1/6 Patterns of Disease in Lung 1 and 2 Flashcards
(52 cards)
What it the basic organization of the airways from mouth to lungs?
Trachea –> Bronchus –> Bronchioles –> Alveoli
What are the regions of the respiratory tract?
Conducting System (nose, trachea, bronchi)
Transitional system (bronchioles)
Exchange System (Alveoli)
What type of tissue is most of the respiratory system made up of?
Ciliated respiratory epithelium (cilia + goblet cells)
What are the features of the respiratory alveolus?
Delicate thin-walled
- Blood-air barrier extremely thin!
Made up of:
- Vascular endothelium
- Basal lamina
- Alveolar epithelium (type 1- wall, type 2- surfactant)
Normal bronchiole and Alveoli histology
What routes do pathogens use to enter the respiratory system?
Aerogenous (inhaled)
Hematogenous (embolic)
Direct Entry
Lymphatic Spread
What are the basic classifications of lung inflammation (pneumonia)?
What are each one’s distribution like?
Bronchopneumonia
- enzootic, suppurative, fibrinous
- contained within an area
Interstitial pneumonia
- Infection within interstitium of lung
- Diffuse pattern, whole lung infected
Granulomatour pneumonia
- Multifocal, random distribution
Embolic
- hematogenous spread –> multifocal, random
Describe the pathogenesis of bronchopneumonia
Inhaled agent
Inflammation at the bronchoalveolar junction
Acute inflammatory response
Exudation of fluid and plasma proteins into bronchioles and alveoli
Recruitment of alveolar macrophages (resident) and emigration of neutrophils (first to respond- acute inflammation)
Describe the distribution of infection in bronchopneumonia.
Cranioventral
- Inhalation + gravity
- Affects bronchi, bronchioles, alveoli
What are the causes of bronchopneumonia?
Bacteria
- Pasteruella multocida (cattle, pigs, cats)
- Mannheimia haemolytica (cattle)
- Bordatella bronchiseptica (dogs, pigs)
Mycoplasmas
Aspiration of food/gut contents
Viruses + secondary bacterial infection
What is the route of entry with bronchopneumonia?
Inhaled
What are the types of bronchopneumonia?
Enzootic
Suppurative
Fibrinous
Aspiration
What are the etiologies of enzootic pneumonia?
Mycoplasma ovipneumoniae (ovine)
Mycoplasma hyopneumoniae (porcine)
+ secondary pathogen
What are other names for enzootic pneumonia?
Cuffing pneumonia, atypical pneumonia, chronic nonprogressive pneumonia
What is the gross appearance of a lung infected with enzootic pneumonia?
Cranioventral, dark red, sharply demarcated, combo of collapse and consolidation
What is the histological appearance of enzootic pneumonia?
Peribronchial cuffing of lymphocytes and plasma cells causing alveolar collapse
(+/- suppurative inflammation within alveoli and airways)
What type of cells do you typically see with suppurative bronchopneumonia?
Suppurative = neutrophils, usually degenerate
What are the possible etiologies of suppurative bronchopneumonia?
Most often bacterial
- Pasteurella, bordetella etc.
- Associated with aspiration of ‘bland’ contents
Viral infection predispose to bacterial infection
What infection distribution is associated with suppurative bronchopneumonia?
Cranioventral
Patchy/confluent areas/whole lobes
What does the gross anatomy of a suppurative pneumonia look like?
Lesions:
- red, consolidated, bilateral
- often sharply demarcated
Describe the histology seen with suppurative pneumonia.
Neutrophils (often degenerate) filling alveoli and airways
NO lymphocytic cuffing
Acute suppurative bronchopneumonia histology slide.
What must be present in fibrinous bronchopneumonia?
Fibrin (yellow strands, acute phase protein)
Oedema
Neutrophils (degenerate)
Necrosis
What are some possible etiologies for fibrinous pneumonia?
Cattle: Mannheimia hemolytica (shipping fever)
Porcine: Actinobacillus pleuropneumonia
Aspiration of gut contents (harsh, cause necrosis)
