gangrene



Overview

It refers to the necrosis of local tissues in large pieces and the secondary infection by putrefactive bacteria, which may cause fever, skin discoloration, numbness, pain and other symptoms, mainly due to blood circulation disorders or traumatic infections. The treatment includes general treatment, medication, surgical treatment, and other therapies.

Definition

Gangrene is defined as localized tissue necrosis of a large piece of tissue secondary to a putrefactive bacterial infection.

Gangrene is mainly caused by blood circulation disorders or infections, and is commonly found in the limbs, but also in the gallbladder, appendix and other parts of the body.

Classification

Classification according to pathological features

Dry gangrene

Commonly found at the end of the limbs where the arteries are blocked but the venous return is still smooth.

Wet gangrene

Mostly occurs in the lungs, intestines, uterus, appendix and gallbladder and other internal organs connected with the outside world, and also occurs in the limbs where the arteries are blocked and the venous return is impeded.

Gas gangrene: belongs to wet gangrene.

Causes

Causes

Gangrene is mainly due to circulation disorders and infections.

Circulatory disorders

Severe blood circulation disorders affect the exchange of substances between blood and tissue cells, metabolites cannot be eliminated, limbs are ischemic and hypoxic, and are susceptible to bacterial infection, leading to the formation of gangrene.

It is often caused by thromboembolic vasculitis, acute arterial embolism, arteriosclerotic occlusive disease of the lower limb, diabetic foot disease, deep vein thrombosis, frostbite and so on.

Prolonged compression leads to local tissue circulation disorders.

Trauma infection

Open trauma that reaches deep into the muscle and triggers anaerobic infection can lead to tissue necrosis at the site of infection, thus causing gangrene.

Common anaerobic bacteria causing gangrene: Pseudomonas aeruginosa, Bacillus, Clostridium, Pseudomonas, Proteus, Streptococcus, Staphylococcus, and so on.

Risk factors

The following factors increase the risk of developing gangrene and are high risk factors for the disease.

Diabetes mellitus

On the one hand, diabetes mellitus is prone to vascular damage, causing impaired blood circulation in tissues.

On the other hand, diabetes mellitus can lead to low immune function, which makes it easy to get infected and it is not easy to control the infection.

Therefore, diabetic patients are prone to gangrene.

Vascular lesions

Atherosclerosis, thrombosis and other vascular diseases can cause narrowing or even complete occlusion of the lumen of blood vessels, hindering blood circulation, thus leading to the interruption of blood supply to certain parts of the tissues of the body and inducing gangrene.

After trauma or surgery

Severe trauma or surgery may result in loss of normal blood supply to local tissues and secondary infections, leading to gangrene.

The presence of deep wounds, tight bandages, prolonged hemostasis and other factors that can lead to an ischemic and hypoxic environment can lead to anaerobic infections and increase the incidence of gas gangrene.

Smoking

Long-term heavy smoking can easily lead to vascular damage, cause tissue blood circulation obstacle, and increase the incidence of gangrene.

Obesity

On the one hand, obesity is prone to diabetes, atherosclerosis and other lesions.

On the other hand, the pressure formed by the overweight itself of obese people will compress the blood vessels, leading to insufficient blood vessels in the tissues.

Both can increase the incidence of gangrene.

Immunodeficiency

Human immunodeficiency virus (HIV) infection, chronic alcoholism, long-term use of immunocompromising agents or glucocorticoids, radiotherapy treatment and other factors can lead to immunocompromise.

Susceptibility to infection, which is not easily controlled, increases the incidence of gangrene.

Symptoms

Main symptoms

The main symptoms of gangrene are fever, skin discoloration, numbness, and pain, which vary by type.

Fever

Fever of varying degrees often occurs, sometimes accompanied by chills and fever.

Skin discoloration

It is one of the most common symptoms of gangrene, which is manifested by the fact that the skin color of the necrotic area is no longer normal, which is obviously different from the surrounding normal tissues, and the skin discoloration varies from one type of gangrene to another.

Dry gangrene

The necrotic area loses more water, and the skin may be pale at the beginning.

With the progress of the disease, the skin in the necrotic area is dry, wrinkled and black.

