Osteopathic Family Physician (2013) 5, 200–207

Exposure injury: Examining heat- and cold-related illnesses and injuries

Bryan D. Grooms, DO, Daryn Straley, DO

From O'Bleness Memorial Hospital, 75 Hospital Dr, Athens, OH.

KEYWORDS: Abstract Heat- and cold-related illnesses represent a broad spectrum of preventable common Exposure injury; conditions affecting diverse populations every year. Clinicians treating patients near areas of outdoor Cold-related illness; recreation and nursing homes or who potentially see critical pediatric, indigent, or intoxicated patients Heat-related illness; can benefit from a better understanding of exposure injuries. Heat-related illnesses include the Heat exhaustion; continuum of heat rash, heat cramps, heat exhaustion, and the potentially deadly heat stroke. Cold- Heat stroke; related illnesses encompass a broad array of conditions ranging from soft tissue injuries like pernio, ; , and frostnip to the more severe effects of and hypothermia. The majority of patients Frostbite; with severe environmental exposure would usually present to an emergency or urgent care center; ; however, milder acute cases and more subtle chronic presentations would generally first be seen by a Pernio; primary care physician. With any temperature-related illness, the family physician's role should most importantly include identification of at-risk populations and promotion of proper preventative strategies allowing early symptom recognition and rapid treatment. r 2013 Elsevier Inc. All rights reserved.

Thermoregulation The amount of heat exchanged is directly proportional to the temperature gradient and surface area contacted. For Heat exchange between the body and the environment is example, the larger the surface area submerged during — accomplished in 5 ways evaporation, conduction, radia- cold-water immersion, the more the heat dissipated. tion, convection, and respiration. Ambient features such as Similarly, radiation is the direct transfer of heat into the humidity and temperature, as well as heat index and wind environment. It is the second most effective method of chill, create a contrast with the body temperature, thus dissipating heat; however, it is largely dependent on the fl greatly in uencing to what extent and velocity heat is lost or ambient temperature being below body temperature. gained. Additionally, medications may predispose a patient Because children have a greater relative surface area-to- fi to signi cant temperature alterations (Table 1). Evaporation mass ratio, more heat is absorbed via radiation than any is the most effective method by which humans dissipate heat other source.1 This becomes particularly important in via perspiration. In optimal conditions, the average preventing heat-related illness, especially in children and individual can dissipate 600 kcal/h and produce up to 1- adolescents, as light-colored clothing reflects more radiant 1,2 2 L of sweat per hour. Conduction relates to the direct energy thus absorbing less heat. Convection depends on air transfer of heat from a warmer surface to a cooler surface. flow around the body to produce a heat gradient. This can be generated from movement through the environment as with Corresponding author: Bryan D. Grooms, O'Bleness Memorial cycling or running or can be dependent on wind current. Hospital, 75 Hospital Drive, 9065 Echo Lane, Athens, OH 45701. Air-conditioning, fans, and loose-fitting clothing contribute 3 E-mail address: [email protected] to increased heat loss via convection. In a better-protected

1877-573X/$ - see front matter r 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.osfp.2013.04.002 Grooms, Straley Exposure injury: Examining heat- and cold-related illnesses and injuries 201

