Gangrene of the leg

The Greeks called a disease or ulcer that eats away at the body due to putrefaction (decay and death) of tissues 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. It 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 extremities, and 40% are associated with surgical interventions. [ 1 ]

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

Half of patients with gas gangrene of the legs develop sepsis (mortality rates are 27-43%), and almost 80% of patients have a history of diabetes.[ 3 ]

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

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

Causes gangrene of the leg

Gangrene of the leg can begin with deep burns, open bone fractures, compression and crush injuries of soft tissues, stab and gunshot wounds - in case of their infection with hemolytic staphylococcus, streptococcus, proteus, clostridia. Frostbite of the feet can be the cause of tissue decomposition. [ 5 ]

Gangrene often affects the distal parts of the legs, in particular the toes. 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 nodular polyarteritis.

In chronic alcoholics, the 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 case of injury or frostbite of the feet in people with long-term alcohol addiction has received an unofficial name - alcoholic gangrene of the legs.

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

With severe atherosclerosis, due to cholesterol deposition on the inner vascular walls, blood circulation in the peripheral arteries worsens, especially in the arteries of the lower extremities - with the development of obliterating diseases of the lower extremities. Narrowing of the lumen of the vessel seriously limits 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 arteries of the extremities with gangrene is coded I70.261-I70.263. [ 6 ]

The consequence of progressive circulatory disorders of the legs over many years, including arterial occlusion or chronic venous insufficiency, is gangrene of the leg in old age, known as senile gangrene. [ 7 ] In addition, after 60 years of age, gangrene of the legs is possible after a stroke - if patients have the same atherosclerosis and the peripheral vascular diseases that arise on its basis, as well as complications of existing diabetes.

At a younger age, tissue necrosis and gangrene of the leg may begin from smoking, 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 gangrene. Most thrombi accumulate near atherosclerotic plaques, and after surgical revascularization of vessels, thrombi may form in vascular prostheses due to coagulopathy.

Summarizing the consequences of venous pathologies, phlebologists note the high potential danger to 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 swelling of the lower extremities in deep vein thrombosis, which blocks collateral circulation and venous outflow, experts argue for a positive answer to the question: can swelling of the legs lead to gangrene? In addition, so-called compartment syndrome, which occurs with peripheral swelling of the soft tissues of the lower extremities, can lead to tissue necrosis.

Those at particularly high risk are diabetics, since gangrene of the leg in diabetes develops as a result of diabetic angiopathy, and, as a rule, it is gangrene of the foot. [ 12 ]

Risk factors

When determining the risk factors for the development of gangrene of the legs, experts note 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 risk 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 in dry gangrene - in the absence of a bacterial infection - has all the parameters of coagulation at the cellular level. In it, tissues are dehydrated, and the necrotic area is dry and cold due to the evaporation of moisture and the cessation of blood circulation. And the 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 gangrene spreads slowly in tissues - to the limit where there is blood circulation, and in the affected area, lysis (dissolution) of necrotic tissue occurs by macrophages and neutrophils.

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

In the case of gas gangrene, the mechanism of tissue necrosis is associated with their infection with strains of the Clostridium spp. bacterium, which is why this gangrene is called clostridial myonecrosis. Clostridial alpha toxins destroy proteins of muscle cell membranes by cleaving peptide bonds of amino acids, causing platelet aggregation, thrombosis, and the release of histamine. Theta toxins directly damage blood vessels and destroy blood leukocytes, 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 ]

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

But for infection with Clostridium spp. bacteria to develop gangrene, the microorganisms must enter ischemic tissues (poorly saturated with oxygen), since only there can clostridia switch from aerobic respiration to the enzymatic method of producing ATP. The virulence of clostridia bacteria depends on the production of these enzymes, which are toxic to tissues.

Symptoms gangrene of the leg

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

Dry gangrene of the legs often begins with aching pain, which is replaced by local numbness with pallor and a decrease in skin temperature. Then the color of the affected area of the limb changes: from pale to reddish or bluish, and later to greenish-brown and black. Over time, this entire area (including subcutaneous tissue and some of the underlying tissue) shrinks, forming a clear boundary between the affected and healthy areas; the necrotic zone takes on the appearance 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 painful crater-like ulcers with gangrene of the legs - with a black rim of dead skin. And in the presence of trophic ulcers in diabetes on the legs, necrosis begins to develop in them. [ 16 ]

The initial stage of wet gangrene of the legs is usually accompanied by swelling and hyperemia of the affected area. Severe pain is also noted with gangrene of the legs associated with a microbial infection. At first, bleeding ulcers or blisters form on the leg, but very soon clear signs of decomposition are observed in the soft tissues: desquamation (peeling off), 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 turns black. The temperature with gangrene of the leg rises (˂ +38°C), so the patient with wet gangrene constantly has a fever. [ 17 ]

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

In the next stage, the swelling spreads and the volume of the affected leg increases significantly. The release of gas by the Clostridium spp. bacteria that have infected the tissues leads to the formation of subcutaneous pustules, and when the skin is palpated, a characteristic crackling sound (crepitation) occurs.

In terminal stages, clostridial infections cause hemolysis and renal failure. This can result in septic shock with fatal consequences.

