11 Tips for a Safe Fourth of July

shutterstock_142548190I thought this article had some particularly great tips for people regarding being safe during the July 4th holiday.

Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

1)  Be a safe swimmer. Water sports and fireworks are two of the biggest pastimes for Fourth of July celebrations, and these are both linked to numerous deaths and injuries each year. Never swim alone, and make sure that kids’ water play is adequately supervised at all times. Many drownings occur when parents and other adults are nearby, so always have a designated chaperone for water play and don’t assume that others are watching the kids. Statistics show that most young children who drown in pools have been out of sight for less than five minutes.

2)  If fireworks are legal in your community and are a part of your celebration, be sure to store and use them safely. Keep the kids away from the fireworks at all times, and keep spectators at a safe distance. Attending fireworks displays organized by professionals is always safer than trying to put on your own show.

3) Use alcohol responsibly.  Alcohol and fireworks can be a hazardous and dangerous combination. Also, have a designated driver to bring partygoers home from the festivities. Remember also that alcohol and swimming can be as dangerous as drinking and driving.

4)  Lakes, waterways, and seas will be crowded with boats. Review safe boating practices, and don’t drink and drive your boat. Alcohol consumption while operating boats or other motorized water vessels is illegal, and you can be arrested for a BWI (boating under the influence!). Be sure that you have an adequate number of life preservers on hand for extra guests. Become familiar with the boating laws in your area.

5)  Cover food and beverages outdoors to discourage bees and wasps from attending your party. If someone is allergic to insect stings, you should have an emergency anaphylaxis kit on hand. Wearing shoes, long sleeves, and long pants outdoors and avoiding fragranced body products, bright colors, and sugary drinks can also help prevent bee stings.

6)  Apply sunscreen both before and during an outdoor party. Ultraviolet rays from the sun can cause both premature aging and skin cancer in the long term, and a painful burn the next day. Even those with darker skin should use a sunscreen with a minimum sun protection factor (SPF) of 15, according to recommendations from the American Academy of Dermatology.

7)  Check prescription medications you are taking to assure you will not have a sun-sensitizing drug reaction to the medication. Check prescription medications you are taking to assure you will not have a sun-sensitizing drug reaction to the medication.

8)  If you’ll be hiking or camping in an area where ticks are abundant, wear long-sleeved, light-colored shirts and long pants tucked into socks or boots to protect yourself from tick-borne diseases. For your skin, you can use a tick repellent with no more than 30% DEET according to the manufacturer’s instructions. Products containing DEET should not be used on children less than 2 months of age and should not be applied to the hands or face of young children. Check yourself (and your pets) for ticks at the end of the day.

9)  Spend adequate time indoors or in the shade and drink plenty of fluids to avoid heat illness in extremely hot climates. The risk of heat illness is increased when participating in strenuous activity or sports, and those with chronic medical conditions and the elderly are also at an increased risk of heat exhaustion and/or heat stroke. Alcohol consumption can also promote dehydration and increase the risk.

10)  Keep children away from campfires and grills. Gas leaks, blocked tubes, and overfilled propane tanks can be a cause of grill fires and explosions.

11)  Don’t leave the picnic spread out all day. Allowing food to sit in outdoor temperatures can invite foodborne illness. The U.S. FDA suggests never leaving food out for more than one hour when the temperature is above 90 F and not more than two hours at other times. Foods that need to be kept cold should be placed in a cooler with plenty of ice or freezing packs and held at a maximum temperature of 40 F. While mayonnaise and other egg dishes are often associated with food poisoning, any food can potentially become contaminated. Adequate hand washing and food preparation can also help prevent food poisoning.


4th of July Safety Tips for Pet Owners

My dogs hate fireworks and I was just discussing what we are going to do with our dogs tomorrow night during all the fireworks.  I will be working in the Urgent Care and my wife will be attending some 4th of July festivities with friends, so our dogs would be home alone.  We will make accommodations so that they will not be alone.  I came across an article that I thought was useful and timely regarding 4th of July safety tips for pet owners.


Denver Pets Examiner

When celebrating with family and friends this 4th of July, remember that fireworks and some common barbecue foods can be hazardous to the well-being of pets.

Despite most firework shows being banned this year in Colorado due to fire dangers, fireworks will still be the biggest perpetrators of 4th of July issues for pets, the most common being pet noise phobias. The loud noises can cause fear and anxiety for pets of all kinds, including dogs and cats and even horses. It is best to keep dogs and cats a safe distance from the activity – indoors is best. For pets with severe noise phobias, a veterinarian can prescribe anti-anxiety drugs or sedatives to help ease the stress. Larger pets, like horses and other livestock, are extremely susceptible to noise phobias.

