Provide pain relief and treat respiratory, gastrointestinal, and soft tissue infections, with special considerations for longer trips and tropical destinations.

Manage reactive airway disease, epistaxis, and cardiovascular problems.

Discuss treatment of gynecologic problems that may arise on longer expeditions.

Distinguish between sterilization, disinfection, and clarification of water, and cite basic methodology for each process.

Assess the advantages and disadvantages of various commercially available water, purification and disinfection systems.

Expedition Medicine and Backcountry Medical Kits

Common components of kit: splint, duct tape, and elastic bandage (ACE-type wrap; will not stabilize blown-out joint but will provide compression); rest, ice, compression, elevation—rest, ice, and elevation difficult on expeditions; ACE-type wrap helps hold adhesive tape in wilderness; nonsteroidal anti-inflammatory drugs (NSAIDs); tell travelers what to bring—bandages, NSAIDs, blister treatments (helps keep expedition medical kit more organized)

Pain relief: always be prepared to relieve pain; acetaminophen with codeine—not always effective; can have high side effect profile; make your own decision on pain relief; NSAID—consider bringing something with less frequent dosing (eg, naproxen [eg, Naprosyn] or celecoxib [Celebrex]) for patients requiring long-term treatment; narcotic by mouth—new buccal fentanyl tablet (Fentora) dissolves in mouth (equivalent to intravenous [IV] dose of fentanyl); reports of death in patients in whom drug contraindicated

Infections: bring antibiotics for main organ systems affected by infection, ie, respiratory, gastrointestinal [GI], or soft tissue

Respiratory: azithromycin—effective; possibly overused; compact; requires few tablets (compliance key on expeditions); low side effect profile; amoxicillin–potassium clavulanate (Augmentin)—certain subset of patients allergic; consider drugs that work best for most people; azithromycin (Z-pack)—expensive (some use samples); effective

Gastrointestinal: ciprofloxacin (eg, Cipro)—second-generation fluoroquinolone; well tested; works well for some diarrheas; third- and fourth-generation drugs may have better gram-positive and anaerobic coverage

Soft tissue: speaker used to carry cephalexin (Keflex); if concerned about community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infection, start patients on trimethoprim-sulfamethoxazole (TMP-SMZ; eg, Septra)

Tropical areas and longer trips: consider doxycycline; used for leptospirosis; useful in remote exotic areas; when someone has fever of unknown origin far away from laboratory; diarrhea—Giardia lamblia often not an issue on shorter trips; for longer trips, carry tinidazole; tinidazole (eg, Tindamax) works better than metronidazole; 2- dose regimen; nitazoxanide—alternative to tinidazole

Airway problems: common for patients to develop reactive airway component with upper respiratory infection (upper or lower tract); wheezing and frequent coughing; use bronchodilators (eg, albuterol) instead of cough medicines

Epistaxis: oxymetazoline (eg, Afrin); have patient blow out blood clot before applying nasal decongestant (vasoconstricts); have patient sit down (not lie down), and apply gentle pressure (15-20 min); if nose continues bleeding, use nasal tampons (eg, Rhino Rockets); lubricate them to start expansion or spray extra oxymetazoline; start antibiotics; many primary care physicians remove tampons too early (leave in 48 hr)

Corticosteroids: prednisone; inexpensive, small, and lightweight; effective for poison oak or ivy and asthma exacerbations (if patient runs out of metered dose inhaler)

Cough: carry cough drops (eg, Ricola)

Tips for crossing borders: no absolute solutions; do not carry white powder in plastic bag; keep medicines organized (plastic bags acceptable); prevent medicine from getting crushed or wet; prepare individually organized and labeled kit; bring copy of medical license; print formalized letter of introduction on high-quality stationery, including details of trip

