Brucella pneumonia
Introduction
Introduction to Brucella pneumonia Pneumoniaduetobrucella species (pneumoniaduetobrucellaspecies) is an acute or chronic infection of the lung caused by Brucella bacteria and is a natural epidemic zoonotic disease. The disease is widely distributed throughout the world, and is popular in northeast China, north China, and northwestern livestock areas. basic knowledge The proportion of illness: 0.0035% Susceptible people: no specific people Mode of transmission: pathogen transmission Complications: sepsis, myocarditis, meningitis, sepsis, myocarditis, meningitis, cholecystitis
Cause
Brucellosis pneumonia
(1) Causes of the disease
Brucella consists of 6 species and 20 biotypes. The main species is Brucella (Br. melitensis) which can infect goats. In 1887, Bruce was isolated from the spleen of Maltese island patients; Brilliant bovis (Br. Abortus) was infected with cattle. In 1897, Bang was obtained from aborted fetuses; Br. suis was infected with pigs. In 1914, Traum was obtained from pig abortion fetuses. Others were Brucella canis (Br .canis), which is mildly ill and rarely infects humans. In addition, rodents include Br. neotomae and Br. ovis.
Brucella is a small aerobic Gram-negative coccus, generally (0.4-1.5) m × (0.4-0.8) m, inactive, no flagella, capsule, no spore formation, acid-fast staining Ziehl-Neelsen The method is characterized by red dyeing. The bacteria has high nutritional requirements. It needs rich vitamins and serum. It can grow in 5% to 10% carbon dioxide environment. It grows best at 37 ° C and pH 6.6-7.1. Liver infusion culture or modified thick medium, after colony on blood-containing solid medium for 2 days, the colony has a large needle tip, and after 4 days, the diameter can reach 2 to 3 mm. The S-type Brucella colony is colorless, transparent and round. The edges are neat, the surface is smooth, moist, convex, homogenous colonies, and sometimes there are small particles in the center. Although the bacteria can use sugar, but do not produce acid, the bacteria is more resistant in nature, especially In the organs and secretions of sick animals, they can generally survive for about 4 months, and can survive for 2 months in food. They are sensitive to light, heat and common chemical disinfectants, so the commonly used disinfection methods are effective.
Brucella produces only endotoxin, which is a kind of lipoprotein with a common antigen between them. Therefore, a live vaccine can be made from the less virulent B. bungeum to prevent the virulence of sheep or pigs. Infected with bacteria, the bacteria can become type 1 in vivo and in vitro, which may be related to recurrence.
(two) pathogenesis
Brucella from the skin, mucous membranes invade the human body, phagocytized by phagocytic cells, with the lymph fluid to the mononuclear phagocytic system and lymph nodes, according to the body's disease resistance and the number and virulence of the invading bacteria, the pathogens are partially destroyed, Or in the lymph nodes to grow and form infection, when the pathogen grows and proliferates to a considerable amount, break through the lymph node barrier and enter the bloodstream. This stage is the incubation period, usually 2 to 3 weeks. In the bacteremia period, due to endotoxin Role, the patient may have symptoms of fever, weakness and other poisoning, the positive rate of blood culture in this period is as high as 70%, and the positive rate gradually decreases after the bacteria enter the liver, spleen, bone marrow, lymph nodes, etc. along the bloodstream to form a new infection. Others such as heart, lung, ovary, testis, prostate, joints, etc. are also invaded, forming multiple lesions, the bacteria in the bloodstream gradually disappear, the body temperature gradually subsides, and the bacteria re-enter the bloodstream when they propagate to a certain extent in the cells. And bacteremia occurs again, the body temperature rises again, and so on, showing wavy fever, the bacteria mainly parasitize in phagocytic cells, antibiotics or antibodies Into the cells, making the disease more difficult to cure, easy to turn into chronic and recurrent, causing migratory lesions throughout the body, recent data suggest that most pneumonia patients through the respiratory tract inhalation of bacterial dust or particles may be an important infection Pathway, the pathogenesis is mainly delayed type allergic reaction, the weakening of cellular immune function will lead to the pathogenic role of Brucella, and increase the susceptibility and severity of primary infection.
The pathological changes of this disease are extremely extensive, and almost invade every organ in the body. Among them, mononuclear phagocytic system such as liver, spleen, lymph node and bone marrow are the most common, and lung involvement is also common. Diffuse cells are often found in the acute phase. Hyperplasia, in the chronic phase, there may be granuloma composed of epithelial cells, macrophages, plasma cells and lymphocytes, an allergic reaction of the tissue to the pathogen, which is similar to the lesions of human sarcoidosis. There is no caseous necrosis, which is a typical lesion of the disease. The lung is hemorrhagic catarrhal inflammation in the acute phase, pulmonary fibrosis or calcification in the chronic phase, and pleurisy may occur.
