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LUNGS PATHOLOGY 3 - Coggle Diagram

- - - - sometimes, also nosocomial infections may occur
    - - community-acquired
        
        bacterial: S. pneumonia, Hemophilus, S. aureus, Legionella, Klebsiella, Pseudomonas, Moxarella catarrhalis, Mycoplasma, Clamydia, Coxiella
        
        clinical features
        
        symptoms:
        abrupt onset of high fever, shaking chills, cough producing mucopurulent sputum and occasionally hemoptysis
        
        pleuritis may be present, generally accompanied by pleuritic pain and pleural friction rub
        
        XR: the whole lobe is radiopaque in lobar pneumonia, whereas there are focal opacities in bronchopneumonia
        
        viral: Influenza, Metapneumovirus, Coronavirus
      - health care-
        associated
        
        Staphylococci, Streptococci, Pseudomonas
        
        hospitalization, IV antibiotics, CT
      - hospital-acquired
        
        Gram neg, Staphylococci, Pseudomonas, Enterobacteria
      - aspiration
        
        Staphylococci, Streptococci, Pseudomonas, Hemophylus, Anaerobic oral flora
        
        acute aspiration of gastric content, partly chemical (irritation) partly bacterial
      - chronic
        
        Nocardia, Actinomyces, Mycobacterium, Histoplasma, Coccidioides, Blastomyces
      - necrotizing
        
        Staphylococci, Streptococci, Klebsiella, Pneumococci
      - immunocompromised
        
        CMV, Pneumocystis, Aspergillosis, Candidosis
    - - patterns of anatomica distribution
        
        lobular bronchopneumonia:
        patchy consolidation of the lung
        
        foci tend to be produced
        
        consolidated areas of acute suppurative inflammation, more often multilobar and frequently bilateral and basal
        
        histology: neutrophil-rich exudate filling bronchi, brinchioles and adjacent alveolar spaces
        
        lobar pneumonia:
        consolidation of a large portion of a lobe or of an entire lobe
        
        congestion: the lung is heavy, bggy, red, with vascular engorgement, intra-alveolar edema fluid with neutrophils and bacteria
        
        red hepatization: massive confluent exudation (neutrophils, red cells, fibrin) in the alveolar spaces
        --> the lobe is red, firm and airless, with a liver-like consistency
        
        gray hepatization: progressive disintegration of red cells and persistence of a fibrino-suppurative exudate
        
        resolution: the exudate in the alveolar spaces is broken down by enzymatic difgestion to produce granular, semifluid debris that is reabsorbed and ingested by macrophages, expectorated or organized by fibroblasts growing into it
      - complications
        
        abscess
        
        empyema
        
        sepsis
        
        lung abscess: local circumscribed suppuraticve process that produces necrosis of lung tissue
        
        risk factors
        
        oropharyngeal surgery, dental procedures, sinobronchial infection, bronchiectasis
        
        pathogenesis
        
        aspiration of infective material, primary lung infection, septic embolism, neoplastic obstruction, direct extension, trauma, cryptogenetic
        
        morphology
        
        between few mm ant 5-6 cm, destruction of the lung parenchyma with central cavitation containing suppurative debris, sometimes air, gangrene, fibrous wall in chronic cases
        
        symptoms
        
        fever, chest pain, weight loss
        
        outcome
        
        resolution or complication with empyema, sepsis, brain abscess
  - - - bacterial superinfections may be a consequence of impairment of local pulmonary defecses
        (e.g. mucociliary clearance)
    - - interstitial inflammatory reaction involving the alveolar wall
    - - when coplicated by ARDS pink hyaline membranes line the alveolar walls
    - - some viruses replicate within cells and make viral aggregates visible as inclusion bodies (HSV) or induce cells to fuse and form mononucleated cells (SYNCYTIA)
        
        HSV PNEUMONIA
        
        in immunocompromised pts or stemming form intubation
        
        necrotizing pneumonia
        
        infected cells contain large pink-to-purple intranuclear inclusions (Cowdry type A), consisting of viral replication proteins and virions that push the host cell chromatin to the edge of the nucleus with a ground glass appearance (Cowdry type B)
        