Table 1 Medications that interfere with thermoregulation vasoconstriction and direct tissue-freeze injury. Under ischemic conditions induced by vasoconstriction, ice Increase heat production crystals form intracellularly (in rapid freezing) or extracell- α-Adrenergic agents Amphetamines ularly (in gradual freezing), causing derangement of cellular Beta blockers proteins, lipids, electrolytes, and hydration, which leads to 7 Calcium channel blockers cytolysis and tissue necrosis. If thawing and refreezing Dietary supplements (ie, ephedra and diet pills) occurs, tissue integrity rapidly deteriorates from ischemia, Diuretics extravasation of fluids, inflammatory mediator cascade Illicit drugs (ie, cocaine, heroin, LSD, and PCP) spikes, and thrombi showers.7 As shivering proceeds, with Monoamine oxidase inhibitors tissue and freeze injury, lactic acid production and Thyroid Agonists muscle-breakdown products develop a metabolic acidosis Tricyclic Antidepressants with impending renal failure with associated hyperkalemia. Decrease sweating Furthermore, as the core temperature decreases along the Anticholinergics continuum of hypothermia, a hypercoagulable state ensues Antihistamines secondary to direct inhibition of enzymes of the clotting Benztropine mesylate cascade and the temperature-dependent production of Typical antipsychotics (phenothiazines, thioxanthines, and thromboxane B2, thus impairing platelet function and butyrophenones) leading to thromboembolism.8 To further complicate the Decrease thirst situation, there is a sequestration of platelets in the Haloperidol splanchnic vasculature, liver, and spleen. As the body temperature falls, blood buffering systems also lose LSD ¼ lysergic acid diethylamide; PCP ¼ phencyclidine. Adapted from Howe and Boden,2 Becker and Stewart, and 3 Moran and effectiveness. Eventually, muscle fatigue and metabolic Gaffin.9 dysfunction along with glycogen depletion lead to multi- organ decompensation and extreme temperature drop. Without proper treatment, neurologic decline, cardiopulmo- individual, such as those in a well-planned mountain nary arrest, and mortality soon occur. expedition, the effects of respiratory heat loss initially Acclimatization to extreme heat or cold can prevent such dominate, in most cases, because of high altitude air that is reactions from occurring, but typically take several weeks. typically colder, more windy, and dry. By understanding the A gradual increase in physical activity over 8-10 days various methods through which heat is lost or gained, the should provide optimal acclimatization. Children need a family physician can work with athletes, coaches, and trainers, longer period of 10-14 days to achieve a similar response.9 as well as specific populations like environmental workers, Physiological adaptations to higher ambient temperatures caregivers, and the elderly, to provide better education on include improved renal function—increased sodium reten- proper strategies, for example appropriate attire, hydration, tion and glomerular filtration rate—and enhanced cardio- and weather conditions, to prevent exposure injury. vascular performance.10 Because of these changes, persons The physiological regulation of body temperature can work, live, and play in more extreme environments than involves a complex array of mechanisms controlled by the what would normally be tolerated. hypothalamus in response to factors such as heat production, absorption, and dissipation. Increases in the core temper- Heat-related illness ature of less than 11C (33.81F) can activate the hypothala- mic thermoregulatory response between the spinal cord and Heat-related illness is a spectrum of common conditions peripheral centers in the skin and organs to help maintain caused by tissue and physiological changes to higher core body temperature between 361C (96.81F) and 37.51C temperatures, which is largely preventable by simple (99.51F).1,3,4 The primary response to the increased core measures. These conditions range from relatively minor temperature is peripheral , which promotes heat ailments like heat rash or heat cramps, to more serious loss and reduces environmental heat gain. The increased illnesses like heat exhaustion and life-threatening heat epidermal blood flow causes a compensatory drop in stroke. Currently, heat is the leading cause of weather- splanchnic blood flow to maintain blood pressure.5 When related deaths in the United States.11 Because of physio- the core body temperature approaches 401C (1041F), this logical differences, access to hydration or air-conditioning, physiological response creates an ischemic environment that or prolonged environmental stress, at-risk populations for promotes the release of gut and renal endotoxins, thereby heat-related illness include the elderly, children, athletes, leading to systemic inflammatory cytokine release, coagu- military recruits, and environmental workers. Individuals lopathies, and multiorgan system dysfunction. If not with heart and lung conditions, mental illness, and those promptly treated, this inflammatory cascade can result in who take medications that may blunt cardiovascular death.6 compensation are also at risk. Of the deaths that occur Similarly, yet on the opposite end of the tempera- because of heat-related illness, the largest percentage ture spectrum, prolonged cold exposure causes peripheral occurred amongst environmental workers, particularly 202 Osteopathic Family Physician, Vol 5, No 5, September/October 2013