Central nervous system conditions: sedation—stress of trip, life transitions, and homesickness can cause transient anxiety, depression, or psychosis; alertness—bring caffeine pill (eg, NoDoz) for all-night rescues and caffeine withdrawal (treat headache with ibuprofen); modafinil (eg, Provigil) commonly used for maintaining alertness (not for caffeine withdrawal); expensive; sedative hypnotic—alprazolam (eg, Xanax) preferred by speaker

Cardiovascular problems: technologic advances now make monitoring patients possible; now carrying advanced cardiac life support (ACLS) kits; nitrates—for probable cardiac symptoms described by patient as “indigestion”; determine contraindications (eg, congestive heart failure, cardiogenic shock); acceptable for most middle-aged adults; for long transports, use transdermal nitrates (more portable); β-blockers—use what you use in emergency department (ED); reduce myocardial oxygen demand; aspirin—can save lives; important to bring for angina or chest pain

Gynecology: reproductive-aged women can die from complications of first trimester pregnancy; on longer trips, most important medical consideration; female trekker with vaginal blood spotting and lower abdominal pain— administer pregnancy test (urine beta human chorionic gonadotropin [ βhCG]); if positive, assume ectopic pregnancy until ruled out; if negative, wait few days (could be mittelschmerz, hemorrhagic cysts, or others); longer trips—bring high-estrogen oral contraceptives (OCs) for dysfunctional uterine bleeding (DUB); hormonally cycles these patients (after 7 days, continue normal dose of OCs or withdraw OC); withdrawal bleeding common; DUB usually stops; do not use high-estrogen OC in βhCG-positive patients; yeast infections—common on expeditions because diarrhea common and antibiotic use frequent; fluconazole (eg, Diflucan) recommended; takes effect after 1 to 3 days; treat local inflammation with topical steroids (instead of specific anti-yeast creams)

GI disorders: constipation—common on long trips; often due to diet changes; add fiber to diet as prophylaxis; hydrate patients to treat; bring bran or fiber supplement (eg, Metamucil) and laxative of choice; sports fluids—source of electrolytes for long-duration activity; important for prolonged diarrhea, vomiting, and blood loss; oral rehydration salts (ORS) commonly available in remote areas; dilute sports drinks 1:1 with water; new formulation for reduced osmolarity ORS (World Health Organization recommendations)

Blisters: blister plasters (eg, Compeed)—recommended for complicated blisters; sticks well; blister prevention aids (eg, Blist-O-Ban)—creates artificial plastic bubble that helps reduce friction

Backcountry Water Purification

Sterilization and disinfection: nothing important about water boiling point; most enteric pathogens have thermal death points far below boiling; sterilize—remove all biologic materials (including bacterial spores); disinfect—remove enteric pathogens; pasteurization of milk and dairy products—150o F for longer time kills all pathogens; bottom line—sufficient to bring water to boil; altitude—for 5000 to 15000 ft, water boiling temperature 185o F (well above temperatures used in pasteurization); altitude usually not problematic until 20000 ft; at sea level, bring water to boil; 10000 ft, add few more minutes of boiling; heat—does not change taste; consider environmental implications of using local wood

Water clarification: sedimentation—let water sit (overnight); coagulation-flocculation—used for removing suspended solids rapidly; works well; requires aluminum potassium sulfate (alum); mix alum (one-eighth to one- fourth teaspoon per gallon water); in minutes, flocculants form and coagulate sediments; filter (can use coffee filter); does not disinfect (might reduce microbial load); granular activated charcoal (GAC)—works well for removing organic pollutants (not heavy metals); removes taste, odor, and color; good for clarification; can be used in conjunction with halogenation