While most pet owners are aware of noise phobias, many are unaware that unused fireworks can be poisonous if ingested by curious dogs or cats. Many contain hazardous chemicals like chlorates, potent oxidizing agents that are harmful to red blood cells and kidneys; soluble barium salts that cause a life-threatening drop in potassium; sulfur; and coloring agents, which can contain dangerous heavy metals. Gastrointestinal issues like vomiting, a painful abdomen and bloody diarrhea can result. The severity of the reaction will depend on the type of firework, the amount ingested and what type of coloring agents it contains. In severe cases, pets can suffer tremors or seizures, along with acute kidney failure, bone marrow changes, shallow breathing and jaundice (yellowing of the skin).

Healthcare Resources for Patients – Do You Trust All The Medical Information Out There?

shutterstock_172524281With all the information out there on the internet, in magazines, books, newsletters, radio, hotlines and on television, sometimes it’s hard to know where to go for information to learn about health and diseases on your own.  I encourage most of my patients to use technology, but I want them to have a list of resources to search when they are looking for information and be able to judge whether it comes from a credible source.  A huge amount of information is available online, however sometimes it’s of variable quality and can be difficult for the patient to decide whether or not a particular source is credible.

I think it’s the medical providers responsibility to educate patients on how they can do their own research, because patients may not have:

1)   An understanding of the biology of the disease process

2)   Knowledge about how to determine if the information is credible based on the type of research study (i.e. case report, single randomized trial or double blinded trial with placebo).

3)   Skepticism about the information that may come from biased sources such as from a drug company, from authors with financial conflict of interests and intellectual zeal, or wish for personal aggrandizement.

4)   Familiarity with how a patient with the disease presents and the signs and symptoms of the illness

5)   An understanding how good scientific research done by well trained scholars in centers of academic excellence

Some hints on finding trustworthy information online:

1)   Was the website recommended from someone you trust, such as your physician, the National Institute of Health or A Medical Library Association?  I recommend using a trusted source of information rather than relying on a search engine and using the first or second webpage that comes up in the search.

2)   Sites such as the Mayo Clinic (http://mayoclinic.com) that display the seal logo on their page.

3)   Websites that are sponsored by medical schools, or the government

4)   If you type your question into a general search engine such as yahoo, or Google, use multiple sites and compare the information based on the criteria below.

How do you know if a website is good quality?  Here are some possible factors to consider:

1)   Who created the website?  Anyone can create a website or blog and the information all is printed and looks legit, but is it?  Is it a well known and respected organization or recommended site by someone you trust?

2)   What is the purpose of the website?  Consider who the intended audience is, and how it was created.

3)   What are the funding sources for the website?  Do the producers of the website have some financial interest or sell something that may bias the information presented on the site?

4)   Consider the date that the information was released.  Medical research is rapidly advancing and the information may be dated.  Look for a date that the site updated or posted the information.

5)   Consider the evidence when examining the treatment recommendations.

6)   Personal experiences of the authors may make for interesting reading material, but should be clearly marked as personal experiences and not be the only rationale for the recommendations.

7)   The author of the website or blog should be available for communication and response.

8)   The website should explain if there are conflicts of interest or limitations in the information provided and that the information does not replace contact with a medical provider or physician.

9)   If there are forums, bulletin boards or interactive chat rooms, be wary of who the participants are.

The Medical Library Association has created a set of criteria to help patients judge the quality of websites for themselveswww.mlanet.org/resources/userguide#3

The US Government has also created a guide called A User’s Guide to Finding and Evaluating Health Information on the webwww.healthfinder.gov

Books:  Some credible books that are produced by the government or medical schools include:

1)   Mayo Clinic Health Book, 4th Ed. New York Time Home Entertainment, 2009

2)   Harvard Medical School Family Health Guide, 1st Edition. New York; Simon and Shuster, 2005

3)   American Medical Association Family Medicine Guide, 4th Ed. Indianapolis, IN, Wiley 2004

Magazines:  Consumer Reports and American Family Physician publish information responsibly.  The information from the American Family Physician magazine is intended for medical providers and may use medical jargon that is less helpful for the average patient however.

Newspapers:  The New York Times and Washington Post have medical writers who are scientific backgrounds and often provider information in a very captivating way.

This document is for informational purposes only, and should not be considered medical advice for any individual patient.  If you have questions please contact your medical provider.


