Gangrene legs

The disease or ulcer that corrodes the body due to rotting (decomposition and death) of tissues, the Greeks called gangraina. So gangrene of the leg is the destruction and death of its tissues, caused by the cessation of blood supply and / or bacterial infection. This is a dangerous disease that can lead to amputation or death.

Epidemiology

As clinical statistics show, about half of cases of wet gangrene are the result of severe injuries to the limbs, and 40% are associated with surgical interventions. [1]

In 59-70% of cases, soft tissue necrosis is caused by polymicrobial infection. [2]

In half of patients with gas gangrene of the legs, sepsis begins (mortality rates are 27-43%), and in almost 80% of cases, patients had a history of diabetes. [3]

According to the International Diabetes Federation (IDF), the prevalence of diabetes-related complications increases with the age of patients, and the development of gangrene, which is observed in a third of patients, increases sharply after 65 years (in men 1.7 times more often than in women).

Globally, up to 45% of all leg amputations are performed in patients with diabetes. [4]

Causes of the gangrene legs

Leg gangrene can begin with deep burns, with open bone fractures, with compression and crushed injuries of soft tissues, stab-cut and gunshot wounds - in case of infection with hemolytic staphylococcus, streptococcus, proteus, clostridia. The cause of tissue decomposition may be  frostbite of the  legs. [5]

Gangrene often affects the distal calving of the legs, in particular, the fingers on the foot. For example, gangrene of the big toe or gangrene of the little finger can be the result of  panaritium  and its most severe form - pandactylitis, as well as polyarteritis nodosa.

In chronic alcoholics, processes of nerve cells gradually atrophy with the development of  alcoholic polyneuropathy , in which the feet partially or completely lose sensitivity to pain and temperature. Therefore, the occurrence of necrosis in the event of injury or frostbite of the feet in people with long-term alcohol dependence has received an unofficial name - alcoholic gangrene of the legs.

The essence of any gangrene is necrosis, and its development is due to oxygen starvation of cells (ischemia) due to the cessation of their blood supply. Since blood supply is provided by the vascular system, in many cases, the causes of gangrene in the legs are associated with  angiopathy of the limbs .

With severe  atherosclerosis,  due to deposition of cholesterol on the internal vascular walls, blood circulation in the peripheral arteries, especially the arteries of the lower extremities, deteriorates - with the development of  obliterating diseases of the lower extremities . The narrowing of the lumen of the vessel seriously restricts blood flow, and it can be completely blocked, and then arterial trophic ulcers occur   and atherosclerotic gangrene of the leg or both legs begins to develop. According to ICD-10, atherosclerosis of native limb arteries with gangrene is encoded I70.261-I70.263. [6]

The consequence of leg blood circulation problems progressing over many years  , including arterial occlusion or  chronic venous insufficiency , is leg gangrene in old age, known as senile gangrene. [7]In addition, after 60 years, gangrene of the legs is possible after a stroke - if the patients have the same atherosclerosis and peripheral vascular diseases arising from it, as well as complications of existing diabetes.

At a younger age, tissue necrosis and leg gangrene from smoking can begin, which in some cases leads to inflammation of the vessels of the lower extremities (arteries and veins), the formation of blood clots and occlusion -  obliterating thromboangiitis . [8]

Thrombotic occlusion is the most common cause of acute limb ischemia leading to the development of gangrene. Most blood clots accumulate near atherosclerotic plaques, and after surgical vascular revascularization, blood clots can form in vascular prostheses due to coagulopathy.

Summarizing the consequences of vein pathologies, phlebologists note a high potential danger to the life  of deep vein thrombosis of the lower extremities  (iliac and femoral) and their thromboembolism, due to which circulatory venous gangrene of both legs can develop. [9],  [10], [11]

The presence of dense edema of the lower extremities with deep vein thrombosis, which blocks collateral circulation and venous outflow, experts argue a positive answer to the question: can leg edema lead to gangrene? In addition, the so-called cider compartment , which occurs with peripheral edema of the soft tissues of the lower extremities, can lead to tissue necrosis .

In the zone of especially high risk - patients with diabetes, since gangrene of the legs with diabetes develops as a result of  diabetic angiopathy , and, as a rule, this is  gangrene of the foot . [12]

Risk factors

Determining the risk factors for developing gangrene of the legs, experts note their injuries of various etiologies, diabetes mellitus, pathological changes in the arteries and veins of the lower extremities, as well as smoking and weakened immunity.