Halogenation: first-order reaction kinetics (ie, can decrease amount of halogen and increase contact time); sensitivity—bacteria very sensitive; viruses moderately sensitive; protozoan cysts (Giardia lamblia and Cryptosporidium parvum) somewhat resistant (even to newer forms of halogen, including chlorine dioxide); temperature dependence—cold water slows reaction, so increase contact time or concentration; free residual halogens—organic pollutants (eg, carbohydrates) bind free iodine, leaving less free halogen for disinfection; if flavoring water with sports fluid, do so after iodination; always wait for full contact time (typically 30-60 min); cloudy water (higher organic load)—double dose of halogen; alkaline water—increase concentration or contact time; reduce bad taste (from iodine-based halogens)—allow normal contact time, then use activated charcoal filter or ascorbic acid tablets (sold in backpacking stores and pharmacies)

Chlorine vs iodine: chlorine—older method; poor taste; less effective against protozoal cysts; short shelf-life; iodine —generally better; still poorly effective against protozoal cysts

Halogenation products: iodine crystals (eg, Polar Pure)— add crystals and water to glass bottle to create saturated iodine solution; allow time to dissolve, then decant solution from bottle; can disinfect 2000 L; glass bottle necessary because crystals caustic (inconvenient on trips); some people worry about ingesting crystals; tincture of iodine—available in many developing areas; consult textbook of wilderness medicine for dose

Povidone iodine (eg, Betadine): appropriate in certain situations (eg, when filter breaks); 10% povidone-iodine— use 4 to 8 drops/L with 30-min contact time (under normal conditions)

Iodine toxicity: avoid in persons with thyroid disease and in pregnancy; studies examining long-term ingestion show subtle changes in thyrotropin (probably not significant in healthy people); most experts advise limiting iodine use to 1 to 4 wk; no known maximum dose, but limit whenever possible

Chlorine dioxide: new halogen compound with advantages over chlorine and iodine (eg, more effective against Cryptosporidium; better tasting); stability issues (discard after 1 yr); speaker recommends; does not affect thyroid; new single-agent forms provide better stability; many preparations formerly made with iodine (eg, Potable Aqua) now also made with chlorine dioxide

Water filters: highly effective against protozoa (eg, Cryptosporidium, Giardia) because of large size (compared to bacteria); viruses not amenable to filtration alone (in most cases); most filters inadequate for developing countries where viral diseases, eg, poliomyelitis, still of concern; when shopping for filters—consider size, weight, ease of pumping, ease of cleaning, output (for your group), and typical life; compare pore size using absolute (not nominal) measures; iodinated resins—used as final stage of filtration process; United States Environmental Protection Agency has removed some resins from market (unable to prove contact time adequate for disinfection); resins probably inadequate for removal of viruses; complete water purifier system (Sawyer)—uses dialysis filters; large surface area; small pumping force required; can filter by sucking through straw; effective for virus removal; may be caveats; provides complete disinfection

Filtration of viruses: chlorine dioxide-based formula (eg, ViralStop)—used as second step in filtration procedure; first filter to remove protozoa and bacteria; then use ViralStop for viruses; reduced contact time (5-15 min), compared to chlorine dioxide without prefiltration (4 hr)

New disinfection system: mixed oxidant disinfectant pen (Miox)—electrolysis reaction in rock salt creates mixed oxidant solution which is used to disinfect water; likely includes chlorine dioxide and other oxidants; effective against Cryptosporidium; takes 4 hr; weighs 8 oz; expensive ($130); requires batteries, test strips, and salt tablets

UV treatment: used for municipal water treatment for decades; miniature UV disinfection systems now made for backcountry; SteriPEN—primary product sold in backpacking stores; works for relatively small amounts of water; easily broken; requires batteries; consider for “soft” adventure trips; new models made for more rugged use; solar- powered chargers available; solar disinfection (SODIS)—water goes into plastic bottle containing UV element; does not work for turbid or cloudy water; website (http://www.sodis.ch/)—explains solar water disinfection for large municipal water supplies using clear soft drink bottles placed on rooftops

Question and answer: do rivers or lakes contain cleaner water? studies of pathogen load indicate lakes contain cleaner water; decant water from first 6 to 10 in of lake water (may be purified by UV light)