Necrotising fasciitis
Whilst not very common, necrotising fasciitis is a severe, fast-progressing infection that causes a lot of damage. It needs to be identified early and treated quickly.
It can occur after a traumatic break in the skin such as small cuts, insect bites or burns. Factors such as being diabetic, smoking, obesity, alcoholism and intravenous drug abuse are risk factors for this occurring.
It usually presents with a pain that is out of proportion to what you can see in the area and this can be an early sign of deep infection. It may also become swollen very quickly.
Other symptoms that may occur are:
- Fever and chills
- Pain proceeding to numbness
- Blistering
Necrotising fasciitis is usually treated through intravenous antibiotics alongside surgical removal of the affected areas. In some cases affected limbs need to be amputated to prevent the spread of the infection, as it can develop very quickly.
How can Hyperbaric Oxygen Therapy Help?
Hyperbaric oxygen has been shown to provide benefit in the treatment of this condition alongside surgical treatment and antibiotics. Studies have shown it increases survival, reduces the amount of surgical intervention required and may reduce the need for amputation. It has also been shown to improve post-treatment outcomes as a result of this.
In our unit we aim to give patients 2 treatments daily until the patient is stable and then treatment will either be reduced to 1 daily or stopped altogether.
Clostridial Myonecrosis (Gas Gangrene)
Gangrene occurs when tissue dies as a result of blood supply. When this is caused by certain bacterial infections, gas forms in the tissues - hence the term 'gas gangrene'. Distinctive black bubbles appear on the skin containing this gas.
Other symptoms that may occur are:
- 'Foul, sweet' smelling discharge from the lesions
- Air in tissues
- Fever
- Pain
Treatment of gas gangrene needs to be urgent - usually the infected tissue needs to be removed, which may require amputation in some cases. IV antibiotics are given alongside the surgery.
How can Hyperbaric Oxygen Therapy Help?
Hyperbaric oxygen can help destroy the bacteria that causes gas gangrene. It can stop the bacteria producing the toxin which damages the muscle tissue reducing the need for amputation. HBOT also has an anti-inflammatory effect.
Necrotising Soft Tissue Infections
Gas gangrene is a fulminating, soft-tissue infection with gram-positive anaerobic bacilli of the species Clostridium, notably Cl. Perfringens. The skin, subcutaneous fat and muscle may all be affected.
The majority of cases are the consequence of contamination of traumatic wounds, where the initial cause of necrosis is not the Clostridium itself, but the fact that tissue damage has resulted in locally hypoxic tissue, so allowing Clostridium to thrive (Malerba F, Oriani G, Farnetti A. 1996. HBO in orthopaedic disorders. In: Oriani G, Marroni A, Wattel F eds. Handbook on Hyperbaric Medicine. Milano: Springer Verlag, 409-427).
Bacteria then produce an alpha-toxin, which causes the necrosis. The toxin is not only haemolytic but also has phospholipase activity, with consequent activation of inflammatory pathways causing increased vascular permeability. This results in oedema of the affected tissues (Sakurai J, Nagahama M, Oda M. 2004. Clostridium perfringens Alpha-Toxin: Characterization and Mode of Action. J Biochem, 136: 569–574), which in turn contributes to hypoxia, so facilitating the further multiplication of the bacteria.
Appropriate surgical management with antibiotic therapy should constitute the first line of management. At tissue oxygen tensions in excess of 250mmHg, alpha-toxin production is halted within minutes of commencing hyperbaric oxygen therapy (Bakker DJ. 1988. Clostridial Myonecrosis. In: Davis JC, Hunt TK eds. Problem Wounds: The Role of Oxygen. New York: Elsevier, 153-172).
The combination of hyperbaric oxygen (HBO) therapy and surgery has been demonstrated to be synergistic in reducing both mortality and morbidity, since the need for extensive debridement and amputation is significantly reduced, with viable and non-viable tissue being more strongly demarcated, thus making possible more accurate tissue debridement (Hart GB, Strauss MB. 1990. Gas gangrene – clostridial myonecrosis: a review. J Hyper Med, 5: 125-44).
It has therefore been proposed that, where there is close contact between surgical and hyperbaric facilities, the initial surgical management should be limited to fasciotomy, with debridement of necrotic tissue performed later, after treatment with hyperbaric oxygen therapy (Cohn GH. 1986. Hyperbaric oxygen therapy; promoting healing in difficult cases. Postgrad Med, 79: 89-92). The extent of ablation may be reduced if early HBO treatment is used to halt progression of the infection.
Further information regarding the Referral and Funding process can be found here.