There Are No Old, Bold Mushroom Hunters

There has been recent interest in psychedelic mushrooms because of experiments performed at Johns Hopkins University in which volunteers ate psilocybin from the mushroom Psilocybe cubensis (a Psilocybe mushroom is pictured here). It can't be overemphasized that while some persons report experiencing a pleasant escape from reality after eating hallucinogenic mushrooms, many others become fearful, frightened, paranoid, or terrorized. Other mushrooms, such as Amanita muscaria, have similar dual effects. In some persons, they can evoke what is perceived as spiritual awakening, while in many others, they invoke nightmares, impaired judgment, and unpleasant hallucinations. Because we don't know exactly how they affect the brain - one theory links certain mushrooms to serotonin receptors - we cannot predict with any degree of certainty who will react positively and who will react negatively.

There are many toxic mushrooms that are mistaken for harmless edible species. Some of these cause extreme gastrointestinal distress (abdominal pain, nausea, vomiting, diarrhea), while others may also induce catastrophic liver failure. Unless you are very experienced and well prepared to pick wild mushrooms, you are best advised to leave them alone.

Tags: poisonous mushrooms, mushrooms, outdoor medicine, wilderness medicine, healthline

photo from the textbook Wilderness Medicine

Permalink | 1 Comments| Email Post

Post your comment

Outdoor Adventurer's Pledge

In wilderness medicine, as well as medicine in general, prevention is the name of the game. No healer likes to see anyone suffer. I've often thought about creating a standard list of admonitions for outdoor enthusiasts in order for them to best avoid accidents, injuries, and illnesses. I believe that if these rules were followed, we'd all happily practice less wilderness medicine:

The Outdoor Adventurer's Pledge

1. I will maintain optimal physical and mental health.
2. I will prepare for all outdoor activities by dressing properly, anticipating likely risks, and carrying proper equipment for first aid.
3. I will break in new boots and shoes before I use them for hiking or climbing.
4. I will carry protective clothing to be used in bad weather.
5. If appropriate, I will be prepared for an unexpected night outdoors.
6. I will seek advice or assistance if I become ill or injured.
7. I will let someone know where I am going and when I expect to return.
8. I will not drink alcohol or use recreational drugs.
9. I will not participate in or tolerate risky horseplay in potentially dangerous situations.
10. I will use proper safety equipment, such as a helmet or life jacket, whenever possible.
11. I will obey all posted warning signs.
12. I will wash and disinfect my hands before eating.
13. I will drink lots of fluids and stay well hydrated. I will disinfect my drinking water and properly prepare all food.
14. I will not closely approach or otherwise provoke wild animals.

Tags: Outdoor Adventurer's Pledge, hiking, safety, medical, physician, health, wilderness medicine, outdoor medicine, healthline

photo by Mathias Schar

Permalink | 1 Comments| Email Post

Post your comment

More Spinach

The spinach scare continues, although I am hopeful that it will let up soon. As additional cases of infection with E. coli 0157:H7 are reported, efforts will be made to determine if they are linked with contaminated spinach.

Although I have heard comments from a few medical people regarding their belief that the advice to avoid eating raw spinach will soon change, the prudent thing now is to continue exercising caution until such time as public health officials sound the "all clear."

Here are a few more facts about E. coli 0157:H7:

1) The infection can be spread person to person. So, in the presence of someone with diarrhea, excellent hand-washing technique should be observed. Bacteria can be excreted in stool by humans for up to 2 weeks after a clinical infection.
2) The bacteria can be spread in food and water. It is possible to acquire an infection by ingesting as few as 10 bacteria.
3) After ingesting the bacteria, an infection may occur after an incubation period of 1 to 10 days, with 3 days being the average delay between exposure and illness.
4) As I mentioned in a previous post, signs and symptoms include abdominal pain, cramping, watery diarrhea (that may turn bloody), nausea, vomiting, fever or no fever, and weakness.
5) The diagnosis is made by taking a stool specimen and "culturing" it. That is, the stool is placed onto a special growth media in the laboratory and if the bacteria are present, they grow in colonies (e.g., multiply) and can be identified.
6) For treatment, antibiotics are not recommended. This is because in some cases, they may worsen the affliction. The precise reason this happens is not known, but one suggestion is that by causing rapid death of large numbers of bacteria, the result is release of large amounts of the Shiga toxin (also known as verocytotoxin), which causes the medical problems. Antidiarrheal agents, such as loperamide (Imodium) are also not recommended, because they are felt to possibly keep the bacteria in contact with the bowel for longer periods of time.
7) Most patients recover without antibiotics in approximately a week. Severely dehydrated individuals may require intravenous fluids. Children infected with E. coli 0157:H7 are at higher risk than are adults for developing hemolytic-uremic syndrome, in which they may suffer kidney failure.