Table 2 Summary of risk factors into the dermis or epidermis secondary to obstruction of sweat glands. It is intensely pruritic in nature, and is often Internal factors External factors described as having a stinging or “prickling” quality to the Age (o15 or 465) Ambient temperature rash. Rapid onset and history of heat exposure and excessive Alcohol consumption Excessive clothing sweating help distinguish heat rash from other causes such wear as viral exanthema, urticaria, or contact .2 Treat- Comorbidities (cardiovascular, Humidity ment is mostly conservative, involving cooling the affected respiratory, hematologic, and areas, wearing loose-fitting clothing where possible, and psychiatric conditions) avoiding oil-based topical lubricants.1,2 The rash is Dehydration Lack of water or generally benign and can take up to a week to resolve; access to cooling however, secondary staphylococcal can occur and Medications Occupation Obesity Wet bulb globe delay resolution. Preventative strategies include limited heat fi temperature exposure, and wearing loose- tting, light-colored clothing Physical disability or impaired mobility preferably with an open weave design to allow sweat to 2 Poor acclimatization dissipate. Poor exercise tolerance or cardiovascular fitness Skin conditions (eczema, psoriasis, Heat cramps sunburn, and burns) Heat cramps or exercise-associated muscle cramps are Adapted from Howe and Boden,2 Becker and Stewart,3 Glazer,4 and Ewald and Baum,16 painful, sporadic abrupt contractions commonly involving the quadriceps, hamstrings, gastrocnemius, and abdominal musculature during rest after vigorous exercise.1-3 These agricultural workers.12 A survey amongst summer high cramps are believed to be caused by sodium loss as the school athletes demonstrated that football players have a result of excessive heat exposure, profuse sweating, and 10-fold increased risk of developing heat-related illness.13 A water intake without adequate electrolyte replacement.2 summary of risk factors is presented in Table 2. Prompt Athletes engaging in strenuous exercise for more than recognition of symptoms and early treatment are crucial to 2 hours, steel mill workers, and military personnel deployed prevent further progression to heat stroke.3 to hot, humid environments have a high incidence of heat cramps.15 The development of heat cramps does not predispose an individual to further heat illness; however, it Heat rash is an early symptom.2 Treatment generally consists of rest and electrolyte replacement. For most cases, oral electrolyte Miliaria rubra, also known as heat rash or prickly heat, is an solutions are effective, although in situations where erythematous, pinpoint papulovesicular rash commonly conservative measures fail, intravenous normal saline at found in areas covered by clothing, such as the waist, 5-10 mL/kg over 20 minutes is recommended.16 Other 14 trunk, or groin (Figure 1). It usually occurs after an treatment measures include cooling, massaging, and stretch- individual is exposed to high heat and humidity causing ing the affected muscles.17 Proper hydration, including profuse sweating, which results in eccrine sweat leakage electrolyte replacement, before and during periods of activity, along with proper loose-fitting attire is key to preventing heat cramps.2

Heat exhaustion

Heat exhaustion continues along the same physiological basis for heat-related illness and is generally divided into 2 etiologies—water depletion or sodium depletion. Water depletion leads to a more rapid onset and occurs secondary to inadequate fluid intake combined with increased fluid losses. Salt depletion has a more gradual course and results from free-water replacement without electrolyte intake.1 Either cause generally produces a myriad of nonspecific symptoms, such as heat cramps, nausea or vomiting, headache, malaise, and myalgias. Persons can also show signs of circulatory collapse, like hypotension and light- headedness.18 Typically, core temperature, accurately meas- Figure 1 Miliaria rubra. ured with a rectal thermometer, is normal or shows slight Grooms, Straley Exposure injury: Examining heat- and cold-related illnesses and injuries 203 —less than 401C (1041F).1 Initial management setting of family medicine—particularly in the pediatric, includes removing excess clothing, moving the victim to a geriatric, and homeless populations. Beyond the extremes of cooler environment and placing them in a supine position age, higher risk is associated with chronic comorbid with the legs elevated. Oral hydration is preferred over conditions and intoxication. During the years of 1999- intravenous if the patient can tolerate it. Continuous 2003, an average of 1536 persons per year in the United monitoring of vital signs should be performed with prompt States died of hypothermia-related diagnoses19—600 of transport to emergency facilities if there is no improvement whom attributed to primary hypothermia—approximately after 20-30 minutes. Heat exhaustion represents a moderate half of whom were elderly, over 65 years of age.20 compromise to afflicted individuals, however, without Multitudes more suffered permanent sequelae such as limb timely treatment; their condition can deteriorate into life- loss and end-organ damage. threatening heat stroke.3

