Scattered blood blisters of different sizes often appear on the skin surface

Introduction The surface of the skin often has different sizes. The bloody vesicle is one of the symptoms of necrotizing fasciitis. The necrotizing of abdomal wall is a necrotic soft tissue infection that occurs in the abdominal wall. There are many kinds of pathogenic bacteria. The infection mainly involves the deep abdominal wall and superficial fascia, and it can also invade the skin, but it does not involve the muscle in the early stage. The disease can occur in any part of the abdominal wall (such as the anterior abdominal wall, lateral abdominal wall, groin area and posterior ventral wall), especially in abdominal trauma or surgical cutting (invasive) mouth and adjacent areas, but also for the buttocks, The infection of the perineum spreads, sometimes after a small stab wound or insect bite. Necrotizing fasciitis has a sharp onset, rapid progress, and a dangerous condition. Delayed diagnosis and treatment often lead to death.

Cause

The disease occurs in patients with low systemic immune function and small vascular disease. It can occur from newborns to the elderly over 60 years old, especially in elderly patients with diabetes, arteriosclerosis or malignant tumors. occur. The vast majority of secondary necrotizing fasciitis, there are causes or risk factors can be investigated; 15% to 18.2% of acute necrotizing fasciitis for unknown reasons, is an idiopathic infection.

1. Risk factors: A comprehensive literature reports that the risk factors associated with the disease are:

(1) Surgery and trauma: Occurred in abdominal surgery and trauma, especially after appendectomy, after colorectal surgery, abdominal injury with abdominal injury or abdominal wall injury, abdominal wall necrotizing fasciitis is more likely to occur. Casall et al reported that 12 cases of necrotizing fasciitis had a history of abdominal injury or abdominal surgery. Other surgical treatments (interventional procedures such as transjugular intrahepatic portosystemic shunt, surgical puncture, CT or ultrasound guided transabdominal abscess drainage, genitourinary device operation, topical herbal or AI fire cauterization, partial closure therapy, etc.) and sputum It is easy to induce the disease after swollen and scratched.

(2) Chronic diseases: diabetes, chronic renal failure, congenital leukopenia, etc., among which diabetes is the most common predisposing factor and risk factor.

(3) vascular diseases: arteriosclerosis, hypertension, peripheral vascular disease, and the like.

(4) Infectious diseases: infections of umbilical inflammation, abdominal infection (acute appendicitis, cholecystitis, peritonitis, etc.), syphilis, typhoid and the like.

(5) Malignant diseases: malignant tumors, leukemia, AIDS, etc.

(6) Old age, malnutrition, etc.

(7) Abuse or long-term use of glucocorticoids and immunosuppressive agents.

(8) chemotherapy, radiotherapy.

(9) Others: alcoholism, drug abuse, obesity, extravasation of urine, abnormal erection of the penis, excessive sexual intercourse, etc.

2. Pathogens:

There are many pathogenic bacteria causing necrotizing fasciitis, and most of them are normal flora of skin, intestine and urethra, especially related to the distribution of normal flora in the wound and the adjacent part of the incision. Among the common aerobic bacteria are Staphylococcus aureus, Group A streptococci, Escherichia coli, Enterococcus, Proteus, Pseudomonas, Klebsiella, etc.; common anaerobic bacteria have anaerobic streptococci, fragile Bacteroides, Clostridium, etc.; and more often caused by aerobic and anaerobic bacteria.

3. Susceptibility factors and pathogens:

In recent years, studies have found that different susceptibility factors are closely related to different pathogens. For example, post-traumatic infection, Clostridium is more common in pathogenic bacteria; infection occurs in diabetic patients, and pathogens are more susceptible to Bacteroides, Escherichia coli, and Staphylococcus aureus. Seen; infections occur in malignant tumors and immunosuppressed patients, with Pseudomonas, Escherichia coli and the like being the most common.

The pathogen of secondary abdominal necrotic fasciitis is mainly invaded by wounds, and is mostly mixed infection of bacteria. Ruose et al reported 16 cases of necrotizing fasciitis, and a total of 75 aerobic and anaerobic bacteria were cultured. Another scholar reported that 81 cases of bacteria produced 375 kinds of bacteria, and some patients can have up to 5~ 6 kinds. Some studies have shown that necrotizing fasciitis in all parts including the abdominal wall is most common in anaerobic and aerobic mixed infections, accounting for 68% of the total; secondly, anaerobic bacteria are the second. About 22%; aerobic bacteria cultured the least, only 10%. It is not difficult to see that anaerobic bacteria are the most common pathogens. The anaerobic rate of necrotizing fasciitis in the inguinal region and lower abdominal wall is the highest. The reason why many patients are negative for anaerobic culture may be related to problems such as collection, storage, transfer or cultivation of inoculation conditions, and/or non-compliance with experimental requirements.

