E-Note for Adult
Robert L. Bratton, MD - VOL 106 / NO 1 / JULY
1999 / POSTGRADUATE MEDICINE
See also Travel Med (2)
As primary care physicians, many of us are asked by our patients to make recommendations about issues affecting travel. It is our responsibility to educate them about travel-related health issues, determine their risk for disease exposure, and prescribe medications and administer immunizations to protect them from harmful organisms and diseases.
All travelers should be encouraged to plan their trips well in advance and use experienced, respected travel agencies to make their reservations. Before departure, all reservations should be confirmed, and a copy of their itinerary should be left with family members or friends. Additional information about the weather, local tours and restaurants, and the amount of activity involved with tours should be provided by the travel agent.
Persons traveling abroad should obtain a passport 6 months before departure and visit their physician at least 1 month before the trip. They should also review their health insurance policy. If provisions for foreign travel are not included, an inexpensive short-term policy may be obtained. Patients with complicated medical conditions should be encouraged to purchase medical evacuation insurance.
All travelers with health-related problems should carry written information
from their physician about their medical history (including a copy of a recent
electrocardiogram, if available) and their current medications. Medical
identification bracelets are also recommended.* Patients who must travel
with inhalers (which may look like explosive devices) or controlled substances
are advised to obtain a letter from their physician in case of customs or
Specific guidelines for required and recommended vaccines are available in
two publications from the Centers for Disease Control and Prevention (CDC)*:
Health Information for International Travel ("The Yellow Book") and
"Summary of Health Information for International Travel" ("The Blue Sheet"),
which is updated weekly. Another publication, "The Green Sheet," provides
up-to-date sanitation inspection reports for cruise ships. Current advice
is also available from the CDC's automated International Traveler's Voice
Information Service (404-332-4559). In addition, numerous online sites
provide travel alerts and advice to travelers (see box below). Guidelines
for international travel also may be obtained from local health
Medications and prescriptions
Many physicians advise their patients to travel with a supply of a general antibiotic (eg, amoxicillin, erythromycin), especially if they are going to remote areas. Other suggested medications include ciprofloxacin (Cipro), norfloxacin (Noroxin), and trimethoprim-sulfamethoxazole (Bactrim, Septra) for treating urinary infections or traveler's diarrhea. Antibiotic prophylaxis against traveler's diarrhea is not recommended . However, several placebo-controlled studies have shown that prophylactic use of bismuth subsalicylate (2 oz or two tablets four times daily) decreases the incidence of diarrhea by about 60% .
Travelers also may want to pack a supply of loperamide hydrochloride, an analgesic and antipyretic drug, an anti-inflammatory agent, an antihistamine, and an antifungal cream. Prednisone is recommended for persons with chronic obstructive pulmonary disease or asthma. In addition, a mild hypnotic agent (eg, zolpidem tartrate [Ambien]) can be helpful for adjusting to new sleep schedules. The need for other medications, such as prophylactic drugs for malaria and altitude sickness, should be determined on the basis of the traveler's destination. While traveling, patients are advised to avoid any antibiotics and nonprescription medications that they have not taken previously.
Risks posed by air travel
On flights longer than 6 hours, the risk of deep venous thrombosis and peripheral edema is increased. Therefore, passengers should be encouraged to walk and stretch during the flight. Cabin pressure in most aircraft is maintained at a level equivalent to that at altitudes of 8,000 ft or lower, which results in a decrease of PaO2 to about 60 mm Hg in healthy persons.
Passengers with lung disease and a preflight PaO2 of less than 70 mm Hg or an oxygen saturation of less than 93% may require supplemental oxygen during the flight (3).
Patients who have had a myocardial infarction should not fly for at least 3 weeks afterwards, and use of supplemental oxygen on a flight should be considered for up to 4 months. A general rule is that patients with cardiac problems should be able to walk 100 yd and climb 12 steps before attempting a long flight (4). Other cardiovascular problems are contraindications to air travel (table 1).
Persons with mobility impairments should contact the airline before the flight to arrange for assistance. In addition, those requiring special diets may wish to pack snacks or contact the airline to request special meals. Travel-related sinus and ear problems may be prevented with use of an oral or nasal decongestant 30 to 40 minutes before departure time. Some returning travelers may require treatment for barotrauma (table 2) (5).
Jet lag is a common problem for travelers who cross multiple time zones. Symptoms include agitation, insomnia, poor concentration, and generalized fatigue. Adjustment usually takes 1 day for each time zone crossed (eg, 5 days to adapt to crossing five time zones) (6). Before a long trip, travelers can begin the adjustment process by going to bed 1 hour earlier or later each day for every time zone to be crossed, which helps entrain new circadian rhythms. Other preventive measures include avoiding alcohol and carbonated drinks before and during a flight, minimizing dehydration by drinking six to eight 8-oz glasses of water or fruit juice daily, and allowing for a flexible, relaxing schedule after arrival at the destination.
