Altitude illness is a condition which occurs in many travelers making rapid ascents to high altitudes. It is commonly referred to as acute mountain sickness (AMS). It most often occurs at altitudes of 3,000 meters (approximately 10,000 feet) or more. In some individuals, it has been reported as low as 2,500 meters (8,000 feet).
We suspect that altitude illness is caused by the body's reaction to lower levels of oxygen found at high altitudes. The disease may occur several hours to days after ascending to high altitudes. Symptoms range from mild to severe.
Classic, high risk areas of the world for altitude illness include any mountain range over 10,000 feet, such as the Alps, Andes, or Himalayas. In addition, travelers to areas of North American, East Africa, and the polar regions are at risk.
Altitude illness can range from mild to severe.
The last group of symptoms may represent fluid accumulation in the brain (high altitude cerebral edema) or lungs (high altitude pulmonary edema). In these severe cases, the disease can be fatal if not treated rapidly and requires descent to lower altitudes. Luckily, in most travelers, altitude illness is mild and does not become severe.
Asthma does not increase the risk of altitude illness. In fact, people with asthma often do well at altitude since there is less pollution in the air.
The best prevention is slow ascent. In general, start with a 2-4 stay at an altitude of 8,000-10,000 feet. This should be followed by a slow ascent of altitudes of no more than 1,000 feet (300 meters) per day about 10,000 feet. Upon arrival at altitude, you should avoid strenuous activity until you acclimate.
Maintain fluid intake to avoid dehydration and follow the maxim, "climb high and sleep low." Avoid alcohol, cigarettes and sedatives (including narcotics).
The active ingredient in coca leaves is a mild stimulant that may help you stay alert and hydrated. This may make you feel better at altitude. Unfortunately, it does not prevent altitude illness.
It is unknown whether these two medications are effective in preventing altitude sickness, and therefore, their use is not recommended.
Physical conditioning does not protect against altitude illness. Susceptibility is based on your body's response to altitude and is not reflective of aerobic capacity.
If slow ascent is not possible or if you have a history of recurrent altitude illness, preventive medications may be needed. An example is Mt. Kilimanjaro (19,340 feet), which is often climbed in less than seven days.
The drug of choice to prevent altitude illness is acetazolamide. Take this medication 24 hours before ascent above 10,000 feet through 24-48 hours after you reach peak altitude. Avoid this medication if you have a history of sulfa antibiotic allergy, liver or kidney disease, or severe lung disease. Acetazolamide may cause tingling of the lips, fingers and toes, frequent urination, and a metallic taste with carbonated beverages.
If you cannot take acetazolamide, dexamethasone can be used. If you've had adverse reactions to steroids or have diabetes, this drug may not be safe for you. Dexamethasone can cause headaches, nausea, dizziness, abdominal pain, and can suppress your immune function if used over a long period of time.
If symptoms of acute mountain sickness develop, you should stop your ascent, rest and get adequate fluids and calories. If altitude illness symptoms worsen, rapid descent to lower altitudes should begin as soon as possible. You should also see a medical professional.
Oxygen, use of hyperbaric chambers and medications may be needed.
Traveler's diarrhea is the most common infectious disease experienced by international travelers. It can be caused by bacteria (most common), viruses or parasites that have been ingested through contaminated food or drink. Traveler's diarrhea can be mild to extreme in severity.
Remember: boil it, cook it, peel it, or forget it! In other words, if you don't boil, cook, or peel your food, you could get sick.
Other prevention tips include:
Traveler's diarrhea can range from mild to severe. Treatment varies based on severity.
Mild traveler's diarrhea is characterized by 3-4 unformed stools in 24 hours with mild cramping.
Symptoms of moderate traveler's diarrhea include increased frequency of unformed bowel movements with one or more of the following: Fever up to 101° F, abdominal pain, nausea or vomiting.
Severe traveler's diarrhea is moderate diarrhea with increased bowel movements and all of the other symptoms. You can take antibiotics if you have severe diarrhea, but if symptoms worsen (increased abdominal pain, inability to drink fluids, or blood diarrhea), seek medical care. You may have giardia or amoebiasis.
Young children (under age 5) are particularly susceptible to becoming dehydrated from diarrhea. Do not use loperamine (Imodium AD™) in children.
If a breastfeeding infant has diarrhea, continue breastfeeding. An infant or toddler should have at least one wet diaper every 4-6 hours. If there is a longer period between wet diapers, the child needs more fluids and should be seen by a health care provider. Parents and guardians should have a low threshold for seeking medical help if a child in their care experiences vomiting and diarrhea.
Malaria is the most significant parasitic disease threat you will face in most tropical and subtropical countries. It is a microscopic blood- borne parasite transmitted to humans by the bites of infected mosquitoes. There are 300 to 500 million cases a year of malaria worldwide —approximately 1000 a year are reported in U.S. travelers.
Dengue fever and dengue hemorrhagic fever are viral illnesses transmitted by the bite/sting of a mosquito. The mosquito species that carries dengue virus is active, biting during daylight hours, with a peak of activity just after daybreak, and then again for several hours before dark. These insects are often present indoors, and are common in areas of human habitation, including urban and rural areas throughout the tropical areas of the world.
Symptoms of dengue fever include:
By avoiding insect bites during your travels to tropical and subtropical regions, you can prevent the following diseases:
Care should be taken to protect yourself and your family from most of the flying bugs you might encounter.
The following products are used to avoid bites and stings of insects, and thereby reduce the risk of contracting the diseases they carry. They can be purchased in many pharmacies and outdoor supply stores (e.g., REI), including at Hall Health Pharmacy. Some specific products are listed for your information.
NOTE: Please note that these repellents are to be used only on exposed skin and not under clothing.
DEET repellent – DEET (N, N-diethyl-m-toluamide) is the most effective repellent against mosquitoes, chiggers, ticks, fleas, and biting flies. Controlled release formulations have longer lasting effectiveness. Avoid contact with eyes, mouth, and synthetic materials. Toxic only if swallowed.
We strongly recommend DEET-containing repellents over all others, based on its proven safety, effectiveness, and ease of use. Look for a minimum concentration of 20% and a maximum concentration of 50%.
Picaridin – available for many years in Europe at 21% concentration. Higher concentrations provide longer duration of protection.
Higher concentrations provide longer lasting protection.
Permethrin is available in various formulations, as a spray for clothing, or as a liquid for soaking clothing or bed nets. It effectively repels and kills insects. See manufacturer's recommendations for application of and duration of effectiveness for the various formulations available.
Some manufacturers now offer clothing that is already impregnated with permethrin. Check outdoor clothing suppliers for more info.
Locally, REI sells mosquito nets. Various companies sell mosquito nets and netting on the web. Here is a sampling, in no particular order, and without endorsement.
Military surplus stores also may stock mosquito nets.
Talk to your travel consultant at Hall Health or your personal health care provider if you are allergic to bee stings. The products discussed above may not be effective against bee stings and you should be appropriately prepared to manage a bee sting reaction.
Check out the Environmental Protection Agency's online tool to find an insect repellent that's right for you.
Schedule an appointment with Hall Health at least 4 weeks prior to your departure date to discuss how to protect yourself from insects.