Pulmonary Infection Disease

Pulmonary Infection Disease Cheng Zhang ， Respiratory Medicine ， Affiliated Hospital of Jining Medicine college 23,Feb

Pneumonia Bacterial Pneumonia

General Consideration • Definition: • location:distal airways ， alveoli ， and interstitium of the lung . • causes: pathogenic microorganisms ， physical or chemical agents ， immunologic injury ， allergic diseases and medicine • Bacteria Pneumonia is the commonest Pneumonia and also the one of the commonest infection disease

Epidemiology • In United States ， CAP affects 4 million adults per year ， costs ＄ 9.7 billion ， 20% admitted • Prevalent rate :0.8~1.5% per year,highest rates at the extremes 0f age and during winter months • Mortality ： 1~5% in out-patients ， 12% in hospital ， 40% in ICU • .

• Aging,smoking,alcoholism,comorbid medical conditions and immunosuppression ， such as AIDS,immunodepressants,transplantation,C OPD,AIDS ， malignant tumor ， diabetes mellitus,mutation of pathogenic microorganisms and abusage of antibiotics and poverty are also partially responsible

Pathogenesis Pulmonary defence mechanisms cough reflex,mucociliary clerance system,immune responses prevent aspiration of oropharyngeal secretions(contaning bacteria or inhalation of infected aerosols) . Pneumonia occurs or not dependents on defects of normal host defence mechanism or numbers and virulence of bacteria

• Pathogenic organisms could raech the lower respiratory tract and result in Pneumonia via the following ways • a.Aspiration of infected aerosols • b.Dissemination via blood stream • c.Spreading by the adjacent organ infections • d.Aspiration of permanent planting organisms in the upper air way • e.Aspiration of gastric-oesophageal reflux

Classification Anatomical Classification A.Lobar Pneumonia （ Alveolar Pneumonia ） 

Start with alveolitis produced by bacteria and expand to the other alveoli throughout the lobe via the pores of Kohn ， and result segments or even whole lobe infection

Classification • Parenchyma infection • Lobe consolidation,bronchus not be involved • Streptococcus pneumonia is the main pathogen • X-ray will show segment or lobar consolidation shadow

B.Lobular pneumonia （ bronchopneumonia ) • Pathogens spread via bronchi and produce infection in the bronchiole ， distal bronchiole and alveoli • Often secondary to some other diseases ， such as bronchitis ， bronchiectasis ， long-term lying in bed

Classification • Pathogens ： Streptococcus pneumonia ， Staphylococci ， viruses ， Mycoplasma pneumonia • Rales(often heard) ， no signs of consolidation • X-ray ： the irregular patch infiltration shadows go along with the lung markings and no appearance of consolidation • Lower lobe is easier to be involved

Classification C.Interstitial pneumonia Involving interstitium ， including the alveolar walls and the connective tissue • Alveoli septa infiltration of lymphocytes ， macrophages ， and plasma cells • It could be caused by infection of bacteria ， mycoplasma ， chlamydia ， virus ， pneu mocystis carinii and so on

Classification Aetiological Classification A.Bacterial Pneumonia 

Classified as Streptococcus pneumonia ， Staphylococci aureus ， Alpha hemolytis streptococcus ， Klebsiella pneumoniae ， Hemophilus influenza ， Pseudomonas aeruginosa pneumonia

Classification B.Atypical Pathogens Pneumonia 

Legionella ， Mycoplasma and Chlamydia

C.Viral pneumonia 

Coronavirus ， adenovirus ， Respiratory syncytial virus ， Influenza virus ， Measles virus ， Cytomegalovirus ， Herpes simplex virus

Classification D.Fungal pneumonia • Candida albicans ， Aspergillus,and Actinomycetes

E.Other Pathogens Associated Pneumonia • Rickett‘s organism ， toxoplasmosis ， protozoa ， p arasite(echinococcosis,schistosomiasis)

F.Physical and chemical Pneumonia • Radiation pneumonia • Chemical pneumonia • Lipoid pneumonia

Classification Classification According To The Circumstances The Patient Acquire Pneumonia 

A.Community-acquired pneumonia ， CAP Occurs outside of hospital or less than 48 hours after admission in a patient who is not hospitalized or residing in a long-term care facility for more than 14 days before the onset of symptoms

Classification Essentials diagnosis ： • Symptoms and signs ： cough with or without purulent sputum ， dyspnea ， with or without chest pain • Fever • Bronchial breath sounds or rales are freqent auscultatory findings • WBC>10×109/L or<4×109/L,with or without shift to the left