        CVM PNEUMONIA
        
        different manifestations on the basis of the age
        
        latent infection of monocytes, reactivated when cellular immunity is depressed
        
        asymptomatoc or mononucleosis-like in healthy; devastating infections in newborns and immunocompromised
        
        infected cells exhibit gigantism of the entire cell
        the nucleus typically contain a large inclusion surrounded by a clear halo
        
        transmission by several routes: saliva, genitals, iatrogenic, transplacental, neonatal
        
        it may progress to ARDS
        
        INFLUENZA/CORONAVIRUS PNEUMONIA
        
        atypical pneumonia with DAD
        
        weakly pathogenic coronaviruses cause mild cold-like infections; highly pathogenic ones may cause severe pneumonia with respiratory failure
        
        in severe forms: respiratory compromisation often associated with bilateral ground glass opacities on chest imaging
        
        viruses bind the ACE2 protein on the surface of pulmonary epithelial cells
        
        inflammation mediated mainly by mononuclear lymphocytes
        
        ARDS and thrombotic damage may occur
      - focal cell damage may cause epithelial cell to become detached forming blisters
      - some viruses cause epithelial cells to proliferate or to develop malignant neoplasms (EBV, HPV)
  - - - inhalation of dust particles from bird or bat, IC pathogen in phagocytes, lesions resemble TBC, at histology 3-5 micron fungal yeasts
    - - pulmonary, disseminated cutaneous form, macrophages ingest the yeasts in the cells and recruit neutrophils leadng to suppurative granulomas
    - - resist IC macrophage killing persisting as thick-walled spherules;
        granulomatous, pyogenic or mized lesions
  - - - pulmonary diseases with atypical manifestations
        
        more severe bacterial and tubercular infections, frequent bacteremia
        
        malignancies: Kaposis sarcoma, non-Hodgkin lymphoma, lung cancer, Pneumocystis, CMV, Aspergillus
  - - - yeast-like fungus that causes lung infection in an opportunistic way in immunodeficient patients
        
        CT: ground glass opacities
        
        rapidly progressive bilateral pneumonia
        
        cysts have cup-shaped appearance, oval central dot
        
        BAL: clusters of microorganism
        
        histology: alveolar interstitial thickening and eosinophilic exudate in the alveolar spaces
    - - ubiquitous mold that causes allergies in healthy people and severe pneumonia in immunocompromised pts
        
        risk factors: neutropenia, use of steroids
        
        sensitization to aspergillus spores produce bronchopulmonary aspergillosis with hypersensitivity and allergic alveolitis
        
        colonizing aspergillosis is growth with minimal or no invasion
        
        invasive aspergillosis with hematogenous spread
- - - - cell-mediated immune response to an unidentified antigen
      - immune abnormalities:
        
        intra-alveolar and interstitial accumulation of CD4+ T cells
        
        increased levels of T cell-derived Th1 cytokines (IL2 and IFgamma), T cell expansion and macrophage activation; TNF production
        
        association with certain HLA genotypes (A1 and B8)
      - morphology:
        
        every organ of the body can be affected
        
        necrotizing granulomas composed of aggregates of tightly clustered epithelioid macrophages, often with giant cells
        
        with chronicity, granulomas tend to become coalescent, enclosed with fibrous rims or replaced by hyaline fibrous scars
        
        Schaumann bodies and asteroid bodies (stellate inclusions) are found in giant cells
        
        concretions composed of calcium and proteins
        
        miliary distribution in the lung parenchyma
        --> along the lymphatics around the bronchi and blood vessels, alveolar lesions and pleural involvement
      - clinical features
        
        unexpectedly discovered on routine chest XR as bilateral hylar adenopathy or peripheral lymphadenopathy, cutaneous lesions, eyes involvement, splenomegaly or hepatomegaly
        
        sometimes respiratory abnormalities (dyspnea, cough, chest pain, hemoptysis) and systemic signs (fever, fatigue, weight loss, anorexia, night sweats)
      - outcome
        
        progressive or with periods of activity and remission
  - - - abnormal sensitivity to the causative antigen, leading to pathological changes primarily involving the alveolar walls
      - progression to serious chronic fibrotic lung disease can be prevented by removal of the environmental agent
    - - inhalation of organic dust containing antigens
        