In addition, there are many pathological conditions and diseases that can lead to the development of gangrene (dry) due to damage to blood vessels. This applies to systemic vasculitis (in particular, the necrotic form of rheumatic purpura), granulomatosis with polyangiitis (Wegener's granulomatosis), systemic lupus erythematosus, reactive arthritis, antiphospholipid syndrome (with a tendency to form blood clots and the threat of vascular occlusion), etc.

Pathogenesis

It has already been noted that the essence of gangrene is  necrosis , and the pathogenesis of gangrenous tissue decomposition has the same histomorphological characteristics.

In particular, ischemic necrosis with dry gangrene - in the absence of a bacterial infection - at the cell level has all the parameters of coagulation. With it, the tissues are dehydrated, and the area of necrosis is dry and cold due to evaporation of moisture and the cessation of blood circulation. A brown or greenish-black color of the affected area indicates the death of red blood cells with the release and biochemical transformation of hemoglobin. Dry type gangrene spreads slowly in tissues - up to the limit where there is blood circulation, and necrotic tissue is lysed (dissolved) by macrophages and neutrophils in the affected area.

The development of wet gangrene of the leg is associated with a microbial infection and histologically manifests itself as collision necrosis. Bacteria that infect tissues cause their swelling (edema) and decomposition, which progresses rapidly due to compression of the vessels by the swollen tissues and the cessation of crosca. Stagnation of blood in the affected area favors the rapid growth of bacteria, and the pus and loose dirty white scab formed as a result of the inflammatory reaction make the necrosis wet. [13]

In the case of gas gangrene, the mechanism of tissue necrosis is associated with their infection with strains of the bacterium Clostridium spp., Therefore this gangrene is called clostridial myonecrosis. Clostridia alpha toxins break down the proteins of cell membranes of muscle tissue by cleaving peptide bonds of amino acids, causing platelet aggregation, thrombosis, and histamine release. Theta toxins directly damage blood vessels and destroy white blood cells, which leads to an inflammatory reaction. The gases released by bacteria facilitate the process of their spread to nearby healthy tissues, and the accumulation of these gases in muscle tissue leads to accelerated tissue necrosis. Also read -  Anaerobic infection . [14]

Concluding the brief description of pathogenesis, it is appropriate to answer the question: is foot gangrene contagious to others? As infectious disease specialists note, with gas gangrene, pathogens can spread by contact - from the area of the limb affected by necrosis. Therefore, in treated institutions, wards with such patients are under special sanitary control.

But for infection by bacteria Clostridium spp. With the development of gangrene, microorganisms must get into tissues with ischemia (poorly saturated with oxygen), since clostridia can only switch from aerobic respiration to the enzymatic method of producing ATP. It is from the production of these enzymes, which are toxic to tissues, that the virulence of the clostridian bacteria depends.

Symptoms of the gangrene legs

How does gangrene of the leg begin? Its first signs vary depending on the particular development of the pathological process - such as tissue necrosis - and the stage of leg gangrene.

Dry gangrene of the legs often begins with aching pain, which is replaced by local numbness with blanching and lowering skin temperature. Then the color of the affected area of the limb changes: from pale to reddish or bluish, and then to greenish-brown and black. Over time, this entire area (including subcutaneous tissue and part of the underlying tissues) is compressed with the formation of a clear border between the affected and healthy areas; the necrosis zone takes the form of mummified flesh. The last stage of dry gangrene is the rejection of dead tissue. [15]

In cases of diabetic foot, the first symptom is often crater-like painful ulcers with gangrene of the legs - with a black rim of dead skin. And in the presence of  trophic ulcers with diabetes on the legs,  necrosis begins to develop in them. [16]

The initial stage of wet gangrene of the legs is usually accompanied by edema and hyperemia of the affected area. Severe pain with gangrene of the legs associated with microbial infection is also noted. First, bleeding ulcers or blisters form on the leg, but very soon there are obvious signs of decomposition in the soft tissues: desquamation (exfoliation), serous-purulent discharge with a putrid odor - due to the release of pentane-1,5-diamine (cadaverine) and 1, 4-diaminobutane (putrescine) during the decomposition of tissue proteins. Deprived of oxygen and nutrients, the tissue becomes moist and blackens. The temperature with leg gangrene rises (˂ + 38 ° C), so the patient with wet gangrene constantly fevers. [17]

The first symptoms of gas gangrene of the legs are manifested by a feeling of heaviness, intense swelling and pain in the affected area. The skin first turns pale, and then acquires a bronze or purple color, followed by the formation of bullae (blisters) containing serous or hemorrhagic exudate with a pungent odor.

