Necrotizing fasciitis: a pathophysiology paper

Necrotizing fasciitis: a pathophysiology paper
Background
Necrotizing fasciitis mostly affects the integumentary system, which is made up of the skin and all of its parts. Under the skin, there are sheets of flexible tissue that make up the subcutaneous fascia. This tissue’s main job is to stabilize, give power, separate muscles, and keep blood vessels open. There are different ways to classify fascia, such as surface, deep, visceral, and based on where it is in the body (Tobin, 2011). The superficial fascia is right under the skin and the superficial fat layer. This fascial is made up of loosely packed collagen and elastic fibers that are linked together. Deep fascia, on the other hand, covers the bones, muscles, nerves, and blood vessels. The deep fascia is further split into the aponeurotic fascia and the epimysial fascia, which wraps around the skeletal muscles.

Fascia supports the tissues around it and moves mechanical stress caused by forces outside the body. When the fascia is healthy, it is loose, wavy, and flexible. When the fascia is hurt or inflamed, these qualities are gone. During these activities, the fascial layers tighten and make it hard for the layers underneath to move, which causes pain and less blood flow. Sensory nerves, such as the nociceptors, proprioceptors, mechanoreceptors, thermoreceptors, and chemoreceptors, are found in the fascia (Tobin, 2011). Between the thick and loose adipose tissue, there is a complex network of blood vessels that bring blood to the skin. Necrotizing fasciitis is a rare disease that causes the muscles, subcutaneous fat, and blood vessels that make up the fascia to become inflamed and die. The disease breaks down the subcutaneous and deep tissue, as well as the blood vessels around them, causing ischemia. The usual treatment for the disease is to remove the dead tissue as soon as possible.

A Brief Look at the Illness

Skin diseases are common in modern medicine, and more than half of all adults have at least one. Even though most of these skin diseases are common and easy to treat, there are a few that are rare and could be deadly. Necrotizing fasciitis (NF) is a rare skin disease that can kill or make people very sick if it is not treated. The disease affects soft organs and destroys both the skin and the tissue under the skin. Necrotizing fasciitis is often called a “flesh-eating disease,” and it is thought that group A Streptococcus is the reason. Studies show that only 15% to 34% of cases are correctly identified (Tessier et al., 2019). This is because the disease is similar to cellulitis and other skin infections. Joseph Jones, a doctor in the Confederate army, was the first person to report the disease in 1883. Children rarely get this disease, and most people who get it are between the ages of 38 and 44. Understanding how the disease shows up and how it works is important because early detection and aggressive surgical treatment are the only ways to reduce death and disability.

How the disease happens and why

Necrotizing fasciitis is a skin disease that gets worse over time and quickly spreads through the fascial planes, destroying a lot of tissue. Necrotizing fasciitis usually starts the same way as other skin diseases, with redness, reddish-purple, or blue-gray skin. At this point, the skin is tender and hurts when touched. After a few days of being infected, bullae form and gangrene can be seen. Since tissues and blood vessels around the impacted area die and break down, the surface is less painful when it gets infected again. But the infection can quickly spread throughout the body, which can lead to signs like fever, fast heart rate, and sepsis (Tessier et al., 2019). At the cellular level, the following method can be used to explain how these things happen.

Microbes can get into the subcutaneous tissue when it is hurt or when the intestines or urogenital organs are punctured. The germs then move through the subcutaneous tissue and release endotoxins, which have been shown to kill tissue and cause diseases that affect the whole body. Depending on the kind of microbial invasion, skin diseases can spread very quickly, sometimes in just a few hours. Aside from endotoxins, these bacteria also make exotoxins, which speed up the infection process. For example, the clostridium species makes alpha toxins that hurt or kill a lot of tissue and cause the heart and lungs to stop working. The M1 and M3 exotoxins are released by the staphylococcus aureus and streptococcus species (Tessier et al., 2019). When the toxins are released, they work through different ways to kill tissue and damage the heart. It has been seen that the M proteins make it easier for bacteria to stick to damaged tissue and avoid being eaten by white blood cells. Other toxins, like A and B, hurt the endothelium. This causes the integrity of the blood vessels to break down, which causes tissue swelling and less blood flow to the capillaries.