I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO

Blog: https://doctorrennie.wordpress.com

Water Disinfection in the Wilderness

shutterstock_125263139I credit much of this information to Dr. Howard Donner who has incredible knowledge of both medicine and the wilderness.  He is also an excellent teacher.

Drinking water can be contaminated with bacteria, viruses, protozoa and other parasites.  The risks of getting ill depends on the number of organisms that are consumed which is determined by the volume of water, concentration of organisms and how well the water treatment system is working.

Disinfection:  Removal or destruction of harmful microorganisms

Pasteurization:  Similar to disinfection but uses heat at temperatures below 100 degree C to kill most pathogenic organisms

Sterilization: Destruction or removal of all life forms – not to be confused with disinfection or pasteurization

Purification:  Removal of organic and inorganic chemicals and particulate matter to remove offensive color, taste and odor.  It may not remove or kill enough microorganisms to ensure microbiologic safety.

The goal of disinfecting water is to achieve minimal microbial hazard so that the likelihood of illness is acceptable. Sterilization is not necessary because all life forms are not human pathogens.

Water treatment methods:  Heat, Filtration and Clarification, Ultraviolet light

Disinfection by Heat:

1)   The boiling time required is important when fuel is limited

2)   Most pathogens including cysts, bacteria, viruses and parasites can be killed at a temperature well below boiling

3)   Thermal death is a function of both time and temperature; therefore, lower temperatures are effective with longer contact times

4)   Microorganisms have varying sensitivity to heat; however all common bacteria that cause diarrhea are readily inactivated by heat

5)   Hepatitis A is a special concern because it seems to have greater thermal resistance

6)   Elevation should not make a large difference unless hepatitis A is a concern because heat inactivation occurs below typical boiling temperatures

7)   The 10 minute boiling rule is for sterilization of water.  Enteric pathogens are killed within seconds by boiling water and rapidly above 140 degrees.  The majority of the time required raiding the temperature of the water to boiling point works toward disinfection so water is safe to drink by the time it has reached a full boil.  For extra safety against hepatitis A, keep the water covered and hot for several minutes after boiling

8)   A pressure cooker saves times and fuel at all elevations

9)   Pasteurization has been achieved using solar heating using a foil-lined cardboard box with a glass window in the lid.

Disinfection by Filtration:

1)   Field filters rely on mechanical removal of microorganisms and are adequate for cysts, and bacteria but do not reliably remove viruses which are a major concern in water where high levels of fecal contamination are present (e.g., in developing countries)

2)   The advantage is they are simple and require no holding time

3)   They do not add any unpleasant taste and may improve taste and appearance of the water

4)   Most viruses adhere to larger particles or clump together into larger aggregates that me be removed by a filter, but filtration alone is not adequate because the infectious dose of the virus may be quite small.

5)   Filters are often expensive and can add considerable weight and bulk to the backpack

6)   The filter pore size that is required to remove microorganisms is difficult to determine because the organisms possess elasticity and deform under pressure and that makes it possible for them to squeeze through filter pores.

7)   Filters are rated by their ability to retain particles of a certain size which is described by two terms.  Absolute rating means that 100% of a certain size of particle is retained in the filter.  Nominal rating indicates that more than 90% of a given particle size will be retained.

8)   All filters eventually clog from suspended particulate matter even in clear streams.  This means that they require cleaning or filter replacement.  The ability to field service the unit easily is an advantage.

9)   As the filter clogs, it requires increasing pressure to drive the water through which can force microorganisms through the filter.

Reverse Osmosis Disinfection:

1)   Reverse osmosis filters use high pressure (100 to 800 psi) to force water through semipermeable membranes that filter out dissolved ions, molecules and solids

2)   Generally used for desalinating water, but may also be used to remove biological contaminants

3)   Small hand-pumped reverse osmosis units have been developed but their high price and slow output currently limit their use by land based wilderness travelers.  They are an essential survival item for ocean travelers

Clarification of cloudy water can be achieved by sedimentation, coagulation-flocculation(CF), or adsorption.

1)   Large particles settle by gravity over 1-2 hours in sedimentation. Which can help if you are using a filter.  Although filters remove particulate debris, thus improving the appearance and taste of “dirty” water, they clog quickly if the water contains large particles. Using sedimentation allows the larger particles to settle out to the bottom of the container helps prevent the filters from clogging so quickly.

2)   Smaller suspended particles can be removed by coagulation-flocculation(C-F).  This is accomplished in the field by adding alum (aluminum potassium sulfate).  Alum is used in the food industry as a pickling powder and is nontoxic.  C-F will remove contaminants that cause unpleasant color and taste as well as some dissolved metals and some microorganisms.