At the next stage, edema spreads, and the volume of the affected leg increases significantly. Gassing of infected tissues by bacteria Clostridium spp. Leads to the formation of subcutaneous pustules, and when palpating the skin there is a characteristic crackling (crepitus).

In the terminal stages, clostridial infections cause hemolysis and renal failure. The result can be septic shock with fatal consequences.

Forms

There are three main types or types of gangrene: dry, wet and gas (which is considered a subtype of wet gangrene).

Dry gangrene of the legs is the result of occlusion of blood vessels, which slowly leads to tissue atrophy, and then its death - gradual drying without signs of inflammation. This type of gangrene is called aseptic, necrosis begins in the distal part of the limb and can be in people suffering from atherosclerosis, diabetes, as well as in smokers. As a result of infection in patients with immunodeficiency and diabetes, dry gangrene can transform into wet gangrene. [18]

The wet type of necrosis of the tissues of the lower extremity in everyday life has a name - wet foot gangrene. The development of wet gangrene is associated with various bacterial strains, including Streptococcus pyogenes (β-hemolytic Streptococcus A group), Staphylococcus aureus, Lysinibacillus fusiformis, Proteus mirabilis, Klebsiella aerosacus, which infect any tissue in violation of skin integrity. [19]

Such gangrene can occur after an injury or as a result of any other factor that suddenly causes a local cessation of blood flow to the fingers, foot or higher located areas of the leg. In diabetes, this type of gangrene is also not uncommon, as diabetics have an increased susceptibility to infections due to poor healing.

The most severe form of gangrene is anaerobic or gas leg gangrene,  [20]usually caused by facultatively anaerobic spore-forming bacteria of the clostridium genus (Clostridium perfringens, Clostridium novyi, Clostridium histolyticum), which produce a variety of exotoxins (which are enzymes and microorganisms). [21]This type of gangrene is most often observed after the initial closure of wounds, especially open injuries due to crushing, as well as contaminated ground. A deadly condition can develop suddenly and progress rapidly. See details -  Gas Gangrene

Iatrogenic gangrene associated with the improper use of vasoactive drugs such as alkaloids adrenaline and ergot. [22]

Complications and consequences

Dry gangrene - if it has not been infected, and it has not transformed into wet - as a rule, is not complicated by blood poisoning and does not cause fatal consequences. However, local tissue necrosis can end with spontaneous amputation - rejection of limb tissues in the affected area with the formation of scars requiring reconstructive surgery.

About 15% of patients have bacteremia, which is usually complicated by the rapid destruction of red blood cells with a sharp decrease in hematocrit. Common complications include jaundice, arterial hypotension, and acute renal failure.

In severe cases, with systemic intoxication, sepsis develops with leg gangrene, which is fatal. [23]

Diagnostics of the gangrene legs

Diagnosis of gangrene is based on a combination of physical examination, medical history and tests.

Blood tests are taken (general, biochemical, for infection); bacteriological blood and fluid from the affected area are carried out - to identify the bacteria causing the infection (and determine the most effective antibacterial agent). [24], [25]

Instrumental diagnostics involves the visualization of blood vessels using  angiography ; duplex ultrasound and  ultrasound of the veins of the lower extremities , as well as CT or MRI, to assess the degree of spread of gangrene.

Ultrasound Doppler sphygmomanometry can be performed (to determine the local capillary perfusion pressure); Doppler flowmetry (for determining the microcirculation index); tissue oximetry (allowing you to set the level of tissue oxygen saturation).

If gas gangrene is a clinical diagnosis, in other cases, differential diagnosis may be carried out with diseases that have some similarity of symptoms. This applies to erysipelas, abscess, gangrenous pyoderma and ecthyma (arising from perivascular invasion of the skin of the legs by the aerobic bacterium Pseudomonas aeruginosa), streptococcal necrotic fasciitis).

Although gas gangrene should be differentiated from myonecrosis, associated with the defeat of the anaerobic gram-negative bacterium Aeromonas hydrophila with penetrating leg injuries received in fresh water. Therefore, accurate diagnosis of gas gangrene often requires surgical examination of the wound.

Treatment of the gangrene legs

The tactics of treating foot gangrene is determined by the type of necrosis, its stage and scale. In the early stages of gangrene, the legs are usually treatable by radical removal of necrotic tissue and the intravenous administration of antibacterial drugs.

That is, surgical treatment is necessary - a necrectomy during which all non-viable tissues are excised, in addition, fluid is removed from the necrosis zone, the edema decreases, and the collication necrosis is transformed into coagulation. This procedure may be repeated. [26]

Is it possible to treat foot gangrene without surgery? With wet and gas gangrene, it is impossible to do without urgent surgical cleaning of the affected area of the limb. But without amputation it is possible, but, alas, not in all cases.

