Thank You to "monash medical student" for Grand Rounds

Thank you to Jeffrey Leow of monash medical student for including my post about poison oak allergic contact dermatitis in this week's edition of Grand Rounds. This week's Grand Rounds, which is a weekly compilation of posts related to health care compiled by a host, was created by Jeff Leow, who is a medical student in Melbourne, Australia. He has done a terrific job tying together a diverse set of posts under the common theme of armed conflict.

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Poison Oak Allergic Contact Dermatitis

Case Reviews in Clinical Dermatology, Volume 1 Issue 3, had an interesting discussion about certain aspects of poison oak/ivy dermatitis. The following are some of the points made by the authors, with additional comments by me:

"Contact dermatitis" (CD) is a broad term used to describe inflammation of the skin caused by direct contact with an irritating substance or allergen (a substance that induces an allergic reaction/response). Allergic contact dermatitis is a hypersensitivity reaction to a substance exposed to the skin to which a person has become allergic.

Sensitization to a substance can develop at any time, including adulthood. It may develop for substances that have been used repeatedly without any difficulty by an individual in the past. Poison oak/ivy allergic contact dermatitis is quite common. It is most likely to occur in persons with significant outdoor exposure, such as forest firefighters and backpackers. Sometimes a person may unknowingly encounter the allergen. For instance, urushiol in poison oak can persist on items such as clothes and gardening tools for years, and may be transmitted to a person from the fur of a pet, in the smoke of a campfire, or from a casual brush with plant that intrudes on a hiking path.

In general, a contact dermatitis eruption due to poison oak appears as itchy blisters, both large and small, on a reddened base in a linear (patterned in lines) distribution. Despite common belief, the fluid contained in the blisters does not spread the rash; only the urushiol resin itself can spread the rash. The resin in the is composed of a mixture of catechols and causes the hypersensitivity reaction when it comes in direct contact with the skin.

Urushiol is a water-soluble substance that can only be removed in significant amounts if washed immediately. Only 50% can be removed after ten minutes of contact, 25% after 15 minutes, and no resin can be removed after one hour of contact with the skin. Prevention of exposure to these plants is the most sensible, but not always the most practical solution. Many attempts have been made to prevent contact with the resin by applying topical skin protectants.

To make some treatment recommendations, the authors of the article offered a clinical case:

A 28-year-old, otherwise healthy man presented with a one-week history of a rash that began as small, itchy blisters on his inner arms a few days after camping in the Sierra Nevada Mountains. A few days later, he started to develop new large, red areas on his back. He felt somewhat fatigued but denied having fever or other symptoms. On physical examination, small blisters and black streaks were apparent in a cluster on his inner arm. There were other large reddened areas on his back. Based on his presentation, the diagnosis was "black spot poison oak contact dermatitis with systematization (spread to other parts of the body)."

The patient was treated with oral prednisone, starting at 60 mg per day and tapered by 10 mg per oral dose every 3 days. His symptoms resolved completely within two weeks.

According to the authors, this case illustrated an unusual presentation of poison oak contact dermatitis and the importance of rapid diagnosis and treatment. "Rhus dermatitis," commonly known as "poison ivy, poison oak, or poison sumac," and currently referred to as "toxicodendron dermatitis," is one of the most common forms of contact dermatitis (CD) in the U.S. It is characterized by itchy blisters on a reddened base in the setting of a history of exposure to an offending plant or some other vehicle (such as a dog's fur) that is carrying the resin.

Poison ivy grows in all states in North America with the exception of Alaska. Poison oak is separated into two categories: Western Poison Oak, which only grows on the Pacific coast of North America, and Atlantic Poison Oak, which is found mostly in sandy soils in the eastern part of the U.S. Poison ivy and poison oak are grouped with other toxicodendron dermatitis agents, including Japanese lacquer tree, cashew nut tree, poison sumac, and other members of the Anacardiaceae family of plants. Marked pruritus is typically the first symptom of toxicodendron dermatitis, beginning between the fingers, and on the eyelids, wrists, and top (opposite the palm) aspects of the fingers within 48 hours of exposure.

Itching is generally followed by inflammation and the characteristic appearance of a linear bumpy (raised) rash with blisters. As long as the plant oil remains on the skin, it can be transferred from the hands to other body parts. However, once the offending agent has been washed off, there is generally no further expansion of the rash, except in areas that have come in contact with the resin. In some cases, CD can become severe, covering over 20% of the body in adults and 10% of the body in children or manifesting systemically with fevers, fatigue (tiredness), and other symptoms.

The offending urushiol is an oleoresin that is both an allergen (causes an allergic response) and a primary irritant. It is a very resilient substance, and can persist for weeks to months on clothes, furniture, and animal fur. Typically, the allergic reaction to urushiol occurs within 24 to 72 hours, but it can be seen as quickly as six hours after exposure, particularly in highly sensitive individuals.

Black spot contact dermatitis is usually caused by poison ivy and poison oak, but can also be caused by sap from the Japanese lacquer tree, because the chemical structures of the oils in both plants are quite similar. When the resin from the Japanese lacquer tree comes into contact with skin, it turns black and attains a shiny appearance that becomes especially noticeable within the first 72 hours after exposure.