PREVENTION IS KEY:

1) Wash hands prior to preparing food, serving food, or eating.
2) Cook all risky food until it reaches a temperature of 160 degrees F for at least a minute.
3) Do not mix raw and cooked foods, particularly meat. After you cook meat, don't serve it on the unwashed dish that carried the raw food.
4) Since raw meat, especially beef, can be a problem, be certain to wash hands, cooking utensils, cutting boards, dishes, and counters after they have been in contact with raw meat.
5) Do not drink unpasteurized milk, cider, or fruit juices. Understand that in the absence of pasteurization, which is a heating process, no product can be guaranteed to not be contaminated with the bacteria normally killed in the pasteurization process. Many of us like to drink fresh fruit juice. When we do so, we take a risk, usually, quite minor, that it may be contaminated.
6) Wash all fruits and vegetables carefully, but understand that this is not absolutely foolproof.
7) Drink disinfected water only.
8) Try to not swallow lake or swimming pool water.
9) If a person is ill with a diarrheal illness, he or she should not prepare food for others or share common bodies of swimming or bathing water.

I understand that we cannot live in a bubble, but common sense and avoiding obvious risks can do much to prevent the spread of communicable diseases.

Tags: spinach, E. coli, diarrhea, E. coli 0157:H7, health, wilderness medicine, outdoor medicine, healthline

photo of E. coli courtesy of www.yosemite.com

Permalink | 0 Comments| Email Post

Post your comment

Doing the Dishes

Proper hygiene is essential to avoiding infectious diarrhea in the outdoors. The most important two activities are proper hand washing (or wiping with disinfectant gel or cream) and disinfection of drinking water. After these come a number of important actions, such as "food rules" (proper washing, cooking, and serving; what foods to avoid), bathroom hygiene, not sharing items like towels and toothbrushes, etc.

One important topic is how best to wash dishes in order to remove diarrhea-causing bacteria and viruses. A recent study published in the journal Wilderness and Environmental Medicine sheds some light on current techniques and offers a recommendation for an effective dishwashing method that can be employed during a camping trip or other expedition.

The author, Joanna Hargreaves, evaluated 18 three-bowl washing-up systems that are commonly used on expeditions or during travel to remote places. Each bowl contained 5 liters (approximately 5 quarts) of water; the variation was what (if anything) was added to the water, and in what order the dishes were washed and rinsed through the three-bowl series. The systems were tested by mixing the bacteria Escherichia coli into porridge in order to simulate contaminated food residue, adding a standard amount of the bacteria-laden porridge to the dishes, then washing and rinsing the dishes. The most effective washing-up system in this laboratory evaluation was removal of most food residue with detergent (5 milliliters or 1 teaspoon) in the water in bowl 1, followed by a finishing wash (scrub until clean) with bleach (10 milliliters or 2 teaspoons of 4% chlorine bleach) in the water in bowl 2, followed by a final rinse in drinkable water in bowl 3. The final rinse was felt to remove the taste of the detergent and bleach (the latter considered to be a disinfectant).

The author made a few final recommendations, including using hot water in bowl 1, using a scouring pad or brush in bowl 2 with the bleach in order to avoid contamination of the scourer, allowing all utensils to air dry after washing, and cleaning the washing-up bowls and allowing them to dry between uses. Another suggestion is to use up to 100 milliliters or 20 teaspoons (3 teaspoons = 1 tablespoon) of bleach in bowl 2 if there is a current outbreak of diarrhea and vomiting. This increases the disinfection power of the second bowl.

Remember, these recommendations are based on an experiment, and can't take into account variables such as more severe contamination, different infectious organisms, how vigorously the dishes have been washed, etc. However, the concentration of bacteria used in this study to contaminate the porridge probably exceeded any that would be found in real life, so the advice offered from this study makes a great deal of sense.