Classification • Parenchymal infiltration or interstitial changes with or without pleural effussion on chest radiograph Any one of the first four points above plus the last one ， and exclude other pulmonary tuberculosis,neuoplasm,non-fectious,pulmonary edema,atelectasis,pulmonary embolism,ILD,the diagnosis of CAP could be confirmed. The pathogens include Streptococcus pneumoniae ， Hemophilus influenza ， Moraxelle catarrhalis ， and atypical pathogens 

Classification B.Hospital-Acquired Pneumonia ， HAP/Nosocomial Pneumonia ， NP Occurs more than 48 hours after admission to the hospital and excludes any infection present at the time of admission

Essentials diagnosis ： 

At least two of the following ： fever ， cough ， leukocyosis ， purulent sputum

Classification • New or progressive parenchymal infiltrate on chest radiograph • Especially common in patients requiring intensive care or mechanical ventilation

Organisms ： • In patients without high infection risk factors are Streptococcus pneumoniae ， Hemophilus influenza ， Staphylococcus aureus, Escherichia coli,Klebsiella pneumoniae

Classification • In patient with high risk factors are Streptococcus pneumoniae ， Pseudomonas aeruginosa ， Enterobacter ， Klebsiella pneumoniae and so forth

Clinical Findings • Pneumonia can range in severity from mild to fulminant and fatal. • The typical pneumonia is characterized by the sudden onset of fever ， cough productive of purulent or bloody sputum, with or without pleuritic chest pain, shortness of breath or distress. • The physical signs associated with pneumonia are fever ， tachypnea, tachycardia ， nasal flaring ， cyanosis • Dullness to percussion may be detected if a parapneumonic pleural effusion or empyema is complicated

Diagnosis and Differential Diagnosis .first upper/lower respiratory tract infections Secondly.orther diseases that mimicthe pneumonia should be excluded

• Pulmonary tuberculosis  Often have an insidious onset and general toxic symptoms ， such as low-grade fever ， night sweat ， fatigue ， weight lost and so forth  X-ray ： Shadows mainly located in the upper zone ， irregular density ， slow disappearance ， cavity formation and bronchial disseminationn  Sputum smear could get positive results  Patients will not respond to the common antibiotic

Diagnosis and Differential Diagnosis

• Lung cancer 



Neoplasm must be excluded in any patient who has pneumonia which clears slowly radiologically or repeats in same part of lung Further investigations include CT ， MRI,bronchoscopy and sputum cytologic examination may help

Diagnosis and Differential Diagnosis

• Lung Abscess  Early stage similar ， but large amount of purulent sputum will be coughed up while the disease progresses  X-ray shows cavity with fluid level

Diagnosis and Differential Diagnosis

• pulmonary thromboembolism 





 

There are phlebothrombosis factors,such as thrombophlebitis,diseases of heart and lung,trauma,surgery,neoplasm and so forth Hemoptysis ， syncope and dyspnea are the characteristic manifestations X-ray lung marking decrease and sometimes a wedge shadow Hypoxemia and hypocapnia D-dimer ， CTPA ， Pulmonary arteriography and MRI can help to differentiate

Diagnosis and Differential Diagnosis • Non-Infectious Pulmonary Infiltration Such as pulmonary interstitial fibrosis ， pulmonary edema ， pulmonary atelectasis ， pulmonary eosinophilia ， pulmonary vasculitis and so on

Assessment of Pneumonia Severity • Severity evaluation is associated with treatment • Pneumonia severity depends on the three factors ： the extent of local inflammation ， the dissemination of pulmonary inflammation and the degree of systemic inflammation response • Besides ， the following risk factors are also associated with the increase of pneumonia severity and mortality ：

History 

Age over 65 years old with coexisting illness

Assessment of Pneumonia Severity Sign      

Respiratory rate>30/min Pulse rate≥120/min Bp<90/60mmHg temperature≥40℃ or ≤35℃ Altered mental status Existence of extrapulmonary infections such as meningitis or sepsis

Assessment of Pneumonia Severity Laboratory and Radiologic Findings 







Blood cells count>20×109/L or <4×109/L ， or neutrophils<1×109/L PaO2<60mmHg ， PaO2/FiO2<300,or PaCO2>50mmHg Serum creatinine >106umol/l or serum urea nitrogen >7.1mmol/l Hb<90g/L or HCT<030

Assessment of Pneumonia Severity   

Serum albumin<25g/l The evidence of sepsis or DIC Multilobar involvement,cavity formation,fast dissemination of the lesion or pleural effusion on the X-ray film

Assessment of Pneumonia Severity • So far,there has not been a definition of severe pneumonia,which is recognized generally.The definition of severe pneumonia established by our country is as follow:   



Confusion Respiratory rate>30/min PaO2<60mmHg ， PaO2/FiO2<300,need for mechanical ventilation Bp<90/60mmHg