Amputation of the leg with gangrene is carried out in cases of ischemic necrosis of vascular etiology and a large amount of decomposed tissues of the limb muscles (both in area and in depth of the lesion) with a wide area of infectious inflammation. Emergency amputation is required with rapidly progressing wet gangrene and severe, sepsis threatening, intoxication with gas gangrene - when there is a real threat to life. In the same cases, amputation of the leg with gangrene in the elderly is necessary. [27] The level of amputation is determined by the demarcation line. [28]

Without delay, antibiotics are given intravenously or intramuscularly for foot gangrene. These are broad-spectrum antibiotics such  as: Clindamycin, Metronidazole, Ciprofloxacin,  Ceftriaxone , Ceftazidime, Amoxiclav, Clarithromycin, Amikacin, Moxifloxacin.

Other drugs include pain medication for foot gangrene (NSAIDs and analgesics, in some cases opioids) and anti-shock infusion fluids. 

How to handle leg gangrene? Antiseptic and antimicrobial agents are used to treat the surface of the necrosis zone: hydrogen peroxide (solution)  Dekasan , Povidone-iodine,  Iodicerin , Betadine solution, Dioxidine, Dioxizole.

The most suitable foot gangrene ointments (on a water-soluble basis) include: Sulfargin ointment or Dermazin and Argosulfan creams (with silver sulfathiazole),   Baneocin antibiotic ointment, Steptolaven ointment.

Due to the fatty basis,  Vishnevsky ointment  with gangrene of the leg in modern clinics is not used either before or after necrectomy.

Supportive physiotherapeutic treatment of leg gangrene - to improve tissue oxygen supply - is carried out using  hyperbaric oxygenation . [29]Although, according to a review by the Cochrane Wounds Group (2015), oxygen therapy does not affect the rate of cure of gas gangrene. [30]

If tissue necrosis is coagulation (dry), then massage with gangrene of the legs (unaffected areas of the limbs) will help to improve the blood supply to intact tissues.

In pathological processes such as tissue necrosis, homeopathy is impractical, but there are remedies for dry gangrene: Secale cornatum, Arsenic Album, for wet gangrene: Anthracinum, Silicea and Lachesis; from gangrene after frostbite - Agaricu, as well as Carbo vegetabilis - from gangrene of the toes in case of circulatory disorders.

How effective alternative treatment of foot gangrene can be is unknown, since no clinical studies of alternative methods have been conducted. Nevertheless, it is advised to treat wet gangrene daily with an alcohol solution of propolis as an adjuvant.

With dry gangrene, it is recommended to make compresses from crushed garlic or onions; lubricate the affected surface with honey, sea buckthorn oil, aloe juice. And also carry out treatment with herbs: foot baths with broth of prickly tatarnik, white melilot, celandine, upright cinquefoil, mountain arnica.

Therapy with Phoenicia lamb flies sericata larvae (Lucilia) can be recommended in cases of intractable gangrene and osteomyelitis, when antibiotic treatment and surgical treatment were unsuccessful. [31], [32]

Prevention

Prevention of the development of foot gangrene is a measure aimed at preventing injuries and vascular pathologies that cause ischemia of the tissues of the lower extremities (see sections - Causes and Risk Factors). Early diagnosis and treatment are critical to ensuring normal circulation.

Patients with diabetes, vasculitis, or immunocompromised patients with any damage to the legs should be treated immediately to prevent infection. And smokers are best to abandon this habit. High-fat, unhealthy diets can exacerbate existing atherosclerosis and increase your risk of gangrene.[33]

Forecast

As a rule, people with dry gangrene have the best chance of a full recovery, since it is not associated with a bacterial infection and spreads more slowly than other types of gangrene.

The prospects for recovering with wet gangrene can hardly be called good - because of the threat of sepsis.

In cases of critical limb ischemia (late stage of angiopathy), the prognosis is negative: in 12%, due to the development of gangrene, amputation of the leg is performed within a year after determining the diagnosis; after five years, death from gangrene of the leg occurs in 35-50% of patients, and after ten years - in 70%.

With gangrene associated with diabetic foot, the number of deaths reaches 32%. Symmetric peripheral gangrene has a mortality rate of 35% to 40% and an equally high incidence rate; literature reports an amputation rate of over 70%. [34],  [35] How many live the rest? According to some reports, the survival rate for one year is fixed at 62.7%; two-year survival is about 49%, and five-year does not exceed 20%.