Legionnaires' disease
Introduction
Introduction to Legionnaires' disease Legionella pneumonia (legionellapneumonia) is a systemic disease caused by pneumonia caused by Legionella. There are 40 species of Legionella, and most of the clinical isolates are legionellapneumophila, followed by Lmicdadei, which is rare. Gram-negative bacilli, but lighter in coloration. Strict aerobic bacteria, special nutritional requirements for isolation and culture in the first generation, the use of selective special media containing antibiotics and cysteine, iron such as activated carbon yeast agar medium (CYE) and BCYE- medium. Adjusting the exact pH of the medium and a certain concentration of CO2 environment (2.5% to 5%) and incubation time (at least 5 days) are the key to ensure the success of bacterial culture and separation. Clinical laboratory tests for this strain are very low, and most of them are diagnosed based on serum antibody. basic knowledge The proportion of illness: 0.058% Susceptible people: no specific population Mode of transmission: airborne Complications: lung abscess pleurisy myocarditis respiratory failure renal failure
Cause
Cause of Legionnaires' disease
Gram-negative bacterial infection (46%):
Legionella is aerobic multi-sex gram-negative bacteria, which are widely found in the natural environment. The source of infection is human, water and air-conditioning systems. Through airborne, Legionella often invades the human body from the respiratory tract, and can also enter from the wound surface. Alveolar and bronchioles, when invaded in the body, adhere to neutrophils and macrophages, and are swallowed. Legionella that enters the cytoplasm can not only be killed, but proliferate, causing cell rupture, producing and releasing enzymes. Classes and cytotoxic factors damage lung tissue. In addition, Legionella can produce and release a variety of toxins that cause persistent damage to the lungs and enter the bloodstream to cause lesions in extrapulmonary organs and tissues.
Prevention
Legionellosis prevention
To prevent this disease, people are required to exercise regularly in daily life, improve their physical fitness; quit smoking, stop drinking, get rid of those bad habits, and enhance their body's resistance. At the same time, large buildings such as office buildings, shopping malls, restaurants, etc. It is necessary to regularly check the central air-conditioning system, cooling towers and other equipment to keep the hot and cold water systems clean. In addition, citizens should regularly check, disinfect and maintain the air conditioners in their homes and showers in the bathrooms. It is hygienic and clean.
1. Close monitoring of clinical suspected Legionella patients and suspicious Legionella outbreaks.
2. Early diagnosis and reasonable treatment can greatly reduce the mortality rate of Legionnaires' disease.
3. Disinfect the environment and water sources.
Complication
Legionella complications Complications lung abscess pleurisy myocarditis respiratory failure renal failure
Complications include lung abscess, pleurisy, myocarditis, respiratory failure, renal failure, and cardiac insufficiency.
Symptom
Legionella symptoms common symptoms, irritability, dizziness, diarrhea, muscle soreness, phlegm, muscle pain, urinary dryness, hemoptysis, increased fatigue, fatigue
The disease is generally epidemic but can also be sporadic. The onset is slow for 2 to 10 days. In the early stage of the disease, patients have general malaise, muscle pain, chest pain, dry cough, mucus with bloodshot, high fever, difficulty breathing, and some are mentally disordered, disorientation , coma, gastrointestinal symptoms are abdominal pain, vomiting and watery diarrhea or mucus, no pus and blood.
Signs: The patient has an acute face, shortness of breath, cyanosis and wheezing in the lungs, and a relatively slow heart rate with fluid accumulation.
Physical examination found:
Acute fever, relatively slow pulse, may have hypotension, shortness of breath, superficial lymph nodes and hepatosplenomegaly, affected lungs can be heard and wet rales, there may be a small amount of pleural effusion, accompanied by extrapulmonary lesions Signs.
According to the clinical manifestations, the patient can be initially diagnosed as a suspicious patient. It is confirmed that there is no bacterial status in the human population, so the diagnosis can be confirmed once the pathogen is examined from the suspected patient.
Examine
Legionella disease examination
(A) X-ray chest radiograph, lack of specificity, early patchy shadow on one side or both sides, late inflammatory infiltration, more common in the lower lung, abscess and cavity only found in immunosuppressed patients, may have pleural effusion.
(2) Pathogen examination:
1, sputum, blood or pleural effusion cultured Legionella can be diagnosed.
2, bacterial antigen and DNA detection, direct fluorescent antibody method (OFA), enzyme-linked immunosorbent assay (ELISA) radioimmunoassay (RIA), gene probe and polymerase chain reaction (PCR).
3, serum specific antibody detection: indirect fluorescent antibody method (IFA), enzyme-linked immunosorbent assay (ELISA), micro-pollution test and test tube test (TAL).
(3) Other examinations: white blood cell counts are normal or slightly elevated, some neutrophil nucleus shifts left, leukocyte reduction has poor prognosis, may have hematuria, aspartate aminotransferase and lactate de-light enzyme increase, jaundice, low copper, hypomagnesemia .
Diagnosis
Diagnosis and identification of Legionnaires' disease
Due to the intricate clinical manifestations, special laboratory tests must be performed, including: 1, bronchial lavage or direct fluorescein-labeled antibody staining of lung tissue; 2 antigen test by enzyme-linked immunosorbent assay; 3 pleural cavity from lung tissue The pathogenic bacteria are cultured in the liquid and in the trachea or through the tracheal aspirate.
History and symptoms:
1, often have smoking, abuse of alcohol and immunosuppression and other predisposing factors.
2. The prodromal symptoms are fatigue, lethargy, fever, headache and myalgia.
3, respiratory symptoms have cough, cough (mucus sputum, purulent sputum or blood stasis), chest pain and difficulty breathing.
4, extrapulmonary symptoms: nausea, vomiting, diarrhea (lean or watery stool), lethargy, confusion, slang, coma, dementia, anxiety, convulsions, disorientation, depression, hallucinations, insomnia, forgetfulness, speech disorders, demeanor Abnormal performance.
Differentiation from pneumonia caused by bronchiectasis and other pathogens such as Staphylococcus aureus pneumonia.