Water Clarification using Alum:

1)   Add a pinch of alum to each gallon of water

2)   Mix well, and stir occasionally for 30 minutes then allow 30-60 minutes for settling

3)   The water should be clear, if it is not then add another pinch of alum and repeat

4)   Decant or pour the water through a paper filter to remove clumps of flocculate.

Charcoal filters/Granular Activated Charcoal (GAC):  Removes organic pollutants, chemicals, and radioactive particles by adsorption.  This improves the color, taste and smell of the water.  Although some microorganisms adhere to the GAC or become trapped in the charcoal filters, GAC does not remove all microorganisms, so it does not disinfect.

1)   Useful for removing halogens such as iodine or chlorine after disinfection

2)   Wait until after the contact time for disinfection before running water through charcoal if you use it to remove the iodine or chlorine from your water

3)   Some filters use iodine resins followed by GAC and rely on a different dynamic

Halogens:  Chlorine and Iodine are effective disinfectants against bacteria, viruses, Giardia and cysts of amebae but not Cryptosporidium.  They are not expensive.

1)   Disinfection with halogens depends on both the concentration of the halogen and the amount of time the halogen is in contact with the water (contact time).  Increase in one allows a decrease in the other (inverse relationship).

2)   Water temperature and the presence of organic contaminants in the water affect this method (colder temperatures slow and organic contaminants decrease its disinfection action).  Thus, in cold water, the contact time or dose should be increased and in polluted water the dose must be increased

3)   Use 4 parts per million (ppm) as a target concentration for surface water and allow extra contact time if the water is cold.

4)   In cloudy water that will not settle out by sedimentation, the halogen dose should be at least 8ppm.  Ideally, use C-F to clarify the water before halogenation, then a smaller amount of halogen may be used.

Organism sensitivity to halogens:

1)   Bacteria are very sensitive to halogens

2)   Viruses and Giardia require higher concentrations or longer contact times

3)   Certain parasite eggs such as round worms are resistant but they are usually not spread in the water.  These eggs or cysts are susceptible to heat or filtration

4)   Cryptosporidium cysts are extremely resistant to halogens

Chlorine vs. Iodine:

1)   Iodine is less affected by pH and tastes better than Chlorine

2)   Chlorine and Iodine are available in liquid or tablet forms

3)   Some people have allergic reactions to iodine

4)   Iodine use is not recommended for people with unstable thyroid disease or unknown iodine allergy

5)   Iodine should not be used during pregnancy for longer than several weeks because of risk of neonatal goiter

6)   Limit exposure to drinking iodinated water to 1 month or less if all water being consumed is treated with iodine

7)   Iodine resins with GAC filters may reduce iodine exposure because they have lower concentration of iodine and remove it with the filter

Problems with halogens:

1)   The taste of water can be unpleasant

2)   The potency of some products (both tablets and solution) decrease with time an are affected by heat or moisture

3)   Liquids are corrosive and can stain clothes or equipment

4)   Cryptosporidium are resistant

5)   The actual concentration (after halogen demand – ie amount of organic material in water) is unknown

Improving the Taste of Water that has been disinfected with halogens:  Add flavoring to the water only after adequate contact time because the sugar and additives can reduce the amount of free iodine available.  Also using charcoal (GAC) to remove the halogen after contact time.  You may also reduce the concentration and increase the contact time for clean water.  You can use a collapsible plastic container to disinfect water with low doses of iodine during the day or overnight.  You can also add a few granules per liter of ascorbic acid (vitamin C) in powder or crystal form after the contact time and this will take out the color and taste of the chlorine or iodine.

 Superchlorination-Dechlorination:  High doses of chlorine are added to the water in the form of calcium hypochlorite crystals to achieve concentrations of 30-200 ppm of free chlorine that are above the margin of safety for field conditions and rapidly kill all bacteria, viruses and protozoa.  After 10-15 minutes, several drops of 30% hydrogen peroxide solution are added.  The minor disadvantage of the two-step process is excellent taste.  This is a good technique for highly polluted or cloudy water and for disinfecting large quantities of water.

Mixed Species Disinfection (Miox Purifier):  Passing a current through a simple brine sale solution generates free available chlorine, as well as other “mixed species” disinfectants that have been demonstrated effective against bacteria, viruses and bacterial spores.  There is potential for malfunction and battery depletion.  A new point-of-use commercial product is available – Miox marketed by MSR.

