Pathology of Pulmonary Infection Flashcards
Lung infections are the outcome of which several opposing factors?
Microorganism pathogenicity
Capacity to resist infection
Population risk
What are some examples of upper respiratory tract infections?
Coryza - common cold
Sore throat syndrome
Croup
Laryngitis
Sinusitis
Acute epiglottis
Explain acute epiglottis
Inflammation of the epiglottis which blocks the flow of air into lungs causing difficulty swallowing
What microorganisms cause acute epiglottis?
Haemophilus influenzae
Group A beta-haemolytic streptococci
Rarely caused by parainfluenza virus type 4 but other viruses may be responsible
Give some examples of lower respiratory tract infections
Bronchitis
Bronchiolitis
Pneumonia
What are the respiratory tract defence mechanisms?
The macrophage muco-ciliary escalator system
General immune system
Respiratory tract secretions
Upper respiratory tract acts as a filter
What are 3 aspects involved in the macrophage muco-ciliary escalator system?
Alveolar macrophages
Muco-ciliary escalator
Cough reflex
Explain the partial clearance from the lungs?
The normal respiratory tract is sterile
Clearance from alveolar macrophage phagocytosis
Which either clear via the muco-ciliary escalator or interstitial pathway via lymph to lymph nodes
What are the aetiological classification of pneumonia?
Community acquired pneumonia
Hospital acquired (Nosocomial) acquired
Pneumonia in the immunocompromised
Atypical pneumonia
Aspiration pneumonia
Recurrent pneumonia
What is bronchopneumonia?
It is the acute inflammation of the bronchi, accompanied by inflamed patches in the nearby lobules of the lungs
Often bilateral basal patchy opacification, relating to the focal nature of
the consolidation
What is the pattern of pneumonia?
Bronchopneumonia, Segmental and Lobar
Hypostatic, Aspiration, Retention, Obstructive, Endogenous liquid
What are some complications of pneumonia?
Pleurisy, pleural effusion, empyema, organisation, lung abscess and bronchiectasis
What can be the result of organisation in pneumonia?
Mass lesion
COP - cryptogenic organising pneumonia
Constrictive bronchiolitis
What is pleurisy?
Inflammation of the pleura, thin layer of tissue that lines the lungs and chest wall.
Fibrinous pleural exudate
What is COP?
Cryptogenic organising pneumonia
Form of idiopathic interstitial pneumonia characterized by lung inflammation and scarring that obstructs the small airways and air sacs of the lungs
Organisation causes fibrosis of tissue in lungs
What can be the causes of lung abscesses?
Obstructed bronchus - tumour
Aspiration
Particular organism - staph. aureus, some pneumococci and Klebsiella
Metastasis in pyaemia
Necrotic lung
What is bronchiectasis?
Pathological dilation of bronchi
Causes accumulation of excess mucus and bacteria resulting in frequent infections and breathing problems
What are the main symptoms of bronchiectasis?
A persistent cough that brings up sputum, Shortness of breath, haemoptysis and signs of chronic infection
The symptoms tend to get worse if you develop an infection in your lungs
What can cause the dilation of bronchi in bronchiectasis?
Severe Infective Episode
Recurrent Infections
Proximal Bronchial Obstruction
Lung Parenchymal (lung tissue) Destruction
What are clinical signs of bronchiectasis?
Coarse crackles
Clubbing
What is the examination and treatment of bronchiectasis?
Thin section CT
Treatment - Postural Drainage, Antibiotics, Surgery
What are the complications of bronchiectasis?
Acute/ chronic suppuration - collection of pus
Haemorrhage
How are the defences failing in recurrent lung disease?
Local bronchial obstruction - tumour or foreign body
Local pulmonary damage - bronchiectasis
Generalised lung disease - COPD, CF
Non-respiratory disease - immunocompromised
What are some causes of aspiration pneumonia?
Vomiting
Oesophageal Lesion
Obstetric Anaesthesia
Neuromuscular Disorders
Sedation
What are opportunistic infections?
Increased chance of ordinary infections
Infection by organisms not normally capable of producing disease in patients with intact lung defences - opportunistic pathogens
What are some opportunistic pathogens?
Low grade bacterial pathogens
CMV
Pneumocystis jirovecii
Other fungi and yeats
