Monthly Archives: October 2013

Asian giant hornet

You may have recently seen news stories about Vespa mandarina “terrorizing” parts of China. What is interesting about this species is that due to their size, their venom has significant effects in addition to the typical hymenoptera anaphylaxis. Yes, most deaths are still from anaphylaxis, but the venom can cause acute renal and hepatic failures, as well as rhabdomyolysis.

This article describes a case report of a Japanese man who received multiple stings while in his yard. He was hypotensive and tachycardic, and as such received epinephrine. In addition to the epi you’re thinking of, he also received intrathecal epinephrine. He also received glycyrrhizin, an active component of licorice roots, commonly used in Japan for hepatitis and skin lesions. Apparently anaphylaxis is included in the “skin lesion” category. They also put gentamicin/steroid ointment on the stings. In spite of this treatment, the sting lesions became hemorrhagic, then necrotic. He also developed rhabdomyolysis and hepatitis.

In writing the case up, the authors did an Ichushi (Japan) literature search to find other cases of organ failure after Vespa stings. They ended up finding 14, and using their case came up with a grand total of 15. All of them had hepatitis and rhabdomyolysis, but surprisingly, 3 did not have anaphylaxis. Thirteen of the 15 had some degree of skin necrosis or hemorrhage, however. Six patients died, and when the data were analyzed, this correlated well with number of stings. Strangely, organ injury did not correlate as well, per the authors.

A Medline search was also performed, but they were unable to find any papers with photographic evidence. The few reports they found simply described the lesions, and some sounded similar to their experiences in Japan. Using written descriptions, they were able to find 15 more cases of wasp stings that had cutaneous manifestations and organ failure. There were also reports of bee sting cases in Zimbabwe, the United Kingdom, and Brazil with similar syndromes.

The authors agree with the Good Samaritan Regional Poison Center recommendation of admission for any pediatric, elderly, and patients with comorbidities if they have more than 50 stings. This seems like a good rule to follow for patients with a significant number of stings from any wasp, hornet, or bee. They also recommend being on the lookout for multiple organ failure if any of the stings become hemorrhagic or necrotic, as this implies either a stronger than usual venom, or a weaker than usual immune response. This seems like a reasonable clinical approach.

Cutaneous hemorrhage or necrosis findings after Vespa mandarinia (wasp) stings may predict the occurrence of multiple organ injury: A case report and review of literature
http://www.ncbi.nlm.nih.gov/pubmed/17952752

The shocking pink dragon millipede

Imagine you’re caving in Thailand, and you see a pink millipede. Against your better judgement, you bend over and pick it up. Then you smell almonds…

This is a slightly different type of article that may or may not have much clinical relevance, but it is an interesting creature nonetheless. At 3cm long, it’s certainly not huge, but it’s bright pink. And that almond smell? The millipede produces hydrogen cyanide from defensive glands. It doesn’t produce enough to kill through skin absorption, but it could certainly ruin your day if you tried to eat one.

Best part of the (relatively dry) article: “We think that such an unusually coloured, conspicuous millipede deserves more than a Latin name and suggest calling it “The shocking pink dragon millipede” (in Thai: Mangkorn Chomphoo).” Who knew that biologists had such a sense of humor?

The shocking pink dragon millipede, Desmoxytes purpurosea, a colorful new species from Thailand (Diplopoda: Polydesmida: Paradoxosomatidae)
http://zoologi.snm.ku.dk/Zm_billeder_container/Enghoff.pdf

Death by Elephant

You don’t want to experience a tusker in the bush at 6 in the morning.  They’re large, dangerous creatures that can be quite aggressive.

This study takes a look at 14 human fatalities in West Bengal between 2007 and 2010. The epidemiology of the attacks is interesting. First, all of the victims were rural inhabitants. This is attributed to the rural farming practices of the area, and outward encroachment into natural elephant habitat.  Fragmentation of the herds is also believed to have a part in the increase in human/elephant interaction.

The pre-winter months of July-September are the worst time of year for attacks.  This closely coincides with the annual “musth” state, which is characterized by heightened reproductive hormones in male elephants.  Testosterone makes elephants more aggressive towards people, other wildlife, and even fellow elephants.

Twelve of the 14 attacks occurred between 4 and 6 am.  Why so early you say? This is attributed to the local practice of waking up, and going to use the bathroom at the edge of the village where the bush starts.  With that in mind, it makes sense that males made up 78.6% of the victims.  Only 1 attack occurred on a worker in a field.

Young male victims were attributed qualitatively to have more injuries.  This was attributed to a propensity to fight off or attempt to escape from the elephant.  “Females and older men are less likely to put up much resistance” is pulled directly from the paper. This may be true, but I would tend to err on the side of putting up a fight.

Finally, all of the deaths involved crushing, with one also involving a fatal penetrating tusk injury to the head and chest. Twelve had crush injuries to the chest, while another 2 had isolated crush injuries to the head. The authors attribute an instinctual sense of the elephant to know where to inflict the most injury.  While elephants are intelligent, I won’t give them this much credit.  This isn’t a big cat going for the neck to kill.  This is a large mammal stepping on something until it stops moving, usually done in a flight of heightened aggression.  Further evidence is given by the lack of using the tusks as aggressive weapons.

