Research progress in the pathogenic mechanisms and imaging of severe frostbite

Patient and treatment characteristics that predict symptom resolution and limb amputation in patients with frostbite

PURPOSE

To describe imaging and treatment received by frostbite patients and determine characteristics that predict symptom resolution and limb amputation.

MATERIALS AND METHODS

This retrospective study included 174 adult patients with acute frostbite at a single institution from May 1, 2004, to August 31, 2019. Demographics, frostbite classification, symptoms present and imaging received at presentation, treatment received, and dates of symptom resolution, were collected.

RESULTS

Patients most commonly received no imaging (60.3 %), followed by x-ray (28.7 %). The most common treatments were debridement (53.4 %), none (24.1 %), other (15.5 %), antibiotics (12.6 %), and tPA (8.0 %). Of 17 who had a limb amputated, the number of affected extremities (p = 0.003), frostbite degree (p = 0.004), and baseline symptoms of abnormal skin color change (p = 0.028), absence of pulse (p = 0.021), swelling (p = 0.010), and necrosis/gangrene (p = 0.002) significantly increased the risk of limb amputation. tPA lowered the risk of limb amputation with an estimated hazard ratio of 0.193 (p = 0.003).

DISCUSSION

Patients received a variety of treatments and imaging for frostbite. tPA was not often used in this study but could play a larger role in the treatment of frostbite since it was shown to lower the risk of limb amputation.

SEASONAL DIFFERENCES IN BURN INJURIES AND OUTCOMES AMONG ADULTS AND OLDER ADULTS AT A CANADIAN PROVINCIAL BURN CENTER

ABSTRACT

Background: The literature provides hints of seasonal influences on burn injury occurrence and outcomes in temperate climates. Still, data for geographic regions experiencing significant changes in climate throughout the year is scarce. Especially the influence of seasonal differences in burn incidence and outcomes for older adults (≥60 years old), a particularly vulnerable patient cohort with increased mortality and morbidity compared to adults (18-59 years old), has not been investigated so far. Because burns pose a significant public health concern, we aimed to understand seasonal burn injury admission patterns and outcomes to utilize them for targetable prevention measures and effective resource allocation. Methods: This retrospective single-center cohort study examined data from adult burn patients (≥18 years) with reported %TBSA (total body surface area) treated between 2006 and 2020 at a provincial burn center in Ontario, Canada. Patients were stratified based on age group: adults (18-59 years) and older adults (≥60 years) Demographic data, comorbidities, and clinical outcomes were compared. Results: A total of 2,445 eligible patients were enrolled in this study. Most burn injuries occurred in Summer, in which the burn patient population was also significantly younger compared to Winter. Summer admissions showed a greater median %TBSA. In contrast, length of stay per %TBSA (LOS:TBSA) revealed a shorter hospitalization in Summer compared to Winter. However, mortality did not show differences across seasons. Conclusion: Seasonal variations in the incidence and severity of burn injuries, along with associated fluctuations in LOS:TBSA, exist between age groups. This understanding can assist in tailoring burn prevention programs and aid in anticipating the types of burn injuries that may occur during specific times of the year to enhance patient care strategies.

AP39, a novel mitochondria-targeted hydrogen sulfide donor, promotes cutaneous wound healing in an in vivo murine model of acute frostbite injury

Frostbite injury refers to cold tissue injury which typically affects the peripheral areas of the body, and is associated with limb loss and high rates of morbidity. Historically, treatment options have been limited to supportive care, leading to suboptimal outcomes for affected patients. The pathophysiology of frostbite injury has been understood in recent years to share similarity with that of cold ischemia-reperfusion injury as seen in solid organ transplantation, of which mitochondria play an important contributing role. The present study investigated whether AP39, a novel mitochondria-targeted slow-releasing hydrogen sulfide donor, applied topically in a vehicle cream at 200 nM or 1 µM could mitigate frostbite injury and promote wound healing in mice. Frostbite injury was induced continuously for 3 min on the dorsal skin of C57BL/6 mice (Mus musculus) using magnets frozen on dry ice (-80 °C). AP39, delivered via a vehicle cream, was used daily to treat frostbite injury until animals were euthanized on day 15 after induction of frostbite injury. Wound tissues were stained with hematoxylin and eosin along with immunofluorescence staining with cleaved caspase-3, CD31, KI-67, CD163, fibronectin and cytokeratin. While 200 nM AP39 improved granulation tissue maturation (p < 0.001), angiogenesis (p < 0.01) and cell proliferation (p < 0.001) compared to vehicle control, 1 µM AP39 further increased granulation tissue formation compared to other frostbite groups (p < 0.001). Thus, AP39 promoted frostbite wound healing, and therefore could be considered as a treatment option for patients with frostbite injury.

