Neurological Effects of Repeated Blast Exposure in Special Operations Personnel

Exposure to blast overpressure has been a pervasive feature of combat-related injuries. Studies exploring the neurological correlates of repeated low-level blast exposure in career "breachers" demonstrated higher levels of tumor necrosis factor alpha (TNFα) and interleukin (IL)-6 and decreases in IL-10 within brain-derived extracellular vesicles (BDEVs). The current pilot study was initiated in partnership with the U.S. Special Operations Command (USSOCOM) to explore whether neuroinflammation is seen within special operators with prior blast exposure. Data were analyzed from 18 service members (SMs), inclusive of 9 blast-exposed special operators with an extensive career history of repeated blast exposures and 9 controls matched by age and duration of service. Neuroinflammation was assessed utilizing positron emission tomography (PET) imaging with [18F]DPA-714. Serum was acquired to assess inflammatory biomarkers within whole serum and BDEVs. The Blast Exposure Threshold Survey (BETS) was acquired to determine blast history. Both self-report and neurocognitive measures were acquired to assess cognition. Similarity-driven Multi-view Linear Reconstruction (SiMLR) was used for joint analysis of acquired data. Analysis of BDEVs indicated significant positive associations with a generalized blast exposure value (GBEV) derived from the BETS. SiMLR-based analyses of neuroimaging demonstrated exposure-related relationships between GBEV, PET-neuroinflammation, cortical thickness, and volume loss within special operators. Affected brain networks included regions associated with memory retrieval and executive functioning, as well as visual and heteromodal processing. Post hoc assessments of cognitive measures failed to demonstrate significant associations with GBEV. This emerging evidence suggests neuroinflammation may be a key feature of the brain response to blast exposure over a career in operational personnel. The common thread of neuroinflammation observed in blast-exposed populations requires further study.

Isolated perivesicular hematoma after military parachuting

BACKGROUND

Isolated perivesicular hematomas are uncommonly described and not an injury typically reported in the literature after parachuting or skydiving.

CASE REPORT

Herein, we described a series of three patients with isolated perivesicular hematomas sustained after military parachuting. All three patients were managed nonoperatively after a somewhat prolonged hospital course. Despite the lack of orthopedic injuries, all required physical therapy consultation and required an assisting device to aide with ambulation at the time of discharge. For all three individuals, follow-up imaging months after the injury demonstrated a continued presence of the hematoma. Clinically, the patients continued to have ambulatory and urological difficulties for several months after their injury.

DISCUSSION

This injury pattern is uncommonly reported in the literature. An appropriate index of suspicion must be maintained or there may be a delay in diagnosis. Management of these injuries requires coordinated care between the trauma service, urology, and physical therapy.

A case of reactive arthritis in a Ranger Indoctrination Program (RIP) student

Musculoskeletal complaints comprise the majority of cases encountered by military physicians when evaluating young active duty Soldier-athletes. This is a case of reactive arthritis in a 19-year-old active duty Soldier-athlete whose failure to improve with conservative therapy initiated further investigation. When evaluating what appear to be routine overuse injuries, it is important to actively include other potential causes of musculoskeletal complaints in the differential diagnosis. Further investigation of disease in patients whose symptoms and complaints do not improve with routine conservative care is paramount. Reactive arthritis, though self-limiting in two-thirds of those affected, can become a chronic disabling disease affecting as many as 40 out of 100 patients. Current theories suggest the persistent presence of non-culturable bacteria and bacterial antigens residing in the joint synovia as the etiology of the disease state. There is no curative therapy for reactive arthritis and management is focused on the treatment of symptoms with non-steroidal anti-inflammatory drugs (NSAIDs), immunomodulator therapy, and antibiotics if an infectious source is suspected.