Monthly Archives: September 2014

What do you do if a puma attacks?


Licensed under CC BY 2.0 via Wikimedia Commons.

Pumas (Puma concolor) are large feline predators that have been known to attack humans. Slightly more concerning is that most attacks on humans are as prey, not as defense. Thus, there are often signs to warn people going into areas where pumas are common. Doing a google image search will bring up comical parodies of said sign. But do the signs give good advice?


Licensed under CC BY 2.0 via Wikimedia Commons

That was what the authors of this article set to find out. They looked at puma attacks in North America from 1890 to 2000, and found 185 attacks with injury, and 155 more close encounters with no injury. They then analysed the data to see if historically anecdotal risk factors for puma attacks were associated with higher likelihood of injury or death. The variables they analysed were:

  • Age (<13 vs older)
  • Group size (alone, two, or 3 or more)
  • Movement (stationary, quickly, or slowly)
  • Posture (crouching, upright, or on horseback/bicycle)
  • Separation from group, and
  • Noise making

As you can see, the sign above involves 5 of these classic variables. Age, separation from group, posture, noise-making, and movement. An argument can be made for saying that group size is inferred by the number of stick figures in the bottom left pictogram. Interestingly, a couple of those make little or no difference in an attack. There was no association with age or group size.

However, moving quickly did decrease likelihood of severe injury or death in proportion to no injury, while moving slowly or being stationary did not. Crouching versus upright posture did not differ in severity of attack, but being elevated (ie on horseback or bicycle) drastically reduced likelihood of injury or death. Being separated from a group has the highest relative risk, with no uninjured people. Not straying from your group gives you a 40% chance of being uninjured. Last, shouting does help a little over being quiet with regards to escaping uninjured. Doing something even louder (specifically in this article, shooting a gun) makes a larger difference, with a nearly 3:1 odds of escaping uninjured.

So what does this mean if you meet a puma in the wild? Mainly, you need to run away quickly(on a horse if possible). You should probably also carry an air horn, whistle, or some other loud noise-making device for an extra bit of safety. Also, stick with the rest of your party, as there is strength in numbers. Running away flies in the face of what the sign (and classic teaching) tells you, which is to slowly back away. Observations of predatory animals in the wild shows that they often stalk the slower moving members of the herd, as these are easy targets. The article even talks of observed predatory behavior captive cats have towards toddlers and those with unsteady gaits, so it makes sense not to appear weak or infirm to an animal trying to eat you.

And if and animal does attack you, fight back with every means possible.

The Effects of Human Age,Group Composition, and Behavior on the Likelihood of Being Injured by Attacking Pumas
http://www.ingentaconnect.com/content/bloomsbury/azoos/2009/00000022/00000001/art00008

Of note, while pumas carry multiple other names, such as mountain lion, catamount, and others, I specifically did not refer to the animal as a cougar, nor did I refer to the attacks as cougar attacks. I don’t need that kind of traffic coming from google searches.

Copperheads don’t cause coagulopathy


CopperheadInLeavesCU“. Licensed under Public domain via Wikimedia Commons.

Copperheads are common across the southeastern US, and are responsible for a significant number of crotalid envenomations in areas where they are endemic. However, they have the least potent venom of all the pit vipers, and often bites are self-limiting. Prior to development of CroFab, copperhead bites were generally not given antivenom, as the risks of the Wyeth product were felt too high for minimal benefits. Now, CroFab is felt to be safe enough to mitigate even mild symptoms of copperhead envenomations.

However, physicians typically work up copperhead bites the same way they do the other crotalid species. This includes chemistry, complete blood count, and coagulation studies. And often patients are admitted for serial checks of these lab values even if there are no significant physical exam findings.  But are these really necessary when the snake is clearly identified as a copperhead?

These authors suggest that it isn’t. They examined more than 10 years of data from their 2 hospitals in St. Louis and found 106 “probable” or confirmed copperhead bites. Of these, 6 had abnormal coagulation studies, all were minimally outside of normal limits. None had bleeding complications either. Thus, the utility of coagulation studies in copperhead bites is suspect.

So can we stop checking coags on these patients? It’s a decent consideration, in the absence of evidence of coagulopathy. More importantly, patients don’t need to be admitted for serial coagulation studies if the snake in question is definitively a copperhead.  Perhaps checking an initial lab, and if it it’s normal, send them home if no other concerning symptoms. However, if you’re considering giving antivenom, you’re not saving any money by not checking, and you’re probably not sending that patient home.

Lack of Coagulopathy After Copperhead Snakebites
http://www.annemergmed.com/article/S0196-0644(14)01130-5/abstract