Black spot poison oak as a diagnosis can be challenging when the presentation consists of only asymptomatic black spots. Patients become concerned when these black spots, appearing as marker or ink spots, do not wipe off, and they sometimes confuse the lesions with melanoma. The ability of the resin to persist on clothes, fur, and tools for years can also complicate the picture since patients may deny a history of exposure because they are unaware of their contact with the resin. This pigment develops not only on the skin but on clothing as well. The black lesions cannot be washed off the skin and are followed by itchy blisters. They eventually peel off, and the skin heals without scarring.

This presentation is not commonly observed, probably because for the black lesions to occur, the skin needs to come into contact with a much higher concentration of plant sap. In most cases, persons experience only brief contact with the offending plant and then further dilute the concentration of oleoresin via perspiration or bathing so the appearance of black spots does not occur.

Regardless of whether or not black coloration occurs, after suspected exposure to the resin, the first step should be to wash the skin with soap to remove the urushiol and prevent further spread of the agent. This is most effective if done within 15 minutes of exposure. All clothes and any other items that came into contact with the offending plant should also be washed. Many patients find cool tub baths helpful in relieving the itching and edema associated with the rash, and oral antihistamines provide nighttime relief from itching. During the acute blistering stage, cool, wet dressings applied for approximately 20 minutes several times a day may help with swelling, especially around the eyes and on the face.

The decision to use topical or oral steroid medication(s) depends on a number of factors, including but not limited to age of the patient, severity of symptoms, amount of body surface area involved, and presence or history of a medical condition in which administration of an oral steroid could cause an adverse reaction.

The American Academy of Dermatology recommends topical steroid treatment only for mild cases. Typically, medium potency topical steroids are used, except on (delicate) skin around the eyes, which requires a less potent steroid. In general, the steroid preparations are liberally applied to the affected areas twice daily for 7 days. Oral steroids are used in more severe cases and in sufferers who have systemic involvement.

In severe cases, oral steroid courses (typically prednisone) are given at 0.75 to 1 mg/kg/day every morning, and this dose is tapered over a three-week period. Generally, oral steroids are tapered by approximately 10 mg every 2 to 3 days. For these severe, generalized cases, short (e.g., a few days) courses of low-dose oral corticosteroids have proven inadequate.

image of black spot reaction courtesy of Professional Education Services Group

Tags: contact dermatitis, rhus dermatitis, poison oak, black spot dermatitis, wilderness medicine, outdoor medicine, healthline

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Sea Salt

Sea Salt is a compilation of memories and essays by underwater cinematographer extraordinaire, Stan Waterman. Stan Waterman is an icon in the scuba diving community. He is a pioneer in the field of underwater cinematography, best known for his pioneering 1971 documentary feature film entitled Blue Water, White Death. I have come to know him a bit this past year through the Academy of Underwater Arts and Sciences, and can vouch for his unbridled enthusiasm, infectious smile, sense of humor, and generosity. When the man enters a room, all eyes are upon him as the swashbuckler lights it up.

The book is a collection of memoirs first and then essays, many of which appeared over the years in other publications, predominantly dive magazines. Therefore, the first part of the book hangs together better than the second, because there is a sequence in the narrative that comprises Stan’s personal history. It is a life of adventure interspersed with glimpses of personal experiences and development that provided the motivations for his eventual migration to become an explorer, both personally and in his profession. The glimpses into the adolescent psychology that motivated a young man to forego the option of privilege for one of self-achievement are telling. I know doctors born with silver spoons who proved themselves in analogous fashion. To a greater or lesser extent, we are all products of our upbringing, and Stan Waterman is no different.

Having dived in many of the waters described by Waterman, I must admit to feeling a bit of kinship in the experiences, even though he usually arrived to these locations many years before me. The emotions of encountering a shark face-to-face, having a close call with a predator, or being exhilarated after a phenomenal dive are the cherished moments in diving. Dive boats, rocky mounds covered with bird excrement in the Galapagos, and magical moments underwater with manta rays are the common ground upon which the conversational ice is broken. Waterman has done as much as any man to successfully capture these moments in visual media, and now he has done much of the same on the written page, which is a rare double talent. Furthermore, having heard him speak in public, I would consider him a true triple threat.

More than anything, Sea Salt is one man’s tale of how a person can combine his or her profession with their passion, which after all, is the mantra of wilderness medicine. I admire the man for what he has accomplished, how he shares with others, and for the role model he has become for a population of senior adventurers that are grey eagles, silver dolphins, and white-maned lions.

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Thank You to Dr. Val Jones, Emergiblog and KevinMD for Grand Rounds

Thank you to KevinMD and Emergiblog for including my post about how to prevent outdoor falls in this week's edition of Grand Rounds (here is the link to Grand Rounds at KevinMD; here is the link to Grand Rounds at Emergiblog. This week's Grand Rounds, which is a weekly compilation of posts related to health care compiled by a host, was created by Dr. Val Jones, who is guest hosting Grand Rounds at KevinMD and Emergiblog. Dr. Jones is one of the leading healthcare bloggers and continues to help all of us refine our craft so that we may offer informative and interesting posts to our readers. The generosity of this weeks' hosts cannot be understated. I continue to be very proud of everyone who takes the time to contribute to the good health and welfare of their readers.

