Gangrene – Causes, Symptoms and Treatment

What is Gangrene?

Gangrene is a serious condition that occurs when body tissue dies due to a lack of blood supply (ischemia) or as a result of a severe bacterial infection. Without adequate oxygen and nutrients, affected tissue becomes necrotic and begins to decay. Gangrene most frequently affects the feet, toes, fingers, and other extremities, but it can also involve internal organs in rare cases.

Causes

The primary causes of gangrene fall into two main categories:

• Impaired blood supply: Conditions such as atherosclerosis, peripheral arterial disease (PAD), diabetes mellitus, thrombosis, and embolism can restrict blood flow to tissues, causing them to die.
• Bacterial infection: Certain bacteria, especially anaerobic organisms such as Clostridium perfringens, can invade damaged tissue and cause a severe, life-threatening form known as gas gangrene.

Additional risk factors include:

• Diabetes mellitus (diabetic foot syndrome)
• Smoking
• Severe injuries or frostbite
• Weakened immune system
• Chronic kidney disease

Types of Gangrene

Dry Gangrene

Dry gangrene occurs when tissue dies gradually and dries out, eventually mummifying. It is most often caused by chronic circulatory insufficiency. The skin turns black or dark brown but remains relatively dry, and the risk of infection spreading is lower than in other forms.

Wet Gangrene

Wet gangrene develops when dead tissue becomes infected with bacteria, causing decomposition, swelling, and a foul odor. This form is life-threatening, as the infection can spread rapidly to surrounding healthy tissue and into the bloodstream (sepsis).

Gas Gangrene

Gas gangrene is a particularly severe and rapidly progressing form caused by anaerobic bacteria, primarily Clostridium perfringens. These bacteria produce gas bubbles within the tissue, which can be felt as a crackling sensation under the skin. Gas gangrene is a medical emergency requiring immediate treatment.

Fournier Gangrene

Fournier gangrene is a rare but dangerous form of necrotizing fasciitis affecting the genital and perineal region. It is caused by a mixed infection of multiple bacterial species and requires urgent surgical intervention.

Symptoms

The symptoms of gangrene vary depending on the type and location of the affected tissue. Common signs include:

• Skin discoloration (initially pale or reddish, later turning black or dark brown)
• Coldness, numbness, or pain in the affected area
• Swelling and foul odor (in wet gangrene)
• Crackling sensation under the skin (in gas gangrene)
• Fever, chills, and general malaise (in infectious forms)
• Visible tissue death (black, dry, or weeping areas)

Diagnosis

Gangrene is diagnosed through a combination of clinical assessment and diagnostic investigations:

• Clinical examination: Visual assessment of the affected tissue, including color, texture, and odor.
• Imaging: Ultrasound, X-ray, CT scan, or MRI to assess the extent of tissue involvement and detect gas in the tissue.
• Laboratory tests: Complete blood count, inflammatory markers (CRP, leukocytes), and blood cultures to identify bacterial pathogens.
• Tissue samples: Microbiological analysis to identify the causative organisms and guide antibiotic therapy.

Treatment

Treatment must be initiated promptly and is tailored to the underlying cause and severity of the condition:

Surgical Intervention

Surgical removal of dead tissue (debridement or necrosectomy) is the cornerstone of gangrene treatment. In severe cases, amputation of the affected limb may be necessary to prevent life-threatening spread of infection.

Antibiotics

In cases involving bacterial infection, intravenous antibiotics are administered to control and eliminate the infection. The choice of antibiotic is guided by laboratory identification of the responsible pathogen.

Vascular Surgery

When the underlying cause is impaired blood flow, vascular surgical procedures such as bypass surgery or balloon angioplasty (percutaneous transluminal angioplasty) may be performed to restore adequate circulation to the affected area.

Hyperbaric Oxygen Therapy

Hyperbaric oxygen therapy (treatment in a pressurized chamber) can be used as an adjunct in selected cases of gangrene. It improves the delivery of oxygen to compromised tissue and inhibits the growth of anaerobic bacteria.

Prevention

The following preventive measures can significantly reduce the risk of developing gangrene:

• Optimal management of diabetes mellitus and hypertension
• Cessation of smoking
• Regular foot care for patients with diabetes (prevention of diabetic foot syndrome)
• Prompt treatment of wounds and infections
• Regular medical monitoring for patients with known peripheral arterial disease

References

1. Herold, G. et al. - Internal Medicine. Self-published, Cologne 2023.
2. World Health Organization (WHO) - Peripheral Vascular Disease and Diabetes: Guidelines and Recommendations. WHO Press, Geneva 2022.
3. Lozano, F.S. et al. - Management of Gas Gangrene and Necrotizing Fasciitis. PubMed, NCBI, 2021. (PMID: 34021984)