Tags: hygiene, dishwashing, diarrhea, wilderness medicine, outdoor medicine, healthline

photo by Paul Auerbach

Permalink | 4 Comments| Email Post

Post your comment

Spinach Woes

The backpacker's adage, "Peel it, wash it, cook it, boil it, or forget it," for avoiding infectious diarrhea may not be sufficient if the bacteria you are trying to avoid is the Shiga toxin-producing Escherichia coli (STEC). This group used to be classified as enterohemorrhagic (bleeding within the gastrointestinal tract) E. coli. These bacteria have caused outbreaks of diarrhea associated with consumption of contaminated beef (often, fast-food hamburgers), unpasteurized apple juice, raw milk, red leaf lettuce, alfalfa sprouts, and venison meat jerky. Contact with contaminated swimming pools and exposure to farm animals have also been associated with this infection. Now for at least the time being, we have contaminated raw spinach from the Salinas, California farm region, to add to the list, not only in camp but at home as well.

These bacteria proliferate within the bowel of humans, release the Shiga toxin that wreaks havoc upon the bowel, and thereby cause copious bloody diarrhea with mucus (hemorrhagic [bloody] colitis), but fever is either low grade or not present. Typical symptoms include severe abdominal cramping, sudden onset of watery diarrhea, frequently bloody, and occasionally vomiting. Most often the illness is mild and self-limited generally lasting 1-3 days. The most important strain from the human clinical perspective of STEC thus far identified is O157:H7. The production of Shiga or similar toxins by these strains may be linked to the hemolytic-uremic syndrome (HUS), which is a disorder marked by breakdown of red blood cells in the body combined with kidney failure. This is a more common complication in children (as compared to adults) infected with STEC O157:H7. HUS may be life-threatening, and to make matters more complicated for doctors, treatment with antibiotic therapy of STEC colitis does not shorten the duration of diarrhea and is perhaps related to more frequent development of HUS, rather than preventing this complication, by a mechanism(s) that has yet to be fully understood.

So, simply washing a leafy vegetable intended to be eaten raw, like lettuce or spinach, is not sufficient to prevent infection and diarrhea. Apparently, the external surfaces trap and hide bacteria in a manner that prevents their wash-off, even with water that has been disinfected. Referring back to the adage in the first paragraph, you cannot trust washing. Until further notice, if you are going to eat spinach, cook it until it has been boiled, even if it has been thoroughly washed.

Tags: spinach, infectious diarrhea, E. coli 0157:H7, Shiga toxin , wilderness medicine, healthline

Permalink | 2 Comments| Email Post

Post your comment

A Diagnostic Dilemma

I have permission from a friend to tell you this story and to display his picture. Last week he informed me that he was suffering low grade fever, chills, sweating, and fatigue. He said that he had muscle spasms, particularly of his back, and that someone had noticed a large red oblong mark on his back near his left shoulder blade. According to my friend, the reddened skin was expanding in dimensions and was warm and tender to the touch. When my friend first called, I was far away from him and busy on the football field acting as a team doctor, so I instructed him to seek care in an emergency department close to his home.

The next morning, I checked in with him, and he informed me that the doctor who treated him in the E.D. felt that my friend had possibly incurred a spider bite, perhaps during his activities at a plant nursery. Furthermore, to the doctor, it looked like a possible “brown recluse spider” bite. These are known to be nasty bites that can cause a great deal of tissue destruction at the site of the bite. I know that many spiders use venom to subdue their prey, and the bites of many species can cause dramatic skin reactions. However, true brown recluse spiders are not indigenous to northern California. They only arrive here if they have hitched a ride on imported (to California) fruit or plants. So, I felt it best to see my friend as soon as possible.

The picture above is what I saw. The rash on his back was a large, raised, red patch with a small entry point (probable bite site) at the top. The entry point was pale grey in color and had a small clear blister in the middle, but no blood in the blister or obvious blackened tissue destruction, such as one would see with a brown recluse bite. It may have well been a spider bite, but I highly doubt that it was from a brown recluse spider or even from one of the more problematic species, like Tegenaria agrestis, found in the Pacific Northwest. The situation might have represented a skin infection from Streptococcus bacteria or even an atypical presentation (a rash known as erythema migrans) of early Lyme disease from the bite of a nymphal tick. So, in addition to the antibiotics my friend had been prescribed the night before, I added another antibiotic to cover Lyme disease. Two days later, the rash had faded and regressed in size considerably, and his other symptoms were nearly gone.

So, what did he have? Perhaps a spider bite reaction complicated by a skin infection. Possibly Lyme disease. We won’t know until we learn the results of some blood tests, but even then, we may not find out, because these tests are imperfect from a diagnostic standpoint. The important thing is that he got better, which is often the case in wilderness medicine. Sometimes, health care professionals and patients need to make an educated guess, and hope that treatment is effective.