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Farewell to Outdoor Falls

There is an increasing body of literature related to fall(s) prevention as a significant factor in reducing injuries in the home, particularly in the elder population. A recent article in the New England Journal of Medicine presented the conclusion that if older persons, their physicians, and others in the healthcare community were taught strategies for keeping old folks on their feet, that serious fall-related injuries were decreased. The techniques used included seminars, education of primary healthcare providers, recruitment of opinion leaders to influence colleagues, as well as posters, brochures, and advertising in various media.

Falls are a significant cause of serious injury and death among elders in the home in the U.S. Each year, an estimated one third of Americans aged 65 and older experience a fall, and nearly one third of those who fall sustain injuries that require medical attention. Based upon studies and intervention programs enacted in the urban environment, specialists believe that these numbers can be improved, perhaps by more than 10 percent. The focus is upon identifying persons at risk, and using a combination of education, surveillance, and in-home intervention to make improvements that might prevent a fall. The programs require participation by healthcare providers, to both identify potential beneficiaries and to reinforce the most important aspects of the programs.

But what about the outdoor environment? What about younger populations? What can be done to diminish the incidence of falls outside of the home? There is not the same attention focused on outside falls, and nothing approaching the programmatic support current directed at the senior population.

Consider the following tragic story:

"A 44-year-old Texas man plunged some 1,000 feet and instantly died while descending Crestone Needle, known for its steep and treacherous terrain. He was scrambling down a 14,197-foot peak in the Sangre de Cristo wilderness Friday afternoon when it is believed he took a wrong turn in the fog and fell. Authorities say he died immediately. Local authorities were alerted to the missing hiker after his hiking partner reported that he had not returned to base camp by nightfall. According to local reports, the hiking partner experienced altitude sickness while the two were ascending the trail, so the deceased decided to continue on his own. He later met up with two other hikers and the three reached the summit. The two hikers left him to descend on his own. His body was found on the edge of the mountain."

Such stories are all too common. Mountaineers fall from precarious ledges, youths fall from slippery rocks near the edges of waterfalls, rock climbers fall off boulders, and hikers get dangerously close to the edge of poorly maintained trails, from which they plunge into canyons.

We can accomplish it in the home. We ought to be able to accomplish it outdoors.

In The New Old Age blog, Jane Gross wrote that "four organizations -- the University of Southern California, the federal Veteran's Administration, the University of California, Los Angeles, and California State University, Fullerton -- have joined forces to create and evaluate model fall prevention programs that could be replicated at reasonable cost in community settings like senior centers." Experts say that "effective fall prevention requires three elements, which the Southern California research consortium is attempting to evaluate more closely: a physical examination and risk assessment conducted by a doctor or other medical professional, a progressive exercise regime implemented by a physical therapist, and an analysis and remediation of potential hazards in the home conducted by an occupational therapist."

The analogy from the home of an elder to the precarious setting on a mountainside or treetop is not one to one, but still, many of the principles are the same. So, pending some meaningful epidemiology and analysis of intervention programs, here are my recommendations for preventing falls in outdoor settings:

1. Heed all posted warning signs.
2. Stay on posted tracks and trails, and travel at a safe speed.
3. Wear properly fitted footwear appropriate for the situation.
4. Do not ingest alcohol or use mind-altering substances in situations of risk for falls. This includes prescription medications.
5. "Rope up" or otherwise connect yourself to a person or object intended to arrest a fall.
6. Avoid traveling in the dark if you will be in rocky or steep terrain. Always wear a headlamp or carry a lantern, torch, or flashlight.
7. Postpone travel during adverse weather conditions.
8. Rest when you are tired.
9. Condition yourself to improve balance. Keep your muscles strong, but maintain flexibility.
10. Wear appropriate vision correction.
11. Use a walking stick.
12. When handrails, or guide ropes or wires are available, hold onto them.
13. Do not ski recklessly.
14. Stay well hydrated.
15. Pay attention to what you are doing. When you take a picture, stop walking, take the photo, then begin to move again.
16. Do not overload your pack. This contributes to poor balance and fatigue.
17. Avoid walking on ice.

photo of narrow path at La Grotta dei Fichi

Tags: falls, injury prevention, trauma, wilderness medicine, outdoor medicine, healthline

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Thank You to RN Central for Recognizing Healthline Health Matters

Hats off and a big "thank you" to rncentral.com for recognizing Healthline's blogging efforts:

Top 50 Health 2.0 Blogs
Published on Wednesday September 17th , 2008

By Alisa Miller

"Health 2.0 embraces the idea of bringing health care into the community of physicians, patients, and those in the health care industry together with technology and the Internet to provide the best possible health care environment. What better way for the various parts of this community to share their thoughts and communicate ideas than through their blogs? From corporate blogs to blogs that are a part of social networks to individual blogs touching on technology or health care policy, these blogs will help bring you into the community, provide information and resources, and may perhaps help you find your voice as well.