Chlorine Dioxide:  This is capable of inactivating most waterborne pathogens including Cryptosporidium parvum oocysts at practical doses and contact times.  It is at least as effective a bactericide as chlorine and in many cases it’s superior.  It’s far better against viruses.

Ultraviolet Light:  In sufficient doses, all waterborne enteric pathogens are inactivated by UV radiation.  UV treatment does not require chemicals and does not affect the taste of the water.  UV works rapidly and overdose to the water does not cause any problems.  It has no residual disinfection power and water may become re-contaminated or regrowth of bacteria can occur.  Particulates in the water however can shield microorganisms from UV rays.  Where strong sunshine is available, solar disinfection of drinking water is an effective, low-cost method for improving water quality and may be very useful in refugee camps and disaster areas.

If you are interested in learning more about wilderness medicine, a great resource for information is the wilderness medicine society:  http://www.wms.org/

This document is for informational purposes only, and should not be considered medical advice for any individual patient.  If you have questions please contact your medical provider.


I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO

Blog: https://doctorrennie.wordpress.com

Hypothermia: It’s Cold Out There

shutterstock_171146414I credit the information that I’ve learned and posted here to Eric Weiss, MD who is an international expert in Wilderness Medicine and Hypothermia.

Patients with accidental hypothermia come to medical providers year-round and in all climates.  Hypothermia is defined as a decrease in core body temperature below 95 degrees F (35 degrees C).

For purposes of emergency management and resuscitation, hypothermia can best be characterized as either mild or severe.  In mild hypothermia (core temperature 87.8-95 degrees F), the victim is conscious, still shivering and generally not prone to developing abnormal heart rhythms.  In severe hypothermia (core temperature below 87.8 degrees F), the patient has altered level of consciousness, diminished or absent shivering and is prone to abnormal heart rhythms.

Mild hypothermic victims can still generate heat through shivering so they generally do well without intensive rewarming.  In severe hypothermic patients, active rewarming techniques such as extracorporeal blood rewarming, inhalation therapy, peritoneal lavage, thoracic cavity lavage or thoracotomy with mediastinal irrigation may be needed.

Pre-hospital Treatment of Mild Hypothermia:  Preventing further heat loss and facilitate rewarming are the goals.  The rescuer should remove all wet clothing and replace it with dry clothing, insulate the patient with sleeping bags, blankets, extra clothing or other suitable material.  Use insulation underneath the patient as well as on top.  Encourage drinking of warm fluids and sugary drinks if they can swallow without aspirating (inhaling the drink into their lungs).  It is not uncommon to observe a continued decline in core temperature after a hypothermic patient is removed from the cold environment and external warming is initiated.  This phenomenon is called core temperature afterdrop.

Pre-hospital Treatment of Severe Hypothermia:  Careful handling is necessary because these patients are prone to develop abnormal heart rhythms through rough handling.  If in the backcountry, consider helicopter transport to prevent jostling that might occur with an overland evacuation.  Keep them horizontal when possible to minimize orthostatic hypotension.  Provide oxygen if you have it.  Administer a minimum of 500ml of heated (98.6-105.8 degrees F) IV normal saline or D5NS.  Lactated ringers should be avoided because when the liver is cold, it poorly metabolizes lactate.  Consider intraossious (I/O) infusion for alternative pathway for fluid replacement for a dehydrated patient who you cannot get IV access. Hot water bottles or heat packs can be placed in the axillae and groin area and along the neck where large blood vessels course near the surface.  Hot water bottles should be wrapped with insulation to prevent thermal burns.

In a severely hypothermic patient, they may feel/look clinically dead. Breathing may be difficult to detect if the breathing rate is significantly depressed. The rescuer should listen to the chest and palpate over carotid or femoral arteries for at least 1 minute to detect a pulse.   If the patient has any sign of life, chest compressions should not be initiated as they may precipitate ventricular fibrillation (abnormal heart rhythm). At a core temperature of 20 degrees C, cardiac arrest is tolerated for up to 30 minutes without clinically significant neurologic or neuropsychological deficits.  This knowledge and the fact that a dead victim may be clinically indistinguishable from one that is severely hypothermic and alive has lead to the adage that “No one should be pronounced dead, until they are warm and dead.”

A serum potassium greater than 10mmol/L in a non-hemolyzed specimen however has been proposed as a reasonable ceiling for viability.

Negative Pressure Rewarming (Thermarescue):  A non-invasive way of creating a direct thermal pipeline between the skin and body core.  The patients forearm is fitted through an acrylic sleeve with an air tight seal around the arm.  Vacuum pressure of -40 mm Hg is established and the thermal load is applied via a chemical heating pad.

