resolution delayed pneumonitis
Introduction
Introduction to Dissipative Delayed Pneumonia Dissipative delayed pneumonia has a poor response to standardized antibacterial therapy. Delayed, non-dissipating, and even progression of lesions is a common clinical problem. It is estimated that about 15% of respiratory specialists or consultants have undergone fiberoptic bronchoscopy. 8%, while nearly 90% of patients in the ICU have persistent lung infiltrates on chest X-rays. Therefore, the correct assessment of so-called dissipative delayed pneumonia, so as to take appropriate treatment, not only prevent misdiagnosis, but also avoid unnecessary long-term treatment or unreasonable application of antibacterial treatment, save medical and health resources, and reduce the selective pressure and resistance of antibiotics Sexuality. basic knowledge The proportion of illness: the incidence rate is about 0.002%-0.003% Susceptible people: no specific population Mode of infection: non-infectious Complications: bacteremia
Cause
Dissipating the cause of delayed pneumonia
Pathogen factors (35%):
(1) Special pathogen infections: especially tuberculosis or non-tuberculous mycobacterial lung disease, viral pneumonia, fungal pneumonia and pulmonary parasite (protozoa) diseases, certain regional infectious diseases or infectious diseases including zoonotic diseases In the case of pulmonary lesions, special attention should be paid to the epidemiological history. The current problems in China are the lag of the diagnosis of viral and fungal pneumonia and the low alertness to tuberculosis and paragonimiasis, which often lead to misdiagnosis and missed diagnosis. .
(2) Bacterial resistance: its confirmation depends on accurate bacteriological diagnosis and drug resistance measurement. The clinical reference factors that may cause drug resistance include: history of antibiotic treatment within 6 months, history of pneumonia within 1 year, hospitalization within 3 months History, hospital acquired pneumonia, etc.
Improper treatment (20%):
Improper drug selection and insufficient dose are one of the most important factors affecting the efficacy and absorption rate of pneumonia. Penicillin treatment of pneumococcal pneumonia and sulfamethoxazole (SMZco) in the treatment of Pneumocystis carinii pneumonia can not be prescribed, otherwise it will cause Insufficient dose, aminoglycoside antibiotics have poor ability to penetrate lung tissue. In the treatment of Pseudomonas aeruginosa pneumonia, it may still need to be according to the traditional dosage regimen. One dose per day is not used in patients with pneumonia. In addition, the drug does not easily reach local lesions. In particular, lung abscess and empyema, it is very important to ensure effective drainage, and should be actively treated. If the absorption of pneumonia is slow due to improper treatment, the antibacterial spectrum, antibacterial activity, pharmacokinetic/pharmacodynamic characteristics of pathogens and antibiotics should be considered. Selecting the drug and formulating a reasonable dosing regimen, if the antibacterial chemotherapy is sufficient and there are substantial reasons to expect that the bacteria have been largely killed, physical therapy such as infrared rays may be used to reduce residual lesions.
Host factor (10%):
Basic diseases (COPD, diabetes, alcoholism, etc.) and a variety of primary or secondary immune damage may cause pneumonia to dissipate slowly, do not dissipate or progress.
Pathogenesis:
Improper drug selection and insufficient dose are one of the most important factors affecting the efficacy and absorption rate of pneumonia.
Prevention
Dissipative delayed pneumonia prevention
As far as infectious pneumonia itself is concerned, the causes of dissipating beyond the expected time are as described above, and the treatment is focused on the clear cause, the most important being the pathogenic diagnosis, so that the selection of sensitive antibacterial therapy, the main factors affecting the disintegration of pneumonia should be differentiated. Actively try to remove.
Complication
Dissipating the complications of delayed pneumonia Complications bacteremia
Pneumonia most commonly occurs in patients with comorbidities or underlying diseases. Community-acquired pneumonia (CAP) in healthy people without comorbidities is mostly absorbed within 4 weeks on the X-ray, and X-ray inflammation is present within 4 weeks of comorbidities. Absorbed and completely clear only 20% to 30%, comorbidities increase with age, such as CAP in age <50 years old with chronic obstructive pulmonary disease (COPD) only about 5%, but CAP in age >50 years old Up to 30% of people with COPD.
Risk factors affecting X-ray dissipation include bacteremia, fever or increased white blood cells for more than 6 days, age > 50 years, combined with COPD or alcoholism.
Haemophilus influenzae is a fairly common pathogen in elderly and smokers with pneumonia. Non-capsulated strains have a low mortality rate, but the course of disease is prone to prolonged. It can be combined with persistent febrile tracheobronitis and Haemophilus influenzae infection. The natural course of disease is rarely known. The risk factors affecting absorption include COPD, malignant tumor, diabetes, alcoholism and immunosuppression. Legionella is an important pathogen of severe CAP, and its absorption rate is significantly slower than other pathogens. Including smoking, alcoholism, >65 years old, hormone-induced immunosuppression, diabetes, bone marrow transplantation, etc. X-ray disease of Mycoplasma pneumoniae pneumonia usually lasts for 2 to 4 weeks, depending on antibiotic treatment, 40% of patients are completely absorbed in the 4th week, and At the 8th week, 90% of the patients completely dissipated on the X-ray. The X-ray absorption of chlamydial pneumonia was between Mycoplasma and Legionella. The complication caused a delay in the dissipation of pneumonia.