2.0 Corporate Blogs

From popular medical websites such as WebMD and Healthline to Health 2.0 sites like Organized Wisdom, these blogs bring you health information on a variety of topics.

#3. Healthline Health Matters . Read the blogs available through Healthline here. Topics include cancer treatment, reproduction, teen health, nutrition, and much more."

This is an awesome ranking. All of the bloggers and support staff at Healthline should be justifiably proud.

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The Desert and Desert Survival 1

This is the third post based upon educational sessions and syllabus material presented at the Wilderness Medical Society Annual Meeting & 25th Anniversary held in Snowmass, Colorado from July 25-30, 2008. This post about the desert and the next two about desert survival are based upon the extensive knowledge of Dr. Edward J. (“Mel”) Otten, who is Professor of Emergency Medicine and Pediatrics, and Director of the Division of Toxinology at the University of Cincinnati. Mel was resplendent in his bee costume at the Wilderness Medical Society ball - it takes someone with supreme self confidence and poise to generate so much genuine and figurative "buzz." Mel is a master!

Deserts are land areas that receive less than 10 inches (25 centimeters) of rain per year. The most influential climatic processes that produce desert areas are the six cells of cold air currents that descend at the poles and near the Tropic of Cancer and Tropic of Capricorn. These air currents, driven by the sun and rotation of the earth, create areas of relatively warm, dry conditions. Many of the world’s deserts are located in “rain shadows,” areas to the leeward side of mountain ranges that prevents the small amount of moisture that is present in the air to move over the mountains. As the air rises, the moisture cools and precipitates in the higher elevations. Therefore, the area in the “shadow” of the mountain range receives little moisture. The air that does descend is quite dry and adds to the evaporative effect. The Atlas Mountains shadow the Sahara, the Andes the Patagonian, the Great Dividing Range the Australian, and the Sierra Nevada and Cascades the Great Basin deserts. The amount of rainfall is not an absolute indicator of “dryness,” because the rate of evaporation and timing of the rainfall must also be taken into consideration. The amount and type of vegetation, soil composition, altitude, average temperature, wind speed, and solar radiation all contribute to “dryness” and desert formation. Antarctica would be the world’s largest desert by the definition of less than 10 inches of rainfall annually. Some areas of that continent have had no recorded rain in 30 years. In contrast to Antarctica is the northern coast of Alaska, which receives less than 4 inches of rain annually, but evaporation is so low that the area is quite wet.

Deserts are increasing in size, likely due to human as well as geological factors. Over-grazing, destruction of forests, global warming, and other aspects of increased human population contribute to desertification. Currently about 15% of the land area of the earth is desert ( 30% if Antarctica is included). Most of the earth’s deserts can be found between 30 degrees South and 30 degrees North latitude, making them hot as well as dry. These deserts include the Sahara, Arabian, Kalahari, Australian, Atacama, Thar, Namib, and southwest United States. Approximately 50% of Africa is desert; the Sahara by itself almost as large as the United States. Approximately 8% of the United States, or 300,000 square miles, is desert. Most of the U.S. desert areas are adjacent to National Parks and Forests and are frequently visited, for example Grand Canyon, Big Bend, Arches, Zion, Organ Pipe, Joshua Tree, Great Basin, Saguaro, and Capital Reef. Beyond 40 degrees South and North latitude and at elevations over 10,000 feet are the “cold” deserts, which have wide swings in temperature. Examples include the Patagonian, Turkestan, Gobi, and Takla Makan.

The large temperature variations in desert regions are greater at higher elevations and latitudes, but are present in all deserts. Lack of vegetation, cloud cover and ground water surface allows 90% of the solar radiation to reach the desert surface. By contrast, a forest may reflect 50 to 60% of the solar radiation and its vegetation disperses the rest. At night, lack of cloud cover and vegetation allows almost 100% of the accumulated heat to escape, as opposed to only 50% from a humid climate. This explains why the desert temperature may reach 120° F (49° C) during the day and drop to 40° F (5° C) at night. Tropical rainforests may only reach 95° F (35° C) during the day but at night the temperature only drops to 85° F (30° C).

It would seem that the extreme desert climate would only allow for sparse life, but this is not the case. Death Valley, one of the harshest environments in North America, where air temperatures have been recorded at 134° F (57° C), is home to 600 species of plants, 30 species of mammals, 25 species of reptiles and 2 species of fishes.

Oases are found in most deserts. These are isolated depressions usually fed by a constant source of water. Underground springs and wells often supply moisture for plants and animals. If water is not visible, one must dig to find it at the lowest point of the depression. Many named oases have supported camel caravans, allowing them to move from oasis to oasis, and thus cross an otherwise impenetrable desert. Many ancient oases have wells hundreds of feet deep that are drying up because of overuse. When the water is used up, the oasis will disappear and desert life along with it.

