, and prevention of blunt and penetrating injuries caused by exposure to blast. The committee concludes, on the basis of its evaluation, that there is inadequate/insufficient evidence to determine whether an association exists between the use of current personal protective equipment and prevention of primary blast-induced (non-impact-induced)
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From page 169... ...
2013. The relation between posttraumatic stress disorder and mild traumatic brain injury acquired during Operations Enduring Freedom and Iraqi Freedom.
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From page 170... ...
2009. Post-traumatic amnesia and the nature of post-traumatic stress disorder after mild traumatic brain injury.
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From page 171... ...
2012. Diffuse and spa tially variable white matter disruptions are associated with blast-related mild traumatic brain injury.
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From page 172... ...
2011. Urologic dysfunction and neurologic outcome in coma survivors after severe traumatic brain injury in the postacute and chronic phase.
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From page 173... ...
2012. Blast-related mild traumatic brain injury is associated with a decline in self-rated health amongst US military personnel.
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From page 174... ...
2009. Gulf War and Health, Volume 7: Long-Term Consequences of Traumatic Brain Injury.
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From page 175... ...
2010. Diffusion tensor imaging of mild to moderate blast-related traumatic brain injury and its sequelae.
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From page 176... ...
2013. Changes in personality after mild traumatic brain injury from primary blast vs.
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From page 177... ...
2005. Traumatic brain injury in the war zone.
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From page 178... ...
2011. Longitudinal effects of mild traumatic brain injury and posttraumatic stress disorder comorbidity on postdeployment outcomes in National Guard soldiers deployed to Iraq.
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From page 179... ...
2008. Headaches among Operation Iraqi Freedom/ Operation Enduring Freedom veterans with mild traumatic brain injury associated with exposures to explosions.
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From page 180... ...
2012. Traumatic brain injury, shell shock, and posttraumatic stress disorder in the military -- past, present, and future.
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From page 181... ...
2011. Evidence of disrupted functional connectivity in the brain after combat-related blast injury.
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From page 182... ...
1998. Findings of mild traumatic brain injury in combat veterans with PTSD and a history of blast concussion.
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From page 183... ...
2012. Epidemio logic aspects of traumatic brain injury in acute combat casualties at a major military medical center: A cohort study.
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