Tick-Borne Illnesses in Emergency and Wilderness Medicine.

This review highlights the causative organisms, clinical features, diagnosis, and treatment of the most common tick-borne illnesses in the United States, including Lyme disease, Rocky Mountain spotted fever, anaplasmosis, ehrlichiosis, tularemia, Powassan virus, and alpha-gal syndrome. Tick bite prevention strategies and some basic tick removal recommendations are also provided.

A novel source of carbon monoxide for suicide attempt.

Carbon monoxide (CO) inhalation is a common method of suicide. The combination of formic acid with sulfuric acid creates carbon monoxide. This novel method is described in readily accessible internet-based resources. We present the case of a 35-year-old woman who developed CO toxicity by using this method. It is important for hyperbaric medicine physicians to be aware of this source of CO toxicity.

Inner ear decompression sickness in a hyperbaric chamber inside tender: a case report.

Inner ear decompression sickness (IEDCS) is a rare diving complication that presents with vestibular dysfunction, cochlear dysfunction, or a combination of both. While scuba diving is a known cause, no cases have been reported in the occupational hyperbaric setting. We present the case of a 55-year-old man who developed IEDCS after working as a hyperbaric multiplace chamber inside tender. The patient was treated with seven sessions of hyperbaric oxygen therapy, resulting in resolution of the majority of his symptoms. This case illustrates a potential occupational hazard of working in a hyperbaric chamber and demonstrates successful treatment with hyperbaric oxygen therapy.

Hyperbaric oxygen therapy for perioperative posterior ischemic optic neuropathy: a case report.

PURPOSE: To report the successful treatment of postoperative posterior ischemic optic neuropathy (PION) with hyperbaric oxygen therapy and to review the current literature on the pathogenesis and treatment of PION. OBSERVATIONS: During an angiographic procedure at a community hospital, an elderly woman had a transient drop in blood pressure after receiving an intravenous dose of hydralazine. During recovery, the patient experienced bilateral vision loss. She was transferred to our specialty referral center for treatment with hyperbaric oxygen. We followed Table 5 in the U.S. Navy Diving Manual, the protocol for decompression sickness. Our patient's vision improved markedly immediately after the first session and continued to improve throughout the course of treatment to its completion. Follow-up ophthalmology visits found the patient's vision to be close to baseline. CONCLUSIONS AND IMPORTANCE: PION is a rare condition. It has been difficult to determine a successful therapeutic approach because of the lack of large case-controlled studies. Hyperbaric oxygen has been used to treat other ischemic ophthalmic conditions, but there are only few reports of its use in patients with PION. Systemic steroids and antiplatelet therapy have also been used, with mixed success. In our patient, the combination of hyperbaric oxygen therapy and steroids was successful in restoring vision after postoperative PION.

The effect of wilderness and medical training on injury and altitude preparedness among backcountry hikers in Rocky Mountain National Park.

BACKGROUND: The purpose of this study was to document the correlation between medical and wilderness training with levels of preparedness for acute mountain sickness (AMS), illness, and injury among backcountry hikers. METHODS: We conducted a cross-sectional, convenience survey in Rocky Mountain National Park in July and August 2015. The study group consisted of 380 hikers who completed a written survey that collected information about demographics, wilderness experience, altitude experience, hiking equipment, communications devices, and trip planning. RESULTS: Factors such as wilderness training (wilderness first aid [WFA], wilderness first responder [WFR], or wilderness emergency medical technician [WEMT]), wilderness experience, and altitude experience all affected hikers' emergency preparedness. Respondents with medical training were more prepared to avoid or respond to AMS (62.3% vs. 34.3% [P<0.001]). They were also more prepared to avoid or manage injury/illness than hikers without medical training (37.7% vs. 20.7% [P=0.003]). Participants with wilderness training were more likely to be prepared to avoid or respond to AMS (52.3% vs. 36.8% [P=0.025]) but not significantly more likely to be prepared to manage illness/injury (31.8% vs. 22.0% [P<0.11]). Adjusting for experience, wilderness training, age, and gender, we found that medical training was associated with increased preparedness for AMS (OR 2.72; 95% CI 1.51-4.91) and injury/illness (OR 2.71; 95% CI 1.5-4.89). CONCLUSION: Medically trained hikers were more likely to be prepared to avoid or manage AMS, medical emergencies, and injuries than their non-medically trained counterparts. Wilderness training increased hikers' preparedness for AMS but did not significantly alter preparedness for illness/injury.