The next post based on presentations from the WMS summer meeting will continue with the theme of desert survival.

photo of Namib Desert courtesty of www.gallery.hd.org
photo of Mel Otten by Luanne Freer, M.D.

Tags: desert survival, desert, survival, wilderness medicine, outdoor medicine, healthline

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Thank You to Nurse Ratched's Place for Grand Rounds

Thank you to Nurse Ratched's Place for including my post about the rabies vaccine shortage in this week's edition of Grand Rounds. Grand Rounds is a weekly compilation of posts related to health care compiled by a host, who makes a great effort to compile an interesting collection for readers.

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Wonder Wash and Hand Sanz

Wonder Wash is a biodegradeable and concentrated all purpose soap from All Terrain that comes in peppermint scent or fragrance free. It is advertised to be for "washing anything, anywhere, anytime," formulated to be gentle on skin, pH neutral, and sufficiently mild to be used as shampoo. It ingredients include purified water, sodium coco sulphate, coco betaine, coco amide, vegetable glycerin, sea salt, olive oil, and citric acid. The soap I tested came in a clear, semi-flexible plastic bottle with a press-to-open/press-to-close cap with a volume of 4 fluid ounces (120 milliliters).

I tested the Fragrance Free product. First, I used it in the kitchen to wash dishes, and it was just fine in terms of lather and apparent detergent action. It felt like soap and acted like soap. My hands did not appear to be overly dry or otherwise affected after I used the soap to clean the dishes and then to wash my hands afterwards. I shampooed once with the product, and my hair was clean, but as you might imagine, didn't have any new artificial fragrance. There was no tingling in my scalp, as I have noticed with some other shampoo products, particularly those that contain peppermint. I didn't test the peppermint product, so perhaps it might have that effect.

To test it on clothing, I poured tomato sauce onto two separate locations on a cotton tee shirt (when I eat spaghetti, it is usually the case that I wind up wearing it...). While the shirt was still moist from the sauce, I used Wonder Wash and warm water to hand scrub the material, comparing that to an area scrubbed and rinsed with warm water alone. The soap definitely improved the rate at which the tomato sauce disappeared from the shirt - in fact, I couldn't completely get the stain out of the shirt in the area where I scrubbed without the soap, so I added a bit of the soap and then it came clean.

The results I observed match up with others I have read on the Internet; however, I wasn't brave enough to test it as a substitute for toothpaste. So, if you are interested in a preservative-free, "environmentally friendly" product, this should fit the bill.

Hand Sanz is advertised as an all natural, moisturizing hand sanitizer. It contains 62% ethyl alcohol, as well as wood cellulose to moisturize and thicken the product. It also contains purified water, vitamin E, and aloe vera. In my work at the hospital, and during travel to foreign countries, I have used many different hand sanitizers. Hand Sanz feels better than most of them, in terms of the combination of ease of application, rapidity of drying, softness, lack of precipitates, and residual skin feel.

Tags: Wonder Wash, Hand Sanz, hand sanitizer, soap, wilderness medicine, outdoor medicine, healthline

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Rabies Vaccine Shortage

The American College of Emergency Physicians has just alerted emergency physicians that because of a shortage of rabies vaccine, they need to obtain a confirmation code from their state health department before ordering doses of the vaccine for post-exposure prophylaxis.

Here is some information about rabies:

Rabies virus infection occurs more frequently in wild than in domestic animals. In some foreign countries where immunization of animals is infrequently practiced, the risk is great even in domesticated animals. The virus is carried in saliva and is transmitted by bite or lick (if the skin is broken). It has been transmitted by bats in caves either by aerosolized saliva or undetected bites. Raccoons, dogs, cats, foxes, coyotes, skunks, wolves, bats, woodchucks, and groundhogs are the most common carriers. Rabies has not been reported in bears. Although rabbits, hares, mice, squirrels, chipmunks, rats, guinea pigs, and ferrets may be rabid, they are rarely involved in the transmission of rabies to humans. Domestic animals such as cattle, horses, and sheep become infected in regions where skunk or raccoon rabies is found. In developing countries in Asia, Africa, and South and Central America, dogs are the most common carriers.

Animals with rabies show abnormal behavior. In the “furious” phase, they are hyperactive, may have a fever, are overtly aggressive, and salivate excessively. With “dumb” rabies, they appear tired, lack coordination, and may become paralyzed.

Because of rabies risk, all wild animal bites or scratches, and bites or scratches of unregistered or strangely behaving cats and dogs, should be reported to the appropriate public health authority. If the animal is a pet with otherwise normal behavior, it should be observed for 10 days. If the animal is rabid, it will become very ill or die during that time, and its brain tissue can be analyzed for the presence of rabies. If the animal is a pet with unusual behavior, or a captured high-risk wild animal, it should be killed and examined. If it is a high-risk animal and cannot be captured, it must be presumed to be rabid.

Immediately scrub an animal bite wound or a wound that has been licked by a potentially rabid animal vigorously with soap and water. If benzalkonium chloride 1% (Zephiran); 10% povidone iodine (Betadine) solution (less effective); or, in a pinch, Bactine (benzalkonium 0.13%) antiseptic is available, one of these should be used to irrigate and deeply swab the wound, since they may kill rabies virus.

