Pathology of Respiratory Tract Infection Flashcards
Upper respiratory tract infections
Coryza (common cold) Sore throat syndrome Acute laryngotracheobronchitis (croup) Laryngitis Sinusitis Acute epiglottitus
Primary pathogens
Infect any of us given an opportunity
Opportunistic pathogens
Less infectious - require host to be suppressed
Facultative
Mostly
Need help to infect
Capacity to resist infection of older patients
Less likely to get viral infections as more likely to have experienced it before and have the immune defences
Lower respiratory tract infections
Bronchitis
Bronchiolitis
Pneumonia
Respiratory tract defence mechanisms
Macrophage-mucociliary escalator system
General immune system - humoral/cellular
Respiratory tract secretions - predispose secondary infections
Upper respiratory tract as a “filter”
Macrophage-mucociliary escalotor system
Alveolar macrophages => mucociliary escalator => cough reflex
Secondary bacterial infection (cause)
Normal epithelium damaged by viral infection destroys MME’s
Aetiological classification of pneumonia
Community acquired Hospital acquired (nosocomial) Pneumonia in the immunocompromised Atypical Aspiration Recurrent
Hospital acquired pneumonia
Organisms more likely to be resistant
Recurrent pneumonia
Suggests organic problem compromising MME’s
Bronchopneumonia
Acute infection - acute inflammation, neutrophil polymorphs, pus in bronchioles which spills into alveoli and replaces air (consolidation)
Spots of infection in lung
Favours lower areas of lung (basal layers)
Retained secretions
Pleural surface not involved
Bi-lateral, patchy, fluffy consolidations
Hypostatic pneumonia
Elderly Cardiac problem Oedema found in lung Secretions in lung Depression of cough reflex
Lobar pneumonia
Total consolidations - airless lungs (normally upper lobes - anterior)