Assessment of Pneumonia Severity 



Bilateral or multilobar involvement on the X-ray film,or≥50% increase of the lesion within the 48 hours after admission Oliguria:urinary production<20ml/h,or <80ml/4h,or acute renal failure need for dialysis

Etiologic Diagnosis • Some common methods used clinically to obtain the sample are as below:

Sputum 





A sputum sample with>25 white blood cells and<10 squamous epithelial cells per low-power field or the ratio of squamous epithelial cells and white blood cells <1:2.5 is suitable for culture. ≥107cfu/ml could be confirmed as the pathogenic bacteria, ≤104cfu/ml as contaminated organisms The same organisms(>2 times,105-106cfu/ml)could also be considerd pathogens

Etiologic Diagnosis Aspiration via fibrous bronchoscope or artificial airway  

Less chance to be polluted ≥105cfu/ml could be defined as pathogens

Protected specimen brush,PSB   

≥103cfu/ml could be defined as pathogens Bronchial alveolar lavage,BAL ≥104cfu/ml or ≥103cfu/ml in the protected BAL sample could be defined as pathogens

Etiologic Diagnosis Percutaneous fine-needle aspiration 

Has good sensitivity and specificity,but has high incidence of complication

Culture of blood and pleural fluid 

Blood culture should be performed but positive is low(5%-20%)

Treatment • The identification of pathogens is very helpful in guiding the treatment(target therapy) • Low sensitivity and specificity and delayed results • Since the etiology of pneumonia is frequently unknown, initial antibiotic therapy is often empirical • Choice of antibiotics must modified based on circumstances (CAP or HAP),epidemiology of community or hospital and cover most likely pathogens

• The following conditions are also considered in selecting the antibiotics and administration route age Underlying disease Radiographic appearance Prior use of antimicrobials Severity of pneumonia Aspiration hospitalization

• Macrolides ,penicillions,first generation of cephalosporins or quinolones are preferred for CAP in adults under age 60 and with no coexisting illnesses • For age over 60with comorbidities or reqiring hospitalization the second or third generation of cephalosporins ,β-lactams/β-lactamase inhibitors or quinolones are considered and the combination of macrolides or aminosides

Treatment • Severe pneumonia should broadspectrum ， dosage and combination • The condition of patient should be assessed 48-72 hours after the antibiotic therapy • When a patient with pneumonia fails to improve 72 hours after administration ， the capital possibilities listed as follow ：  The pathogens are not covered  The infection of specific pathogens  Complications or host factors  Non-infectious disease

Prevention • smoking cessation • Exercise • Influenza and pneumococcal vaccination appropriately

Bacterial Pneumonia • Streptococcus pneumonia • Staphylococcal pneumonia

Streptococcus pneumonia • Streptococcus pneumonia is caused by Streptococcus pneumoniae or pneumococcus pneumoniae • About half of CAP • A sudden attack of fever ， chills ， cough ， bloody sputum and chest pain • X-ray ： acute pulmonary consolidation distributed in segment or lobar

Aetiology and Pathogenesis • Pneumococci are spherical gram-positive bacteria • The bacteria are classified as 86 serotype according to their polysaccharide capsule antigen. • Pathogenicity and virulence are related toproperties of the outer capsules and cell walls.

• Susceptible are the previously healthy young adults ， elderly and infants • Pneumococci are aerosolized from the nasopharynx to the alveolus and cause alveolar wall adema and that followed by exudation of white blood cells and red blood cells

• Pneumococci are aerosolized from the nasopharynx to the alveolus and cause alveolar wall edema and that is followed by exudation of white blood cells and red cells.the edema fluidswith bacteria spreads rapidly throughout the lobe via the pore of cohn, resulting in a mostly lobar distribution of consolidation.Because the inflamation starts from peripheral lung tissue,the pleural membrane is easy to be involved and that is related to the pleuritis and pleural effusion

Pathology • Four stages ：    

Congestion Red hepatisation Gray hepatisation Resolution

Clinical Manifestations • A. Symptoms • Often have a history of cold ,fatigue,drunkness,viral infection before the onset 



Sudden attack of high fever （ 3940℃ ）， chills ， myalgia ， cough ， bloody or rusty sputum ， dyspnea ， pleuritic chest pain Nausea ， vomitting ， abdominal pain ， diarrhea

Clinical Manifestations • B. Signs  Flush ， cyanosis ， braeth rapidly and shallowly,alae nasi moving  Moving less on the affected side,Dull to percussion ， increased tactile ， vocal fremitus ， bronchial breath sounds ， rales ， pleural friction rub  Nature history is 1-2 weeks,defervescence may occur either gradually or dramatically 5~10 days after onset or 1~3 days with effective antibiotic therapy