The boundary with the surrounding normal tissue is clear, and the change of corruption is mild.

It is often accompanied by cold skin in the necrotic area.

Wet gangrene

The necrotic area has more water, and the putrefactive bacteria are easy to reproduce.

The skin in the necrotic area is more moist, often swollen and bluish-green, and the boundary with the surrounding normal tissue is not clear.

One or more blisters containing fluid may appear.

Gas gangrene

The skin in the necrotic area is obviously swollen and may be brown, red or purple.

The skin in the necrotic area produces a lot of gas, one or more gas-containing bumps may appear, and there is often a twisting sensation when pressed.

Numbness

Numbness of the skin in the necrotic area, decreased sensation, or even loss of sensation.

Pain

The necrotic area is often painful in different degrees.

In gas gangrene, the pain is often very severe.

Other symptoms

Foul odor

In wet gangrene (including gas gangrene), secretions may appear, often accompanied by a foul odor.

Complications

If gangrene is left untreated, complications such as disability, septicemia, and multi-organ dysfunction may occur.

Disability

In severe ischemia of the arteries of the limb with severe infection, the limb becomes necrotic, requiring amputation of that part of the limb, leading to disability.

Septicemia

If left untreated after gangrene, it may lead to severe infection and induce septicemia.

High fever, low blood pressure, increased heart rate, and impaired consciousness may occur.

Multi-organ dysfunction

Gangrene induced sepsis may further lead to multi-organ dysfunction.

Chest tightness, dyspnea, jaundice, oliguria or anuria may occur.

Consultation

Department

General Surgery

If symptoms such as fever, skin discoloration, numbness, pain, etc. appear, it is recommended to consult a doctor promptly.

Emergency Department

When symptoms such as high fever, low blood pressure, increased heart rate, and impaired consciousness occur, it is recommended to consult the Emergency Department or call the 120 emergency number immediately.

Preparation for medical treatment

Preparation for medical consultation: registration, preparation of documents, common problems

Tips

Wear loose-fitting clothes and pants to facilitate the doctor’s examination.

Wash your skin and keep the affected area clean before going to the doctor.

Preparation Checklist

Symptom list

Pay special attention to the time of onset of symptoms, special manifestations, etc.

Is there fever, chills, or chills?

Is there skin discoloration?

Is there any numbness of the skin, decreased sensation, or even loss of sensation?

Is there pain in the necrotic area?

Is there any discharge from the necrotic area? Is it accompanied by a foul odor?

List of medical history

Is there diabetes mellitus, AIDS?

Are there any vascular lesions such as atherosclerosis, acute arterial embolism, atherosclerotic occlusive disease of the lower extremities, thromboembolic vasculitis, deep vein thrombosis, etc.?

Are there any trauma, frostbite and surgery?

Have you been smoking or drinking heavily for a long time?

Any long-term use of immunosuppressants or glucocorticoids or received radiotherapy treatment?

Checklist

Test results of the last six months, which can be brought to the doctor’s office

Laboratory tests: routine blood tests, C-reactive protein, calcitoninogen, blood biochemistry, glycosylated hemoglobin, pathogen detection and drug sensitivity tests.

Imaging tests: ultrasonography, CT scan, magnetic resonance imaging (MRI), angiography.

Medication list

Medication used in the last 3 months, if available in a box or package, bring it with you to the doctor’s office

Antibiotics: penicillin, macrolides (e.g., Erythromycin Succinate, Madicillin), and nitroimidazole (e.g., Metronidazole, Tinidazole)

Diagnosis

Diagnosis is based on

Medical history

Having diabetes mellitus, AIDS.

Suffering from vascular lesions such as atherosclerosis, thrombosis, acute arterial embolism, atherosclerotic occlusion of the lower extremities, thromboembolic vasculitis, and deep vein thrombosis.

Have had trauma, frostbite and surgery.

Long-term heavy smoking and alcohol consumption.

Long-term use of immunocompromising agents or glucocorticoids or treatment with radiotherapy.

Clinical manifestations

The main symptoms of gangrene are fever, skin discoloration, numbness and pain.

Dry gangrene has dry and wrinkled skin in the necrotic area and decreased skin temperature.