The standard instructions in times of plentiful rabies vaccine supply are:

If rabies is a consideration, the victim should seek the assistance of a physician, who will determine the need for postexposure rabies vaccination (a series of five injections) and injection of antirabies serum (human rabies immune globulin; as much as possible is injected around the bite wound, and the remainder intramuscularly). A person who has been previously immunized against rabies still needs two booster doses of rabies vaccine after high-risk contact with a rabid animal. In countries (Africa, Asia) where rabies in very prevalent in dogs and cats, the vaccination status of the biting animal should be ignored, because the vaccination may not have occurred or may have been ineffective. Begin vaccination and then discontinue after 10 days if the animal is observed to remain healthy during that time period.

Preexposure vaccination against rabies should be administered to people at high risk of exposure (animal handlers, cavers, hunters, and trappers in rabies-endemic areas, along with travelers to certain foreign countries). This is given as a series of three intramuscular injections over 28 days, although a newer 1 week schedule for the injections appears to be quite effective. An intradermal regimen can be used for immunization, but this technique may result in lower antibody level.

The incubation period of rabies ranges from 9 days to more than 1 year, but is usually between 2 and 16 weeks. The first symptoms are fatigue, weakness, anxiety, irritability, fever, headache, nausea and vomiting, sore throat, abdominal pain, and loss of appetite. Some victims complain of numbness and tingling where they were initially bitten. After a few days to 2 weeks, the virus shows its devastating effect upon the nervous system, with symptoms of increased agitation, hyperactivity, seizures, hallucinations, uncontrollable behavior, and inability to drink (hydrophobia) due to muscle spasms in the throat. This constellation is called “furious rabies.” With “dumb” rabies, a person becomes progressively weak, uncoordinated, and paralyzed. Unfortunately, rabies is virtually always fatal, with the terminal events being one or more of coma, respiratory failure, seizures, abnormal heart rhythms, paralysis, and pneumonia.

To avoid rabies, be certain that all pets and livestock are properly vaccinated, do not feed or handle wild animals, do not feed or touch stray animals, avoid sick or strange-acting animals, keep garbage and food (including feed for animals) covered and away from wild animals, do not keep wild animals as pets, do not touch or pick up dead animals, and do not handle bats.

With the current vaccine shortage, the protocol for post-exposure vaccination has been modified. Complete details are found at the CDC website dedicated to information about rabies. To emphasize some of the information:

As of August 29, 2008, Sanofi Pasteur in coordination with the Centers for Disease Control and Prevention (CDC) will resume shipping IMOVAX® Rabies, Rabies Vaccine for post-exposure prophylaxis only. Novartis Vaccines will no longer be shipping supplies of RabAvert®.

For a physician to obtain IMOVAX rabies vaccine, he or she must first contact the appropriate Rabies State Health Official so that a risk-assessment can be conducted for the suspected exposure. If the Official determines that post-exposure prophylaxis is required, the inquiring physician will be provided with a pass code to place on the Sanofi Pasteur Rabies Post-Exposure Form. The form must be filled out in its entirety, including the required physician’s signature and pass code provided by the Rabies State Health Official. Sanofi Pasteur may be contacted at 1-800-VACCINE to obtain the required form.

Vaccine availability for pre-exposure vaccination continues to be limited, and will be distributed on approval from state and federal public health authorities for those first responders with a critical need and in consideration of available supplies. These measures will allow responsible management of currently limited supplies of this vaccine for individuals at highest risk of exposure.

Why is there an interruption in supply?

Starting in June 2007, Sanofi Pasteur began renovating its IMOVAX Rabies vaccine production facility in France to maintain compliance with the most current requirements from FDA and the French regulatory body. Prior to these renovations, Sanofi Pasteur established an inventory based on historical levels of sales and projected market demand. The facility is scheduled to be approved and operational by mid-to-late 2009. Until the facility is operational, Sanofi Pasteur has a finite amount of IMOVAX Rabies vaccine.

After the renovations began, Novartis, the other supplier of rabies vaccine for the United States, was unable to meet projected rabies vaccine supplies. Since early 2008, Novartis has been supplying its rabies vaccine, RabAvert, for post-exposure use only. Consequently, Sanofi Pasteur has been supplying nearly all of the market for rabies vaccine. The increase in demand for IMOVAX is outpacing the company’s historical levels of supply.

Persons at increased risk for rabies exposure should take appropriate precautions to avoid rabies exposure. Vaccine is available for pre-exposure prophylaxis, and providers should consult with their local or state public health department to ensure appropriate use of such prophylaxis. General rabies awareness and prevention messages should be emphasized to avoid exposure (e.g., avoid wildlife contact, vaccinate pets/livestock, capture/observe/test exposing animal, etc.).

Tags: rabies vaccine, rabies, wilderness medicine, outdoor medicine, healthline

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Lightning Precautions

Spring, summer (peak season), and autumn are the seasons during which we witness most thunderstorms, and during which people and animals are struck by lightning. The National Oceanic and Atmospheric Administration indicates that approximately 50 Americans are struck and killed each year by lightning.

