Diseases of the Lungs Flashcards
What is pneumonia/pneumonitis
Infection of the lung causing alveolar inflammation
What are the types of pneumonia
Lobar pneumonia
Bronchopneumonia
Atypical pneumonia
What bacteria causes lobar pneumonia in 90% of cases
Streptococcus pneumoniae
What are the clinical features of lobar pneumonia
High grade fevers with rigors, productive cough, rusty sputum, pleuritic chest pain and signs of consolidation
What are the 4 pathological stages of lobar pneumonia
Congestion
Red hepatisation
Grey hepatisation
Resolution
Describe the features of the congestion stage of lobar pneumonia
Occurs for 24 hours Vessels engorged Oedema in alveoli Heavy Red lung
Describe the features of the red hepatisation stage of lobar pneumonia
Occurs for 2-4 days Outpouring of neutrophils and RBC's into alveoli Red Solid Airless "liver like" lung
Describe the features of the grey hepatisation stage of lobar pneumonia
Occurs for 4-8 days Fibrin and macrophages replace neutrophils and RBC's Grey Solid Airless lung
Describe the features of the resolution stage of lobar pneumonia
Occurs for 8-10 days
Gradual return to normal
What is the most common form of pneumonia
Bronchopneumonia
“hospital acquired”
What are the 4 typical clinical settings in which bronchopneumonia is found
- Chronic debilitating illness
- secondary to viral infections
- Infancy
- Old age
How does bronchopneumonia often develop
starts as bronchitis and bronchiolitis then spreads to the alveoli
Which bacteria tend to cause bronchopneumonia
Staph
Strepto viridans
H influenzae
Coliforms
Describe the histology of bronchopneumonia
- Bilateral, basal, patchy
- Grey or grey-red spots of consolidation
- Microscopically acute inflammatory infiltrate in bronchioles and alveoli
What are some of the complications of bronchopneumonia
Death, cus usually happens with other illnesses/extreme age
Resolution
Scarring
Abscess/empyema - rare
What kind of infection can cause interstitial (atypical) pneumonia
Mycoplasmal or viral
Where does inflammation occur in atypical pneumonia
Restricted to the alveolar septa and interstitial tissues
Why is interstitial pneumonia referred to as “atypical”
There is no alveolar exudate
What bacteria causes TB
Mycobacterium tuberculosis
Describe the symptoms and features of primary TB
- Represents response to first contact with tubercle bacilli
- Usually asymptomatic
- Ghon complex: lesion typically 1cm focus in midzone with draining lymph node
- Heals with fibrosis and calcification
Describe the pathology of secondary TB
- Reinfection or reactivation
* Fibrosis is usually apical, about 3cm at clinical presentation
Describe the microscopic pathology of TB
- Characteristic inflammation based changes resulting from Type IV hypersensitivity
- Granulomas that try to attack TB bacteria with caseous necrosis, Langhan’s giant cells and epithelioid macrophages
- Ziehl-Neelsen stain reveals the characteristic acid-fast bacilli
- Definitive diagnosis is by sputum culture
What does Pulmonary TB do over time to the lungs
Causes progressive fibrocavitary TB, gradually destroys lung through necrosis, cavitation and fibrosis
Give some examples of COPDs
- Chronic bronchitis
- Emphysema
- Bronchial Asthma
- Bronchiectasis
What is almost always the cause of bronchitis and emphysema
Smoking
Which COPD almost always occurs with chronic bronchitis
Emphysema
What causes chronic bronchitis
Mucous gland hypertrophy and therefore mucous hyper secretion
What are some symptoms of chronic bronchitis
- Productive cough
- Hypoxia
- Hypercapnia
What causes emphysema
Permanent dilatation of airways distal to terminal bronchiole
Caused by elastin destruction leading to loss of elastic recoil
What is bronchial asthma and what can be a symptom
This is an increased irritability of the bronchial tree and causes paroxysms of reversible bronchospasm
What causes the most common form of bronchial asthma
Most common = Atopic
Caused by type 1 hypersensitivity to common allergen
What is bronchiectasis
Permanent dilatation of bronchi and bronchioles with necrosis of their walls.