Hypothermia Heat stroke Hypothermia is defined as a core body temperature less than Heat stroke represents the most severe and life-threatening 351C (951F). Once this diagnosis is determined, continuous condition in the continuum of heat-related illness and is a monitoring should be performed to assess for core temper- true medical emergency. Most episodes occur during ature and myocardial electrical activity as an ongoing summer heat waves with several days of high ambient evaluation for oxygenation, metabolic derangement, hema- temperatures and humidity. The elderly have the highest risk tocrit changes, renal function, and neurologic decline. More for mortality, but outdoor laborers, children, and athletes are indolent, subtle hypothermia may present in the elderly or also at-risk populations. Diagnosis of heat stroke relies on young pediatric patients whereas more severe presentations 1 1 elevated core temperature of 40 C (104 F) or greater and are more commonly associated with outdoor enthusiasts, profound central nervous system symptoms, which may homeless population, immersion accidents, and in more include seizures, delirium, hallucinations, irritability, ataxia, remotely populated regions. Additional medical or behav- loss of sweating, and hypotension, along with symptoms of 1,3,4 ioral comorbidities further worsen the adaptation mecha- heat exhaustion. As the body tries to maximize heat nisms to cold and thus the prognosis. Patients presenting dissipation, tachycardia ensues. Hypotension is a late from seemingly acclimatized environments should raise the finding in the condition and represents impending circu- 1 suspicion of intoxication, medication effects (especially latory collapse. After recognizing the symptoms of heat sedative-hypnotics and phenothiazines), neurologic insult, stroke, treatment should be initiated immediately at the severe , and endocrine failure involving the adre- scene with focus on addressing airway, breathing, and nals, thyroid, or central pituitary axis. Early hypothermia is circulation, as well as activation of the emergency response typically associated with hypocapnia and alkalosis, shifting system. Once these are addressed, on-site rapid cooling the oxygen dissociation curve to the left, thereby leading to before transfer to an emergency facility should be initiated. impaired tissue oxygen absorption from hemoglobin. This Cold-water immersion is the treatment of choice and has process is aggravated by colder, more viscous blood that been shown to greatly reduce morbidity and mortality, also gradually increases in hematocrit by 2% per 1oC however, if this is not possible, applying ice packs or cold (33.81F) drop in core body temperature8 and reactive peri- wet towels to the head, neck, axilla, and groin is a viable 3 pheral vasoconstriction designed to reduce further heat loss option. Evaporative cooling with water mist and fanning is from the body surface. another alternative and is likely to be better tolerated for 1 The clinical continuum of depressed core temperature small children. Regardless of method, treatment goals are provides a useful assessment and prognostic tool for aimed to achieve a core body temperature of less than anticipated pathologic events (Table 3). Clinical manifes- 1 1 38.9 C (102 F). Controversy exists about the best treatment tations can range from mild variations in vital signs and approach for heat stroke; however with morbidity and shivering to severe central nervous system suppression, mortality being directly related to the duration and intensity cardiac arrest, and death. of elevated core temperature, cooling modality should be In addition to maintaining normal core temperature and fi 9 based on rst availability. hydration, the presence of peripheral tissue-freeze injuries (pernio or chilblains, frostnip, trench foot, and frostbite) Cold-related illnesses mandates additional measures to improve distal perfusion while preventing further heat loss. In any environment— Cold-related illnesses encompass hypothermia and soft typically in the field—where tissue refreeze after thawing is tissue injuries ranging from various forms of nonfreezing likely, warming techniques are contraindicated because of cold injuries (NFCI), such as pernio and trench foot, to the resulting severe, subsequent injury augmentation. In frostnip and frostbite. Although cold-related illnesses and addition, the risks of ambulation on a frozen extremity with injuries are a major problem for recreationalists in the expansion of tissue damage needs to be weighed against the wilderness, they are also frequently encountered in the risks of attempting alternative evacuation options. 204 Osteopathic Family Physician, Vol 5, No 5, September/October 2013