One of the world's experts on lightning injuries is Dr. Mary Ann Cooper, who is Professor of Emergency Medicine and Director of the Lightning Injury Research Program at the University of Illinois at Chicago. This year, Dr. Cooper was the recipient of the Research Award from the Wilderness Medical Society at its annual scientific meeting held in Snowmass, Colorado. She is also senior author of the chapter on lightning injuries in the textbook Wilderness Medicine.

As Dr. Cooper has noted, most people seriously underestimate the risk of being struck and do not know when or where to take shelter. NOAA data indicate that of persons struck and killed by lightning, 25 percent were standing under a tree and 25 percent occurred on or near the water. It is logical that nearly all persons killed by lightning are struck outdoors, so it is very important that everyone who might be caught in a thunderstorm be able to make a rapid assessment of the risk, and seek the best shelter or protective positioning possible. This is a personal responsibility for most, and a very important skill for group leaders.

Here is some information intended to help you understand the behavior of lightning in order to improve avoidance techniques:

1. Lightning strikes the earth at least 100 times per second during an estimated 3,000 thunderstorms per day. Fortunately, the odds of being struck by lightning are not very great. The wise traveler respects thunderstorms and seeks shelter at all times during a lightning storm.

2. Thunder, which is always present with lightning, is attributed to the nearly explosive expansion of air heated and ionized by the stroke of lightning. To estimate the approximate distance in miles from your location to the lightning strike, time the difference in seconds between the flash of light and the onset of the thunder, and divide by five.

3. Lightning can injure a person in five ways:

A. Direct hit, which most often occurs in the open.
B. Splash, which occurs when lightning hits another object (tree, building). The current seeks the path of least resistance, and may jump to a human. Splashes may occur from person to person, or from a metal fence.
C. Contact, when a person is holding on to a conductive material that is hit or splashed by lightning.
D. Step (stride) voltage (or ground current), when lightning hits the ground or an object nearby. The current spreads like waves in a pond.
E. Blunt injury, which occurs from the victim’s own muscle contractions and/or from the explosive force of the shock wave produced by the lightning strike. These can combine to cause the victim to be thrown, sometimes a considerable distance.

4. When lightning strikes a person directly, splashes at him from a tree or building, or is conducted along the ground, it usually largely flows around the outside of the body (flashover phenomenon), which causes a unique constellation of signs and symptoms. The victim is frequently thrown, clothes may be burned or torn (“exploded” off by the instantaneous conversion of sweat to steam), metallic objects (such as belt buckles) may be heated, and shoes removed. The victim often undergoes severe muscle contractions—sufficient to dislocate limbs. In most cases, the person struck is confused and rendered temporarily blind and/or deaf. In some cases, there are linear (11/2 to 2 in, or 1.3 to 5 cm, wide, following areas of heavy sweat concentration), “feathered” (fernlike; keraunographism; Lichtenberg’s flowers—cutaneous imprints from electron showers that track over the skin), or “sunburst” patterns of punctate burns over the skin, loss of consciousness, ruptured eardrums, and inability to breathe. Occasionally, the victim ceases breathing and suffers a cardiac arrest. Seizures or direct brain damage may occur. Eye injuries occur in half of victims.

5. A victim struck by lightning may not remember the flash or thunder, or even recognize that he has been hit. The confusion, muscle aches, body tingling, and amnesia can last for days. With a more severe case, the skin may be mottled, the legs and/or arms may be paralyzed, and it may be difficult to locate a pulse in the radial (wrist) artery, because the muscles in the wall of the artery are in spasm. First-, second-, or third-degree skin burns may be present. Broken bones are not uncommon.
If a person is found confused, burned, or collapsed in the vicinity of a thunderstorm, consider the possibility that he was struck by lightning. The victim is not “electrified” or “charged”—you will not be jolted or stunned if you touch him.

6. If you are in the vicinity of a thunderstorm, seek shelter for the victim and yourself. Lightning can strike twice in the same place!

Lightning Avoidance

1. Know the weather patterns for your area. Don’t travel in times of high thunderstorm risk. Avoid being outdoors during a thunderstorm. Carry a radio to monitor weather reports. Lightning can lash out from 10 miles in front of a storm cloud, in seemingly clear weather. If you calculate (see above) that a nearby lightning strike is within 3 miles (5 km) of your location, anticipate that the next strike will be in your immediate area. The “30-30 rule” specifies that if you see lightning and count less than 30 seconds prior to hearing thunder, seek shelter immediately. Since thunder is rarely heard from more than 10 miles away, if you hear thunder, it is best to curtail activities and seek shelter from lightning. Do not resume activities outdoors for at least 30 minutes after the lightning is seen and the last thunder heard.

2. If a storm enters your area, immediately seek shelter. Enter a hard-roofed auto or large building, if possible. Tents and convertible autos offer essentially no protection from lightning. Tent poles are lightning rods. Metal sheds are dangerous because of the risk of side splashes. Indoors, stay away from windows, open doors, fireplaces, and large metal fixtures. Inside a building, avoid plumbing fixtures, telephones, and other appliances attached by metal to the outside of the building.

