Uremic pneumonia

Introduction to uremia pneumonia The lung is one of the most common organs of uremia. In the narrow sense of uremic pneumonia, the chest X-ray shows a symmetric butterfly wing shadow radiating from the lung door to the sides. The lesion is mainly pulmonary edema. Performance, generalized uremic pneumonia refers to the pathophysiological changes and clinical manifestations of the respiratory system during uremia, including pulmonary edema, pulmonary calcification, pleurisy, pulmonary infarction, pulmonary fibrosis and pulmonary hypertension. basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people. Mode of infection: non-infectious Complications: pulmonary edema, pleurisy, endocarditis

Uremia pneumonia

Alveolar-capillary permeability increased (20%):

(1) Small molecular substances: including urea, terpenoids and amines. Urea is the most abundant metabolite in body fluids. In the middle and late stages of chronic renal failure, the serum concentration of urea is gradually increasing. Clinically common uremia Symptoms such as headache, fatigue, nausea, vomiting, lethargy, and bleeding tendency are all related to urea. It can also diffusely damage the alveolar-capillary membrane to increase its permeability. The longer the urea is present in the body, the greater its toxicity. The terpenoids are metabolites of certain amino acids and creatinine. Normal people discharge about 10g from the urine every day. The uremia patients increase with the serum creatinine level, and the sputum in the serum also rises in parallel. Similar to urea, amines including aliphatic amines, aromatic amines and polyamines, aliphatic amines and aromatic amines can inhibit the activity of certain enzymes, affect metabolism, polyamines can promote red blood cell lysis, inhibit the production of erythropoietin It inhibits the activity of Na+-K--ATPase and Mg-ATPase, increases the permeability of microcirculation, and promotes the production of uremia pulmonary edema.

(2) Molecular substances: including hormones with normal structure but increased concentration, high concentrations of normal metabolites, cell or bacterial lysates, high concentrations of molecular substances can cause peripheral neuropathy, inhibition of erythropoiesis, inhibition of various antibody production The cellular immune function is reduced, and the parathyroid hormone (PTH) is the most obvious diffuse damage to the alveolar-capillary membrane, which can also affect myocardial function and myocardial cell metabolism.

(3) Immune factors: Since the glomerular basement membrane and the pulmonary capillary basement membrane have the same antigenic determinant, the causes of uremia such as chronic glomerulonephritis and nephrotic syndrome can damage the pulmonary capillary basement membrane. To change its permeability.

Increased capacity load (15%):

Lung lesions appear in animal models of acute renal failure caused by ligation of the ureter, which proves that the mechanism of the disease depends on excessive water, urinary urinary urinary urination, increased volume load due to urinary closure, is the most important pathophysiological change, and forms pulmonary edema. One of the important reasons.

Plasma colloid osmotic pressure decreased (15%):

A large amount of proteinuria, malnutrition, combined with anemia, etc., cause the plasma colloid osmotic pressure to drop, causing fluid to exude to the interstitial, causing interstitial edema, regulating the flow of transpulmonary capillary fluid according to the Starling formula, that is, the flow of purified water is determined by the cross The membrane water pressure difference (P), the transmembrane colloid osmotic pressure difference (), and the membrane filtration coefficient (Kf) interact, and maintain a certain balance between P and during normal operation. Regulated by the lymphatic system, primary pulmonary edema occurs in the membrane Kf, the fluid leakage of the membrane increases beyond the lymphatic system drainage, the interstitial fluid accumulation in the lung tissue occurs, and the secondary pulmonary edema changes due to or P, resulting in lung The fluid in the capillaries enters the pulmonary interstitial, and the patient does not necessarily exhibit excessive body fluid volume, but may have increased intracardiac pressure and pulmonary wedge pressure.

Left heart dysfunction (15%):

In uremia, myocardial function is impeded, left ventricular dysfunction leads to elevated pulmonary capillary pressure, causing pulmonary edema and decreased lung compliance. In the late stage of uremia, cardiovascular abnormalities of the chest X-ray and urea nitrogen (BUN), creatinine (Scr) is not necessarily related, indicating that pulmonary edema formation is a comprehensive factor.

