Top 10 Worst-case Scenario Medical Conditions

Cold has a drastic effect on humans. We weren't born with fur like our mammal cousins, so being caught in severe cold can lead to illness and even death. In fact, the total number of deaths goes up 15 percent in the winter thanks to hypothermia, pneumonia and influenza [source: globalbiowether.com].

Hypothermia is pretty simple -- your body loses more heat than it produces and your body temperature drops. If you're caught in the cold, watch out for the following symptoms of hypothermia:

To fight off hypothermia, find shelter from the wind and cover up with anything you can find -- blankets, sleeping bag, pillows or even newspaper. Most of your body heat is lost through your head, so cover your noggin. If you have on wet clothes, replace them with dry duds immediately. If you don't have anything dry to wear, it's better to strip naked and dry your clothes by a fire than to wear something wet.

If you're with someone who's slipping into hypothermia, handle him or her with care -- he or she could go into cardiac arrest. Keep him or her horizontal. Get into a sleeping bag with your partner or simply hug each other tight to create warmth. If you're not trapped in the wilderness, seek professional medical attention as soon as possible.

If you're caught in the dry heat of the desert or humid, tropical conditions of an island, you could succumb to a heat related illness -- when your body fails to regulate your core temperature because it's losing water and salt through excessive sweating. The sodium and chlorine in salt are the electrolytes your muscles need to function properly. Heat cramps are followed by heat exhaustion and eventually heatstroke, or a complete failure of your body's heat-regulating system. Your body temperature rises rapidly, and you're unable to sweat and cool down. The symptoms are:

To treat heatstroke, hit the shade, lie down, elevate your feet, loosen your clothing and drink water. Pour cool water on your skin and have someone fan you vigorously. You could die from heatstroke, so it's not the time to conserve your water. If you have a cool compress in your first-aid kit, apply it to your armpits and groin area. This will help to lower your overall body temperature. If you don't have a compress, douse a towel or bandana and apply it to your skin. Stay in the shade until you feel yourself cooling down. Your stomach will settle and your heart rate will steady. Only then should you think about moving again.

If you're stuck in freezing conditions, you have more than just hypothermia to worry about. Frostbite is when your skin falls below the freezing point and ice crystals form within your skin cells, which kills them. There are two kinds of frostbite -- superficial and severe. If you re-warm your skin in short order, you have the superficial variety. Your skin will form a blister, change from blue to black in color and harden into a shell. This shell eventually falls off to expose new skin underneath if the damage isn't too drastic.

Severe frostbite actually penetrates all the way to the muscle and bone, usually causes tissue damage, and can even lead to amputation of fingers, toes, hands and feet. The stages of frostbite are:

With frostbite, it's vital to re-warm your skin gradually. Cover your ears and warm your fingers under your arms. Never rub the damaged skin or submerge it in hot water -- use warm water between 100 and 106 degrees Fahrenheit (37.7 and 41 degrees Celsius). Head to a warmer area immediately, even if it's just a tent. Remove any tight clothing that may restrict blood flow. Put gauze or cloth between your fingers and toes to soak up moisture and prevent them from sticking together. It also helps to slightly elevate the affected area to reduce swelling. As with any medical condition, get to a doctor as soon as you can.­

Dehydration can strike in any kind of weather. It simply means you aren't supplying your body with enough water. It's dangerous no matter where it hits you, but comes on quicker in hot conditions because you're losing lots of water through perspiration. In fact, if you're caught in severe heat with no water, dehydration can set in within one hour.

Besides sweat, you also lose water through your feces, urine and even breathing. Every cell and organ in your body needs water to function. With mild dehydration, you'll experience the following:

Moderate dehydration:

Severe dehydration:

The final stages of dehydration are shock and then death. If you're in reasonably good shape and you aren't stranded in severe heat, you may be able to survive for three to five days without water. But your body needs as many ounces of water as half your body weight each day to keep chugging. If you weigh 200 pounds (90.7 kilgrams), then you should take in at least 100 ounces (2.8 kilograms), or 12 and a half cups of water each day.

To treat dehydration, drink water and avoid soda, tea or anything with caffeine -- these will only increase your urine output and slow down your body's rehydration process.

Medically speaking, humans can go about four to eight weeks without food as long as they have water [source: professorshouse]. Hunger strikes have lasted longer, and people have starved to death in less time -- it all depends on the individual and several other factors.

The body stores energy in the form of fat, carbohydrates and proteins. Carbs are the first to go if you aren't eating. Fat goes next, which explains why people with more of it can survive longer. Then it's protein's turn. If you reach the point where your body is using up proteins -- basically itself -- you're in bad shape.

Your metabolism, converting food to energy, plays a role as well. If your metabolism is slow, you'll burn food slower and go longer without replacing it. If you go without food for a length of time, your metabolism adjusts itself on its own, pitching in for survival's sake.

Climate plays a part as well -- both cold and hot weather are no good if you have no food. In terms of living without food, heat means faster dehydration; cold means more energy is burned to keep the body's temperature at a cozy 98.6 degrees Fahrenheit (37 degrees Celsius). If you're lucky enough to be in a comfy 68 to 78 degrees Fahrenheit (20 to 25 degrees Celsius) environment, you'll be able to live a little longer without food.