The airways become saclike and are filled with foul smelling pus.
What are some symptoms of bronchiectasis
Chronic paroxysmal cough, typically brought on by change in posture, copious amounts of foul smelling sputum
What usually precedes bronchiectasis
Obstruction or childhood viral pneumonia
What complications can arise as a result of bronchiectasis
Abscess, fibrosis, amyloid, clubbing
What is the mist common site for secondary cancers
The lungs
Name some factors that cause lung cancer
Cigarette smoking, asbestos, mineral dusts, radiation, pollution
Name a few cancers that can be caused by smoking
Lip, tongue, floor of mouth, larynx, oesophagus, urinary bladder, pancreas and kidney
Describe the development of the respiratory epithelium into a carcinoma
- Respiratory epithelium - ciliated, mucus secreting, pseudo stratified, columnar
- Stratified squamous
- Squamous Dysplasia
- Carcinoma
What are the different histological classifications of lung cancer
- Squamous cell carcinoma (25-40%)
- Adenocarcinoma (25-40%)
- Small cell carcinoma (20-25%)
- Large cell carcinoma (10-15%)
Describe the clinical features of small cell carcinomas
- Not treatable surgically
- Usually widely disseminated at time of diagnosis
- Rx chemotherapy
Describe the clinical features of non small cell carcinoma
- Surgically treatable
- Classification into adeno or squamous important for targeted therapy; many new molecular targets available
What are the local and general symptoms of lung cancer
Local - Cough, haemoptysis and pain
General - Weight loss, Clubbing, Hypertrophic pulmonary osteoarthropathy
What are paraneoplastic syndromes
A group of rare disorders that are triggered by ectopic hormone production by tumour cells
Give an example of paraneoplastic syndromes
Hypercalcaemia
SIADH - Symptoms of inappropriate anti diuretic hormone
What are occupational lung diseases caused by
Diseases caused by inhalation of dust particles, mineral or organic substances over many years due to occupational exposure
What are the 2 main mechanisms of injury to the lungs in occupational lung diseases
– scarring from chronic irritation: inert
substances , eg coal workers’ pneumoconiosis
– hypersensitivity: organic dusts
What can coal workers’ pneumoconiosis cause
Anthracosis,
Macules,
Progressive massive fibrosis
What can silicon occupational inhalation cause
Silicosis, Caplan’s syndrome
What can asbestos occupational inhalation cause
Asbestosis, pleural plaques, Caplan synd, mesothelioma, Ca lung, lx, stomach, colon
What can organic dust occupational inhalation cause
Farmers’ lung,
Baggassosis,
Byssinosis,
Bid breeders’ lung
Name some lung diseases that come from a vascular origin
- Pulmonary Oedema
- Diffuse Alveolar Damage (ARDS, shock lung)
- Emboli and Infarction
- Pulmonary Hypertension
Describe the clinical features of pulmonary oedemas
- As BP increases fluid is pushed into lungs and causes heavy and wet lungs
- Alveolar pink granular fluid may contain haemosiderin-laden macrophages (heart failure cells)
What are the causes of Diffuse alveolar damage (ARDS, shock lung)
Oedema caused by injury to alveolar capillary endothelium
- Shock
- Trauma
- Sepsis
- Viral infections
- Noxious gases
- Radiation
How does Diffuse alveolar damage progress
It proceeds to cause severe scarring and is a rapid life threatening respiratory situation
What causes emboli and infarctions in the lungs
Occlusion of pulmonary arteries by circulating clots usually from the low limb veins
Describe the complications associated with large saddle emboli
Immediately fatal - lodge at bifurcation of pulmonary trunk
Describe the features of small emboli
Causes a characteristic wedge shaped infarcts
How long should a productive cough last before you diagnose chronic bronchitis
more than 3 months
