Spinal-Injury.net :  Spinal Cord Injury - Hypothermia



Because of your spinal cord injury, the temperature of your body has an increased tendency to fluctuate according to the temperature of the environment. If you are in a hot room your temperature may increase (hyperthermia); if you are in a cold room, your temperature may decrease (hypothermia). This occurs because of the altered function of the autonomic nervous system. The higher the level of injury, the greater the tendency for fluctuations in your body temperature.

Hypothermia refers to an decresae in body temperature. For example, it may occur on a cold day if you are out-of-doors, sitting in a cold  car, or not wearing sufficient outdoor clothing . A consequence of lesions above T6 is the body's inability to regulate body temperature effectively anymore.  This usually means an inability to warm the body's extremities properly too.

Measured orally, a healthy person's body temperature can fluctuate between 97F (36.1C) and 100F (37.8C). Survival depends on maintaining temperature stability within this range by balancing the heat produced by metabolism with the heat lost to the environment through (for the most part) the skin and lungs. When environmental or other changes cause heat loss to outpace heat production, the brain triggers physiological and behavioral responses to restore the balance. The involuntary muscular activity of shivering, for example, aids heat production by accelerating metabolism. But if the cold stress is too great and the body's defenses are overwhelmed, body temperature begins to fall. Hypothermia is considered to begin once body temperature reaches 95F (35C), though even smaller drops in temperature can have an adverse effect.

Hypothermia is divided into two types: primary and secondary. Primary hypothermia occurs when the body's heat-balancing mechanisms are working properly but are subjected to extreme cold, whereas secondary hypothermia affects people whose heat-balancing mechanisms are impaired in some way and cannot respond adequately to moderate or perhaps even mild cold. Primary hypothermia typically involves exposure to cold air or immersion in cold water. The cold air variety usually takes at least several hours to develop, but immersion hypothermia will occur within about an hour of entering the water, since water draws heat away from the body much faster than air does. In secondary hypothermia, the body's heat-balancing mechanisms can fail for any number of reasons, including strokes, diabetes, malnutrition, bacterial infection, thyroid disease, spinal cord injuries (which prevent the brain from receiving crucial temperature-related information from other parts of the body), and the use of medications and other substances that affect the brain or spinal cord. Alcohol is one such substance. In smaller amounts it can put people at risk by interfering with their ability to recognize and avoid cold-weather dangers. In larger amounts it shuts down the body's heat-balancing mechanisms.

Secondary hypothermia is often a threat to the elderly, who may be on medications or suffering from illnesses that affect their ability to conserve heat. Malnutrition and immobility can also put the elderly at risk. Some medical research suggests as well that shivering and blood vessel narrowing-two of the body's defenses against cold-may not be triggered as quickly in older people. For these and other reasons, the elderly can, over a period of days or even weeks, fall victim to hypothermia in poorly insulated homes or other surroundings that family, friends, and caregivers may not recognize as life threatening. Another risk for the elderly is the fact that hypothermia can easily be misdiagnosed as a stroke or some other common illness of old age.

The signs and symptoms of hypothermia follow a typical course, though the body temperatures at which they occur vary from person to person depending on age, health, and other factors. The impact of hypothermia on the nervous system often becomes apparent quite early. Coordination, for instance, may begin to suffer as soon as body temperature reaches 95F (35C). The early signs of hypothermia also include cold and pale skin and intense shivering; the latter stops between 90F (32.2C) and 86F (30C). As body temperature continues to fall, speech becomes slurred, the muscles go rigid, and the victim becomes disoriented and experiences eyesight problems. Other harmful consequences include dehydration as well as liver and kidney failure. Heart rate, respiratory rate, and blood pressure rise during the first stages of hypothermia, but fall once the 90F (32.2C) mark is passed. Below 86F (30C) most victims are comatose, and below 82F (27.8C) the heart's rhythm becomes dangerously disordered. Yet even at very low body temperatures, people can survive for several hours and be successfully revived, though they may appear to be dead.

Skin Breakdown
Osteoporosis and Fractures
Heterotopic Ossification
Urinary Tract Infections
Autonomic Dysreflexia
Deep Vein Thrombosis
Pulmonary Embolism
Orthostatic Hypotension
Cardiovascular Disease
Neuropathic / Spinal Cord Pain
Medication Problems

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Spinal-Injury.net :  Spinal Cord Injury - Hypothermia



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