Psychosocial and personal predisposing factors of frostbite injury and associated amputation: a systematic review

OBJECTIVE

To date, systematic reviews of frostbite injuries predominantly focus on the treatment of frostbite, which narrows the scope of prevention and disregards the impact of frostbite-related predisposing factors. Comprehensively synthesizing relevant evidence to understand the psychosocial and personal predisposing factors to frostbite injury and related amputation would provide new insight into frostbite injury prevention. This review investigated the psychosocial and personal predisposing factors of frostbite injury and associated amputation.

METHODS

Databases, including Embase, PubMed, and PsycINFO, were systematically searched for relevant studies. Two independent reviewers performed the screening, data extraction, and quality assessment. Inclusion criteria were studies that reported cold injury, predisposing factors for frostbite injury or related amputations, and assessed the relationship between a predisposing factor and the frostbite injury or amputation outcome based on a descriptive or inferential test.

RESULTS

Thirty-six (36) studies met the inclusion criteria; 29 reported on both frostbite injury and amputations, and seven reported on only frostbite injury. Six psychosocial predisposing factors were observed in 28 out of the 36 studies reviewed, which included people experiencing homelessness, low socioeconomic status, alcohol intoxication/abuse, smoking, psychiatric disorders, and substance use. Personal predisposing factors identified included inadequate/improper winter clothing, delay in seeking medical care, and lack of knowledge of how to deal with the cold.

CONCLUSIONS

While it is crucial to allocate additional resources and research toward improving the treatment of individuals affected by frostbite injuries and associated limb loss, it is equally important to direct efforts toward addressing the psychosocial and personal predisposing factors that predispose individuals to these injuries and amputations.

Cold Injury

Cold injury has been documented for centuries and remains a concern for military personnel, winter recreationalists, and urban homeless populations. Treatment advances in the last decades have included thrombolytic and prostaglandin therapies however the mainstay remains early recognition and rapid rewarming. This chapter focuses on frostbite, with a brief overview of other cold related conditions.

Dermorphin [D-Arg2, Lys4] (1-4) Amide Alleviates Frostbite-Induced Pain by Regulating TRP Channel-Mediated Microglial Activation and Neuroinflammation

Cold injury or frostbite is a common medical condition that causes serious clinical complications including sensory abnormalities and chronic pain ultimately affecting overall well-being. Opioids are the first-choice drug for the treatment of frostbite-induced chronic pain; however, their notable side effects, including sedation, motor incoordination, respiratory depression, and drug addiction, present substantial obstacle to their clinical utility. To address this challenge, we have exploited peripheral mu-opioid receptors as potential target for the treatment of frostbite-induced chronic pain. In this study, we investigated the effect of dermorphin [D-Arg2, Lys4] (1-4) amide (DALDA), a peripheral mu-opioid receptor agonist, on frostbite injury and hypersensitivity induced by deep freeze magnet exposure in rats. Animals with frostbite injury displayed significant hypersensitivity to mechanical, thermal, and cold stimuli which was significant ameliorated on treatment with different doses of DALDA (1, 3, and 10 mg/kg) and ibuprofen (100 mg/kg). Further, molecular biology investigations unveiled heightened oxido-nitrosative stress, coupled with a notable upregulation in the expression of TRP channels (TRPA1, TRPV1, and TRPM8), glial cell activation, and neuroinflammation (TNF-α, IL-1β) in the sciatic nerve, dorsal root ganglion (DRG), and spinal cord of frostbite-injured rats. Treatment with DALDA leads to substantial reduction in TRP channels, microglial activation, and suppression of the inflammatory cascade in the ipsilateral L4-L5 DRG and spinal cord of rats. Overall, findings from the present study suggest that activation of peripheral mu-opioid receptors mitigates chronic pain in rats by modulating the expression of TRP channels and suppressing glial cell activation and neuroinflammation.

Development and validation of clinically Mimicable model of frostbite injury-induced chronic pain

Frostbite, a debilitating condition, significantly affects the well-being of military veterans and high-altitude residents, causing severe clinical complications such as chronic pain that markedly impacts overall quality of life. There has been a notable increase in the development of pre-clinical models for studying frostbite injury, but their suitability for pain evaluation remains limited. The major hurdle in the development of novel therapeutics for the treatment of frostbite-induced chronic pain is the unavailability of well-established preclinical models. In this study, we employed deep-frozen magnets to induce frostbite injury and conducted validation for chronic pain through assessments of face, predictive, and mechanistic validity. Behavioral assays demonstrated that frostbite injury exhibited significant mechanical, thermal & cold hypersensitivity in rats. Further, molecular analysis indicated that frostbite injury triggered the activation of TRP channels (TRPA1, TRPV1 and TRPM8), microgliosis, and neuroinflammation in the dorsal root ganglion (DRG) and spinal cord of rats. Notably, NR2B protein expressions were significantly upregulated in the DRG of injured rats, while no changes were observed in spinal NR2B expressions. Furthermore, the administration of ibuprofen (25, 50, and 100 mg/kg, i.p.) resulted in a significant improvement in behavioral, biochemical, and molecular alterations in frostbite-injured rats. Overall, results suggested that established frostbite model effectively recapitulates face, pharmacological, and mechanistic validity, highlighting its potential for screening future treatment modalities and exploring the intricate mechanisms associated with frostbite-induced chronic pain.