Prevention
Brucella pneumonia prevention
1. Control and eliminate sources of infection including:
1 Adopting methods such as slaughtering sick animals and sicking and grazing of sick and healthy animals, livestock imported from other places must be confirmed by serological and bacteriological examinations to be disease-free before grazing.
2 aborted fetal lamb and yak should be deep-buried after adding lime.
3 patients should be hospitalized until the symptoms disappear, blood culture is negative, the patient's urine should be disinfected.
2. Cut off the transmission route including:
1 Strengthen the management of manure water to prevent the waste of diseased animals or patients from polluting water sources.
2 Strengthen the hygiene supervision of animal products,
3 Do a good job in personal protection.
Complication
Brucella pneumonia complications Complications sepsis myocarditis meningitis sepsis myocarditis meningitis cholecystitis
The disease is easy to be combined with sepsis, some cases are explosive, fatal, often accompanied by multiple visceral abscess, acute complicated with myocarditis, pericarditis, endocarditis, meningitis, cholecystitis, liver and spleen abscess, osteomyelitis, testis Inflammation, etc., individual pregnant women can cause miscarriage, chronic joints can have joint and spine stiffness, muscle contracture and hard.
Symptom
Brucellosis pneumonia symptoms common symptoms sepsis high fever shiver
The clinical manifestations are more complicated, ranging from simple fever to acute sepsis. Early shock can occur, often with multiple organ damage, and lung involvement is common. Generally, the cow type is lighter, and the sheep type and pig type are mostly heavier. Acute, sometimes explosive sepsis is rapidly fatal and can be chronic.
1. The incidence of acute phase is slow, and only 10% to 30% of patients with acute onset of illness. Most patients have aura symptoms of upper respiratory tract infection. The main clinical manifestations of this period are as follows:
(1) fever and hyperhidrosis: the most characteristic of wavy heat type, can also be relaxation heat or irregular heat, fever lasts for 1 to several weeks, intermittent several days to 2 weeks, as little as 2 to 3 waves, more More than 10 waves, high fever is often accompanied by chills and chills, more prominent is sweating, compared with other heat sexually transmitted diseases, often sudden temperature drops, sweating, accompanied by fatigue, irritability, headache, loss of appetite , weight loss, etc.
(2) Pulmonary manifestations: cough, cough, chest pain, dyspnea and other symptoms can occur, 10% to 33% of patients with dry cough, a small number of patients can also cough, sputum mucus, purulent or bloody, occasional sound Hey, pleurisy, lungs can have dry, wet voice and physical signs.
(3) joint pain: migratory large joint swelling and pain (shoulder, knee, ankle and hip joint) is characterized by some small joints can also occur, asymmetry, pain is acupuncture-like, and some can occur muscle Pain, more common in the two thighs and buttocks, sometimes aching pain.
(4) Hepatosplenomegaly: Some patients may have liver, spleen, and swollen lymph nodes.
2. Chronic period is low fever, cough, cough, often mucopurulent sputum or occasional bloodshot, more often involving the pleura, pleurisy, may be associated with loss of appetite, weight loss, fatigue, insomnia, joint pain, neuralgia, The liver, spleen and lymph nodes are slightly enlarged, and the course of disease varies from several months to several years. Some of them are more than 2 years old, and the joints may be stiff or contracted for a long time.
In recent years, the disease has gradually reduced, showing a rapid onset, a short fever period, a marked reduction in hyperthermia, mild symptoms of poisoning, no obvious hepatosplenomegaly, and less damage in various systems and organs. Widespread vaccination in endemic areas is associated with the widespread use of antibiotics.
Examine
Examination of brucellosis pneumonia
1. The white blood cell count of blood is in the normal range or low, the relative or absolute increase of lymphocytes, sometimes abnormal lymphocytes, erythrocyte sedimentation rate, and some cases may have positive pigmented large cell anemia.
2. Bacterial culture Blood culture and bone marrow culture can isolate pathogenic bacteria. B. brucei is not easy to grow when it is initially separated. It needs a suitable carbon dioxide environment. The positive rate of blood culture of Brucella sheep is higher, and it can be reached in acute phase or relapse. 70%80%, bone marrow culture can be higher, pleural effusion, bronchoalveolar lavage fluid, swollen lymph nodes, pulmonary granuloma biopsy can also isolate pathogens, others such as cerebrospinal fluid (cases of meningitis), joint bursa Liquid, milk, vaginal secretions, urine, feces, etc. can be isolated from pathogenic bacteria, and the positive rate of various cultures in the chronic phase is very low.
3. Serological examination
(1) Brucella agglutination test
1 Slide agglutination reaction: This method is rapid, simple, and sensitive. It can directly react with the stained antigen on the slide with undiluted serum. Anyone who has obvious agglutination within 5-10 minutes is considered positive.