If you are interested in learning more about wilderness medicine, a great resource for information is the wilderness medicine society:  http://www.wms.org/

This document is for informational purposes only, and should not be considered medical advice for any individual patient.  If you have questions please contact your medical provider.


I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO

Blog: https://doctorrennie.wordpress.com

Frostbite and cold induced injuries

Photo credit:  http://www.everester.org/BlogViewer.aspx?Id=DCD57FDDA64B2206


Much of the information presented here comes from Peter Hackett, MD who is an expert in Wilderness Medicine and especially mountain and high altitude medical illness and care.

Frostbite:  A severe, localized cold-induced injury.  Tissue destruction of frostbite is due to both immediate cold-induced cell death and more gradual development of localized inflammatory process and tissue ischemia.  Following exposure to subfreezing temperatures, ice crystals form outside the tissue cells.  If freezing is rapid, ice crystals may also form inside cells.  The initial cellular damage and subsequent inflammatory process are made worse in the setting of thawing followed by refreezing of the area.

Areas most often affected:  Ears, nose, cheeks, chin, fingers and toes

Causes:  Anything that increases localized heat loss or decreases heat production.  Exposure to wind, or conductive heat loss due to contact with metal or water

1)   Inadequate insulation

2)   Circulatory compromise

3)   Dehydration

4)   Moisture

Behavioral risk factors:

1)   Mental illness

2)   Alcohol and drugs

3)   Fear, apathy, panic

Vascular Stage- Post thaw:  Recovery of circulation and then thrombosis, ischemia, necrosis and even gangrene can result.  Intracellular ice and tissue death occurs if there is refreezing.

Classification of frostbite injuries:

1)   Mild or Superficial (no tissue loss)

2)   Severe or Deep (with tissue loss)

3)   Historical classification 1st to 4th degree had no clinical usefulness

Treatment (Pre-Hospital):

1)   Supportive care for trauma, and dehydration (splint/pad affected area)

2)   Avoid additional heat loss – remove wet clothing

3)   If frozen and rescue is near keep frozen unless you can do a warm water thaw and there is no danger of refreezing.

4)   Do not rub frost bitten areas as this can cause further tissue damage

5)   If already thawed, avoid refreezing

6)   Avoid using stoves or fires to rewarm frostbitten tissue

Treatment (Hospital):

1)   Hydration

2)   Wound care – early debridement or amputation of dead or dying areas while preserving viable tissue

3)   Pharmacology – Dextran, NSAIDs, Nifedipine

4)   Imaging studies (X-rays may show coincidental trauma related fractures or cold-induced soft tissue swelling), Technetium (Tc)-99 scintigraphy is commonly used to predict long-term tissue viability.

5)   Sympathetic block or surgery if needed

Methods of Thawing:

1)   Rapid rewarming in warm water (37-41 degrees C) is optimum

2)   Gradual thawing – often unavoidable

3)   Harmful methods – delayed thawing with ice or snow or excessive heat

Non-freezing Cold Injury:  Frostnip, Chilblain/Pernio, Trenchfoot, Raynaud’s

Frostnip:  Cold-induced, localized parasthesias that resolve with warming and there is no permanent tissue damage.

Pernio/chilblain:  Localized inflammatory lesions that can result from acute or repetitive exposure to damp coldness above the freezing point.  Lesions are swollen, often reddish or purple and may be painful or itchy.  Pernio is most common in young women but both sexes and all age ranges may be affected.

Trenchfoot (immersion foot):  Injury to the sympathetic nerves and small blood vessels of the feet.  First described in 1914 during WWI during trench warfare.  It results from prolonged exposure of the feet to a combination of dampness and cold.  Tight-fitting boots exacerbate the condition.  Feet, and sometimes hands are red, swollen and can be extremely painful and often are covered with bloody blisters.  Tissue loss can occur.


1)   Pay attention to weather forecasts (predicted high and low temperatures, forecasted precipitation and wind chill index)

2)   Dress appropriately for the weather

3)   Have an emergency plan when going into remote areas

4)   Avoid alcohol consumption and smoking

5)   Avoid exposure to metal surfaces

6)   Maintain adequate calorie intake

7)   There is inadequate evidence to support the use of applying emollients to exposed skin to prevent frostbite and it is not suggested

8)   Carry emergency supplies in the backcountry or in remote areas in case your group becomes stranded