In wet gangrene, the skin in the necrotic area is swollen, and secretions may appear, accompanied by a bad odor.

Gas gangrene may be accompanied by a subcutaneous twisting sensation when it is due to gas gangrene.

Laboratory examination

Blood tests, C-reactive protein (CRP) and calcitonin (PCT).

To understand the peripheral blood picture and to assess the extent of infection.

Elevated leukocytes and neutrophils are often seen, while some patients may have normal or even hypokalemic leukocytes.

Blood glucose and glycosylated hemoglobin

To know the current blood glucose and the blood glucose status in the previous 3 months.

Elevated blood glucose and glycosylated hemoglobin are often seen in diabetic patients.

Blood Biochemistry

Creatine kinase is found primarily in skeletal and cardiac muscle; an increase in creatine kinase suggests muscle damage.

Electrolytes (including potassium, sodium, calcium, etc.), if elevated or decreased, suggest electrolyte disorders.

Pathogen detection and drug sensitivity test

Pathogen culture of blood and enteric fistulae can be used to clarify the presence or absence of pathogen infection and the specific type of pathogen that is infected.

Drug sensitivity test can determine the degree of sensitivity of microorganisms to various antimicrobial drugs. According to the drug sensitivity test, appropriate drugs can be selected for treatment.

Imaging

Ultrasound

Wet gangrene is poorly demarcated from the surrounding normal tissues, and ultrasonography can be used to understand the location, extent, and degree of the lesion and to make a definitive diagnosis.

Ultrasonography can also evaluate blood flow status and other vascular conditions.

CT examination

CT examination is more accurate than ultrasound in the diagnosis of wet gangrene.

It is able to check whether there is gas accumulation at the lesion site and clearly diagnose gas gangrene.

However, it cannot assess the vascularization.

Magnetic resonance imaging (MRI)

Magnetic Resonance Imaging (MRI) provides information about the location and extent of the lesion, and assesses the presence and extent of vascular disease.

It is also able to examine tissues and internal organs for gas accumulation and diagnose gas gangrene.

Angiography

Impaired blood circulation is the underlying mechanism for the development of dry gangrene.

Angiography is effective in detecting abnormal blood flow and thus diagnosing dry gangrene.

Differential diagnosis

Cellulitis

Similarities: Both may cause fever, skin discoloration, pain, etc.

Differences

Dengue

Similarities: both can cause fever, skin discoloration, pain, and other symptoms.

Differences

Necrotizing fasciitis

Similarities: both can cause fever, skin discoloration, and pain.

Differences

Treatment

Treatment purpose: timely clean up the necrotic tissue, avoid gangrene deterioration, reduce the probability of amputation, prevent and control complications such as sepsis and multi-organ dysfunction.

Treatment principle: once diagnosed, urgent surgical treatment is needed, and antibiotics and other medications should be applied at the same time, which can be supplemented by general treatment and other treatments.

Surgery

debridement

Indications

Patients diagnosed with gangrene need timely and thorough debridement.

Purpose

Remove necrotic tissues and foreign matter, destroy the anaerobic environment suitable for the propagation of pathogens, and avoid the spread of infection.

At the same time, repair damaged blood vessels and restore blood supply.

Contraindication

Patients with uncorrected severe coagulation disorders.

Precautions

Leave the wound open and flush with oxidizing agent or apply wet compresses.

Blood creatine kinase (CK) level should be monitored after debridement. If creatine kinase (CK) increases, it suggests that muscle necrosis is still progressing, and the wound should be debrided again within 24 hours.

Amputation

Indications

The disease is severe and progresses rapidly, and it is impossible to clear the wound completely.

The whole limb has been involved or severely disfigured.

Contraindication

Those with serious coagulation disorders that have not been corrected.

The heart, brain, lungs, kidneys and other important organs have serious dysfunction and cannot tolerate surgery and anesthesia.

Precautions

The stump is open and not sutured.

Use oxidizing agent to flush and wet dress the wound after surgery.

Observe the dressing for oozing, change the dressing in time and clean the wound again if necessary.