Travelers should be encouraged to adjust to local times for eating and sleeping as soon as they arrive. A short-acting hypnotic (eg, zolpidem, 5 to 10 mg at bedtime) may help establish a new sleep schedule. Studies in travelers have shown small but inconsistent reductions in jet lag symptoms with use of melatonin (7).
Motion sickness may affect travelers at any time during their trip. In most cases, symptoms can be minimized with use of dimenhydrinate (50 to 100 mg every 4 to 6 hours) or meclizine (25 mg every 6 hours) beginning at least 1 hour before motion. The transdermal scopolamine patch (Transderm-Scop) has returned to the market and is well tolerated. All of these medications have anticholinergic side effects, and they should be prescribed cautiously, especially in the elderly. Some patients have reported relief with pressure-point bands (eg, Sea Bands) worn on the wrist; however, objective evidence of benefit is lacking.
Altitude sickness primarily affects travelers who spend more than 8 hours at altitudes above 10,000 ft. Mild illness involves headache (most common symptom), nausea, generalized fatigue, and shortness of breath. More severe symptoms include vomiting, ataxia, changes in mental state, fever, and cyanosis.
Mild symptoms may be treated with over-the-counter analgesics; however, more severe cases may require hospitalization. Prophylactic use of acetazolamide (Dazamide, Diamox), 250 mg twice daily, can prevent symptoms. Common side effects include paresthesias (particularly a tingling sensation in the extremities), drowsiness, nausea, anorexia, photosensitivity, and taste alterations. Acetazolamide should be avoided in patients who are allergic to sulfa drugs. A day's stay at an intermediate altitude before going to a higher altitude also may help prevent altitude sickness.
Risks to pregnant travelers
Air travel during pregnancy is usually safe but should be done cautiously after the eighth month. Although most airlines no longer require a physician's note for travel, they do recommend that pregnant women contact their physician for travel advice. If extensive immunizations or prophylactic medications (eg, antimalarial drugs) are recommended, travel should be avoided. During the flight, pregnant passengers should walk around the cabin at least every 2 hours to help prevent deep venous thrombosis.
The greatest risk to international travelers who are pregnant is the development of a complication in an area with inadequate facilities to manage the complication. When traveling by automobile, pregnant women should wear their seat belt with the lap belt positioned under the abdomen and the shoulder strap between the breasts. There is no evidence that use of safety restraints increases risk of fetal injury. The chief cause of fetal death in motor vehicle accidents is the death of the mother (8).
Patients with diabetes mellitus who travel abroad need to closely monitor their serum glucose levels. They often experience vast changes in their diet and amount of exercise (eg, walking on tours). Although patients whose condition is stable are quite capable of extensive travel, those with newly diagnosed or poorly controlled diabetes should be stabilized before taking a trip across multiple time zones.
Before a long flight, diabetic passengers can request special meals from the airline. Travelers with type 2 diabetes who take oral hypoglycemic agents can maintain their dosing schedule without regard to time zone changes. Patients with type 1 diabetes can adjust their insulin dosing according to the direction of travel (table 3). The Diabetic Alert Card, which provides emergency information in 13 languages, can be obtained from the American Diabetes Association (see box below).
Insulin containers should be kept in carry-on luggage and packed between layers of clothing to protect against breakage and temperature extremes (5). Insulin keeps for at least 1 month unrefrigerated if protected from freezing and temperatures above 30°C (86°F). Ideally, however, it should be refrigerated in hot climates. An insulated thermos is commercially available.*
*Medicool Insulin Protector, 23520 Telo Ave, No. 6, Torrance, CA 90505; 800-433-2469 (in California, 800-654-1565).
The risk of traveler's diarrhea in developing countries can be as high as 60%. Contaminated foods not adequately prepared are a common cause of intestinal infections. To help prevent such illnesses, travelers should be encouraged to thoroughly clean and cook all vegetables and meats. Food should be served hot. Peeled fruits are generally safe. However, milk and milk products (eg, cheese, ice cream) that are not pasteurized, as well as cold buffets, salads, and chilled desserts, should be avoided. Consumption of seafood, beef, pork, or sausage that is raw, undercooked, smoked, pickled, or salted can lead to trichinosis or tapeworm infection. Game fish from tropical waters also may cause ciguatera poisoning. Travelers should avoid buying food from street vendors and eating in establishments that have dirty rest rooms (2,9,10).
Unsafe drinking water
Water supplies in European and other industrialized countries are generally considered safe by US standards. However, drinking water (including ice cubes and water used for brushing teeth) in remote areas or developing countries should be avoided because of the risk of giardiasis and infection with numerous other intestinal pathogens.
