Pneumocystis
Introduction
Introduction to Pneumocystis Pneumocystis is a chronic fungal disease of the lung caused by sporotrichumschenskii and is one of the most common deep mycosis diseases. basic knowledge The proportion of sickness: 0.0052% Susceptible people: no specific population Mode of infection: contact spread Complications: respiratory failure
Cause
Causes of pneumocystis
(1) Causes of the disease
S. sphaeroides belongs to the fungus phylum, the subgenus subgenus, the genus Trichosporium, the genus Trichosporium, the genus Phytophthora, the spore genus, is a biphasic fungus, is yeast type in the tissue, greenhouse culture It is a mycelial type.
(two) pathogenesis
Sporotrichosis mainly invades the skin, mucous membrane, and local lymphatic system, causing granulomatous damage. The early stage of lung disease is segmental distribution of bronchitis and bronchial pneumonia. The pathological changes are non-specific inflammatory changes, and the infiltrating inflammatory cells include neutral. Granulocytes, lymphocytes, plasma cells and a small number of epithelial cells, with the prolongation of the disease, the formation of chronic non-specific granuloma, leading to nodular pneumonia, the typical lesions from the inside to the outside: the central region is a chronic suppuration, mainly by neutral A small abscess composed of polynuclear white blood cells mixed with a few tissue cells and lymphocytes. There are a large number of epithelial cells and multinucleated giant cells around. The periphery is mainly lymphocytes and fibroblasts. The biopsy tissue sections were firstly treated with amylase at 37 ° C for 1 h and then stained with PAS. The round or oval bodies of 4 to 6 m in size can be seen, which are 4 to 8 m long in fashion. Cigar-shaped bodies and stellate bodies.
Prevention
Pneumocystis prevention
Sporotrichosis is a painless chronic disease, but if it is secondary to bacterial infection, it can cause sepsis and may die. Oral itraconazole is the first choice for treatment. It can replace long-term therapy with potassium iodide saturated solution. And often cause annoying toxic effects, intravenous amphotericin B can successfully treat most systemic infections
Complication
Pulmonary sporotosis complications Complications, respiratory failure
The course of the disease is other pulmonary fungal diseases, the onset is acute pneumonia or bronchitis with fever, cough, fatigue, etc., occurs in pneumonia, often misdiagnosed as tuberculosis, when it becomes chronic pneumonia, there are nodular lesions, thin-walled cavities, fibrosis And when the pleural effusion was taken seriously, the development of severe time and space increased to cause cheese-like necrosis and death.
Symptom
Symptoms of Pneumocystis sinensis Common symptoms Lymph node enlargement Difficulty in breathing Low heat and high heat Joint stiffness
Primary pneumocystis sinensis has three types of lesions: 1 bronchial pneumonia type: acute onset, like acute bacterial pneumonia, fever, cough, cough, fatigue, chest discomfort, pain, etc., sometimes local audible And wet voice. 2 Chronic cavities: Most of them are caused by pneumonia-type lesions. The nodular lesions in the lungs are fused, softened and necrotic. When necrosis breaks into the bronchus, localized thin-walled cavities are formed. The clinical patients are mainly low-heat or moderate. Fever, cough, cough, intermittent chest tightness, difficulty breathing, cyanosis or respiratory failure, or even death. 3 large lymph nodes: the main lesions are located in the hilar or mediastinal lymph nodes, most of the onset of insidious, accidental discovery of hilar or mediastinal shadow on the X-ray examination, some cases can be compressed by the enlarged lymph nodes, resulting in obstructive Lung lesions, coughing, coughing, varying degrees of fever and chest tightness, shortness of breath and so on.
Disseminated sporozoites, more common in diabetes, AIDS, long-term use of adrenal cortical hormones and immunosuppressive immunocompromised patients, in addition to extensive lung lesions, often accompanied by skin, bones, muscles and liver, kidney, Invasion of vital organs such as the brain, manifested as acute onset, high fever, severe fatigue, anorexia, weight loss, joint stiffness, musculoskeletal pain, jaundice, renal dysfunction or systemic failure, if not actively treated mostly after onset Death inside.
Examine
Examination of pneumocystis sclerotia
Pathogen examination
(1) Direct microscopy: take sputum, pus or biopsy tissue directly smear for Gram staining or PAS staining. Gram staining is positive in multinucleated cells or in large mononuclear cells or around cells. Shape or fusiform, small spores of 2 ~ 5m in diameter, occasionally hyphae and astral.
(2) Bacterial culture:
1 Glucose protein agar medium, at room temperature, there is bacterial growth, after 6 days, the colony is 0.5cm in diameter, showing a gray-brown membranous colony, slightly higher than the culture surface, and the colony reaches a diameter of 1.5 to 2.0 cm after 10 days. 3 belts with a membranous white halo at the edges. The middle belt is dark brown. The central bulge has wrinkles and unevenness. There are a few thorn-like hyphae in between. The colonies in 2 weeks are dark brown and the edges are sinking. When the materials are examined, the colonies are very sticky and difficult to remove. The diameter can be seen by microscopy. 2 m of elongated hyphae, conidial stalks grow from both sides of the hyphae, at right angles to the hyphae, and there are 3 to 5 groups of pear-shaped small conidia at the top (2 to 4) m × (2 ~ 6) m size, arranged in plum blossoms.
2 Cystine glucose blood agar or brain heart infusion glucose blood agar base, cultured at 37 ° C, showing white colonies, microscopic examination of round or fusiform spores, sometimes budding, Gram stain positive.
3 Electron microscopy showed round or oval spores and slender segregating mycelium spores. The electron density is high, the shape is radiation, the center is dark, the outer coat is attached to the outer side of the cell wall, the cell wall of the cell is medium electron density, and the cytoplasm is fine particles. Shape, inner mitochondria, endoplasmic reticulum and vacuoles, the budding mode is internal bud type, the mechanical break of hyphae during biphasic migration is hyphae fragmentation, and the formation of conidia is pleomorphic, hyphae phase, A pseudo-axis-shaped conidiophore can be seen and a plurality of terminal conidia are formed.
2. Immunological examination
(1) Skin test: 0.1 ml of 1:1000 vaccine was injected intradermally, and nodules were positive at 24 to 48 hours.
(2) Serological examination: serum precipitin and lectin positive (increased titer), positive complement binding test.
3. X-ray examination: different types of lesions, chest X-ray performance is different: 1 bronchial pneumonia type: patchy, nodular shadows with focal distribution, can also diffuse infiltration. 2 Chronic cavity type: the light-transmitting area appears in the original inflammatory infiltrating shadow, that is, the thin-walled cavity is formed. 3 lymph node enlargement: mainly for the hilar and/or mediastinal shadow enlargement and thickening, can be unilateral or bilateral, when accompanied by bronchial obstructive lesions, localized emphysema, or localized lung may occur Not Zhang.
Diagnosis
Diagnosis and identification of pneumocystis
According to the clinical and X-ray findings, combined with the results of pathogen examination, especially the culture examination, the diagnosis is not difficult, such as the association of nodular ulcer-like lesions on the skin, which supports the diagnosis of this disease.
Because the lungs in this disease are not characteristic, they need to be differentiated from pneumonia, tuberculosis, intrathoracic sarcoidosis, tumors and other intrapulmonary fungal diseases. If necessary, fiberoptic bronchoscopy or mediastinoscopy should be performed to obtain pathogens and diseases. Physical examination specimens, peripheral lesions, percutaneous lung puncture, bronchial biopsy or thoracoscopic acquisition of tissue, skin test has a certain diagnostic value, but serum immunological examination is not specific.