Non-surgical treatment

Non-surgical treatment mainly consists of the application of antibiotics, hyperbaric oxygen, maintaining the stability of the internal environment, nutritional support and other symptomatic supportive treatment.

Application of antibiotics

It is recommended to choose effective antibiotics as early as possible and in sufficient quantity to control the infection rapidly, which can be chosen empirically at the initial stage, and according to the results of drug sensitivity test after improving the pathogen detection in time.

Commonly used drugs: penicillin, macrolides (e.g., erythromycin succinate, madicillin) and nitroimidazole (e.g., metronidazole, tinidazole).

Rash, nausea, vomiting, hepatic and renal impairment and other adverse reactions may occur.

Pay attention to monitor the changes of liver and kidney function during the use of drugs, need to be used in full dosage, full course of treatment, do not stop the drug.

Hyperbaric Oxygen Therapy

It can increase the oxygen content in the blood, improve the symptoms of ischemia and hypoxia in the tissues of necrotic area, and at the same time inhibit the growth of bacteria.

Patients with contraindications to hyperbaric oxygen therapy such as pneumothorax, pulmonary herniation, unstable blood pressure, etc. should not undergo it.

Maintaining the stability of the internal environment

Sodium chloride injection, dextrose and other rehydration fluids are often applied to replenish the lack of electrolytes, avoid water-electrolyte and acid-base imbalance, and maintain the stability of the internal environment.

Nutritional support

Strengthen nutrition, ensure sufficient daily calorie and nutrient intake, and main nutritional balance.

For those who have difficulty in feeding through mouth or gastrointestinal dysfunction, attention should be paid to strengthening intravenous nutritional support.

Prognosis

Cure

Overall prognosis

The prognosis of each type of gangrene varies. The prognosis of dry gangrene and wet gangrene is acceptable after active treatment of mild cases, but the prognosis of severe cases and gas gangrene is poor.

Prognosis of each type

Dry gangrene

Mild cases are curable with active treatment and have a favorable prognosis.

Severe cases are difficult to be cured and have a poor prognosis.

Wet gangrene

Most of the mild cases can be controlled after active treatment, and the prognosis is quite good.

Severe patients are prone to septicemia and have poor prognosis.

Gas gangrene

Most of them progress rapidly, with high mortality and amputation rate and poor prognosis.

Prognostic factors

The prognosis of gangrene is affected by a variety of factors, the following factors often lead to a poor prognosis.

Diabetes mellitus with unstable blood sugar.

Infection after trauma or surgery and untimely treatment.

Having vascular lesions such as atherosclerosis and thrombosis.

Smoking, obesity, low immunity.

Causes serious complications such as sepsis and multi-organ failure.

Harmfulness

It can cause serious complications such as sepsis, multi-organ failure and lead to death of the patient.

Amputation is required when the lesion is severe, which can lead to disability and affect the patient’s normal life and work.

Daily

Daily Management

Dietary management

It is recommended to eat food rich in high quality protein (e.g. lean meat, eggs, etc.) and vitamins (e.g. fresh fruits and vegetables) to ensure sufficient and balanced intake of nutrients and to promote disease recovery.

Life management

Quit smoking and drinking.

Pay attention to personal hygiene and keep the living environment clean and tidy to avoid secondary infection.

Regular work and rest, avoid exertion.

Disease monitoring

Patients with fever should learn to measure body temperature correctly and record daily temperature changes.

Pay attention to symptoms such as skin discoloration, numbness and pain.

Follow-up

During the recovery period, patients should have regular follow-up examinations so that the doctor can assess their condition and adjust the treatment plan.

The time for follow-up should be determined by the doctor according to the patient’s condition.

The checkups usually include routine blood tests, C-reactive protein, calcitoninogen, ultrasound, etc.

Prevention

Strict blood sugar control for diabetic patients.

Strengthen exercise, reasonable diet, avoid obesity.

Stop smoking and drinking.

Seek medical treatment in time after injury, and clean the wound thoroughly.

Those who suffer from atherosclerosis, acute arterial embolism, arteriosclerotic occlusion of the lower limbs, thromboembolic vasculitis and other vascular lesions should be treated in time to avoid aggravation.

People with low immunity should pay attention to the prevention and treatment of infection.