Forms

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

Dry gangrene of the legs is the result of vascular occlusion, which slowly leads to tissue atrophy and then 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 occur in people with atherosclerosis, diabetes, and 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 limb is commonly known as wet gangrene of the leg. The development of wet gangrene is associated with various strains of bacteria, including Streptococcus pyogenes (group A β-hemolytic streptococcus), Staphylococcus aureus, Lysinibacillus fusiformis, Proteus mirabilis, Klebsiella aerosacus, which infect any tissue when the integrity of the skin is compromised. [ 19 ]

This type of gangrene can occur after an injury or any other factor that suddenly causes a localized cessation of blood flow to the toes, foot, or higher areas of the leg. This type of gangrene is also common in diabetes, as diabetics are more susceptible to infections due to poor healing.

The most severe form of gangrene is anaerobic or gas gangrene of the legs, [ 20 ] usually caused by facultatively anaerobic spore-forming bacteria of the genus Clostridium (Clostridium perfringens, Clostridium novyi, Clostridium histolyticum), which produce a number of exotoxins (which are enzymes of microorganisms) and gases. [ 21 ] This type of gangrene is most often observed after the primary closure of wounds, especially open injuries due to crushing, as well as those contaminated with soil. A life-threatening condition can develop suddenly and progress rapidly. For more information, see – Gas gangrene

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

Complications and consequences

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

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

In severe cases, systemic intoxication leads to sepsis with gangrene of the leg, which can be fatal. [ 23 ]

Diagnostics gangrene of the leg

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

Blood tests are taken (general, biochemical, for the presence of infection); bacterial culture of blood and fluid from the affected area is performed to identify the bacteria causing the infection (and determine the most effective antibacterial agent). [ 24 ], [ 25 ]

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

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

If gas gangrene is a clinical diagnosis, then in other cases differential diagnostics can be carried out with diseases that have some similarity in symptoms. This applies to erysipelas, abscess, gangrenous pyoderma and ecthyma (occurring with 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 anaerobic gram-negative bacterium Aeromonas hydrophila in penetrating leg injuries sustained in fresh water, accurate diagnosis of gas gangrene often requires surgical exploration of the wound.

Treatment gangrene of the leg

The treatment tactics for gangrene of the leg are determined by the type of necrosis, its stage and scale. In the early stages, gangrene of the leg is usually curable with the help of radical removal of necrotic tissue and intravenous administration of antibacterial drugs.

That is, surgical treatment is necessary - necrectomy, during which all non-viable tissues are excised, in addition, fluid is removed from the necrosis zone, the edema decreases, and colliquative necrosis is transformed into coagulative necrosis. It is possible to repeat this procedure. [ 26 ]

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

Amputation of the leg in case of gangrene is performed in cases of ischemic necrosis of vascular etiology and a large volume of decomposed muscle tissue of the limb (both in area and in depth of damage) with an extensive zone of infectious inflammation. Emergency amputation is required in case of rapidly progressing wet gangrene and severe, threatening sepsis, intoxication in gas gangrene - when there is a real threat to life. In the same cases, amputation of the leg is necessary in case of gangrene in old age. [ 27 ] The level of amputation is determined by the demarcation line. [ 28 ]

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

Other medications include pain relievers for gangrene of the legs (NSAIDs and analgesics, in some cases opioids) and anti-shock infusion fluids.

How to treat gangrene of the leg? To treat the surface of the necrosis zone, use antiseptic and antimicrobial agents: hydrogen peroxide (solution) Dekasan, Povidone-iodine, Ioddicerin, Betadine solution, Dioxidine, Dioxizol.

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

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

Supportive physiotherapy treatment for gangrene of the legs – to improve tissue oxygen supply – is carried out using the hyperbaric oxygenation method. [ 29 ] Although, according to a review by the Cochrane Wounds Group (2015), oxygen therapy does not affect the rate of healing of gas gangrene. [ 30 ]

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

In pathological processes of this kind, such as tissue necrosis, homeopathy is inappropriate, however there are remedies for dry gangrene: Secale cornatum, Arsenic Album, for wet gangrene: Anthracinum, Silicea and Lachesis; for gangrene after frostbite - Agaricu, and also Carbo vegetabilis - for gangrene of the toes due to circulatory disorders.

It is unknown how effective folk treatment of gangrene of the legs can be, since there have been no clinical studies of alternative methods. However, it is recommended to treat wet gangrene with an alcohol solution of propolis daily as an auxiliary remedy.

For dry gangrene, it is recommended to make compresses from crushed garlic or onions; lubricate the affected area with honey, sea buckthorn oil, aloe juice. And also carry out herbal treatment: foot baths with a decoction of prickly thistle, white sweet clover, celandine, erect cinquefoil, mountain arnica.

Therapy with sericata larvae of the sheep fly Phoenicia (Lucilia) may be recommended in cases of intractable gangrene and osteomyelitis when antibiotic treatment and surgical debridement have failed. [ 31 ], [ 32 ]

Prevention

Prevention of the development of gangrene of the legs are measures 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 crucial to ensure normal blood circulation.

Patients with diabetes, vasculitis or weakened immune systems should treat any injury to the legs immediately to prevent infection. And smokers should quit smoking. An unhealthy diet high in fat can worsen existing atherosclerosis and increase the risk of developing gangrene. [ 33 ]

Forecast

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

The prospects for recovery from wet gangrene can hardly be called good due to the risk of developing sepsis.

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

In gangrene associated with diabetic foot, the mortality rate reaches 32%. Symmetrical peripheral gangrene has a mortality rate of 35% to 40% and an equally high morbidity rate; the literature reports amputation rates of over 70%. [ 34 ], [ 35 ] How long do the rest live? According to some data, one-year survival is recorded at 62.7%; two-year survival is about 49%, and five-year survival does not exceed 20%.