Suffice it to say, there are only a few take home points from this paper.  Don’t go alone into the bush of West Bengal (or anywhere!).  Avoid elephants during musth.  And finally, if you have to go to the bathroom early in the morning, try to hold it.

Human fatalities from wild elephant attacks – a study of fourteen cases
http://www.ncbi.nlm.nih.gov/pubmed/21550563

Brown Recluse Bites

Last October, a report of death by loxoscelism was reported in Annals.  It’s a sad story about a previously healthy 3 year old girl who was bitten by a witnessed brown recluse in Tennessee.  She went to a rural ED, was evaluated and discharged.  Only physical finding at that time was small red patch on the right breast.  Later that evening she developed signs of systemic loxoscelism, then the following morning evidence of myoglobinuria.  Went to Vanderbilt ED, where her initial labs of WBC 20.7, Hgb 9.5, 2+ spherocytes, and platelets of 54 were concerning.  INR was 1.8.  CMP was hemolyzed of course. They started transfusing, but sadly, she became apneic and pulseless shortly after, and was unable to be resuscitated.  Autopsy was consistent with systemic loxoscelism.

Emergency Department Death from Systemic Loxoscelism
http://www.ncbi.nlm.nih.gov/pubmed/22305333

Thankfully, loxoscelism deaths are rare (or rarely diagnosed!) in the US.  Current recommendations for treatment of systemic loxoscelism are aggressive supportive care, with blood products as needed.  No antivenom available in the US, but may help those in South America.

What about treating the more common incidences of cutanous loxoscelism? Sadly, the literature abounds with interesting if not useful papers that misdiagnose MRSA (and other) cutaneous abscesses as recluse bites.  Thus, it is hard to get good data on appropriate treatment as there are so many confounders.  Things that may work for all other necrotic wounds may not work for cutaneous loxoscelism and vice versa. The list of potential treatments is large, and the following list is not all-encompassing:

  • Cold packs
  • Heat packs
  • Electric shock
  • Hyperbarics
  • Nitroglycerin
  • Steroids
  • Surgical excision
  • Symptomatic treatment
  • Dapsone

So what does work? Truthfully, not a lot.  Very little human evidence for any treatments.

Cold packs might help, and heat packs might worsen lesions.  Not a lot of data to this effect, and in one letter to the editor the authors reference their other papers, which doesn’t mention heat or cold at all.

Brown recluse spider bites: Stay cool
http://www.ncbi.nlm.nih.gov/pubmed/4057509

Electric shock certainly isn’t helpful in animal studies, but probably is entertaining.  Why every type of envenomation needs a trial of electric shock is beyond me.

Dapsone or electric shock therapy of brown recluse spider envenomation?
http://www.ncbi.nlm.nih.gov/pubmed/8010544

Hyperbaric oxygen therapy helps many wounds.  Unclear benefit in humans, in animal studies no benefits were observed. This paper doesn’t have clearly identified spider bites, and has a small sample size.

Brown Recluse Spider Bites: Beneficial Effects of Hyperbaric Oxygen.
http://archive.rubicon-foundation.org/4477

Topical nitroglycerin has theoretical benefit of decreased vasoconstriction, but no actual benefit in rabbits. It may actually worsen systemic effects by dispersing venom instead of keeping it localized.

A controlled trial of topical nitroglycerin in a New Zealand white rabbit model of brown recluse spider envenomation.
http://www.ncbi.nlm.nih.gov/pubmed/11174233

Steroids don’t decrease ulcer size, but may help with systemic symptoms such as pruritis.

North American Loxoscelism: Necrotic Bite of the Brown Recluse Spider.
http://www.ncbi.nlm.nih.gov/pubmed/14107209

Surgical excision helps if done late (like, 6 weeks later), but will cause worsening local effects if done early in the process.

Brown recluse spider bites. A comparison of early surgical excision versus dapsone and delayed surgical excision.
http://www.ncbi.nlm.nih.gov/pubmed/4051613

Dapsone is the old standby.  Theoretically prevents PMN infiltration, but in practice is incredibly harmful.  It causes hemolysis in all patients, as well methemoglobinemia to a degree in all, profound in certain patients.  It also has side effects of headaches, GI upset, hepatitis, exfoliative dermatitis, agranulocytosis, and motor neuropathy.  There have also not been any prospective trials on humans with any benefit.  Just don’t use it.

Loxoscelism
http://www.ncbi.nlm.nih.gov/pubmed/16714202

Symptomatic treatment, e.g. antihistamines and analgesics, are probably most effective at what they do, but they don’t do much for ulcers or systemic pathology. Just don’t expect a lot of evidence on their behalf.

So what to do if someone comes in and says they have a brown recluse bite?  If you live in an endemic area, 99 times out of 100 it’s still MRSA.  If you live somewhere they don’t live, which is anywhere east of Tennessee, north of Missouri, or the small region near the Mexican border from Texas to California, it’s always MRSA.  In the off chance you do have an identified spider and a small red lesion, rest assured that it will become necrotic less than 10% of the time.  However, you may want to check a urine as it’s an easy and non-invasive way to check for hemolysis.  While you’re at it, put a cold pack on the area.  And by cold pack I mean ice pack, not the chemical variety.  Beyond that, the evidence for anything is lacking.  Just supportive care.