In addition to increasing comorbidity, aging can be an independent factor affecting the absorption of pneumonia. 90% of pneumonia in young people under 50 years old dissipates within 4 weeks. On the contrary, CAP in patients without comorbidity over 50 years old can Absorbers are only 30%.
Symptom
Dissipative delayed pneumonia symptoms common symptoms vocal fever
To determine whether the pneumonia dissipates or does not dissipate, it is first necessary to understand the natural course of pneumonia, but so far little is known about it. The judgment of the natural course of pneumonia includes both clinical and X-ray. Although the clinical criteria are preliminary and rough, Still the most basic, indispensable, the current clinical indicators include fever, voice, cough, white blood cell count, PaO2 and C-protein, which are the fastest recovery of C-protein in these indicators (1~3) Day), cough improvement and disappearance is relatively slow (4 to 9 days), other indicators are in the middle, such as fever for 2 to 5 days, lung voice is 3 to 6 days, white blood cells are increased for 3 to 4 days, dissipation is slow Or non-dissipative pneumonia is not based on clinical symptoms, but on the rate of dissipation of imaging (mainly conventional chest X-ray) lung infiltration, affecting the disintegration of pneumonia, including comorbidities, age, severity of disease and Pathogens, etc.
Dissipative or non-dissipative pneumonia is not based on clinical symptoms, but on the rate of dissection of imaging (mainly conventional chest X-ray) lung infiltration.
Examine
Dissipation of delayed pneumonia
The increase in white blood cells is 3 to 4 days.
The severity of CAP affects the rate of pneumonia absorption. The absorption of severe CAP on the X-ray generally takes about 10 weeks, while the CAP absorption time of mild-onset CAP is 3 to 4 weeks.
The absorption rate and clinical improvement of pneumonia in different pathogens can be very different. The clinical improvement of pneumococcal pneumonia in patients without comorbidities is quite rapid. According to the study, the regression of fever is very rapid, and only about 6% lasting for more than 20 days; There were still 8% of abnormal signs in the month, mainly in patients with severe disease and multiple lobar lesions. However, the absorption on the X-ray was relatively slow. 20% to 30% of patients with X-ray follow-up at 1 week had no absorption, and they were often seen. The initial deterioration.
In short, the natural course of pneumonia or the dissipating time of X-rays may present a normal distribution curve and be affected by many factors.
Diagnosis
Diagnostic differential diagnosis of dissipative delayed pneumonia
There are 10% to 20% of patients with pneumonia whose dissipation exceeds the general rule. However, as mentioned above, the natural course of pneumonia is affected by many factors, some of which have not yet been fully revealed. There is still no precise definition of dissipative delay. In addition to dissipative delay, there may be Several other states, that is, do not dissipate, progress and relapse.
1. Dissipative delayed pneumonia is generally accepted as the definition of immune-pneumonia patients with antipyretic fever, improved symptoms, and the disappearance of chest X-ray abnormalities in the fourth week is less than 50%, although the X-line dissipated slowly, but the patient's prognosis is good.
According to the degree of inflammation dissipation and fibrosis, some patients have residual disease, which can be further differentiated into dissipative pneumonia with mechanized, organized pneumonia and post-inflammatory pseudotumor.
2. Does not dissipate pneumonia or chronic pneumonia refers to patients with immune-supplemented pneumonia who are generally considered effective antibacterial therapy, clinical symptoms and X-ray abnormalities lasting 1 month.
3. Progressive pneumonia refers to the abnormal expansion of X-rays in anticipation, accompanied by the deterioration of clinical symptoms, the main reason is bacterial resistance or specific pathogen infection, must emphasize:
(1) About half of hospitalized CAP patients have lung infiltration at a certain stage of the treatment, especially early stage X-line lesions have expanded, as long as the clinical condition does not deteriorate, does not necessarily indicate progress.
(2) In patients with neutropenia or deficiency (<500/mm3), the initial inflammatory response is weakened, and with effective treatment, especially the increase in the number of granulocytes, the pulmonary inflammatory response is restored, and the lung infiltrating shadow on the X-ray is increased. Progress in the disease can be a sign of improvement in the condition.
(3) Many of the so-called progressive pneumonia are not infectious, but are imaging-like pneumonia. For example, in some cases of lung cancer, this situation should not be regarded as progressive pneumonia.
The clinical treatment of patients with pneumonia does not need to eliminate non-infectious lesions. Many diseases can be characterized by fever and pulmonary infiltration, which is easily misdiagnosed as infectious pneumonia.
To collect clinical data in detail and use other imaging techniques (such as CT, MRI, radionuclide scanning), histopathology and immunology to further confirm the diagnosis, please refer to the relevant chapters.