Read the update on this case: "A Diagnostic Dilemma" Update

Tags: spider bite, brown recluse spider, spider, skin rash, Lyme disease, medical, physician, health, wilderness medicine, outdoor medicine, healthline

photo by Paul Auerbach

Permalink | 1 Comments| Email Post

Post your comment

Slaughtering Stingrays

Although my blogs are about medicine for the outdoors and wilderness medicine, I feel compelled to comment upon the slaughter of stingrays in Australia, apparently in response to the untimely death of Steve Irwin, whose heart was punctured by a stingray that he approached too closely.

Perhaps the daily slaughter of scores of people in the Middle East and other areas of human conflict has some persons steeled against atrocities, but I am bothered by senseless killing of marine animals that are no more responsible for the death of Steve Irwin than are you and me. Even more reprehensible is the fact that some of the animals had their tails cut off, which one can only assume was done in retribution for the fatal sting inflicted upon the unfortunate late Crocodile Hunter.

Stingrays are not man-hunters. To my knowledge, they have only injured humans who have attempted to handle them, intentionally positioned body parts against their mouths, or approached them closely enough to provoke a defensive action. The last was the case with Mr. Irwin, who certainly meant no harm, but was caught in a tragic encounter. Underwater, stingrays are almost never aggressive; it is only when they are trapped, otherwise frightened, or captured that they become agitated. Indeed, some rays appear to enjoy the company of people, in that over time, they become habituated to our presence and will approach them closely in order to obtain food or, in the case of larger rays such as mantas, achieve body contact. The behavior of stingrays at Stingray City in the Cayman Islands is testimony to the normal docile behavior of these animals. I don’t pretend to know what a ray is thinking, or if it is even capable of thought, but I am fairly confident that the reactions of these animals represents at most indifference to humans, and perhaps some form of piscine curiosity.

Killing wild animals for the sake of trophies, excitement, sport, or any other non-utilitarian purpose makes no sense. It is a form of wilderness depradation. I am not a expert conservationist, but I am certain that mutilating stingrays in apparent revenge is inhumane, cowardly, and foolish. Even if it is driven by strong emotion like outrage or grief, it is shallow and uncaring, callous in a manner that calls for strong rebuke. A person that would cut off the tail of a stingray and cause it to perish for no good reason is not accomplishing anything good, and is only making a sad situation worse.

Every man and woman should cherish the diversity of animals on this planet and do everything possible to promote wildlife preservation. The same is true for our plants, forests, mountains, and oceans. Without the wilderness, there is no wilderness medicine.

Tags: Steve Irwin, stingray, hazardous marine animals, medical, physician, health, wilderness medicine, outdoor medicine, healthline

photo of manta ray by Paul Auerbach

Permalink | 4 Comments| Email Post

Post your comment

Stinging Fishes

A recent article published in the Journal of Heredity calls our attention to the extraordinary number of venomous spined fishes that inhabit the oceans. This has been a clinical area of special interest to me for nearly 30 years, and one in which I have acquired some expertise. The treatment of venomous fish stings is unique and not always well known by the lay public, or indeed, by medical practitioners.

In the Journal of Heredity article, Dr. William Smith and Ward Wheeler, a curator at the American Museum of Natural History, suggest that there are at least 1,200 species of venomous fishes. This was accomplished by comparing DNA sequences from 233 known venomous species and then creating a new family tree for spiny-rayed fishes, such as lionfishes, scorpionfishes, and stonefishes. As I have maintained for years, the stings from many other fishes, such as surgeonfishes, rabbitfishes, and stargazers, are also painful (and thus, persumably induced by venom). Indeed, if one is punctured by the "prongs" near the head of a spiny lobster, the wound may burn and throb way out of proportion to the magnitude of the wound. Is this another venomous species? Dr. Smith took his observations and dissected more than 100 fish species not previously identified as venomous, and in 61 of these, discovered anatomy that suggested a venomous nature.

The clinical observation is that the most consistently effective therapeutic intervention in the field is immersion into hot water ("to tolerance") no warmer than 45 degrees C or 113 degrees F. We don't know why this relieves the pain - perhaps it is due to inactivation of protein components of the venom, or perhaps the warmth simply interrupts pain pathways conducted by the nervous system. However, it often works, and should be used in preference to other less-effective folk remedies, such as urinating on wounds or applying vinegar or rubbing alcohol (the latter two are often effective, however, for jellyfish stings). For stings from species with less potent (pain-producing) venom (such as lionfishes), hot water immersion may work well. However, if a sting is from a more potent Indo-Pacific scorpionfish or the dreaded stonefish, it may be ineffective. In that case, the victim requires more agressive pain management.

