Mycetoma

Introduction to foot swelling Mycetoma is a chronic pyogenic granulomatous disease of the skin and subcutaneous tissue with fistula formation and effusion of granules, caused by a variety of pathogenic bacteria. The disease occurs in tropical, humid and rainy regions and seasons. Asia's India, Africa's Sudan and Central America's Mexico are the most common. China has also reported that patients are more male than female, middle-aged, and barefoot working people. Most susceptible to infection. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: infection Complications: swelling

Cause of foot swelling

The pathogens are different in particle size, hardness and color. For example, Madura foot granules are generally 0.5mm in size, sterile sheath, hard and black, while P. sphaeroides granules are 1mm large and have a sheath. Soft, yellowish white; Madura actinomycetes are generally larger than 0.5mm, soft, with bacterial sheath, yellowish white, while the Slug's bacteria bacteria 0.5mm large, can have fungal sheath, soft, white; only white The granules of the pedicure are red, and the above pathogenic bacteria are present in the soil except for the actinomycetes, and are also pathogenic bacteria of the plants.

(1) Causes of the disease

The main pathogens are Nocardia and Foot bacterium, and according to the different pathogens, the foot edema is divided into two categories:

Eumycetic mycetoma: pathogens including white granules forming a white granule, Cladosporium fulvum, Phytophthora sinensis, Aspergillus nidulans, Aspergillus flavus, Fusarium solani, Rosatoxin , Pseudomonas aeruginosa (synonymous spores), and the formation of black particles of Curvularia lunata, Klebsiella pneumoniae, Pseudomonas, Senegal globular bacteria, Tompkins globular bacteria , Actinomyces fuliginea, Phyllostachys praecox, R. serrata and C. sinensis, actinomycetic mycetoma ( Actinomycetic mycetoma) from Actinobacter sp. (8 cases caused by (Nocardia brasilliensis) and actinomadura madurae).

(two) pathogenesis

The disease is often inoculated into the body after trauma, the infection begins with papules or deep nodules, the nodules gradually expand into a mass, the purulent formation of the fistula, the pus discharge from the body, the damage can heal, dissipate, and later clinical symptoms appear repeatedly. It is caused by fungi or actinomycetes in the natural environment invading the deep or subcutaneous tissues of the dermis. Chronic suppurative granuloma characterized by bacterial-coated particles, purulent granuloma with fistula of the skin and subcutaneous tissue, typical Granules, surrounded by neutrophils and other inflammatory cells.

Foot swelling prevention

Because this disease is caused by the invasion of skin caused by pathological bacteria in the field, it is necessary to improve the awareness of self-protection, try to avoid trauma and contact with decaying substances, and should be debrided in time when there is trauma. For smaller lesions, it should be as early as possible. Treatment can avoid aggravation.

Foot complication Complications swelling

It can spread and destroy adjacent muscles, tendons, fascia and bones in months or even years. There are no signs of systemic dissemination or signs of systemic infection. Eventually the muscles are thin, deformed and damaged by tissue, making the affected limb unusable. In the late stage of infection, the affected limbs are deformed and swollen to form a rod-like cystic mass with multiple interconnected drainage sinus and fistulas, and a thick or serum bloody exudate containing characteristic particles is discharged.

Symptoms of foot edema common symptoms periostitis chicken pustule abscess skin adhesion osteolysis papule osteoporosis

The disease is more common in middle-aged people, more men than women, occurs in the exposed parts of the limbs, especially hands, feet are common, the course of the disease is chronic, often history of trauma, skin lesions begin with dark red papules, nodules, pus The blister gradually merges into a mass and multiple abscesses, adheres to the skin, and the surface is dark red. After the abscess is broken, the fistula is formed. The drainage of the fistula is purulent and bloody. When the subcutaneous tissue is destroyed, the fatty fluid flows out, and the drainage is mixed. Particles and granules may be yellow, white or black depending on the pathogen. The size varies from 0.3 to 4 m in diameter. Over time, some old skin lesions are scarred, and new nodules appear continuously, forming nodules, masses, and fistulas. The scar is also covered with affected limbs, and the abscess invades adjacent structures including muscles, tendons, fascia, bones, causing periostitis, osteomyelitis and osteonecrosis, leading to severe deformities and disability.

The condition progresses slowly and generally does not affect the whole body, but some pathogens can spread through lymph and blood, involving the internal organs.

Foot swollen examination

Bacterial culture can determine the pathogen species.

Pathogen inspection:

1. Direct microscopic examination After washing the granules with physiological saline, put them on a glass slide and add 1 drop of 20% sodium hydroxide. Under the microscope, the agglomerates are intertwined with hyphae and spores. The hyphae are wide and separated. About 2 ~ 5m, there are many swollen cells at the end of the hyphae and the periphery of the particles, and some thick-walled spores can be seen in the granules. If there is no broad hyphae, it may be caused by actinomycetes.

2. Culture on sandcastle agar containing antibiotics, and then identify the strains. It is important to identify the strains due to different treatment and prognosis.

3. Imaging examination: X-ray can show osteonecrosis, osteoporosis and small bone fusion when bone is involved, localized bone hypertrophy and osteolysis, and extensive invasive shadows in pulmonary infection.

4. Histopathology: purulent granuloma with fistula of skin and subcutaneous tissue, typical particles, neutrophils and other inflammatory cells infiltrated around the particles, and a few cases can also show degenerative myositis, lymphangitis, periostitis , changes in osteolysis and bone fiber degeneration.

Diagnosis and identification of foot bacteria

diagnosis

According to the typical clinical manifestations, the particles are found in the pus or tissue and the structure is examined microscopically, or the particles are found in the histopathology, and the diagnosis can be made. The bacterial culture can determine the pathogen species, and some pathogens of the disease can also cause other fungi. The disease is such as dark filamentous mildew or actinomycosis, so it can only be diagnosed as a foot swelling if it meets the clinical characteristics of the disease.

1. Observe the specimens taken from the pus in the deep drainage of the fistula, or scrape the tissue inside the lesion and the biopsy material, and observe the particles in a sterile dish. The particles are round or irregular, and the pathogens are different. There are also differences in particle size, texture, and color.

2. Pathogen examination.

3. Imaging examination of the bone involvement X-ray can show osteonecrosis, osteoporosis and small bone fusion, localized bone hypertrophy and osteolysis, lung infection can be characterized by a wide range of invasive shadows.

4. Histopathology

Differential diagnosis

1. Sickle skin tuberculosis: a plaque-like proliferative plaque with clear boundary, and histopathology shows a tuberculous granuloma-like structure in the dermis.

2. Sporotrichosis: mostly a nodule arranged along a lymphatic vessel, or a single plaque nodule, and the fungal culture is a sporozoite growth.

3. Coloring fungal disease: no fistula formation and pus with particles, fungal culture for dark fungus growth.

In addition, it is differentiated from diseases with sinus formation, such as staphylococcal disease, malignant tumors such as squamous cell carcinoma, chondrosarcoma and Kaposi's sarcoma, skin tuberculosis, and elephantiasis.

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