        Farmer's lung: exposure to dusts generated from humid, warm, newly harvested hay, permitting the rapid proliferation of the spores of thermophilic actinomycetes
        
        Pigeon breeder's lung: provoked by proteins from birds serum, excreta or feathers
        
        Humidifier/Air-conditioner lung: thermophilic bacteria in heated water reservoirs
    - - acute: acute alveolar damage with eosinophils
      - subacute: centered on bronchioles, consisting of lymphocytes, plasma cells and macrophages
        (EOSINOPHILS ARE RARE)
        
        interstitial poorly formed non-necrotizing granulomas
      - chronic: interstitial fibrosis with fibroblastic foci, honeycombing and obliterative bronchiolitis together with granulomas
    - - acute attacks: episodes of fever, dyspnea, cough and leukocytosis; micronodular interstitial infiltrates appearing in the chest radiograph and pulmonary function tests show an acute restrictive disorder
      - subacute symptoms: caused by continuous re-exposure, dyspnea and impaired PFT
      - chronic symptoms: protracted exposure, progressive fibrosis, dyspnea, cyanosis
  - - - unknown etiology
        
        a rapid onset with fever, dyspnea, hypoxemic respiratory failure
        
        chest radiograph shows diffuse infiltrates
        
        BAL contains >25% of eosinophils
        
        histology shows diffuse alveolar damage and many eosinophils
        
        prompt response to corticosteroids
    - - in parasitic, fungal and bacterial infections
        
        in hypersensitivity pneumonitis
        
        in drug allergies
        
        in asthma, allergic bronchopulmonary aspergillosis or Churg-Strauss syndrome
    - - focal areas of cellular consolidation of the parenchyma distributed in the periphery of the lung fields
      - aggregates of lymphocytes and eosinophils within the septal walls and the alveolar spaces
  - - - emphysema
        
        chronic bronchitis
    - - DESQUAMATIVE INTERSTITIAL PNEUMONIA
        
        large collections of macrophages with aboundant cytoplasm containning dusty brown pigment
        
        thickened alveolar septa due to inflammatory infiltrate
        
        emphysema is often present
        
        symptoms: dyspnea, dry cough, restrictive PFT
        therapy: steroids and smoking cessation
      - RESPIRATORY BRONCHIOLITIS
        (INTERSTITIAL LUNG DISEASE)
        
        chronic inflammation and peribronchial fibrosis
        
        often an incidental finding
        
        sometimes, significant pulmonary symptoms with abnormal PFT
        
        morphology: patchy and bronchiolocentric organization, with aggregates of dusty brown macrophages, peribronchial fibrosis, centrilobular emphysema
      - PULMONARY LANGERHANS
        CELL HISTIOCYTOSIS
        
        rare disease, characterized by focal collections of LCs
        
        stellate scarring occurs, leading to airways destruction and alveolar damage
        
        irregular cystic spaces appearance
        
        cystic and nodular abnormalities
        
        S100+, CD1a+ and CD68-
      - PULMONARY ALVEOLAR PROTEINOSIS
        
        rare disease, caused by defects in pulmonary macrophage function due to deficient GM-CSF staining, resulting in the intra-alveolar and bronchiolar spaces
        
        XR: bilateral patchy asymmetric pulmonary opacifications
        
        forms: autoimmune, secondary, hereditary
        
        morphology: accumulation of intra-alveolar precipitates containing surfactant proteins, causing focal-to-confluent consolidation of large areas of the lungs with minimal inflammatory reaction; alveolar precipitate is pink, homogenoeus and contains cholesterol clefts and surfactant proteins
        
        clinical: adult patients, cough and abundant sputum, often containing chonks of gelatinous material