Hemiplegia and bilateral globus pallidus infarcts after carbon monoxide poisoning: case report.

The vast clinical manifestations of carbon monoxide (CO) poisoning can involve the neurological, neuropsychological and cardiac systems as well as others. In this case report, we describe our management of a 64-year-old woman exposed to CO in her apartment. Her presentation was unusual in that she had symmetric globus pallidus lesions, no evidence of thrombosis, but the lateralizing neurologic manifestation of severe hemiplegia.

Carbon monoxide and ST-elevation myocardial infarction: case reports.

We describe two cases of myocardial infarction with ST-segment elevation on electrocardiogram associated with carbon monoxide (CO) poisoning, a condition rarely reported in the literature. The first was a 62-year-old woman who experienced chest pain in the emergency department (ED) while being assessed for exposure to carbon monoxide in her home. The second was an 80-year-old man who fainted at home and was found to have ST elevation during the ED workup. After hospitalization, he returned home and soon thereafter had difficulty walking and speaking. The responding paramedics detected a very high CO level in the home. Both patients received hyperbaric oxygen therapy within the first several hours of presentation. For this combination of conditions, it is difficult to derive evidence-based management recommendations, given the paucity of cases reported to date. We conclude that rapid consultation with interventional cardiology and consideration of angioplasty or stenting are appropriate, especially when electrocardiographic findings and echocardiography point to a specific coronary distribution. Hyperbaric oxygen therapy might have a role in the treatment, based on its effects on myocardial ischemia and injury in other models.

Association of microparticles and neutrophil activation with decompression sickness.

Decompression sickness (DCS) is a systemic disorder, assumed due to gas bubbles, but additional factors are likely to play a role. Circulating microparticles (MPs)--vesicular structures with diameters of 0.1-1.0 µm--have been implicated, but data in human divers have been lacking. We hypothesized that the number of blood-borne, Annexin V-positive MPs and neutrophil activation, assessed as surface MPO staining, would differ between self-contained underwater breathing-apparatus divers suffering from DCS vs. asymptomatic divers. Blood was analyzed from 280 divers who had been exposed to maximum depths from 7 to 105 meters; 185 were control/asymptomatic divers, and 90 were diagnosed with DCS. Elevations of MPs and neutrophil activation occurred in all divers but normalized within 24 h in those who were asymptomatic. MPs, bearing the following proteins: CD66b, CD41, CD31, CD142, CD235, and von Willebrand factor, were between 2.4- and 11.7-fold higher in blood from divers with DCS vs. asymptomatic divers, matched for time of sample acquisition, maximum diving depth, and breathing gas. Multiple logistic regression analysis documented significant associations (P < 0.001) between DCS and MPs and for neutrophil MPO staining. Effect estimates were not altered by gender, body mass index, use of nonsteroidal anti-inflammatory agents, or emergency oxygen treatment and were modestly influenced by divers' age, choice of breathing gas during diving, maximum diving depth, and whether repetitive diving had been performed. There were no significant associations between DCS and number of MPs without surface proteins listed above. We conclude that MP production and neutrophil activation exhibit strong associations with DCS.

Wilderness medicine.

BACKGROUND: Human activity in wilderness areas has increased globally in recent decades, leading to increased risk of injury and illness. Wilderness medicine has developed in response to both need and interest. METHODS: The field of wilderness medicine encompasses many areas of interest. Some focus on special circumstances (such as avalanches) while others have a broader scope (such as trauma care). Several core areas of key interest within wilderness medicine are discussed in this study. RESULTS: Wilderness medicine is characterized by remote and improvised care of patients with routine or exotic illnesses or trauma, limited resources and manpower, and delayed evacuation to definitive care. Wilderness medicine is developing rapidly and draws from the breadth of medical and surgical subspecialties as well as the technical fields of mountaineering, climbing, and diving. Research, epidemiology, and evidence-based guidelines are evolving. A hallmark of this field is injury prevention and risk mitigation. The range of topics encompasses high-altitude cerebral edema, decompression sickness, snake envenomation, lightning injury, extremity trauma, and gastroenteritis. Several professional societies, academic fellowships, and training organizations offer education and resources for laypeople and health care professionals. CONCLUSIONS: THE FUTURE OF WILDERNESS MEDICINE IS UNFOLDING ON MULTIPLE FRONTS: education, research, training, technology, communications, and environment. Although wilderness medicine research is technically difficult to perform, it is essential to deepening our understanding of the contribution of specific techniques in achieving improvements in clinical outcomes.