Gangrene is characterized as the death of a body tissue that had occurred because of lack of blood flow. The presence of bacterial infection can also lead to gangrene.
Gangrene normally affects extremities, which include fingers, toes and limbs. In some cases, gangrene may also affect internal organs and muscles.
The risks of gangrene are high if the affected individual is suffering from a medical condition that can damage the blood vessels and distress the flow of blood. Medical conditions like atherosclerosis and diabetes are just some of disorders that can cause gangrene in the long run.
Antibiotics and surgical removal of dead tissues are some of the treatments for gangrene. The chances of recovery are better if gangrene is diagnosed early. 
Causes of Gangrene
The possible causes of gangrene are:
Loss of blood supply. The blood is responsible for providing oxygen and other required nutrients to feed the cells. If there is not enough supply of blood, the cells may not survive long, resulting to decaying of the tissue.
Infection. If the bacteria’s not treated, infection may occur and it may cause the tissue to diethen gangrene follows. 
Symptoms of Gangrene
Discoloration of the skin that had affected the four fingernails due to diabetes.
Symptoms of gangrene may include:
- Discoloration of skin. Depending on the kind of gangrene that affects an individual, the skin may have different hue. It may range from pale to bluish and black appearance.
- Extreme pain. Extreme pain is felt followed by numbness.
- Foul-smelling discharge. A discharge from the sore may have bad smell. 
If internal gangrene or gas gangrene affects you, additional symptoms are:
- Inflammation.The affected tissues are inflamed and can be very painful.
- Fever. A person maybe running a fever and generally feel sick.
If the bacterial infection that causes the gangrene had spread to other parts of the body, other symptoms are observed:
- Low blood pressure. Blood pressure may be low during the presence of gangrene.
- High fever. The person may have a high fever that is greater than 100.4 F.
- Increased heart rate. The patient may have increased heart rate and shortness of breath.
- Confusion. Extreme cases of gangrene may lead to confusion.
You need to call a doctor right away if one or more of these symptoms appear:
- Skin changes. The skin may have discoloration, blisters and lesions that do not heal.
- Foul smelling-discharge. If the discharge from the sore has bad smell.
- Pain. Sudden pain at the location of surgery.
Types of Gangrene
The six types of gangrene may include:
- Dry gangrene. This occurs when there is an obstruction of blood flow to the organ. Toes and fingers are often affected with this type of gangrene. Patients suffering with type 1 or type 2 diabetes are at high risks of developing dry gangrene.
- Wet gangrene. A kind of gangrene where the bacterial infection invades deeper issues after frostbites, burns and injuries. If not treated, wet gangrene can spread quickly which may lead to septic shock.
- Gas Gangrene. The cause of gas gangrene is Clostridium, a bacteria that is commonly found in the soil. There are at least twenty types of Clostridium that can result to gangrene. The problem with this type of bacteria is that they are considered anaerobic, meaning it can continue to grow even if there is no bacteria in the affected area. Among all the kinds of gangrene, this is considered the most fatal. It can cause rapid death to the person. 
- Internal gangrene. Internal gangrene occurs when the supply of blood is altered by pressure caused by another body organ. Example of this type is hernia.
- Noma. A type of gangrene that affects the face.
- Fournier’s gangrene. A rare type of gangrene that may occur in the genitals. Normally, this affects patients with blood sugar problems. 
The images shown above are samples of gas gangrene.
- To diagnose gangrene, several tests are needed. Some of the tests that are used include: 
- Imaging tests. Tests like X-ray, CT scan and MRI scan are used to see the body structures that are affected with gangrene. The severity of the condition is also determined through imaging tests.
- Blood test. High levels of white blood cells may be an indicator that there is a bacterial infection.
- Tissue gangrene. A sample of the skin may be removed from the affected area. The sample is then observed under a microscope to know if there are symptoms of cell death.
- Surgical procedure. This is often performed to know all the areas affected by gangrene.
Treatment of Gangrene
- Oftentimes, gangrene spread rapidly, it may need more than antibiotics to treat the condition. Some of the treatments of gangrene are: 
- Antibiotics. These are given to slow down the infection that causes gangrene.
- Debridement or amputation. Debridement is the process of cutting away the infected flesh to stop the infection from spreading. If the condition is severe, amputation is performed.
- Hyperbaric chamber. This is a sealed metal tank that can provide lots of oxygen under high pressure. The pressure that is placed into the tissues can prevent the spreading of the anaerobic bacteria.
Prevention of Gangrene
- Prevention plays a key role in gangrene. Here are the preventive steps to avoid gangrene:
- Foot Care. Foot is the common affected area for gangrene. If you have diabetes, it is important that you take special precaution of your feet. Have your feet checked regularly if you have diabetes. More check-ups are needed if you feel numbness in the foot or if you have history of foot ulcers.
- Avoid smoking. Tobacco smoking can block the flow of blood to your arteries. This may result to loss of blood supply to your lower limbs and extremities.
- Diet. Consuming foods that are high in fat can make your atherosclerosis worse. This can increase the risks of having gangrene. Try to avoid foods that contain too much saturated fats like processed meats, butter, lard, cream and biscuits and cakes.
- Alcohol. Avoid too much alcohol. For men, 3 to 4 units of alcohol are recommended and for women, 2 to 3 units of alcohol are enough.
- Exercise. Healthy exercise can normalize blood pressure and keep cholesterol levels at bay. This can prevent the damage of blood vessels. 
- http://bodyandhealth.canada.com/channel_condition_info_details.asp disease_id=160&channel_id=1020&relation_id=70907