Some symptoms you may see if you go more than a couple of days without food are:

Advanced starvation will cause your organs to shut down one at a time. If you're in the throes of severe starvation, you might experience the following:

If you're suffering from starvation, look to plants and insects for some protein and food energy. A rule of thumb for both is to avoid eating any insect or plant that's brightly colored, spiny or gives off a strong, pungent odor.

We've all been there -- tired and worn out from a long day of physical activity. In a survival scenario, fatigue is a little more dangerous than being tired. You might also find yourself short on food and water and dealing with mental stress and anxiety. All of these factors will only worsen your fatigue. Aside from just feeling tired and weak, you could experience the following:

Your best survival tool is the good health of your brain and your body. Fatigue can put a dent in both of these. If you're lost and hiking toward civilization, take more frequent breaks or suspend your hike for a full day or two in order to regain energy. Camp as close to a food and water source as possible to decrease the level of energy you need to get both. While you're taking your break, try to relax your mind as well. Keeping a positive outlook and avoiding panic and anxiety will restore your energy levels as well.

Sleep is very important in combating fatigue, so make sure your bedtime situation is as conducive to sleep as possible. Relax and give gentle massages to your overworked muscles. Stay horizontal as much as possible until you feel your energy levels increase. From that point, take more frequent breaks until you feel completely restored.

Eating the wrong thing in a survival scenario can render an outdoor expert in great physical condition powerless and weak. Eating meat that's tainted or undercooked can leave you with any number of diseases, including E. coli or salmonella. You can also get sick eating an insect or a poisonous plant in a survival scenario. All of the above will most likely leave you with some or all of the following:

The bad news is that these symptoms will also speed up your rate of starvation and dehydration. You can avoid foodborne illnesses by cooking any meats until they're well done. If there's any doubt, cook it some more. Never eat anything that you haven't caught yourself or if it's already dead when you first find it. Even the freshest road kill is most likely riddled with harmful bacteria.

If you need to resort to eating insects and plants, avoid anything that's brightly colored, extremely pungent or has thorns or spikes -- nature's way of saying "avoid me." If you have to eat insects, pull off the legs, arms and head and cook the body by boiling or roasting it. Plants can be checked using the universal edibility test -- rub the plant on your wrist and place a small piece in your mouth without swallowing it to see if you have a reaction. If it tastes extremely bitter or of there are any signs of a rash or swelling, don't eat it.

Water is the most important thing in any worst case survival scenario. Without it, you'll be dead within a week. Clean water is just as important. Clear rivers and lakes may look clean, but there are millions of organisms in fresh water. If you don't purify it, you can get extremely sick from bacteria or viruses. Freshwater springs can be safe to drink from without filtering, but in a survival situation you should err on the side of caution.

Boil water for at least 10 minutes to avoid waterborne disease. Rainwater in most rural areas can usually be consumed without risk of disease or illness as well, so catch some if you can. Sadly, most areas of the earth are touched by litter. Use this to your advantage -- look for an aluminum can, glass jar or a large seashell to boil water in.

Another way to purify water is with purification tablets. The tablets use either iodine or chlorine to treat the water. Murky water often needs more than one tablet to make it safe, and any tablet needs at least 30 minutes to be fully effective. Like with boiling, it's best to give the water an initial straining with some kind of cloth. It's also safer to drink warmer water, so if it's from a cold mountain stream, allow it to heat up a little in the sun first.

Most people have had some kind of skin irritation due to contact with the wrong plant. Poison ivy and poison oak are two of the main culprits. Whether you get a minor rash or irritating blisters depends on the plant, the degree of contact and the relative susceptibility of the person. Some people may not be allergic to poison ivy at all, while others will break out in hives from minimal contact. You can also suffer from an allergic reaction due to wind blown spores or pollen. Aside from poison ivy and oak, the following plant parts may cause some form of skin irritation:

Poison ivy and oak are bright green and have a leaf pattern of three per branch. The old saying, "Leaves three, leave it be," should be heeded at all times. If you come into contact with any of these plants, wash your skin thoroughly with soap and water. Many times, washing immediately will greatly reduce the irritation. If you have some calamine lotion in your first aid kit, use it to avoid spreading the rash and try your best not to scratch your skin.

If you're in a worst case insects. Not only are they annoying, but insects can carry diseases. In fact, mosquito-borne illnesses kill more people worldwide than anything else [source: Outside Magazine]. Ticks carry Rocky Mountain spotted fever and Lyme disease. Even biting flies can transmit typhoid, cholera and dysentery.

If you're traveling to some place where these diseases run rampant, look into immunizations and use insect repellent and netting. To avoid ticks, give your body and head a good once-over three times a day. If you find a tick, coat it with something like Vaseline or tree sap to cut off its air supply. This will choke the tick, and it will release itself. You can also touch it with a hot match or ember, but be careful not to burn yourself. Use tweezers if you have them to remove the entire tick and wash the area immediately with soap and water.

If you're stung by a bee or wasp, remove the stinger and venom sac by scraping it out with a clean knife blade. Wash the sting site, and if you're allergic to any kind of insect, don't forget to bring your remedy along. If you get bitten or stung, avoid the temptation to scratch the area. This could lead to infection. Apply a cold compress or make a nice cool mud paste for the bite or sting.

Venomous spider bites may not be painful at first, but local pain will soon develop and then spread over your entire body. You'll also likely experience stomach cramps, nausea and vomiting, weakness, tremors and sweating. Clean the infected area immediately and be prepared to perform CPR in severe cases. Get to an emergency room as soon as possible.