Covered in some ways in the previous article https://cumbria-hyperbaric.org/2019/08/06/wound-healing/ today’s discussion tightens the focus a little on the anti-bacterial and antibiotic properties of oxygen, specifically hyperbaric oxygenation. In the article on wound healing we discussed problematic wounds which are slow to heal or even do not heal at all. Some wounds go that step further, and when bacteria normally found outside the skin barrier enters the body through a wound, necrotising infections can occur. This can include of course Gangrene and Gas Gangrene.
Also known as Clostridial Myonecrosis and Myonecrosis, gas gangrene is a condition usually arising from infection by the bacteria Clostridium Perfringens. (Hyperbaric Oxygen Therapy (Review) Tibbles Et al 1996).
It produces its namesake, tell-tale gas in gangrenous tissues. Other organisms may occasionally cause gas gangrene (for example, Klebsiella pneumoniae in the context of diabetes). We’ll spare readers picture of this although we can point you to resources if you wish to identify what it looks like.
Many independent units, (off-label as they are called), around the world, include gas gangrene on their list of treatments they will treat. Fortunately, this is the case, as this is to be considered a medical emergency. It is very much a time sensitive condition which can deteriorate to life threatening levels in hours rather than days.
Unfortunately, not all state funded health authorities commission HBOT for gas gangrene and other necrostising infections, and this is not covered by many state funded treatment centres. In many cases, although even these are rare, massive antibiotic treatment regimes, debridement and amputation is standard course in the absence of a hyperbaric chamber.
Although myonecrosis differs a little from other types of tissue necrosis, the underlying cause is very similar. Superficial necrosis, while not pleasant to look at, and which can result in serious scaring, presents fairly good chances of survival. Large scale myonecrosis affects much larger areas and can result in the loss of an entire limb if allowed to progress.
As a condition which requires a low oxygen environment to proliferate, it makes sense that hyper oxygenation complicates the ability for bacteria to grow. This, put simply, is the antibiotic effect of oxygen. Bacteria generally doesn’t like oxygen and doesn’t grow well in a super oxygenated environment. This allows the natural immune response to do its job with greater ease and efficiency. Oxygen takes much of the load off. Healing is more effective without the additional problem of having to combat exponential bacterial growth whilst generating tissue scaffolds and the business of actually replacing damaged tissue. Not to mention the additional factors which are up-regulated in tissue renewal and granulation covered in the article on wound healing.
Differing from other anaerobic (low oxygen) infections, myonecrosis exhibits discharge of watery pus rather than normal pus. It is much thinner than normal pus discharge. This is due to the actions of lysis of neutrophils. The breaking down of cell membranes and release of lysate in fluid form is caused by the lecithinases and other toxins present. Further to this, recovery is complicated by the release of inflammatory cytokines along with distribution of bacterial toxins.
Untreated, massive infection can lead to septic shock and death. There are three familiar concepts in the above description. Namely, inflammation, anaerobia and neutrophils. All three of which have been discussed in various previous articles.
Where these three conditions exist, HBOT can be, and is of benefit owing to its anti inflammatory properties discussed in the article https://cumbria-hyperbaric.org/2019/07/25/oxygen-as-an-anti-inflammatory-and-multiple-sclerosis/.
The inhibition or inability to control anaerobic pathogenesis (growth and development of bacteria in a low oxygen environment), as well as the deployment of neutrophils, which in excess, can lead to a destructive cycle of inflammation, fluid leakage into tissues, and further tissue hypoxia and cell death due to poor oxygen transport and blood flow, is followed by massive tissue loss and tissue death as discussed in the articles covering hypoxia.
It seems to be well recognised by many that hyperbaric oxygen therapy/treatment is one of the accepted and highly effective forms of treatment for this condition. In restoring oxygenation and reducing tissue loss whilst inhibiting pathogenesis, favourable outcomes are observed. Greater availability of chambers at medical facilities would improve outcomes further for patients.
References to peer reviewed papers on this subject can be found on the Links and references page across the menu bar.