Effects of oxygen free radicals, adhesion molecules and cytokines (15%):

In uremic patients, due to the decrease of residual nephron, creatinine metabolism and infection, the oxygen free radicals are increased, and the systemic antioxidant capacity of patients is significantly reduced. These superoxide anions can not be removed quickly and effectively, which leads to the exacerbation of tissue damage while removing foreign bodies. Among them, hypochlorous acid accelerates the metabolism of creatinine, and the metabolites formed are easily penetrated into the cells to cause cytotoxicity and damage the tissues. The lungs have high sensitivity to hypochlorous acid, which is caused by lung tissue damage caused by neutrophils. The main role, due to the use of biocompatible membranes, activation of complement, causing leukocytes to accumulate in the lung microcirculation, release various lysosomal enzymes, causing lung damage, and studies have shown that white blood cells accumulate in the lung microcirculation Increased expression of surface adhesion molecules is associated with increased leukocyte activity.

Respiratory muscle disorder (10%):

In uremic disease, due to malnutrition, lack of active vitamin D3, hyperparathyroidism, malnutrition and other factors, resulting in muscle weakness and disuse, chest wall compliance changes, affecting lung function, showing maximum inspiratory pressure, maximum exhalation Both the pressure and the transthoracic muscle pressure decreased.

Other factors are clinically inadequate management of water intake, metabolic acidosis and electrolyte imbalance, and are also highly likely to cause pulmonary edema.

Pathogenesis

Gross observation of the lungs is a diffuse rubber-like hardness change, and the weight is increased. The lesions in the lungs under the microscope are prominent. It is found that the alveoli are rich in protein-soluble cellulose aqueous solution, sometimes with dense transparent blocks, and may have mononuclear cell infiltration. Alveolar basement membrane and small blood vessel amyloid deposits, but also pulmonary hemorrhage and hemosiderin deposition, the latter can lead to fibrosis, fibrinous pleurisy in 20% of cases, repeated with the course of the disease, recurrent pulmonary edema and Pulmonary calcification, pulmonary fibrosis is common at autopsy, diffuse patchy changes in both lungs, or fibrous tissue replaces the entire sub-segment.

Uremia pneumonia prevention

In the early stage of renal dysfunction, although there is no pulmonary symptoms, the patient should be gradually monitored for lung function. The decline of lung diffusing function and the degree of limited ventilatory function damage are related to the degree of renal function decline. Pulmonary edema should be noted in patients with abnormal pulmonary function. When the patient's creatinine clearance rate is <10ml/min, the dialysis pathway is established and long-term dialysis treatment can prevent pulmonary edema.

Uremia pneumonia complications Complications Pulmonary edema pleurisy endocarditis

Often combined with other parts of the infection. Such as:

1. Pulmonary edema, two small lungs appear in a large piece or large piece of shadow, the density is not high, continuous and fuzzy, typical is butterfly wing. This type accounts for about 19% of the clinical.

2. Pleuritis, a causative agent that stimulates pleural inflammation caused by the pleura. The most common symptom is chest pain. Chest pain often occurs suddenly and varies widely. It can only occur when the patient takes a deep breath or cough. It can also persist and is exacerbated by deep breathing or coughing.

3. Endocarditis, an inflammatory disease caused by Neisseria catarrhalis invading the endocardium, and a thrombus (sputum) formed on the surface of the heart valve contains pathogenic microorganisms. The performance is: fever, heart murmur, etc.

Uremic pneumonia symptoms Common symptoms Dyspnea hypoxemia, purulent sputum, no urine, oliguria, metabolic acidosis, pain, dry cough

Difficulty breathing

Mostly mild to moderate, characterized by the ability to supine, the incidence rate is between 30% and 80%, each report is different, when the condition is serious, the gas is obvious, showing deep breathing. Followed by cough, the incidence rate of 50% to 65%, usually dry cough or cough a small amount of white sticky sputum, a large number of yellow purulent sputum in the combined infection. The fever rate is 12.9%, and the body temperature is around 38 °C. Most of them are complicated by lung or other parts. Hemoptysis accounts for 8% to 32%, with little hemoptysis. A small number of patients also felt double chest pain. There must be a serious kidney disease, and the detection of renal function meets the uremia criteria. More common in oliguria, anuria, excessive sodium intake or inadequate dialysis ultrafiltration.