2 tube agglutination test: is a relative quantitative test, has a high specificity, this reaction is generally positive results 7 days after infection, often strong positive in the second week, a single serum agglutination titer in 1 : 100 or more or double serum agglutination titer increased more than 4 times to help the diagnosis of the disease, the acute rate of positive rate of 80% to 90%, only 30% to 60% of the chronic phase, had vaccinated cholera or rabbit fever vaccine For brucein intradermal test or Yersinia enteritis, the agglutination test can be false positive.
3 blocking antibody: is an incomplete antibody, can make the serological test negative in the low dilution of serum (pre-band phenomenon), but it is positive in the higher dilution, can be detected by Coombs anti-globulin test, The positive standard is 1:1601:320, which is an important experimental diagnosis method in the chronic stage of Brucellosis.
4 thiol-containing compound treatment serum agglutination reaction: treatment of serum with thiol-containing compounds such as dimercaptoethanol or cysteine to destroy IgM, determination of IgG antibodies in serum, such as serum titer after treatment is lower than the total titer before treatment 20 More than 30%, that is, there is a diagnostic significance, this method only needs to check a single serum, which has certain significance for the identification of brucellosis and vaccine immune effect.
(2) Complement binding assay: Complement-binding antibody (mainly IgG) appears later, about 20 to 25 days after onset, and its titer titer is 1:16 or more positive, sensitivity is less than agglutination, but specificity High, plays a decisive role in the diagnosis of brucellosis.
(3) Delayed skin allergic reaction: Intradermal injection of brucellin or Brucella protein extract to determine skin allergic reaction, 24-48 hours observation, infiltration 1 ~ 2cm is weakly positive, 2 ~ 3cm Positive, 4 ~ 6cm is strongly positive, such as redness disappeared within 6 ~ 8h is false positive, skin test can increase serum antibodies, or systemic reaction, the patient's skin reaction appears later than the antibody, but lasts for a long time, Some can be maintained for several years, and individual cases can be up to 10 years. Therefore, it is helpful for retrospective diagnosis. It is also applicable to epidemiological investigations. When judging results, the false positive results due to immunization should be excluded.
X-ray changes usually appear as invasive shadows or single granulomatous lesions around the hilum and bronchi, unilateral hilar lymphadenopathy and pleural effusion are rare, pulmonary fibrosis or calcification can occur in the chronic phase, and hip joints show hips The joint space is narrowed, and the bones on both sides of the joint are sparse, accompanied by bone hyperplasia or hardening.
Diagnosis
Diagnosis and identification of brucellosis pneumonia
Diagnostic criteria
1 Epidemiological data and occupations are of great value in assisting in the diagnosis of this disease.
2 clinical manifestations of recurrent fever, excessive sweating, joint pain, cough, chest pain, dyspnea and other symptoms, often accompanied by liver, spleen, lymphadenopathy and other signs, but should exclude other suspected diseases,
3 Brucella can be cultured in blood or sputum or tissue samples to confirm the diagnosis.
4 combined with clinical manifestations for specific antibody detection, serological tests such as agglutination titer of 1:160 or more or more than four times the increase in titer, more diagnostic value,
5 lung tissue, bone marrow, lymph nodes and other biopsy to find granulomatous changes can help diagnose.
Differential diagnosis
The clinical manifestations of this disease are complex and must be differentiated from various diseases such as fever, arthritis, orchitis, meningitis and hepatosplenomegaly. The following are common.
1. Pulmonary tuberculosis active invasive pulmonary tuberculosis, caseous pneumonia and acute miliary tuberculosis, can cause acute fever and lung disease, but localized symptoms such as joint pain and neuralgia, can be found in tuberculosis, tuberculosis Positive test, anti-tuberculosis drugs are effective.
2. Typhoid fever, paratyphoid fever, rose rash, sweating, fat test, blood culture is isolated as typhoid or paratyphoid.
3. Malaria fever is rapid, periodic chills, recurrent fever, obvious spleen, blood or bone marrow smear can find malaria parasites.
4. Rheumatic fever, leukocytosis, markedly increased erythrocyte sedimentation rate, heart valve and myocardial lesions, ring erythema, anti-streptolysin "O" increased, good effect on salicylic acid preparations.
5. Subacute bacterial endocarditis usually occurs on the basis of organic heart disease, the recent appearance of heart murmur and intensity and quality changes, skin defects, embolism, blood culture positive.
6. Others should be associated with rheumatoid arthritis, influenza, sepsis, rabbit fever, leptospirosis, lymphogranuloma, viral hepatitis, liver echinococcosis, kala-azar, tuberculous orchitis, systemic lupus erythematosus, etc. Identification.