9)   Use a buddy system for monitoring

10)  Perform an equipment and clothing check

11)  Keep hydrated

12)  Carefully wash and dry feet

13)  Do not sleep in wet socks

14)  Avoid tight socks and shoes

15)  Do not add socks for warmth, get a larger shoe

16)  Rewarm gently, do not use a strong heat source

17)  Do not rub the skin, use passive skin-to-skin contact

18)  Elevate the feet above the level of the heart

19)  Consider antiperspirant with aluminum hydroxide for a week before exposure

Raynaud’s Vasodilation Training: (Physician Sports Med, March 1990; vol18 no3)

1)   Immerse hands in hot tap water

2)   Stay indoors for 5 minutes, then in the cold for 10 minutes, then back indoors for 5 minutes (one cycle)

3)   Do 3-6 cycles per day every other day

4)   50 cycles established effect, but variable

Tips to control moisture and cold:

1)   Wear socks with moisture-wicking capabilities

2)   Change socks and dry them frequently

3)   Use foot powders that control fungus and absorb moisture

4)   Wear shoes with adequate draining capabilities or make holes

5)   Consider waterproof socks, either SealSkinz, Waterproof MVT, Seirus Neo-Sock or Stormsock

6)   When resting or sleeping, take off wet shoes and socks to allow feet to breath and socks to dry against your body in your sleeping bag

If you are interested in learning more about wilderness medicine, a great resource for information is the wilderness medicine society:  http://www.wms.org/

This document is for informational purposes only, and should not be considered medical advice for any individual patient.  If you have questions please contact your medical provider.


I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO

Blog: https://doctorrennie.wordpress.com

Foreign Travel Tips

shutterstock_144889000The information listed below is a smattering of information gained from real life experience, Wilderness Medicine Conferences, and is mostly credited to Gene Allred, MD a very experienced physician and world traveler.

Two major categories for foreign travelers:

A)  The senior traveler (age 65 and above) who have the resources to travel and may have a bucket list.  They have chronic medical conditions and in many foreign countries, access to medical care and medications is more difficult.  Think about access – i.e. there is probably not a wheelchair ramp available in many areas.  Bring your medications.  I don’t know how many times I’ve had patients travel here to Hawaii and not bring enough of their blood pressure medications with them, and I’m sure it happens when the go other places too.  Many seniors may might not get altitude sickness but may have cardiac strain from lower levels of oxygen or increased physical exertion.  Plan accordingly.

B)  The adventure/exotic traveler (all ages) who tend to participate in more dangerous activities – mountain climbing, rock climbing, wilderness expeditions like kayaking the Nile river, etc.  These travelers have a higher incidence of trauma from MVA or injury from their activities.  Homicides in some areas may be more of a problem than an MVA.  We don’t think twice about putting on our seatbelt when we get in a car here in the USA, so don’t get in a taxi or bus without a seatbelt (the roads are often worse in other countries and there may be less lighting and more people).  If you do get into an MVA abroad, the medical care is probably not going to be as good as you would get in first world countries.

Causes of death in foreign travelers:

1)   Almost 50% are from heart attacks and strokes, the other 50% is from trauma (motor vehicle accidents, drowning, falls and homicide) – also be aware that most counties outside of the US, Canada, Australia, New Zealand, Europe and Japan don’t screen their blood for HIV or Hepatitis C.

2)   Only 1% of death in foreign travel results from Infectious disease

Most dangerous aspect for foreign travel:  Motor Vehicle Accidents – account for 25% of fatalities of U.S. travelers.  In Langos, Nigeria buses are called danfos “flying coffins.”  The rate of motor vehicle deaths compared to the USA:

1)   Sri Lanka – 23x more deaths from MVA than USA

2)   Turkey – 44x more deaths from MVA than USA

3)   China has 2% of the worlds driver’s and 15% of the fatalities – WHO 2007

4)   In Ghana 722 drivers were selected at random and 21% had blood alcohol level >80 mg/dl; 4% of the bus drivers had this level.  70% of the trauma patients here are transported by taxi or bus, and 22% and transported by private vehicle.  5% are transported by police and only 3% of trauma victims are transported by ambulance.

In the USA, 60% of the motor vehicle crash deaths occur among the drivers.  In the 3rd world countries, 90% occur among passengers, pedestrians and cyclists.  Urban pedestrians account for 50-70% of the deaths due to motor vehicle accident.

In contrast, the leading cause of injury/illness in foreign travel is infectious disease.  Up to 75% of travelers become ill from infectious disease, however only 1% of the deaths of international travelers are from infectious disease.

Recommendation:  Before you travel, consult your physician, CDC or travel clinic.  Let your medical provider know the type of activities you are planning including whether going to a remote region, participating in a strenuous activity (cycling, mountain climbing, swimming in fresh water, or diving, etc.)