Whenever water purity is questionable, travelers are advised to drink bottled water (properly sealed). If bottled water is not available, drinking water should be boiled for 5 minutes before consumption. Water can also be purified with chlorine and iodine tablets. Use of water filters is not recommended, because they do not eliminate contamination with viruses, which are too small to be extracted by the filtering process. In general, hot tea, coffee, carbonated beverages, and fresh fruit juices are considered safe (11). Beer and wine are also safe, but mixed drinks containing water or ice cubes are not. Contrary to popular belief, the alcohol in mixed drinks does not kill infectious organisms.
Travelers to tropical areas are exposed to intense sunlight and dry conditions. The major cause of sunburn is exposure to ultraviolet B radiation. To block harmful radiation, travelers are advised to use a sunscreen containing para-aminobenzoic acid with a sun protection factor of at least 15. They should also wear long-sleeved, loose (preferably cotton) clothing; a wide-brimmed hat; and lip balm for dry or cracked lips. Infants and the elderly are particularly at risk and should be protected adequately. Persons taking certain medications (eg, sulfonamides, tetracycline, doxycycline, chlorothiazide [Diurigen, Diuril], phenothiazines, furosemide [Lasix], amiodarone hydrochloride [Cordarone], psoralens, nalidixic acid [NegGram], naproxen) may have an exaggerated sunburn response (12). Sunglasses with wraparound lenses should also be worn to protect the eyes against harmful ultraviolet radiation.
Protection against insects
Many diseases affecting travelers (eg, malaria, dengue fever) are carried by mosquitoes, fleas, ticks, sand flies, and tsetse flies. Protection against these vectors includes wearing proper clothing with tight-fitting wristbands, collars, and pant cuffs. An insect repellent containing at least 33% diethyltoluamide (deet) should be applied to any exposed skin, especially between dusk and dawn. Children exposed to deet may have adverse side effects (ie, ataxia, encephalopathy, seizures, and coma). Formulas containing less than 10% deet are considered safe and effective and are recommended for children (13). In remote areas, travelers should sleep in screened enclosures or under mosquito netting.
Swimming in freshwater lakes, ponds, rivers, or streams in developing countries can lead to schistosomiasis or other serious infections. In addition, many bodies of water in developing countries may be polluted and should be avoided. Chlorinated pools and salt water are generally safe and pose minimal risk of disease. Contact with jellyfish, Portuguese man-of-war, and other marine life may result in injury and should be avoided.
Medical care away from home
From witch doctors to physicians trained in Western medicine, the spectrum of healthcare providers in foreign countries varies. The local US Embassy is a good source of information about reputable practitioners and hospitals. Other sources include travel agents, hotel concierges, and English-language newspapers. A list of English-speaking physicians is also available from the International Association for Medical Assistance to Travellers (see box below).
Travelers needing medical attention in a foreign country should avoid receiving any injections or blood transfusions unless the situation is life-threatening, because sterile conditions cannot be ensured.
All travelers to foreign destinations should be aware of safety risks. Crime is rampant in many areas of the world, and travelers are often thought to be easy victims. General safety recommendations to give patients include:
The leading cause of health problems in international travelers is motor vehicle accidents (14). Therefore, travelers should research locations and review directions before embarking on unsupervised tours or trips. They should wear a seat belt at all times and exercise caution when driving or walking in countries where vehicles drive on the opposite side of the road.
A few simple precautions can help travelers protect themselves in the event of an emergency. On an airline flight, passengers should book an aisle seat next to an exit (14). Similarly, they should request a hotel room near an exit on a lower floor. Health risks to avoid in foreign countries include sexual encounters with prostitutes and casual acquaintances, tattooing, acupuncture, and dental procedures.
Persons traveling in foreign countries for less than 6 months usually require no tests upon their return unless symptoms develop. However, those returning from extended stays in developing countries may want to have a complete blood cell count to check for anemia and eosinophilia, liver enzyme tests, urinalysis, a tuberculin skin test, and stool cultures for ova and parasites. Further evaluation may be needed in travelers with known or suspected exposure to infectious disease.
As international travel becomes increasingly common, primary care physicians are often asked for advice about travel-related health issues. Having a basic knowledge of both health and safety issues is essential. Pregnant women and patients with chronic medical conditions need to be aware of factors that can compromise their health during airline flights. All travelers need to know about required and recommended immunizations; prevention and treatment of jet lag, motion sickness, altitude sickness, food-borne illness, traveler's diarrhea, and sunburn; protection from insects and swimming hazards; how to obtain medical care in foreign countries; and how to protect themselves in the event of a crime or medical emergency.
Online travel medicine resources
Centers for Disease Control and Prevention Travel Information
International Association for Medical Assistance to Travellers
Pan American Health Organization
Health Canada Online
World Health Organization
Shoreland's Travel Health Online
Medical Advisory Services for Travellers Abroad
International Federation of Red Cross and Red Crescent Societies
Doc's Diving Medicine Home Page