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Travel medicine

What is altitude illness?

mountain.jpgAltitude 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.

Symptoms of altitude illness

Altitude illness can range from mild to severe.

Mild symptoms

  • Headache
  • Fatigue
  • Sleep disturbance
  • Appetite loss
  • Nausea
  • Difficulty breathing

Severe symptoms

  • Shortness of breath while resting
  • Rapid pulse at rest (>100-110 beats per minute or BPM)
  • Decreased urination
  • Visual changes
  • Severe headache
  • Loss of coordination
  • Mental confusion
  • Productive cough

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.

Prevention of altitude illness

The best prevention is slow ascent. In general, ascent of altitudes of no more than 1,000 feet (300 meters) per day above 10,000 feet is recommended. Upon arrival at altitude, you should avoid strenuous activity until you fully acclimatize.

Maintain fluid intake to avoid dehydration and follow the maxim, "climb high and sleep low." Avoid alcohol, cigarettes and sedatives (including narcotics).

Use of coca tea or coca leaves

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.

coca.jpgGingko biloba or Viagra™ (sildenafil)

It is unknown whether these two medications are effective in preventing altitude sickness, and therefore, their use is not recommended.

Fitness level

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.

Treating altitude illness

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.

Acetazolamide (Diamox)

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.

Dexamethasone

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.

Treating severe altitude illness

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.

Additional resources

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff (AT), May 2014


What is malaria?

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. 

Symptoms can include: fever and flu-like symptoms, chills, generalized muscle aches and pains, tiredness, headache, abdominal pain, and even diarrhea.  Symptoms usually begin 1 to 2 weeks after an infected bite, but onset can be as late as 4 or more weeks afterwards in some cases.  If left untreated, malaria can cause anemia, jaundice, kidney failure, coma, and death. 

Travelers can decrease the risk of malaria by taking certain drugs to prevent a malaria attack (malaria chemoprophylaxis) and by using measures to prevent mosquito bites.  However, in spite of all precautions, travelers occasionally might become infected with malaria.  Therefore, while traveling and up to five years after returning home, travelers should seek medical evaluation for any flu-like illness accompanied by fever.

If you have an extended period of travel or experience numerous mosquito bites in a malaria area, you may need additional anti-malarial medication after your return, to eradicate a possible asymptomatic incubating malaria infection.  If this situation applies to you, continue your prescribed malaria chemo-prophylaxis medication and seek care within two weeks after your return.

You are excluded from blood donation for 1 year after being in a malarious area.

Prevention

Travelers should limit their time outdoors in rural tropical areas between dusk and dawn, when the mosquitoes transmitting malaria are most likely to bite.  When outdoors, prevent mosquito bites by staying in screened areas as much as possible; wearing protective clothing that covers arms and legs; using an insect repellent on exposed skin areas when outdoors; and using a mosquito net where you sleep.  For more detailed information on procedures and products to prevent mosquito and other insect bites, see our health information article or brochure Avoiding Insects.

Drugs against malaria

No anti-malaria drug is 100% effective and drug resistant strains of malaria are being reported throughout the world.  Selection of the most effective regimen depends on itinerary, whether drug resistant malaria is reported at destination areas, age, health, allergies, and other factors. One of the following options may be selected.

1. Chloroquine Phosphate  (Aralen®)

Adult dosage: 500 mg orally once/week for use in areas with chloroquine-sensitive Plasmodium falciparum malaria. Take weekly dose starting 1 week before entering a malaria area, each week while there, and for 4 weeks after leaving the area.

Notes on Chloroquine:

  • Drug interactions can occur with Kaopectate®, methotrexate, metronidazole (Flagyl®), Phenergan®, and cimetidine.
  • Chloroquine can be used with caution in persons who have psoriasis, porphyria, or liver dysfunction, but not in those with retinal degeneration.
  • Chloroquine can decrease the effectiveness of the rabies vaccine given by intra-dermal administration, if taken sooner than 1 week following the last vaccine dose.
  • Chloroquine is considered safe in pregnancy.

2. Hydroxychloroquine Sulfate (Plaquenil®)

Adult dosage: 400 mg (2x 200 mg) orally once/ week—an alternative to chloroquine.