Tags: venomous fishes, lionfish, scorpionfish, stonefish, medical, physician, health, wilderness medicine, outdoor medicine, healthline

photo by Paul Auerbach

Permalink | 1 Comments| Email Post

Post your comment

Permethrin as an Insect Repellent

A reader asks: “Do you feel that it’s worthwhile to purchase clothes that are pre-washed with permethrin? Is it a good idea to wash your hiking clothes with this prior to going on a hike? Should I buy permethrin soap and wash my kids with it?”

Please DO NOT wash your kids with permethrin. Permethrin, a synthetic pyrethroid based upon the naturally-occurring pyrethroids that are extracted from the East African pyrethrum flower (a chrysanthemum), is actually an insecticide; that is, permethrin-containing products kill insects and ticks. Because permethrin carries some potential toxicity to humans it should be used only on clothing (or on shoes, certain camping gear, bed nets, etc.), not on skin. For instance, permethrin is known to cause eye irritation if the chemical comes in contact with a person’s eyes. Although permethrin in a 5% lotion or cream is sometimes prescribed by physicians for application to skin for treatment of mite (e.g., scabies) infestation, these medical dermatologic preparations are not recommended for use as insect repellents. In the past, combination DEET-permethrin (the latter in very low concentration) soaps have been field tested for use as an insect repellent. While they have been acceptable to the persons that used them, a commercial product based upon this concept has not yet come to market.

There is ongoing discussion about the toxicities possibly associated with permethrin. These include potential cancer-causing potential, and perhaps abnormalities of the immune system. Properly used (e.g., applied to clothing and not directly to skin), it has not yet been directly linked with serious adverse effects upon humans, so it remains an effective barrier against insect-borne infections, , such as Lyme disease and West Nile virus. It is best used in combination in its application to clothing with an approved insect repellent (such as picaridin or DEET), when the latter is applied to skin.

There are many permethrin wash-in products for clothing on the market. An example is Sawyer Permethrin Wash-In Clothing Treatment™. Another is BUZZ OFF Insect Shield™ apparel, which is claimed to provide effective and convenient protection against mosquitoes, ticks, ants, flies, chiggers and midges. It is important to closely follow the label instructions. Clothing that is sold pre-treated with permethrin is often advertised to be effective (as a repellent) for up to 25 washings. If you are going to be in a high-risk (for an insect or arthropod bite capable of transmitting a disease) situation, to play it safe, the effectiveness should be assumed to begin to decrease after half the advertised allowable number of washings.

If you decide to apply permethrin spray to clothing, be certain to do the following (as recommended by the Connecticut Department of Environmental Protection):

1) Follow manufacturer’s instructions closely. Do not exceed recommended spraying times.
2) Treat clothing only. Do not apply to skin.
3) Apply the permethrin in a well-ventilated outdoor area, protected from the wind.
4) Only spray the permethrin on the outer surface of clothing and shoes.
5) Apply enough to lightly moisten the outer surface of the clothing item; it is not necessary to have the clothing soaked through (saturated).
6) Be certain to apply completely cover socks, trouser cuffs and shirt cuffs, where insects may attempt to crawl or fly through openings to your skin.
7) Hang treated clothing outdoors and allow to dry for at least 2 hours in non-humid conditions and for at least 4 hours in humid conditions.
8) Treat clothing no more often than every 2 weeks.
9) Launder treated clothing separately from other clothing at least once before re-treating.
10) Assume that your treated clothing is effective for repellency for 2 weeks or more. Wear it only when you need to repel insects and arthropods. Store it in a separate impermeable (to permethrin) bag when not in use.

Tags: permethrin, insect repellent, clothing, medical, physician, health, wilderness medicine, outdoor medicine, healthline

photo courtesy 3Dchem.com

Permalink | 0 Comments| Email Post

Post your comment

A Stingray Wound to the Heart

We are now certain from eyewitness reports that Steve Irwin pulled the stingray's detached jagged spine from his chest immediately after he was struck by the animal. I have been asked repeatedly whether he would have had a better chance for survival had he not removed the spine from his wound. It is quite possible that this might be the case. Although the instructions for management of a stingray injury (which usually occurs on the leg or arm) are to remove any visible portions of the spine (because they continue to release venom into the wound and thereby cause pain and increase the possibility of tissue damage), Steve's situation was different. This was a very unusual (for a stingray wound) situation. By having a spine lodged in his chest, Steve Irwin was as much a victim of a stab wound, akin to that from a knife or dagger, as of an envenomation.

