I needed to write something about snakes - I dislike snakes very much, but living here you have to take some interest in them as they are a fairly common occurrence, having the capacity to kill nearly 20,000 people per year in both South Africa and Swaziland, they are a little bit of an environmental hazard.
I was very ignorant to the various species of snakes in existence, the spectrum of sizes, colours and head shapes and of course venomous qualities. Having acquired some knowledge of them, I still quite dislike them but have gained a new found respect and admiration.
I thought I would educate myself and you all on snakes that pose dangers to us and the community in Mseleni.
We should start with Black Mamba Snake, it is the largest and deadliest and most feared snake in Africa and is not black at all, the 'black' arises from the fact that the inside of its mouth is black. The black mamba is very agile and is said to be the fastest snake in the world, capable of moving at 4.5-5.4m/sec (16–20 km/hr). It has yellowish-green to light greyish skin and reaching an average length of 2.5m but can reach up to 4.3m. Its notoriety lies in its fatal neurotoxic venom. The mortality rate is nearly 100%, unless the snakebite victim is promptly treated with antivenom. Black mamba bites can potentially kill a human within 20 minutes, but death usually occurs after 30–60 minutes. Fortunately, we have a polyvalent antivenom produced by SAIMR (South African Institute for Medical Research) to treat all black mamba bites from different localities.
Next up is the Puff Adder; they grow be a metre in length but are quite stout. Though not as notorious as the black mambo, it is considered to be Africa's deadliest snake because it is responsible for the most human fatalities. The incidence of puff adder bites are high for a variety of factors; they are common and widely distributed; their preference to camouflage rather than flee; their habit of basking by footpaths and general willingness to bite with their quite potent venom. The venom has cytotoxic effects, which means it may cause local tissue swelling, pain, tenderness to ulceration and considerable necrosis, as well as severe bruising and bleeding systemically. If not treated carefully, necrosis will spread, causing skin, subcutaneous tissue and muscle to separate from healthy tissue and eventually slough. Gangrene and secondary infections commonly occurs and can result in loss of digits and limbs. Despite this, deaths are exceptional and probably occur in less than 10% of all untreated cases.
Final up is the Boomslang, which is an extraordinarily dangerous snake but luckily human fatalities are rare, since this snake is remarkably timid. It is a tree-dwelling snake (Boomslang means "tree snake" in Afrikaans), with reaches an average length of 1-1.6m. The Boomslang has exceptionally large eyes proportionate to its distinctive egg-shaped head. Females are brown, and males are light green with black highlights. Their fangs interestingly lie at the back of their jaw. The Boomslang venom is primarily a haemotoxic - which disables the blood clotting process and may cause death as a result of internal and external bleeding. Because the venom is slow to act, symptoms may not be manifest until many hours after the bite. On the one hand, this provides time for procuring the serum, while on the other hand it may lead victims to underestimate the seriousness of the bite.
I wouldn't underestimate a snake and completely understand why locals fear them most fervently.
Monday, 12 July 2010
24.6.2010 GUNSHOT WOUNDS
I never thought much about gunshot wounds before today, I suppose I never really needed to.
But after I had encountered a lady who was shot in the right side of her abdomen at close range and remained pretty much unscathed, because the bullet routed itself through her womanly 'muffin' abdominal excess and came out the other side, leaving the intra-abdominal cavity untouched, I was just very intrigued by the effect of the bullet on human tissue.
After a spot of reading around the subject, I discovered, that an entrance wound, would characteristically leave soot on the outside skin or lacerate the skin from the gas effects (exception is when an airgun is used!). The closer the range shot, the more soot stippling on skin. Distance shots tend to lack the soot component but will exhibit a hole that approximately equates to the calibre of the bullet fired.
When the bullet is in, the injury sustained depends on a number of factors - bullet deformation, bullet fragmentation, characteristics of the bodily tissue impacted on.