The cause of idiopathic abdominal wall necrotizing fasciitis is unclear. Studies have shown that immune dysfunction, especially with malignant tumors, diabetes, arteriosclerosis, application of glucocorticoids and immunosuppressants, is closely related. The pathogen may be spread from other parts of the body to the affected area, such as from the teeth and throat and tonsils.

an examination

Related inspection

Urine routine blood glucose

Diagnosis is based on medical history, clinical signs, and examination results.

Basal cells that heal on the edge of the blood vessels begin to proliferate and migrate below the clot to the center of the wound, forming a single layer of epithelium covering the surface of the granulation tissue. When these cells meet each other, migration ceases and proliferates and differentiates into squamous epithelium. Healthy granulation tissue is important for epidermal regeneration because it provides the nutrients and growth factors needed for epithelial regeneration.

Differential diagnosis

1. Acute cellulitis: acute, diffuse, suppurative infection of subcutaneous, subfascial, intermuscular or deep loose connective tissue. Its clinical features are:

(1) The pathogenic bacteria are mainly hemolytic streptococcus, followed by Staphylococcus aureus and anaerobic bacteria.

(2) The image shows thickening of the subcutaneous tissue, increased density of adipose tissue, irregular reinforcement with cord-like, with or without subcutaneous and superficial fascial effusion, and the deep structure is normal.

(3) MRIT2-weighted images of necrotizing fasciitis showed that the deep fascia mostly showed a homogeneous dome-shaped high-signal area, while the uncomplicated infectious cellulitis had a T2-weighted image high signal compared with necrotizing fasciitis. The dome-shaped area is smaller and thinner, and the realm is unclear.

(4) Most cases of acute cellulitis can be cured by the use of antibiotics. The application of antibiotics in necrotizing fasciitis is not effective, but it requires more surgical treatment. When the operation is seen, the fascia pale necrosis is old cotton-like, and the toughness is poor. However, the muscles are not necrotic or affected, and the subcutaneous tissue is extensively damaged or pitted-like necrosis occurs, and the skin edge is sneaked.

Due to the pathogenic bacteria, pathological and clinical features of acute cellulitis, especially acute anaerobic bacteria (anaerobic streptococci, enterococci, Bacteroides, non-C. difficile, etc.) caused by acute cellulitis, lesions Necrosis can also occur in the cellulite, fascia and skin. It also has the characteristics of rapid spread and difficulty in limitation. The systemic symptoms are severe, the pus is stinky, the body is also pronounced, and the clinical manifestations of necrotizing fasciitis are very similar. Therefore, in most cases, it is difficult to identify clinically by physical examination and imaging examination. The purpose of the diagnosis is to determine the treatment plan. Although it may be possible to obtain a part of the identification basis by observing the effect of antibiotic treatment, the significance of the identification basis and the value of determining the treatment plan will be greatly reduced. Because of necrotizing fasciitis, early surgery is required. treatment. Therefore, for those suspected of necrotizing fasciitis, it is difficult to rule out the diagnosis of acute cellulitis. It is advisable to have early surgical treatment and to perform rapid frozen section examination by surgical biopsy to avoid delay in surgery and cause adverse consequences.

2. Gas gangrene: It is an acute infection caused by Clostridium, mainly in patients with extensive damage of muscle tissue. It occurs in the abdominal wall incision, which is characterized by edema, tension, paleness and rapid change around the wound. It is purple-black and has blister of different sizes, with extensive muscle necrosis; local and systemic symptoms are more serious than necrotizing fasciitis, and the disease progresses more rapidly; the smears of wound secretions are examined by Gram staining and found a large number of leathers. Blue staining positive for crude bacilli, decreased white blood cell count, and X-ray examination of gas between wound muscle groups.

3. Myositis and non-gangrene muscle necrosis: caused by soft tissue infection between muscles, characterized by: significant muscle involvement, pain, hyperesthesia, signs of systemic poisoning; creatinine phosphokinase in the blood, muscle fibers in the hematuria protein. CT showed that myositis was affected by muscle thickening, with or without heterogeneous enhancement, and muscle necrosis showed low-density areas or muscle breaks in the muscle-enhancing part. The T2-weighted image of MRI shows a high-signal region of the muscle spindle or round border clearing of the septic myositis lesion. Necrotizing fasciitis is secondary to muscle involvement, which is caused by primary fascia infection spreading to adjacent muscles. Imaging changes after fascia and soft tissue changes.

4. Other diseases: such as peritonitis.

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