11.1 Pathology of pneumonia Flashcards
what are the secretory cells of the lungs and where are they located?
- Goblet cells - bronchi
- clara cells - bronchioles
- type 2 pneumocytes - alveoli
what lines the bronchus?
ciliated pseudostratified columnar epithelium with goblet cells
what lines the bronchioles?
ciliated columnar epithelium with increasing numbers of clara cells
what is the difference between infection and inflammation?
Infection is caused by an exogenous pathogen while inflammation is the response of the organism to the pathogen
what are the three main components of acute inflammation?
vascular dilation endothelial activation (increased permeability) Neutrophil activation (transmigration across endothelial surfaces out into the tissue)
what are the four stages in lobar pneumonia?
- congestion
- red hepatisation
- grey hepatisation
- resolution
what are the complications of bacterial pneumonia - broncho and lobar?
broncho - healing by fibrosis and abscess formation
lobar - pleuritis, empyema, abscess formation, haematogenous seeding, death
What are the airway defences?
nasal clearance tracheobronchial clearance (muco-ciliary action) alveolar clearance (alveolar macrophages)
what are the characteristics of bronchopneimonia and when is it most common?
it is the patchy consolidation of the lung - makes it look solid. it is extension of pre existing bronchitis and is common at the extremes of life
what usually causes lobar pneumonia?
a virulent organism - now infrequent due to antibiotic treatment
what occurs in the congestion stage of lobar pneumonia?
lung is heavy, boggy, and red. It is characterized by vascular engorgement, intra-alveolar fluid with few neutrophils, and often the presence of numerous bacteria.
what happens in the red hepatisation stage of pneumonia?
massive confluent exudation, as neutrophils, red cells, and fibrin fill the alveolar spaces. On gross examination, the lobe is red, firm, and airless, with a liver-like consistency, hence the term hepatization
What happens in the grey hepatisation stage of lobar pneumonia?
progressive disintegration of red cells and the persistence of a fibrinosuppurative exudate resulting in a colour change to grey-brown
LOTS OF NEUTROPHILS
what occurs in the resolution phase of lobar pneumonia?
exudate within the alveolar spaces is broken down by enzymatic digestion to produce granular, semifluid debris that is resorbed, ingested by macrophages, expecto- rated, or organized by fibroblasts growing into it
- liquefication of previously solid exudate
what are the symptoms and signs of bacterial pneumonia?
fever leulocytosis cough sputum pleuritic chest pain (pleuritis) increased respiratory rate cyanosis