Table 3 Stages of hypothermia and clinical features core temperature drop early in rewarming as cold peripheral blood reenters the systemic circulation. With the available Mild, 32.2oC-35oC (90oF-95oF) services in extenuating circumstances, the most effective Initial cold exposure agitation Hypertension approach is extracorporeal blood rewarming via cardiopul- Shivering monary bypass, arteriovenous rewarming, venovenous 21 Tachycardia rewarming, or hemodialysis. The potential for core o Tachypnea temperature increase is 1.01C-2.0 C (33.81F-35.61F) every Vasoconstriction 3-5 minutes.22 Although arterial blood gas, coagulation, and electrolyte evaluations may be remarkably abnormal, years Subsequent fatigue onset of research have shown that correction of these abnormal- Apathy Ataxia ities is generally detrimental because of their self-correction Renal dysfunction—cold diuresis tendency during rewarming. Hypovolemia Impaired judgment NFCI Moderate, 28oC-32.1oC (82.4oF-89.9oF) Atrial dysrhythmias Commonly mistaken for frostbite, it is important to first Bradycardia consider NFCI, such as pernio (chilblains) and trench foot Declining consciousness Bradypnea (immersion foot), to provide the best treatment and Pupillary dilation prevention techniques. Although sometimes heralding a Diminished GAG reflex connective tissue disease, pernio is more typically an Cessation of shivering idiopathic, localized, bluish red lesion pattern of recurring, Hyporeflexia acral ulcerations that are painful and itchy after cold Hypotension exposure, which respond well to rewarming (Figure 2).23 J Waves Repeated, seasonal exposures typically lead to increasing Severe, o28oC (82.4oF) severity of subcutaneous arterial vasoconstriction and . Apnea Precipitating cold cryoglobulinemia may present similarly Coma and respond equally well to warming and cold avoidance. Electroencephalographic Becoming infamous during World War I and again in World Senescence War II, immersion foot injuries combine the effects of Pupillary areflexia vasoconstrictive perfusion loss in the setting of opportun- Oliguria istic infection (usually fungal) and tissue decay after Pulmonary edema prolonged wet and cold conditions. Pain, fear, physically Ventricular dysrhythmia or asystole constrictive footwear, and immobility maintain persistent Adapted from Hypothermia-Related Deaths—United States, 1999- vasoconstriction during a heightened sympathetic nervous 2002 and 2005.19 system response with subsequent peripheral nerve ische- mia.24 Free radical formation leads to further endothelial If the core temperature is below 32oC (89.61F), in damage, interstitial edema, and tissue hypoxia thereby addition to hospitalization and passive rewarming, active leading to necrosis. After the initial blanching appearance, core rewarming is necessary. Although mild hypothermia rewarming can involve significant hyperemia, pain, - and frostbite could be simultaneously treated, moderate and ing, hemorrhage, edema, and necrosis. severe hypothermia should be treated before frostbite.7 This may involve the use of external hot water bottles, heating pads or blankets, forced warm air, humidified oxygen at 40oC (1041F), or limb portion immersion in water at 45oC (1131F). Concurrently, an algorithm of gradual escalation of internal warming techniques can be employed. This should begin with warmed (401C-45oC) intravenous fluids—ideally with 5% dextrose and normal saline to restore depleted glycogen stores—and carefully escalated. Advancement of active rewarming should be performed in a hospital setting with sophisticated monitoring capabilities and could involve warm-fluid gastric, bladder, colonic, and even intrathoracic or peritoneal lavage. Medical management should carefully consider the risks and benefits of each intervention and carefully monitor for cardiac dysrhythmia, rewarming acidosis, and core temperature afterdrop—a paradoxical Figure 2 Pernio. Grooms, Straley Exposure injury: Examining heat- and cold-related illnesses and injuries 205