Notes on Hydroxychloroquine:

  • Drug interactions can occur with digoxin and rifampin and possibly with the drugs listed above under Chloroquine.
  • Hydroxychlorquine can be used with caution in persons who have psoriasis, porphyria, or liver dysfunction, but not in those with retinal degeneration.
  • Hydroxychloroquine can decrease the effectiveness of rabies vaccine given by intra-dermal administration, if taken sooner than 1 week following the last dose.

3. Malarone® (Atovaquone/Proguanil)

This drug is recommended for travelers going to areas of chloroquine-resistant Plasmodium falciparum malaria.

Dosing: 1 tab daily. Dose 1 day before through 7 days after leaving area of malaria risk.

Adult dosage: 250mg/100mg

Pediatric dosage: 62.5mg/25mg

Notes on Malarone:

  • Common side effects include mild stomach upset, headache, nausea and mouth ulcerations
  • Serous/rare side effects are hair loss, rash
  • Take with food or milky drink at same time each day
  • Do not take with tetracycline, rifampin, or metoclopramide

4. Doxycycline

Used for patients with intolerance to other antimalarials.

Adult dosage: Take 1 (100mg) tablet daily with evening meal starting 2 days before entering malarious area, each day while in the area and daily for an additional 4 weeks after leaving. Missing even one day's pill can result in malaria.

Notes on Doxycycline:

  • Doxycycline is not to be used by pregnant women or children under 9 years of age.
  • Due to increased sensitivity to the sun, wear a   sunscreen with a high SPF that covers both UVA and UVB.
  • Other potential side effects: vaginal yeast infections; erosion of esophagus if taken immediately before reclining without adequate liquids.
  • Pepto-Bismol® interferes with doxycycline absorption.

Treatment

If you have any of the aforementioned symptoms during or up to 3 years after leaving a malarious area, seek medical counseling. If a fever develops within 3 months after possible exposure, immediately seek medical help. Malaria can be treated if caught early enough, but delay in appropriate therapy can have serious or fatal consequences.

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff (AT), May 2014


What is dengue (deng-gay) fever?

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

Symptoms of dengue fever include:

  • Relatively sudden onset of high fever
  • Severe frontal headache
  • Muscle and joint pains
  • Nausea and/or vomiting
  • Rash

On the third or fourth day of the fever, many people will develop a rash on the torso, which then spreads to the arms and legs.

Usually the illness is "self-limited" in travelers and relatively mild, meaning it runs its course over a week or two, though in rare circumstances it can cause severe symptoms.

Another name for this illness is "break-bone fever" due to the extreme bone pain that can accompany this disease.

Treatment

There is no specific treatment for classic dengue fever, and most people recover within 2 weeks. To help with recovery:

  • Get plenty of bed rest
  • Drink lots of fluids
  • Take acetaminophen to reduce fever (not aspirin nor non-steroidal anti-inflammatory products such as aspirin or ibuprofen)

Risk to travelers

International travelers to areas where Dengue Fever occurs are at risk, more so if there is current epidemic activity underway at the time of the trip. Dengue is becoming an increasing health concern worldwide due to spread of significant disease in 2005-2007 in areas of the world without previous recent Dengue Fever.

Luckily, cases of severe Dengue Hemorrhagic Fever are rare, since this typically afflicts only those persons who reside in areas where dengue exists and are subject to repeated infections. Your travel health care adviser will let you know if dengue is a risk for you on your planned travel abroad.

Prevention of dengue fever

Since there is no vaccine against dengue at this time, the best prevention is to avoid getting bitten by mosquitoes in the first place. Follow these tips to prevent being bitten by mosquitoes:

  • Stay in screened or air-conditioned environments as much as possible
  • Use DEET-containing insect repellent on your skin

Your travel health adviser will discuss use of DEET in preventing dengue and other mosquito-borne diseases including malaria during your Travel Clinic visit.

If you have dengue fever

  • Avoid mosquito bites while you have a fever. Don't let mosquitoes bite you. They can infect other members of your family with dengue after biting you.
  • Use mosquito barriers until the fever subsides, to prevent day-biting mosquitoes from biting a sick person, becoming infected, and then biting someone else.
  • Rest in a screened room or under a bed net.
  • Use insect repellents and spray insecticide indoors if there are mosquitoes.

Additional resources

 

Authored by: Hall Health Center Travel Clinic staff

Reviewed by: Hall Health Center Travel Clinic staff (AT), May 2014


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