Relative density (mass/volume) is vital to understanding tissue damage, the greater the density the greater the damage. Whereas, elasticity reduces the level of damage. So we can then see why lung tissue with a low density and high elasticity would be damaged far less than muscle, and even more less than organs like the liver, spleen, brain. Bone, has a more dramatic effect of causing fragmentation of both the bone and bullet, which goes on to do collateral damage and make the hole much larger too. Then we have fluid filled organs, which just explode and release their contents, which itself can be even more problematic.
The bullet itself may vary in its quality and ability to execute damage, a hollow point bullet will actually give you an increase in volume of disrupted tissue and fragmentation, without giving you an exit wound. A fully coated metal bullet will give you an exit wound, but these may also recoil off bone.
My patients bullet did exit out very neatly, however most bullets are designed not too exit (then they do more damage of course). If you were try and distinguish between exit and entrance wounds, you would note the exit wound is larger, as the bullet has expanded or deviated from its initial alignment. There may also be less gunshot residue. You might also need to bear in mind there may be more than one exit wound (fragmentation of the bullet resulting in secondary missiles ) and the exiting bullet will necessarily come out at the opposite end to the entrance, as the bullet is unlikely to make a linear track out. The bullet track can be influenced by the targets position, so the organs affected on the sitting target will alter from that of the standing targets.
This patient, was extremely lucky, she got away fairly intact despite a close range bullet shot, a few sutures at the entrance and exit wounds, were the (physical) remnants of her encounter with a bullet.
And me, I feel I have acquainted myself very well to bullet trajectory and if I dwell any further it wouldn't provide anyone with any additional benefit and I might be labelled as slightly fanatic :)
But after I had encountered a lady who was shot in the right side of her abdomen at close range and remained pretty much unscathed, because the bullet routed itself through her womanly 'muffin' abdominal excess and came out the other side, leaving the intra-abdominal cavity untouched, I was just very intrigued by the effect of the bullet on human tissue.
After a spot of reading around the subject, I discovered, that an entrance wound, would characteristically leave soot on the outside skin or lacerate the skin from the gas effects (exception is when an airgun is used!). The closer the range shot, the more soot stippling on skin. Distance shots tend to lack the soot component but will exhibit a hole that approximately equates to the calibre of the bullet fired.
When the bullet is in, the injury sustained depends on a number of factors - bullet deformation, bullet fragmentation, characteristics of the bodily tissue impacted on.
Relative density (mass/volume) is vital to understanding tissue damage, the greater the density the greater the damage. Whereas, elasticity reduces the level of damage. So we can then see why lung tissue with a low density and high elasticity would be damaged far less than muscle, and even more less than organs like the liver, spleen, brain. Bone, has a more dramatic effect of causing fragmentation of both the bone and bullet, which goes on to do collateral damage and make the hole much larger too. Then we have fluid filled organs, which just explode and release their contents, which itself can be even more problematic.
The bullet itself may vary in its quality and ability to execute damage, a hollow point bullet will actually give you an increase in volume of disrupted tissue and fragmentation, without giving you an exit wound. A fully coated metal bullet will give you an exit wound, but these may also recoil off bone.
My patients bullet did exit out very neatly, however most bullets are designed not too exit (then they do more damage of course). If you were try and distinguish between exit and entrance wounds, you would note the exit wound is larger, as the bullet has expanded or deviated from its initial alignment. There may also be less gunshot residue. You might also need to bear in mind there may be more than one exit wound (fragmentation of the bullet resulting in secondary missiles ) and the exiting bullet will necessarily come out at the opposite end to the entrance, as the bullet is unlikely to make a linear track out. The bullet track can be influenced by the targets position, so the organs affected on the sitting target will alter from that of the standing targets.
This patient, was extremely lucky, she got away fairly intact despite a close range bullet shot, a few sutures at the entrance and exit wounds, were the (physical) remnants of her encounter with a bullet.
And me, I feel I have acquainted myself very well to bullet trajectory and if I dwell any further it wouldn't provide anyone with any additional benefit and I might be labelled as slightly fanatic :)
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