Pernio and cryoglobulinemia are best treated by Table 4 Summary of prehospital and initial hospital frostbite prevention of cold exposure and tissue rewarming, and management intensively with calcium channel blocker vasodilation to fi 1 Basic life support (BLS) and advanced cardiac life support facilitate healing. In the event of signi cant, prolonged (ACLS/PALS) as appropriate freezing with or without thawing in an ambient temperature 2 Remove jewelry and extraneous materials from affected o o ranging from −15 to −6 C, (51F-21.21F) cellular damage body part and microvascular insults collectively would likely lead to 3 Rapid, active rewarming of core and involved limb (s) per partial (superficial) or full-thickness (deep) soft tissue above frostbite and necrosis.25 Upon clinical stability of core 4 Ibuprofen (12 mg/kg/d divided twice daily) (evidence 2C) hypothermia management, concurrent NFCI or frostbite 5 Analgesia medication and tetanus prophylaxis (evidence therapy may be initiated. Paradoxically, immersion foot 1C) should begin with core warming while actually keeping the 6 Air dry affected extremity cool, thus lowering metabolic demands, 7 Protect from refreezing and trauma; avoid unnecessary ambulation until hyperemia subsides.24 As with all soft tissue cold 8 Debridement injuries, rubbing should always be avoided. 9 Topical Aloe vera (evidence 2C) and dry, bulky dressing change every 6 h Frostnip and frostbite 10 Elevate affected body part 11 Systemic hydration (evidence 1C) 12 Thrombolytic therapy consideration for deep frostbite Most patients presenting with soft tissue injury complain of if o24 h after thawing; utilize angiography for localized numbness following prolonged cold exposure; prethrombolytic intervention and progress monitoring however, the exact extent of permanent tissue damage (evidence 1C) cannot be clearly predicted until a reevaluation of tissue 13 Clinical interval examination (plus angiography or changes occurring during and after rewarming. Although technietium-99 bone scan or both if necessary) to more specificdefinitions exist for tissue cold-injury determine surgical margins as appropriate classification, for the primary care physician it is sufficient 14 Surgical evaluation as appropriate for suspected further to categorize them as superficial or deep-freeze injury. debridement or or both Superficial frostbite may be preceded by frostnip, distinctly PALS = pediatric advanced life support. Adapted from McIntosh a nonfreezing injury involving intense vasoconstriction. By et al.7 definition, ice crystal formation is limited to the surface and results in moderate numbness, possible paresthesia, and primary care setting transitioning to the hospital. Although pallor without permanent tissue damage. there is mixed evidence regarding the routine use of As frostnip proceeds to superficial frostbite, there is an antibiotics in otherwise clean, necrotic tissue, the incidence intensification of numbness, , white or yellow of opportunistic infection in trench foot or other contami- plaques with mild tissue sloughing, and edema—sometimes nated areas is quite high. In the examination of the advancing to clear or milky fluid vesiculation (Figure 3).26 recommendations listed in Table 4, evidence guidelines Tissue loss is expected to be superficial and minimal. from the American College of Chest Physicians regarding Deeper injuries extending into or through the dermis, into management are given grade recommendation strength the subcutaneous tissue, or into muscle and bone result in based upon the quality of clinical evidence. Grade 1 is hemorrhagic and full-thickness tissue necrosis, given strong recommendation with Category A having a which is expected to result in considerable tissue loss.7 high level of evidence, Category B with moderate evidence, Although initial management of frostbite and inflamma- 27,28 and Category C with low evidence. tory tissue damage varies significantly, whether beginning In localized hypercoagulation, such as in the distal in the field or in hospital, Table 4 describes an adaptation of extremities, however, many studies have revealed limb- the recommended first-line approaches that apply best to a saving benefits of intra-arterial-directed tissue plasminogen activator (tPA) when provided within 24 hours of thawing following initial hospital management techniques.7 During therapeutic augmentation, the risks and benefits of each escalation should be measured for the specific clinical scenario. In severe soft tissue-freeze injuries, such aggres- sive interventions have shown considerable preservation of viable tissue. Never to be used in the field, the use of these thrombolytics should be carefully analyzed for benefits vs risks, such as catheter-site bleeding, compartment syn- drome, and failure of tissue salvage, thereby