Clinical Manifestations • C. complications  Septic shock  Pleuritis  Empyema  Pericarditis  Meningitis  Arthritis

Laboratory Findings • • • • •

WBC is increased Sputum smear Sputum culture PCR Blood culture or pleural fluid culture

Radiographic Diagnosis • Chest radiography may confirm the diagnosis • Assess severity and response to therapy over time • Radiographic findingscan range from patchy airspace infiltrates to lobar consolidation with air bronchograms. • Finds pleural effusions and cavitation • Clearing of pulmonary infiltrates can take 3-4 weeks

Diagnosis and Differential Diagnosis • According to symptoms ， signs and chest Radiographic findings • Atypical Clinical Manifestations should differentiate

Treatment • A. Antibiotic therapy  Therapy should be initiated promptly after the diagnosis of pneumonia is established  Penicillin ， quinolones or third generation of cephalosporins ， Vancomycine  Therapy for two weeks or until the patient is afebrile for at least 72 hours

Treatment • B. Treatment of complications  Therapy according to symptoms ， such as to relieve chest pain ， thoracentesis when pleural fluid formation

Staphylococcal pneumonia • Staphylococcal pneumonia is an acute pulmonary suppuration caused by staphylococcus • It often affects persons with co-morbid illness and usually has sudden onset of high fever ， chills ， chest pain ， and purulent sputum • X-ray presents with necrotizing pneumonia ， such as lung abscesses ， air cyst and empyema • It has a very high mortality if not being treated properly

Aetiology and Pathogenesis • Staphylococci are gram-positive coccus and can be classified as coagulase-positive （ Staphylococcus aureus ） coagulase-negative （ S.epidermidis and S.saprophyticus ） • The pathogenic materials of staphylococcus are toxins and enzymes ， such as hematoxin ， leucocidin ， enterotoxin and so on • The virulence of staphylococcus can be determined by testing the coagulase

Aetiology and Pathogenesis • The coagulase-positive agent has stronger virulence • Staphylococci has been implicated in 11%-25% of CAP and there have been reports about the epidemic outbreak of methicillin resistent S.aureus （ MRSA ） in the hospital in the recent years

Pathology • S.aureus can gain access to the lung parenchyma by two routes ， aspiration of upper respiratory flora and hematogenous spread • The pneumonia associated with aspiration will present with lobar consolidation or extensively distributed bronchial pneumonia • Lung abscess ， air cyst ， empyema ， and pyopneumothorax are the common typical pathologic changes

Pathology

• Hematogenous seeding of the lungs with S.aureus follows embolization from an intravascular nidus of infection • Common settings for septic pulmonary emboliazation are right-sided endocarditis （ especially common among injection drug users ） and septic thromboophlebitis ， which is most often a complication of an indwelling venous catheter • The bacterial embolus can also come from cutaneous infections such as furuncle ， carbuncle ， cellulites ， and wound infection

Clinical Manifestations • Only rarely does S.aureus cause pneumonia without predisposing epidemiologic or host factors that favour colonization of the respiratory tract and/or that impair defense mechanisms • Clinical findings is characterized by sudden attack of high fever （ 39-40℃ ）， chills ， chest pain ， cough productive of purulent sputum or blood tinged purulent sputum • Systemic toxicity includes myalgia ， arthralgia ， and prostration

Clinical Manifestations • Ciuculatory collapse can occur in early stage in case with severe condition • The onset can be insidious in patient with HAP and temperature will go up gradually • The elderly may present atypical manifestations • The patient with hematogenous spread usually has a history of indwelling venous catheter ， wound infection and drug abuse by intravenous • They often strat with the symptoms of primary lesion and have less respiratory manifestations

Clinical Manifestations • Few signs can be detected in early stage that is not parallel with the severe toxic symptoms • Afterward ， the signs of pneumonia ， pleural effusion or pneumothorax can be found • Radiograph shows consolidation of segment or lobar ， cavity formation ， and air cyst with fluid level • Multiple nodular or fluffy infiltrates suggest hemotogenous spread

Diagnosis • The initial diagnosis can be made according to the systemic toxicity ， produtive cough with blood stained purulent sputum ， increase of WBC and radiographic changes • Aetiological evidence can confirm the diagnosis ， which can obtain from the culture of sputum ， pleural fluid and blood

Treatment • Semisynthetic penicillins or cephalosporins combined with aminoglycosides are preferred as the first antimicrobial choice ， because most of S.aureus are resistant to penicillin （ -90% ） • Amoxicillin or ampicillin plus β-lactamase inhibitor can be used for coagulase-positive Staphylococcus • Vancomycin and teicoplanin are highly active against MRSA