Necrosis

Necrosis refers to the death of cells or tissue in a living organism, triggered by oxygen deficiency, injuries or infections. In dogs, necrosis can affect various tissues, such as skin, muscles, organs or bones, and poses a serious threat to health. Untreated necrosis can spread and lead to infections, tissue decay and even systemic disease. Rapid veterinary diagnosis and treatment are therefore essential.

What is Necrosis?

Necrosis describes the death of cells and tissue that is no longer sufficiently supplied with oxygen or nutrients. Necrotic cells lose their ability to perform normal functions and break down. This causes an inflammatory reaction in the surrounding tissue, which can trigger infections or toxic reactions in the body. Depending on the cause and affected tissue, severity and manifestation vary considerably.

Causes of Necrosis in Dogs

Necrosis in dogs has many possible causes, which are often due to circulatory disorders, injuries or infections. The most common causes are:

1. Trauma or injuries: Injuries that cause a restriction of blood supply, such as crush injuries, bone fractures or deep wounds, can trigger necrosis in the affected tissue. There is a high risk particularly with wounds that heal poorly or are infected.
2. Infections: Bacterial infections, especially by aggressive pathogens such as Clostridia or Staphylococci, can trigger necrotic processes. Such bacteria often produce toxins that destroy tissue and prevent the healing process.
   Gangrene, a severe form of tissue necrosis, frequently occurs with untreated infections.
3. Oxygen deficiency (hypoxia): Tissue that is not sufficiently supplied with oxygen over a prolonged period begins to die. The cause can be blocked blood flow or vascular damage, as seen in thromboses, embolisms or severe burns.
4. Autoimmune diseases: In rare cases, autoimmune diseases, in which the immune system attacks its own cells, can cause necrosis in affected tissues.
5. Chemical or toxic effects: Contact with chemical substances or poisons can lead to necrosis, particularly if the substances damage cell membranes or block blood circulation.
6. Tumours: Malignant tumours can impair the blood supply of the surrounding tissue through their growth and cause necrosis both in the tumour itself and in the adjacent tissue.

Types of Necrosis

Depending on the underlying causes and the affected tissue, various forms of necrosis occur:

1. Coagulation necrosis: Common in ischaemia, when blood supply is interrupted. The tissue becomes firm and dry but retains its original shape. Coagulation necrosis often occurs in muscles and organs such as the liver or kidneys.
2. Liquefactive necrosis: Leads to liquefaction of the tissue and frequently occurs in infections or in the brain. Through enzymatic decomposition, the affected tissue is converted into a liquid mass.
3. Gangrenous necrosis: Gangrene develops when necrosis is exacerbated by bacterial infections, particularly by bacteria that thrive in poorly perfused or dead tissue. This form is particularly dangerous and often occurs in the extremities or in the intestine.
4. Fat necrosis: Affects adipose tissue and can be triggered by pancreatitis (inflammation of the pancreas) or injuries to adipose tissue. The affected tissue undergoes hardening and calcification.
5. Tumour necrosis: Rapidly growing malignant tumours can displace surrounding tissue and reduce its blood supply, leading to necrosis.

Symptoms of Necrosis in Dogs

The symptoms depend heavily on which tissue is affected and how advanced the necrotic process is. The most common signs include:

• Swelling and hardening of the affected tissue.
• Discolouration of the skin or the affected area, often blue, black or grey.
• Pain sensitivity in the early stages; later, the area may become numb due to tissue breakdown.
• Discharge of fluid, purulent secretions or an unpleasant odour in the case of infected necrosis.
• Lethargy and fever, if the necrosis leads to a systemic infection (sepsis).
• Impaired wound healing: Open wounds that do not close or remain constantly inflamed.

In the case of internal organs such as the liver, kidneys or intestines, symptoms such as vomiting, diarrhoea, abdominal pain and weight loss may occur.

Diagnosis of Necrosis

To make a diagnosis, the vet combines a clinical examination with targeted diagnostic tests:

1. Clinical examination: Visible necrosis on the skin and limbs can often be classified based on their appearance. The vet checks whether the affected area is swollen, discoloured or sensitive to pressure.
2. Imaging techniques: For internal necrosis, for example in organs, X-rays, ultrasound or MRI are used to determine the extent of the damage.
3. Blood tests: Blood tests provide a general health profile of the dog and can indicate infections or organ failure.
4. Tissue sample (biopsy): A biopsy can be taken to determine the cause of the necrosis and clarify whether an infection, a tumour or another underlying disease is present.

Treatment of Necrosis in Dogs

The treatment aims to remove the dead tissue, combat infections and stop further spread. Common methods include:

1. Surgical removal: In many cases, the necrotic tissue must be surgically removed so that healing can begin and further damage to the surrounding tissue can be prevented. In severe cases such as gangrene, an amputation may be necessary to save the dog’s life.
2. Antibiotics: If the necrosis is caused by an infection or has become infected, antibiotics are prescribed to combat the infection and prevent sepsis.
3. Wound care: For superficial necrosis, careful wound care is paramount, including regular cleaning and dressing of the affected areas, as well as the application of antimicrobial ointments.
4. Oxygen therapy: In certain cases, hyperbaric oxygen therapy can be used to accelerate the healing process. The increased oxygen content promotes wound healing and counteracts bacterial infections that thrive in necrotic tissue.
5. Painkillers and supportive therapy: To support the dog during healing, painkillers, anti-inflammatories and fluid therapies can be administered.

Prevention of Necrosis in Dogs

Preventively, it is mainly about rapid wound healing and healthy blood circulation:

• Wounds should be monitored and cleaned regularly to avoid infections.
• Dogs suffering from circulatory disorders or diabetes require careful monitoring, as they are more susceptible to tissue necrosis.
• Regular veterinary examinations help to detect and treat infections, tumours or other health problems at an early stage.

Conclusion

Necrosis in dogs is a serious condition, where prompt veterinary treatment is crucial to stop tissue breakdown and prevent secondary infections. Owners who notice signs of tissue changes, pain or infection should consult a vet without delay.