necessitating Figure 3 Frostbitten hand. intensive monitoring capabilities.7 Owing to the altered 206 Osteopathic Family Physician, Vol 5, No 5, September/October 2013 pharmacodynamics, liver metabolism, and protein binding appropriate hydration, and access to cooling methods. of core hypothermia, the potential toxic drug effects upon Family physicians should assert preventative strategies, warming generally deems pharmacotherapy of any kind to including community-sponsored cooling shelters, as part of be overly hazardous until a more normal physiological their anticipatory guidance to the indigent, elderly, and temperature range is reached. Early successes of limb pediatric populations as well as their caregivers.9 Physicians salvage using combined thrombolytics and vasodilators, working with sports programs should educate players, however, have led to ongoing evaluation for efficacy of coaches, and trainers on of exposure aspirin plus buflomedil, iloprost, and intravenous tPA plus injury, proper hydration—before, during, and after activity iloprost.7 Currently, there are insufficient data to support —and encourage the use of lightweight, reflective clothing heparin-derived and vasodilation therapies unless used as during periods of high ambient temperatures.3 Rapid access adjuncts to tPA. Although antibiotics are not routinely to air-conditioning has been shown to be the most effective recommended, it is important to ensure tetanus prophylaxis method at reducing heat-related illness. Although many and is beneficial to administer topical Aloe vera to thawed communities distribute fans among at-risk populations, tissues along with oral ibuprofen (12 mg/kg divided twice these are inadequate during times of extreme heat and daily) until the heals or is surgically debrided.7 humidity.4 Beginning with discussions about the prevention of cold-induced injuries, the primary care physician is well Osteopathic manipulative treatment (OMT) poised to assist in reducing the potentially permanent or considerations lethal sequelae of hypothermia. Specific at-risk populations, as identified previously, need to be educated on the proper Studies evaluating the efficacy of OMT for exposure injuries attire to prevent heat loss during cooler weather. This are lacking in the literature; however, from what is known includes personal protective strategies such as layering attire about the pathophysiology of heat-related illness, it is preferably with moisture-wicking undergarments, and the intuitive that OMT would be a beneficial adjunct to current use of gloves, socks, hats, and scarves. Exercise during therapies. The catecholamine release leading to cardiovas- winter months should be encouraged, as inactivity has cular compensation and sweat gland activation is driven shown to reduce cold tolerance. More advanced preventa- through the sympathetic ganglion. Rib or thoracic dysfunc- tive strategies include properly insulating and weatherizing tion and fascial restrictions along the paravertebral ganglion homes.29 Although most cold injuries presenting to the could alter this sympathetic drive and thus diminish proper primary care setting are relatively mild, failure to identify physiological response to core temperature elevation. and correctly treat them can lead to significant long-term Functional methods, rib raising, or myofascial release could morbidity and mortality. Additionally, most clinical settings be used to restore balance along the sympathetic chain and are not completely isolated from potentially more severe promote balanced response. Impaired lymphatic flow can environmental exposure pathology. For the practitioner cause congestion of inflammatory cytokines and heat stress working within urgent or emergent care delivery systems or proteins potentially exacerbating the condition. Release of personally involved in an outdoor activity, a thorough the lymphatic diaphragms can facilitate restoration of flow understanding of the presentation and management of and removal of harmful toxins. Further study is needed to exposure injuries is essential to effectively reduce disability determine the efficacy of OMT techniques and should not and death. Although no one is immune to extreme heat- or delay standard treatments. cold-related illness, by implementing these strategies, the Although no official recommendation has been devel- number of cases can greatly be reduced. oped, owing to the risks of further injury to frozen tissues or mobilization of freeze-induced emboli, manipulative ther- apy should be reserved for postnormalization of core References hypothermia and milder soft tissue injury such as frostnip. Although there are intuitive benefits to lymphatic and 1. Grubenoff JA, Ford K, Roosevelt GE. Heat-related illness. 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