When poisons get into the body’s tissues, they cause CD4 cells and macrophages to make tumor necrosis factor (TNF) and interleukins 1 and 6. These cytokines are what start the inflammatory process, which is deadly for the person who is affected. Most of the time, the disease gets worse and leads to shock, organ failure in multiple systems, and death. In particular, the alpha tumor necrosis factor damages the endothelium of the blood vessels, while the T cells turn on the complement system, which causes clotting and thrombosis, which lead to ischemia of the tissue. Studies show that the complex activation of the immune system makes it harder for the polymorphonuclear cells to destroy bacteria through oxidation. This means that antibiotics can’t be used to treat the sickness (Sarani et al., 2009). The only way to treat the sickness is through surgery, because antibiotics don’t do much to stop the bacteria from spreading.

Necrotizing fasciitis is caused by blocked blood vessels that reach the skin. This is the disease’s most important symptom. Before skin changes can be seen, there must be clotting of the small blood vessels under the skin. Because of the infected dermal capillaries under the skin, the infection is generally worse than expected when it is first diagnosed. (Sarani et al., 2009) say that thrombosis is caused by higher interstitial pressure, platelet-neutrophil plugging, and hypercoagulation, all of which lead to less blood flow to the nearby tissues. Most of the time, the surface skin and deeper muscles are protected until the late stages, when lesions develop liquefactive necrosis at all levels of tissue.

How to Find and Treat the Disease

Clinical Manifestation

Necrotizing fasciitis increases the risk of death and illness, but early identification and the right treatment can reduce these risks. NF is hard to identify because its symptoms aren’t always clear and its course can change over time. But classic signs and the use of approved diagnostic tests can make it much easier to figure out what’s wrong and treat it. Taking a patient’s history and doing a physical check are the first steps in making a correct diagnosis. Pain, nervousness, and sweating are common signs of necrotizing soft tissue injuries that get worse quickly (Sun & Xie, 2015). During the history, the patient might say that they were hurt or their skin broke down a few hours or days before the symptoms started.

NF and other accidents that cause soft tissue to die, like cellulitis, are diagnosed in the same way. For example, both diseases are marked by pain and swelling. But NF causes a lot of pain that doesn’t make sense based on what the body shows. Due to the growth of the infection under the skin, a person with a small blister or bullae may feel more pain than usual. In cellulitis, the infection starts where the dermis and surface fascia meet, but in NF, the infection starts where the subcutaneous fat and deep fascia meet. At first, the epidermis and dermis are not affected, and a lack of redness or swelling can cause less experienced doctors to make the wrong diagnosis.

Changes in the skin are rare in NF unless the disease is very far along. Because the disease spreads under the skin, the skin always looks fine in the early stages. The rate at which the disease gets worse can vary from getting sick to quickly getting worse and dying within hours. Bullae, or blisters, can be a sign of NF, but they usually show up after tissue hypoxia or a lot of clots in the blood vessels underneath. Also, people in the late stages of NF will show signs of shock, failure of multiple organ systems, and toxic shock syndrome. Tachypnea, tachycardia, confusion, coagulopathy, and thrombocytopenia are all things that these people have in common.

The cause of NF also affects how it shows up in the body. For example, fulminant NF, which is caused by the bacteria vibrio fulfinicus, is linked to heart failure before tissue damage shows up. It has been seen that the bacteria cause fast inflammation of the whole body, which shuts down the heart and lungs before the skin changes. Cardiovascular breakdown is caused by the release of toxins made by bacteria and cytokines made by the body itself. It is suggested that surgery debridement be done once the patient has been brought back to life and is stable. Due to how hard it is to diagnose NF and how important it is to treat it well, the disease shows itself in three forms. In the first stage, the skin gets red, feels sore, swells up, and gets hot. In the second stage, the skin shows signs like bullae, boils, and changes in texture. In the third stage of NF, there are blood blisters, crepitus, skin death, and gangrene.

Diagnostic Measures

Necrotizing fasciitis is mostly diagnosed based on how it looks, and the gold standard is to look at the tissue. But NF can only be diagnosed by a doctor after a set of tests. Radiographic imaging tests can be used to find out if a soft tissue injury has caused it to die. Even though it is not accurate, a plain X-ray can show subcutaneous gas or soft tissue swelling. A CT scan can show signs of inflammation, such as swelling, thickness, and the formation of gas. Most of the time, these imaging tests find fluid and gas buildup in the tissues under the skin, so they are not clear. With the use of contrast, an MRI can be more specific than a CT scan because it shows signs that are very strong in the deep fascia and on the edges.

The second way to figure out if someone has NF is to do tests in a lab and use a marking system to grade the results. Hematological changes like leukocytosis, coagulopathy, thrombocytopenia, and anemia are all consistent with septic processes. The results of biochemistry can show that blood creatinine kinase is high, which is a sign of myonecrosis. Second, there is hypocalcemia because of fat decomposition and the buildup of calcium in the dead tissues. When there is inflammation and necrosis, C-reactive proteins (CRP) may grow. (Tessier et al., 2019) say that germs are found in the blood of about 60% of the patients. The best test is a tissue sample, but percutaneous needle aspiration is sometimes used.