The classic teaching for treatment of impalement (e.g., by a knife or arrow) is to leave the object in place undisturbed until the victim has been brought to a controlled medical (surgical) environment before attempting its removal. The reason for this is that the object may be a “finger in the dike” if it has punctured a large blood vessel or, in Steve’s case, the heart. When the dagger (spine) is removed, it is no longer occluding the hole that it created, and bleeding can be torrential through the now-unblocked opening. In addition, the removal process itself can worsen the internal damage, by cutting additional tissue on the way out. This might have been worsened by the rear-facing serrations on the rigid spine, which could easily catch and tear human tissue during a forceful extraction.

Had Steve been brought to a trauma center, the surgeons would have tried to wait until they were set up for surgery before removing the spine. Had the removal occurred where a surgeon(s) could rapidly expose the complete path of the wounding object and stop the bleeding caused by the primary injury and the effects of the object's removal, then Steve may have survived.

Steve was not a trained medical professional, and what he did was a normal response to what was in all likelihood an extremely painful predicament. He had a stingray spine sticking into his chest. This was undoubtedly a very painful and visually frightening situation. He reacted and did what he thought was the quickest maneuver to relieve his suffering and pulled out the spine. Anyone in this situation would have probably done the same thing, and absent someone underwater with him to manage his response and a trauma surgeon or an emergency physician on scene to guide the immediate rescue, what happened is understandable. So, might he have had a better chance if the spine was left in place? Perhaps, if his heart or a great vessel was penetrated and his body could tolerate the presence of a venom-bearing spine until he could be taken to an operating room.

Based on the reports I have read about the autopsy, it is not possible to tell whether the cause of death was blood loss, a heart attack, abnormal heart rhythm, compression of his heart within a blood-filled pericardium, or some combination of these. The venom itself causes toxicity to human tissue, but it is not certain to what degree the envenomation aspect of this wound contributed to Steve's demise. The trauma (hole in the heart) alone would certainly have been sufficient to account for the outcome.

It is important to once again emphasize that stingrays are wild animals, and therefore not completely predictable. Most rays will flee when disturbed by humans. However, it is impossible to know which ray will tolerate an approach and which ray will flee or strike out to thwart an agressor. I am unaware of any episode in which a ray pursued a human or struck out with its barbed tail unless in a provoked manner in self defense. I have been underwater with solo stingrays and rays in large schools, and except for places like Stingray City in the Cayman Islands (where they are regularly fed and handled by tourists) and certain popular diving locations like Cocos Island (Costa Rica) where they have similarly apparently become habituated to people in their underwater habitat, I have never witnessed one to closely approach a human. But, like many other divers, I have accidentally startled rays and witnessed how fast they can move with powerful flaps of their "wings." Like the caged tiger that tolerates its trainer for years before a seemingly inexplicable attack, stingrays should be respected for their feral nature. They are graceful and beautiful animals that should be admired from a distance - certainly out of range of a possible tail strike.

Steve's death has called attention to the need for divers and other ocean-goers to be aware and respectful of hazardous marine animals. As shall everyone else familiar with his good work and lust for life, I will miss him.

Tags: Steve Irwin, stingray, hazardous marine life, medical, heart, health, wilderness medicine, outdoor medicine, healthline

photo of blue-spotted stingray by Paul Auerbach

Permalink | 1 Comments| Email Post

Post your comment

Stingray Catastrophe: Steve Irwin, 1962-2006

We are saddened by the untimely death of Steve Irwin, who was killed by a stingray on September 4, 2006. As it has been reported, Steve was filming a segment for a series entitled “Ocean’s Deadliest” at Batt reef off the coast of northeastern Queensland, Australia. While in the water, he closely approached a stingray, which struck him in the left side of his chest with the venomous barb attached to its tail. He is reported to have pulled the detached barb from his chest, then to have died. According to the treating physician, the wound likely penetrated Steve’s heart. It is not determined at the time of this writing whether the cause of death was bleeding (blood loss), compression of the heart because of blood trapped within the fibrous lining around his heart (pericardium), fatal disruption of the heart’s rhythm from the shock of penetration and effects of the venom, a heart attack, or some combination of these.

