6. Respiratory Pathology Flashcards
Definition, epidemiology, aetiology, pathogenesis and key clinical features of:
Asthma
Chronic inflammatory disorder of the airways that is AT LEAST partially reversible (‘twitchy airways’)
Epidemiology: Common, children + young adults
Acute asthma is the commonest occupational lung disease
Aetiology: Dust mites, NSAIDs, cold, exercise, infections, emotions, Aspergillus (ABPA)
Pathogenesis: Type I hypersensitivity reaction involving IgE bearing mast cells and histamines
Clinical features:
Paroxysmal bronchospasm, wheeze, cough, bronchoconstriction, SOB, hyperinflation
Definition, epidemiology, aetiology, pathogenesis and key clinical features of:
Bronchiectasis
Permanent dilation of bronchi and bronchioles caused by destruction of the muscle and elastic tissue as a result of chronic necrotizing infection.
Epidemiology: Rare
Aetiology: Predisposed to infections if you have cystic fibrosis, primary ciliary dyskinesia (Kartagener syndrome), lupus, rheumatoid arthiritis, IBD, GVHD (graft vs host disease)
Pathogenesis: destruction of muscle and elastic tissue by chronic necrotizing infection
Clinical features:
Cough, fever, a lot of foul smelling sputum
Definition, epidemiology, aetiology, pathogenesis and key clinical features of:
Chronic obstructive pulmonary disease (COPD)
COPD is the clinical grouping of ‘chronic bronchitis’ and ‘emphysema’.
Chronic bronchitis = coughing with sputum for 3 months in 2 consecutive years.
Emphysema = abnormal enlargement of the alveolar air spaces
Epidemiology: Smokers, middle + old age, 1 in 20 GP consultations of patients over 65
Aeitology: Cigarette smoke
Pathogenesis: Mucus gland hyperplasia + hypersecretion leading to infections. Chronic inflammation of small airways causes wall weakness and destruction.
Clinical features: Dyspnoea (progressive + worsening), SOB, cough, sputum, infection, right sided heart failure (fewer capillaries, therefore right side of heart has to work harder to compensate pulmonary circulation, eventually failing)
What type of emphysema is associated with a1 antitrypsin deficiency?
Panacinar/panlobular emphysema - (destruction of bronchioles AND alveoli)
severest in lower lobes
(a1 antitrypsin protects lung tissue from breakdown due to inflammatory enzymes, if your deficient in AAT then you are more susceptible to developing COPD when you smoke since you don’t have that extra layer of protection)
What type of emphysema is associated with coal dust and smoking?
Centriacinar/centrilobular emphysema - (destruction of bronchioles NOT alveoli)
In what conditions is bronchiectasis seen in?
- Cystic fibrosis
- Kartagener syndrome / primary ciliary dyskinesia
- Bronchial obstruction due to tumour or foreign body
- Rheumatoid arthritis
- Inflammatory bowel disease
What changes are seen in interstitial lung diseases?
Diseases of pulmonary connective tissue:
- Alveolar walls (mainly)
- Bronchioles
- Alveolar spaces
these are either thickened or lost which decreases gas exchange and lung compliance.
‘Diffuse alveolar damage’ and ‘adult respiratory distress syndrome’ are examples of what type of interstitial lung disease?
Acute
Diffuse alveolar damage = Type 1 pneumocytes which line the alveoli die and form a hyaline membrane that prevents gas exchange
Adult respiratory distress syndrome = fluid leaks into the alveoli and stops them functioning. Can results from shock, trauma, infection, smoke, toxic gases, paraquat, narcotics, radiation
Progressive dyspnoea, clubbing, fine crackles, dry cough and an end-stage ‘honey comb lung’ are seen in what disease?
Chronic interstitial lung disease
A lung disease with an unknown cause seen typically in young adult females that is characterised by non-caseating granulomas.
Sarcoidosis
A lung disease that is usually occupational, caused by the inhalation of dusts.
Pneumoconioses
the nature of the disease depends on the type of dust you inhaled e.g. coal worker’s pneumoconiosis
Lung disease associated with in the inhalation of silica - sand and stone dust.
Silicosis
What is a Type III hypersensitivity reaction to organic dusts?
Hypersensitivity pneumonitis
(inflammation of the alveoli due to organic dusts.
e.g. farmers’ lung + pigeon fanciers’ lung)
Definition, epidemiology, aetiology, pathogenesis and key clinical features of:
Cystic fibrosis
Inherited multiorgans disorder of the epithelial cells and their fluid secretion in the epithelial linings of the respiratory, GI and reproductive organs.
Epidemiology: Common (1 in 25 are carriers), mainly caucasians
Aetiology: Autosomal recessive inheritance, abnormality of chromosome 7, faulty CFTR (chloride channel protein) = thick mucus
Pathogenesis: Bronchioles filled with mucus, resulting in repeat infections > severe bronchitis + bronchiectasis.
Clinical features: Lung infections, bronchiectasis, meconium ileus (blockage in the ileum), cirrhosis of liver (due to mucus plugging of bile canaliculi), atrophy + fibrosis of salivary glands, 95% of males are infertile
What is the drug lumacaftor–ivacaftor used to treat?
Cystic fibrosis
controversially expensive drug
The most common type of primary malignant tumour.
Carcinoma (>90%)
What are the 3 differences between small cell and non-small cell carcinomas?
Small cell carcinoma =
- Less cytoplasm
- Nuclear chromatin is fine
- Less prominent/no nucleoli
Non small cell carcinoma =
- More cytoplasm
- Nuclei are usually clumped together
- More prominent nucleoli
Most common type of primary lung carcinoma.
Adenocarcinoma
What are the 4 major types of primary lung carcinoma?
- Adenocarcinoma - gland formation
- Squamous cell carcinoma - shows keratinization
- Small cell carcinoma - diagnosis based on nuclear characteristics
- Large cell undifferentiated carcinoma - doesn’t have the other features
Low grade malignant lung tumours with better survival chances.
Carcinoid tumours
Most common type of malignant lung tumour?
Secondary lung tumour
carcinomas from other sites e.g. breast, GI tract, kidneys
(sarcoma, lymphoma, myeloma)
Lung cancer is the most common cause of cancer death in the UK and world wide.
True or False?
TRUE
A gene mutation that predisposed you to lung cancer even if you have never smoked?
- EGFR
- KRAS
- ALK
(either of these)
What is lymphangitis carcinomatosa?
Diffuse spread of the tumour into the pulmonary lymphatics system
What is the latent period for asbestos exposure and the development of carcinoma?
20 years
Which lung cell carcinoma shows keratinisation?
Squamous cell carcinoma
What is the most common type of malignant mesenchymal lung tumour?
Synovial sarcoma
mesenchymal tumour = sarcoma