Necrotizing fasciitis can kill, so any illness that spreads quickly through soft tissue needs to be treated quickly. The Laboratory Risk Indicator Infection Score (LRINEC) was made in 2004 to help doctors figure out how to diagnose NF and other soft tissue injuries. CRP, creatinine, hemoglobin, white cell count, sodium, and serum glucose are the most important ways to tell the difference between necrotizing and non-necrotizing soft-tissue diseases. Each of the six predictors has its own score, and the LRINEC score is made up of the scores from each of the discovered factors. A total score of more than 6 has a 92% chance of being right and a 96% chance of being wrong. Tessier et al. (2019) found that a number of 8 is a strong indicator of NF, with a positive predictive value of 93.4%.

Treatment

Early identification, aggressive resuscitation, surgical debridement, the use of antibiotics, and supportive care are all important ways to treat NF. The goal of resuscitation is to get the blood flow back to normal, especially in people with septic shock. To avoid nosocomial infections, these people need to be fed well while being cared for. Surgical debridement is the most important treatment for NF because it gets rid of the source of the infection and poisons (Sun & Xie, 2015). Debridement also makes sure that medicines work when they are used later. When the infection is broad, it may be necessary to do multiple debridements to make sure that the infection is completely under control. The best way to treat NF is to use medicines that kill specific microorganisms. (Sun & Xie, 2015) Some drugs that are often used are tazocin, piperacillin, clindamycin, and carbapenems. The use of hyperbaric oxygen and IV antibody therapy are also suggested as ways to treat the disease.

Case Study in a Clinic

A man who was 35 years old went to the emergency room because his right lower leg was swollen. The patient said that his knee had been hurt two weeks before he was admitted. On inspection, the limb was a little sore, and it was swollen and warm to the touch. The primary care doctor thought that the patient had cellulitis and sent them home with medicines. The patient was brought back to the hospital the next day, unable to walk, and limb swelling was seen getting worse. More tests showed that the person had constipation, crepitations in both lungs, multiple small cuts that were getting worse, and numbness in some part of the lower leg. MRI was used to make a quick clinical diagnosis, but the patient died before any further care could be given.

From what you’ve read, which stage of NF was the patient in?
Stage 1
Stage 2
Stage 3
Stage 4

Answer: Stage 3 is the right answer. Signs of stage 3 NF include crepitus, skin necrosis, and gangrene.

What is the best way to find soft tissue diseases that have started to die?
CT scans on a computer
Magnetic resonance imaging
Checking out in the lab
Ultrasonography

Magnetic resonance imaging (MRI) is most often used because it has the best soft tissue contrast and sensitivity for finding soft tissue fluid, as well as better spatial precision and the ability to work in more than one plane.

The most accurate things to say about the diagnosis of NF are:
Fine needle suction is the best way to find out what’s wrong.
Tissue biopsy is the best way to find out what’s wrong.
For diagnosing NF, you should use the LRINEC scoring method and an MRI.
When there is a strong clinical diagnosis of NF, CT imaging can help.
All of these

Answer: A tissue sample is the best way to find out what’s wrong. The best way to tell if someone has NF is to take a tissue sample after surgical exploration. The biopsy will show that the fascia doesn’t have the standard amount of resistance, that the dermis is swollen, and that there are polymorphonuclear cells in the dermis.

References

Sarani, B., Strong, M., Pascual, J., & Schwab, C. W. (2009). Necrotizing fasciitis: Current concepts and review of the literature. Journal of the American College of Surgeons, 208(2), 279-288. DOI: 10.1016/j.jamcollsurg.2008.10.032

Sun, X., & Xie, T. (2015). Management of necrotizing fasciitis and its surgical aspects. The International Journal of Lower Extremity Wounds, 14(4), 328-334. https://doi.org/10.1177/1534734615606522

Tessier, J. M., Sanders, J., Sartelli, M., Ulrych, J., De Simone, B., Grabowski, J., … & Duane, T. M. (2019). Necrotizing soft tissue infections: A focused review of pathophysiology, diagnosis, operative management, antimicrobial therapy, and pediatrics. Surgical Infections, 21(2), 81-93. https://doi.org/10.1089/sur.2019.219

Tobin, D. J. (2011). The anatomy and physiology of the skin. Springer Publishing Company, New York, New York, USA.

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