Stingrays are wild animals, and while they usually make every effort to flee encounters with perceived predators, they will sometimes act in defense, by striking out with their tails in order to cause injury with the attached stinger(s). Under no circumstances should anyone assume that a stingray approached in the wild is “tame,” even if it has been habituated to the presence of humans. What follows is a brief medical tutorial on stingrays, adapted from a chapter about hazardous marine animals in the forthcoming edition of the textbook Wilderness Medicine:

The stingrays are the most commonly incriminated group of fish involved in human envenomations. They have been recognized as venomous since ancient times, known as “demons of the deep” and “devil fish.”

It is likely that at least 2000 stingray injuries take place each year in the United States. At least that many more occur in coastal waters worldwide. Most attacks occur during the summer and autumn months, as vacationers venture into the surf that may be laden with rays.

Stingrays are usually found in tropical, subtropical, and warm temperate oceans, generally in shallow (intertidal) water areas, such as sheltered bays, shoal lagoons, river mouths, and sandy areas between patch reefs. Although rays are generally found above moderate depths, at least one deep sea species has been discovered. Rays can enter brackish and fresh waters, as well. For instance, freshwater stingrays are common in rivers and tributaries in South America.


Stingrays are small (several inches) to large (up to 12 feet by 6 feet) creatures observed lying on top of the sand and mud or partially submerged, with only the eyes, spiracles, and part of the tail exposed. Their flattened bodies are round , diamond , or kite shaped, with wide pectoral fins that look like wings. These ripple or flap to propel the animal through the water. Rays are nonaggressive scavengers and bottom feeders that burrow into the sand or mud to feed on worms, mollusks, and crustaceans.

The venom organ of stingrays consists of one to four venomous stings on the dorsum of an elongate, whiplike “tail.” In some species, the sting may be in excess of 12 inches. The efficiency of the apparatus is related to the length and musculature of the tail and to the location and length of the sting. Eagle rays and some mantas have a stinging apparatus, but it is less of a threat because the spine is located at the base of the tail and is not well adapted as a striking organ. A stingray “hickey” is a mouth bite, created by powerful grinding plates, that produces superficial erosions and bruising in an oral pattern. Persons who hand feed stingrays may incur this type of injury, as well as lose parts of fingers.

In all cases, the venom apparatus of stingrays consists of a bilaterally retro-serrated spine or spines and an enveloping skin tissue sheath. The spine is firmly attached to the top of the tail (whip) is edged on either side by a series of sharp rear-facing serrations. Along either edge on the underside of the spine are the two grooves, which house the venom glands. The entire spine is encased by the skin tissue sheath. The sting is often covered with a film of venom and mucus.

Stingray “attacks” are purely defensive gestures that occur when an unwary human handles, corners, too closely approaches, or steps on a creature while wading in shallow waters. The tail of the ray reflexively whips upward and accurately thrusts the spine or spines into the victim, producing a puncture wound or jagged cut. The sheath covering the spine is ruptured and venom is released into the wound, along with mucus, pieces of the sheath, and fragments of the spine. On occasion the entire spine tip is broken off and remains in the wound.

A stingray wound from a spine puncture is both a traumatic injury and an envenomation. The former involves the physical damage caused by the sting itself. Because of the serrations and powerful strikes, significant cuts can result. Secondary bacterial infection is common. Most injuries occur when the victim steps on a ray; another common cause is handling a ray during its extraction from a fishing net or hook. The lower limbs, particularly the ankle and foot, are involved most often, followed by the upper limbs, abdomen, and chest. In a rare case, the heart may be directly injured. There have been two reported cases of survival following cardiac injury.

The envenomation classically causes immediate local intense pain, swelling, and sometimes bleeding. The pain peaks at 30 to 60 minutes, and may last for up to 2 days. The wound is initially dusky or bluish and rapidly progresses to redness and a bruised appearance. Blood-filled blisters resembling a severe thermal burn or frostbite may occur, and may be worsened by overzealous therapeutic hot water immersion (see below). Delayed healing seen following stingray injuries is usually attributed to direct venom toxicity and infections.

A person stung by a stingray may show weakness, nausea, vomiting, diarrhea, sweating, dizziness, rapid heart rate, headache, fainting, seizures, groin and armpit pain, muscle cramps and quivering, generalized swelling, paralysis, low blood pressure, abnormal heart rhythms, and on rare occasion may die. The paralysis may represent spastic muscle contractions induced by pain, which are a tremendous hazard for a diver or swimmer.