3. Do not carry a lightning rod, such as a fishing pole or golf club. Avoid tall objects, such as ski lifts and power lines. Avoid being near boat masts or flagpoles. Do not seek refuge near power lines or tall metal structures. If you are in a boat, try to get out of the water. If you are swimming in the water, get out. Do not stand near a metal boat. Insulate yourself from ground current by crouching on a sleeping pad, backpack, or coiled rope.

4. Move off ridges and summits. Thunderstorms tend to occur in the afternoon, so attempt to summit early and be heading back down by noon. In the woods, avoid the tallest trees (stay at a distance from the tree that’s at least equal to the tree’s height) or hilltops. Shelter yourself in a stand of smaller trees. Avoid clearings—you become the tallest tree. Don’t stay at or near the top of a peak or ridge. Avoid cave entrances. In the open, crouch down or roll into a ball.

5. Stay in your car. If it is a convertible, huddle on the ground at least 50 yards (46 m) from the vehicle.

6. If you are part of a group of people, spread the group out so that everyone isn’t struck by a single discharge.

7. If your hair stands on end, you hear high-pitched or crackling noises, or see a blue halo (St. Elmo’s fire) around objects, there is electrical activity near you that precedes a lightning strike. If you can’t get away from the area immediately, crouch down on the balls of your feet and keep your head down. Don’t touch the ground with your hands.

8. The StrikeAlert Personal Lightning Detector (Outdoor Technologies, Inc.) is the size and configuration of a pager and uses an audible warning and LED display to show the wearer how far away lightning is striking and if a storm is approaching or leaving.

Tags: lightning strike, lightning, Mary Ann Cooper, wilderness medicine, outdoor medicine, healthline

Labels: injury prevention, lightning, outdoor recreational injury

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Drowning (Submersion Incidents) Terminology

In response to my post entitled "Prevention of Submersion (Near-Drowning) Incidents," a reader corresponded: "Would you please include in an upcoming entry an explanation of the consensus definition of drowning which was adopted at the 2002 World Congress of Drowning and then subsequently by the Centers for Disease Control? It was also be helpful to discuss where adoption of this uniform definition, the process of experiencing respiratory impairment from submersion/immersion in liquid, leaves related terms such as near-drowning, wet drowning, dry drowning, active or passive drowning, secondary drowning, silent drowning, etc. There still seems to be a lot of confusion about this subject, even within the medical community, but especially among lay people involved with aquatics."

At the 2002 World Congress mentioned above, the following definition was adopted by consensus of the conference attendees: "Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid." It was further recommended that drowning outcomes should be classified as death, morbidity, and no morbidity. As noted in a paper entitled "A new definition of drowning: towards documentation and prevention of a global health problem," authored by E.F. van Beeck, C.M. Branche, D. Szpilman, J.H. Modell, and J.J.L.M. Bierens (Bulletin of the World Health Organization 2005;83:853-856), other recommendations emanating from the conference include that the terms "wet," "dry," "active," "passive," "silent," and "secondary" drowning should no longer be used. The reason for simplifying the definition of drowning and avoiding the use of modifying terms for which there have been few uniform definitions, is to "facilitate surveillance and lead to more reliable and comprehensive epidemiological information on this global, and frequently preventable, public health problem."

I concur with the conclusion of the authors. For instance, let's consider the term "dry drowning." This has been taken by some to mean the initial laryngospasm that is sometimes seen when water enters the oropharynx and assaults the vocal cords, regardless of the ultimate outcome (e.g., life or death), and by others to mean a death from drowning in which little or no water appears to have entered the lungs. Imprecise definitions lead to errors in recording of epidemiological data, and therefore to under- or overestimation of situations and outcomes.

The pathophysiology of submersion/immersion and drowning is complex, and varies to some degree with the victim (e.g., age, underlying health, lung status), water properties (e.g., temperature, salinity), co-morbid conditions, time of submersion/immersion, and many other factors. These should all be described as best possible when case reports are recorded or data are collected, to aid doctors, epidemiologists, and researchers in their efforts to improve rescue techniques, field medicine, in-hospital therapies, and the advice offered to laypersons.

For the purposes of persons involved with aquatics, the consensus definition and recommendations are sufficient. For the purposes of persons seeking to understand the nuances of the medical presentations and the impacts of interventions, more details are necessary. However, the necessity to "complete the picture" on any particular victim is not unique to drowning. Whether we attempt to assist someone with drowning, frostbite, or high altitude cerebral edema, the devil's in the details.

Tags: submersion, near-drowning, drowning, wilderness medicine, outdoor medicine, healthline

Labels: drowning, near-drowning, submersion

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Thank You to A Chronic Dose for Grand Rounds

Thank you to Laurie Edwards of A Chronic Dose for including my second post about managing blisters in this week's edition of Grand Rounds. Grand Rounds is a weekly compilation of posts related to health care compiled by a host, who makes a great effort to compile an interesting collection for readers.

Labels: A Chronic Dose, Grand Rounds

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