Management of multiple frostbite casualties at a burn center: San Antonio, Texas, 12-20 February 2021

BACKGROUND

Frostbite is an insidious disease that normally affects people of cold climates. Winter Storm Uri, which occurred from February 12-20, 2021, created unique metrological conditions for Texas. It caused prolonged sub-freezing temperatures and led to rolling blackouts, affecting 2.8 million Texans including 300,000 people in San Antonio. We report 13 frostbite patients admitted to one burn center during this event.

OBJECTIVE

We aimed to determine the at-risk population for frostbite, to categorize their injury severity, and to describe their treatment. A secondary aim was to describe the rehabilitation management of these patients.

METHODS

This is a single-center retrospective study. Each patient's injuries were assessed by a topographical grading system. Comparisons were made among those who were admitted to the intensive care unit (ICU), admitted to the progressive care unit (PCU), and treated as outpatients.

RESULTS

Thirteen patients were identified. Ten (76.9 %) considered themselves homeless, and 9 (69.2 %) were directly exposed to the elements. The median delay between time of injury and presentation to a medical facility was 3 days (IQR 1-6). Only 3 patients presented to a medical facility within 24 h. Six (46 %) sustained grade 2 injuries, 2 (15 %) sustained grade 3 injuries, and 5 (38%) sustained grade 4 injuries. Only one patient met criteria to receive tissue plasminogen activator (tPA), which was discontinued due to hematochezia. Patients admitted to the ICU, when compared to patients admitted to the ward, had a longer length of stay (median 73 days v. 12 days, p = 0.0215), and required more amputations at below-the-knee or higher levels (3 v. 0, p-value 0.0442).

CONCLUSION

In a region unaccustomed and perhaps unprepared to deal with winter storms, the population is particularly vulnerable to frostbite. Lack of awareness of frostbite injuries likely led to the delay in the presentation of patients, which prevented the timely use of tPA. Increasing public awareness may increase readiness.

Effects and mechanisms of extremely cold environment on body response after trauma

With the outbreak of the Ukrainian crisis, extremely cold environment warfare has once again become the focus of international attention. People exposed to extremely cold environments may suffer from cold damage, further aggravate trauma, trigger high disability and mortality rates, and even cause serious sequelae. To declare the effects and mechanisms of the extremely cold environment on the body after trauma, this paper reviews, firstly, physiological reaction of human body in an extremely cold environment. Then, the post-traumatic body response in an extremely cold environment was introduced, and finally, the sequelae of trauma in extremely cold environment was further summarized in the paper. The results indicated that extremely cold environment can cause a series of damage to the body, especially the body after trauma. The extremely cold factor is a double-edged sword, showing a favorable and unfavorable side in different aspects. Moreover, in addition to the trauma suffered by the body, the subsequent sequelae such as cognitive dysfunction, anxiety, depression and even post-traumatic stress disorder may also be induced. The paper summarizes the human body's physiological response in an extremely cold environment, and declares the effects and mechanisms of the extremely cold environment on the body after trauma, which may provide a theoretical basis for effectively improving the level of combat trauma treatment in extremely cold regions.

Bone scintigraphy outperformed anatomic images in frostbite injuries: a case report

Frostbite is a localized cold thermal injury, as a result of tissue exposure to temperatures below freezing point for a prolonged period of time. The spectrum of injury is broad; thus, frostbite injuries may have deleterious effects with the possibility of losing part or whole extremities. We aim to present the case of a 38-year-old male patient evaluated with multiphase technetium-99m-methylene diphosphonate bone scintigraphy. This methodology may accelerate clinical management of frostbite injuries because it provides precise clinical-imaging correlation by determining the extent of injury and can accurately predict the level of amputation if required.

Severe Frostbite on Both Hands and Feet in a Vignette Case: From Physics to Clinics

Frostbite is a cold injury that predominantly affects homeless or intoxicated people, adventurers, and soldiers. It can lead to both superficial tissue damage and tissue necrosis to amputation; thereby leading to significant patient morbidity and disability. The most affected parts of the body for cold injuries are toes, fingers, and exposed facial parts. Of note, these injuries are relatively frequent in the colder climate part of the world, but they can also occur in regions with a warmer climate, during the winter months. We present a vignette case of a 40-year-old male admitted to the department of surgery with severe frostbite lesions on both hands and feet. The aforementioned injury occurred a few months ago, during the winter. During the first hospitalization, immediately after the injury, the patient was initially admitted and treated with conservative therapy with a multidisciplinary approach, to which he did not respond well. To this end, amputation was indicated, which the patient refused. At that time, the patient stopped the treatment and left the hospital. Five months after the injury, he agreed to the amputation treatment. Mummification of fingers of both hands and whole feet was present at the time of the last hospitalization. Amputation was performed with full patient recovery. Better knowledge of frostbite might help in better treatment of the cases.