Pneumocystis carinii pneumonia

Introduction to Pneumocystis carinii pneumonia Pneumocystis carinii pneumonia, also known as Pneumocystis carinii pneumonia, is an interstitial plasma cell pneumonia caused by Pneumocystis carinii and is a conditional pulmonary infection. The disease was only seen in premature infants and malnourished infants before the 1950s. With the application of immunosuppressive agents in the past 10 years, the popularity of cancer chemotherapy, especially the emergence of AIDS, has increased significantly, and has become the most common AIDS patients. The chance of infection and the leading cause of death. basic knowledge Sickness ratio: 0.05% Susceptible people: good for children Mode of infection: non-infectious Complications: respiratory failure

Causes of Pneumocystis carinii pneumonia

(1) Causes of the disease

Pneumocystis carinii is a single-celled organism characterized by both protozoa and fungi. Pneumocystis carinii is mainly composed of cysts and trophozoites. The trophozoites are variable polymorphs with fine feet and pseudopods. Similar to amoeba, the capsule is round and has a diameter of 4-6 m. The cystic wall contains intracapsular bodies (or sporozoites). In the fully mature capsule, there are generally 8 capsules. Encapsulation is an important diagnostic form. The parasitic part of Pneumocystis carinii is confined to the alveolar cavity. The mature cyst ruptures after entering the alveoli. The cystic body becomes a trophozoite after decapsulation. The trophozoite is close to the alveolar epithelium and proliferate. The cyst is mostly located in the middle of the alveoli.

(two) pathogenesis

Pneumocystis is a low pathogenicity, slow-growing parasitic protozoa. The healthy host has the ability to resist and only form a recessive infection. Impaired cellular immunity is the main predisposing factor of the host, such as infant malnutrition, innate immunity. Defective children, malignant tumors, organ transplantation or immunosuppressive therapy and AIDS patients, the incidence of AIDS patients up to 80% to 90%, when T cell immune function is inhibited, parasitic alveolar parasites can multiply, Epithelial cells cause direct toxin damage, causing type I epithelial desquamative alveolitis, alveolar septum with plasma cells, mononuclear cell infiltration, alveolar epithelial hyperplasia, thickening, filled with eosinophilic foam-like substances and protein-like infiltration In the case of serious cases, there are extensive interstitial and alveolar edema. The alveolar cavity is filled with inflammatory cells, protein-like exudates and worms, which hinder gas exchange and produce clinical symptoms.

Pneumocystis carinii pneumonia prevention

Pay attention to the isolation of immunosuppressors from patients, prevent cross-infection, and pay close attention to high-risk groups. For patients with the risk of occurrence of K. cerevisiae, drug prevention can effectively prevent potential infections from turning into clinical diseases and recurrence after treatment. Generally, TMP 5mg/kg, SMZ 25mg/kg, orally three times a day or three times a week can be used as a second-line preventive medication.

Pneumocystis carinii pneumonia complications Complications, respiratory failure

100% died of respiratory failure without treatment.

Symptoms of Pneumocystis carinii pneumonia Common symptoms Low fever High fever Dyspnea Diarrhea Capsing liver splenomegaly Dry cough hair sputum Respiratory failure Lymph node enlargement

The incubation period is 4 to 8 weeks, and AIDS patients are longer, with an average of 6 weeks, or even up to 1 year.

1. Epidemic infant type (classic)

Popular in baby-care institutions, the onset is slow, first fearful, diarrhea, low fever, gradually coughing, difficulty breathing, progressive progressive exacerbations, untreated mortality rate of 20% to 50%.

2. Children-Adult (Modern)

The onset is more urgent, the beginning of dry cough, rapid emergence of high fever, shortness of breath, cyanosis, lung signs are rare, may have hepatosplenomegaly, from onset to diagnosis, typically 1 to 2 weeks, receiving large doses of hormone therapy The disease course is short and can die in 4-8 days. The course of AIDS patients is slow, gradual, first weight loss, night sweats, swollen lymph nodes, general malaise, and then the above respiratory symptoms can last for weeks to months. Treatment of 100% died of respiratory failure, the symptoms of this disease is serious, but the lungs are less signs, most patients have no abnormal auscultation of the lungs, some patients can smell and scattered in the wet voice.

Examination of Pneumocystis carinii pneumonia

Hematological examination

Leukocytes are elevated or normal, associated with underlying diseases, eosinophils are slightly elevated, and serum lactate dehydrogenase is often increased.

2. Blood gas and lung function

Arterial blood gases often have hypoxemia and respiratory alkalosis, pulmonary function tests reduce lung capacity, and lung diffusion function (DLCO) is less than 70% estimated.

3. Pathogen examination

, bronchoalveolar lavage fluid, specific staining by fiberoptic bronchoscopy lung biopsy such as Giemsa staining, methylene blue (TBO) staining, Gomori large methylenetetramine silver (GMS) staining, seizure The hydatid with 8 intracapsular bodies is the basis for diagnosis.

4. Serological examination

At present, common methods include convective immunoelectrophoresis detection of antigen, indirect fluorescence test, immunoblotting test, detection of serum antibody and complement binding test, but lack of good sensitivity and specificity, can not be used to diagnose Pneumocystis carinii disease.

X-ray findings are non-specific, 10% to 25% of patients with chest X-ray can be normal, typical X-ray findings of diffuse pulmonary interstitial infiltration, mainly reticular nodules, from the hilar to the outward expansion, the condition Progression, rapid development of alveolar consolidation, extensive and concentric distribution, similar to pulmonary edema, mixed with emphysema and small atelectasis in the consolidation lesions, with the most obvious peripheral lung, rare pneumothorax or pleural effusion For pleural lesions, there were also localized nodular shadows, unilateral infiltration, lung function tests, lung capacity reduction, and lung diffusion function (DLCO) below 70%.

Diagnosis and identification of Pneumocystis carinii pneumonia

diagnosis

The diagnosis of this disease is difficult. The diagnosis of high-risk group combined with clinical manifestations and X-ray examination can be considered, and then the pathogen examination can be used to confirm the diagnosis. The positive rate of pathogen detection is extremely low. After 3% hypertonic saline can be atomized, cough is induced, bronchoalveolar The positive rate of lavage (BAL) and fiberoptic bronchoscopy lung biopsy can reach 80%100%. BAL can be found in the same period as anatomical examination. It can be used for early diagnosis. The positive rate of open chest biopsy is high, but it is not easy for patients. Accepted, and the severity of the disease, the risk is large, has been rarely used, in recent years advocated a thoracoscopic biopsy to replace the thoracotomy.

Differential diagnosis

The disease should be differentiated from chlamydial pneumonia, tuberculosis, and pulmonary fungal infection.

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