The most common clinical symptom of uremia pneumonia is difficulty breathing, but it can be supine. X-ray films are typically characterized by extensive lamellae or large exudative shadows in both lower lungs and can change rapidly in the short term. The total number of white blood cells and the ratio of neutrophils were not increased in the blood test. There was no pathogenic bacteria in the sputum culture, and the chest X-ray showed no correlation with the infection. Arterial blood gas analysis was hypoxemia and metabolic acidosis. Pulmonary function test showed that the diffuse function decline was the earliest and always existed, and the restrictive ventilation change accounted for more than 51%. The anti-infective effect is not obvious, and the effect of hemodialysis is obvious.

Hairpin

The incidence rate is about 6.3%. Nearly half of the patients have no lung signs. More than 50% of the patients have audible and popping sounds in the lungs. 30% to 40% of the patients have lower lung breath sounds. Individual patients can smell dry sputum. sound.

Examination of uremia pneumonia

Blood gas analysis showed metabolic acidosis, hypoxemia, early or mid-term PaCO2 decreased or normal, when PaCO2 was significantly elevated, suggesting that the condition was critical.

Chest X-ray

(1) Image characteristics of the lungs:

1 variety of forms: can be butterfly-winged, miliary, isolated or diffuse small pieces, single or multiple large pieces, agglomerate or multiple nodules and other shadows, typical butterfly wing is rare, accounting for 4% ~ About 10%, lung texture increased, rough and most common, accounting for 71%.

2 Density is different: the density can be light and strong, and it can be mixed evenly or in multiple images.

3 position is uncertain: can live on both sides or one side of the lungs, can be located on both sides of the whole lung or both lungs in the lower field, can also be seen on one side of the whole lung or a lung lobe lung segment, the overall impression: right lung more than left lung The middle belt is more than the outer belt, the middle and lower lung leaves are more than the upper lung, and the right lower lobe is extremely vulnerable.

4 changes faster: after hemodialysis, cardiac, diuretic and other treatment, with the improvement of the kidney and heart function, the lung shadow can be absorbed or completely dissipated in a short time.

(2) lung image classification

1 pulmonary hemorrhagic type: the most common clinical, accounting for about 60%, showing double lung hilar shadows, blurred, lung texture thickening.

2 interstitial pulmonary edema type: enlarged hilar shadow, unclear edge, increased upper and lower lung texture, thickening and blurring, about 13% K line, B line 7%, A line 2% ~ 3%.

3 alveolar pulmonary edema type: two small lungs appear extensively small or large-like shadow, density is not high, continuous and fuzzy, typical is butterfly wing, this type accounts for about 19% of clinical.

4 pulmonary interstitial fibrosis: most cord-like and grid-like shadows in the lung field, accounting for about 21% of the clinical.

5 heart enlargement: alveolar and interstitial edema type more common heart enlargement and heart failure, heart, chest > 0.5 accounted for 61%.

6 pleurisy: a small amount or medium effusion, generally only the rib angle becomes dull, clinically accounted for 31%.

2. CT and magnetic resonance high-resolution CT and magnetic resonance imaging (MRI) have been widely used in clinical practice, and sub-clinical pulmonary edema in such patients can be found, which is more specific and sensitive.

3. Pulmonary function: Patients with uremia have pulmonary dysfunction in the early stage. When 47% of patients have abnormal pulmonary function, chest X-ray is still normal. It can be seen that pulmonary function test has certain significance for early detection of lung invasion in uremic patients.

Lung capacity and forced expiratory lung capacity and 1s forced expiratory volume were lower than the normal expected value. The ventilatory function, diffuse function and large and small airway ventilation function of uremic patients decreased, showing a forced expiratory rate of one second (FEV1%). The maximum expiratory flow (V25, V50) of 50% and 25% of lung capacity decreased, and the amount of carbon monoxide diffused decreased. The decrease of lung function index was negatively correlated with the increase of plasma urea nitrogen concentration, and the change of carbon monoxide diffusion function (DLCO) was the most Important, in the early stage of uremia, the edema of the alveolar membrane, the secondary pulmonary fibrosis, the reduction of the alveolar capillary area, and the reduction of hemoglobin in the pulmonary capillaries during anemia are the pathological basis for the decline of diffuse function. The condition worsened and the mixed ventilatory dysfunction gradually became apparent.

Diagnosis and diagnosis of uremia pneumonia

Diagnostic criteria

1. There must be a serious kidney disease, and the detection of renal function meets the uremia criteria.

2. More common in oliguria, no urine, excessive sodium intake or insufficient dialysis ultrafiltration.

3. The main clinical symptoms are difficulty breathing, but can be supine.

4. X-ray chest X-rays are typically characterized by extensive small or large exudative shadows in both lower lungs and can change rapidly in the short term.