Everyone needs Hepatitis A immunization when traveling to a high endemic area.

Hepatitis A and B vaccinations are a lifetime investment.

There are stories about bogus drugs and dirty needles used in certain areas.

New Delhi, India (CNN) 2/21/09 –

“Authorities were carrying out raids in India’s western Gujarat state for bogus drugs and recycled syringes after a hepatitis B outbreak left 32 people dead, officials said Saturday.”

            *  Five medical practitioners were also arrested for violations

            *  One arrested for reusing injection syringes

            *  111 cases of hepatitis B in the district over two weeks with 32 dead

I’m not saying that you should bring your own needles when traveling, but the news report above is frightening.

Before your travel, consider the following:

1)  Plan at least three months ahead (buy your tickets, look into what visas you might need, if there a restrictions  and plan what to bring with you).

2)  Look at the CDC website – http://www.cdc.gov/travel and study up on where you are going and what diseases you need to be protected against.

3)  Get excellent travel insurance – there are many companies that offer this – International SOS is one of them https://www.internationalsos.com/en/.   Read the fine print and make sure the company that you go with doesn’t say something like “will evacuate to most appropriate facility” and something more specific like “Will evacuate to USA, Canada, Japan, Australia, New Zealand, or Europe”

4)   Decide what medical resources are available in the foreign country

5)  Plan for diarrheal illness – bring antibiotics (sometimes you might take prophylaxis) and medications to help slow the bowls such as Imodium.

6)   How will I get around while there?  Avoid car crashes – don’t get on a crowded bus, a motorcycle or scooter.  Wear your seatbelt!

7)  Stay sober when out in public – you are more of a helpless target if you’re drunk.  If you drink – do it in the hotel where it’s safer.

8)  Don’t look rich – avoid wearing fancy jewelry/watches or you’ll look like a good target.

9)   Problems of counterfeit drugs – i.e. take own medications

10)   Take a copy of your medical history/prescriptions, driver’s license, passport and visas.  Leave one copy at home with a friend and bring the original and one copy with you.

11)   Consider the season you are traveling in when going to a foreign country i.e. rainy vs. dry.  In malaria endemic regions, this may dramatically influence your risk

12)   Traveling in motor vehicles at night in third world countries substantially increases your risks of injury or death

13)   Acclimatize yourself to the altitude

14)   Bring sunblock

15)   Think about heat exposure

16)  Take drinking water precautions (chlorine dioxide, etc.)

17)  Be wary of swimming in fresh water or going barefooted – consider infections due to Schistosomiasis, Leptosirosis or Cryptosporidium

18)  Think about safety/security – 9% of U.S. travel fatalities are due to homicide.  9000 homicides in Sao Paulo in 1999, compared with 700 in New York City.

19)  Avoid dangerous situations – khakis = N. American, avoid going out alone at night, don’t wear expensive jewelry, carry no more cash than you need for the day and don’t flash roll of bills.  Use a hotel safe when available.  Fanny packs and purses are “one-stop” shopping targets – be aware of “slash and grab.”  Don’t accept food from strangers – “drug and rob scam,” Beware of “spilled food scam” (e.g. mustard), use licensed taxis over unlicensed taxis.  Scan your passport and then email it to yourself so you’ll be able to retrieve a copy.

20)  Protect yourself from insects – Dengue fever, Malaria (1-2 million deaths/year), West Nile Virus, etc.   The higher the concentration of DEET, the longer lasting it is – 99% DEET = 10 hours, 30% DEET is safe in kids down to 2 months of age.  DEET + Permethrin is > 99% effective.  Most malaria is Chloroquine resistant.  Three drugs of choice for malaria are Mefloquine, doxycycline and malarone (primaquine is 2nd line option).

21)  The unexpected usually happens.  Accept the things that are beyond your control.  Resign yourself to the fact that your luggage will be lost, your hotel reservations will be canceled, and your last flight out will leave without you.  They key is to then decide what you are going to do about it.  No matter how bad you think things are now, they can always get worse.  Always have a contingency plan.  Research alternative travel arrangements such as accommodations, research climate, local health risks, etc.  Instead of letting problems accumulate, deal with each challenge “head on.”  Work to “fix” one problem at a time and then move on to the next.

If you are interested in learning more about wilderness medicine, a great resource for information is the wilderness medicine society:  http://www.wms.org/

This document is for informational purposes only, and should not be considered medical advice for any individual patient.  If you have questions please contact your medical provider.


I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO

Blog: https://doctorrennie.wordpress.com