The success of therapy is largely related to the rapidity with which it is undertaken. Treatment is directed at combating the effects of the venom, alleviating pain, and preventing infection:

As soon as possible, the wound should be soaked in nonscalding hot water to tolerance (upper limit 45° C [113° F]) for 30 to 90 minutes. During the hot water soak (or at any time, if soaking is not an option), the wound should be inspected for any readily removable pieces of the sting or its sheath, which would continue to envenom the victim. No folk remedy, such as the application of macerated cockroaches, cactus juice, “mile a minute” leaves, fresh human urine, or tobacco juice, has been proven effective. However, application of the cut surface of half a bulb of onion directly to the wound has been andecdotally reported to decrease the pain and perhaps inhibit infection after a sting from the blue spotted stingray. Although the standard recommendation is to remove the sting as soon as possible (to limit the extent of envenomation), if it has acted as a dagger deeply into the chest, abdomen, or neck (this is extremely rare) and may have penetrated a critical blood vessel or the heart, it should be left in place (if possible) until the victim is brought to a controlled operating environment where emergency surgery can be performed to control bleeding that may occur upon its removal.

Pain control should be initiated during the first soaking period. If the pain is severe and persistent, a physician may need to administer narcotics, inject the wound with a local anesthetic, or apply a nerve block. If the wound is more than very minor, the treating doctor may administer an antibiotic, then observe the victim for a few hours in order to detect any deterioration in the person’s condition. The doctor may also order x-rays or special imaging studies, such as an MRI (magnetic resonance imaging), to locate any suspected retained pieces of spine.

Prevention of stingray injuries is very important. As mentioned above, the animals should be given a wide berth and never handled or approached closely. A stingray spine can penetrate a wet suit, leather or rubber boot, and even the side of a wooden boat; therefore a wet suit or pair of athletic sneakers is not adequate protection. Persons walking through shallow waters known to be frequented by stingrays should shuffle along and create enough disturbance to frighten off any nearby animals.

To Steve Irwin’s family, I offer my heartfelt condolences. It is no consolation to his wife and children that death from a stingray envenomation is a highly unusual event, as they have lost a husband and father.

Tags: Steve Irwin, stingray, hazardous marine life, medical, physician, health, wilderness medicine, outdoor medicine, healthline

photo of Steve Irwin from online.edfac.unimelb.edu.au
photo of diver handling stingray by Howard Hall
photo of stingray spine in foot by Robert Hayes

Permalink | 1 Comments| Email Post

Post your comment

Is My Bee Sting Infected?

A reader asks (about a bee or wasp sting): “How do I know if it’s infected and that I need antibiotics?”

As you can see from the previous post, a bee or wasp sting can cause a skin reaction with redness, swelling, itching, and pain. This is very similar to the appearance of skin that is inflamed by a bacterial infection - a condition sometimes referred to as cellulitis. A wasp sting may also cause blistering with or without "brawny" swelling, which is when the skin feels thickened, warm, and bumpy to the touch. Either a sting or an infection can cause lymph nodes ("glands") that drain the region to become swollen and tender.

So, the determination of an infection becomes a judgment call. Infection following a sting usually develops 48 to 72 hours after the sting, so if someone has suffered a sting, appears to be improving, then has his or her condition deteriorate, infection should be suspected. Fever can be present with a sting or an infection, but is more common with an infection. If the area of skin initially affected by the skin seems to be stable for a few days, then begins to spread, particularly if there is any reddish streaking traveling up an arm or leg towards the heart, increasing skin warmth, or increasing skin tenderness, that may indicate an infection. If any liquid leaks from the site of the sting, particularly if it appears cloudy or thickened, like pus, one should suspect an infection. If the wound develops a crunchy or "Rice Krispies" feel to it, that is a medical emergency, because it may represent the formation of gas from a severe infection.

If an infection is diagnosed or highly suspected, the treating medical professional will usually recommend antibiotics. Sometimes, it is impossible to determine if the skin reaction represents the effects of the venom or an infection that has subsequently developed. In that case, your doctor may decide to treat you both for the toxic-allergic component, as well as for a possible infection. Finally, always remember to keep your immunization against tetanus up to date.

Tags: infection, bee sting, wasp, medical, physician, health, wilderness medicine, outdoor medicine, healthline

photo of non-infected wasp sting by Paul Auerbach

Permalink | 14 Comments| Email Post

Post your comment