5. Blood examination The total number of white blood cells and neutrophil ratio did not increase, and the sputum culture was free of pathogenic bacteria, and the X-ray chest radiograph showed inconsistent with infection.

6. Arterial blood gas analysis for hypoxemia and metabolic acidosis.

7. Pulmonary function test The decline of diffuse function appeared first and always existed, and restrictive ventilation changes accounted for more than 51%.

8. The anti-infection effect is not obvious, and the effect of hemodialysis is obvious.

Differential diagnosis

1. Cardiac pulmonary edema: Some scholars believe that left heart failure is an important cause of uremia in the lungs. There are many factors affecting heart function in uremia, and there are few isolated uremic pulmonary edema under X-ray. It is also incapable of distinguishing between uremic pulmonary edema and cardiogenic pulmonary edema. Other scholars believe that there is still a certain difference between the two.

(1) Cardiogenic pulmonary edema:

1 has a history of coronary heart disease, cardiomyopathy.

2 typical people have chest tightness, shortness of breath, pain in the precordial area, cough pink foamy sputum, sputum, can not supine, early cough history when lying, sitting on the respiratory history.

3 hairpin is obvious, the auscultation of both lungs can be heard and a wide range of dry and wet voices.

4 ECG has special changes related to the primary disease.

The early stage of X-ray chest radiograph is interstitial pulmonary edema, followed by pulmonary blood-like changes. Pulmonary congestion is mainly characterized by vascular engorgement of the upper lung and blurred blood vessel edges.

6 strong heart, diuretic treatment has obvious effect.

(2) uremia pulmonary edema:

1 Even if the lung edema is heavier, the symptoms such as cough and cough are still very light.

2 In addition to metabolic acidosis can cause deep breathing, the air is also light, still able to supine.

3 hemoptysis is rare, there is very little pink foam .

X-ray chest radiographs in 440% of patients had no cardiovascular abnormalities.

5 The basic pathological pathology is fibrinous exudation, and the change of pulmonary congestion is vasodilation of the whole lung.

6 anti-infective treatment, cardiac and diuretic treatment are ineffective, and dialysis treatment is good.

2. Pulmonary infection: patients with chronic renal failure are often accompanied by decreased immune function, plus anemia, metabolic acidosis and other factors that make the body's defense factors difficult, susceptible to various infections, lung viruses, bacterial infections bear the brunt.

(1) There is fever, cough is aggravated, cough and purulent sputum, and the air is aggravated.

(2) Auscultation of the lungs can be heard and dry, wet and squeaky.

(3) Blood routine examination revealed an increase in the total number of white blood cells and an increase in the proportion of neutrophils.

(4) The measured value of C-reactive protein was significantly increased.

(5) Positive results can be obtained from sputum culture, and the anti-infective treatment effect is obvious according to the susceptibility test.

3. Tuberculosis: uremia patients have about 20% of tuberculosis, and uremia is 2 to 3 months after dialysis is a good period of tuberculosis.

(1) Symptoms are not typical: due to low immune function, there may be no low fever in the afternoon, but also high fever that is ineffective against general antibiotics, night sweats, loss of appetite, weight loss and other symptoms are often masked by the primary disease symptoms, tuberculin test is often false negative.

(2) ESR is obviously accelerated, up to 100mm/h, sputum smear or culture, tuberculosis can be found, the positive rate is 20% to 30%, and the positive rate of PCR detection of tuberculosis can be significantly improved.

(3) X-ray films may not have typical tuberculosis, and CT examination has certain significance.

(4) Experimental anti-tuberculosis treatment is effective.

4. Pulmonary hemorrhage-nephritis syndrome: The late stage of this syndrome has no differential significance in the stage of uremia, and it has its characteristics in the early and middle stages.

(1) The disease is mostly males under the age of 16.

(2) intermittent hemoptysis, hemoptysis.

(3) Hemosiderin macrophages can be found in sputum.

(4) Pulmonary function was restricted ventilatory dysfunction; diffuse function decreased; arterial blood carbon dioxide partial pressure decreased, indicating hyperventilation.

(5) X-ray chest radiographs see diffuse granules or nodular shadows in both lungs, the shadows can be migratory, and the tip of the lungs is clear.

(6) Blood test anti-glomerular basement membrane (GBM) antibody positive.

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