P10 - Pulmonary pathology Flashcards
What are clinical presentations of lung disease?
- Cough, wheeze
- Breathlessness (dyspnoea)
- Chest pain (often due to pleural disease)
Are the lungs themselves sensitive to pain?
No- but the chest wall is
What are the 2 functional classifications of lung disease?
- Obstructive
- Restrictive
Describe obstructive lung disease.
Normal volume but difficulty getting air out (asthma)
Describe restrictive lung disease.
Decreased lung volumes (scarring /fibrosis in lungs)
Name 5 ways of investigation of a patient with lung disease.
- Chest x-ray +/- CT scan
- Hb, white cell count etc
- Arterial blood gases (pO2, pCO2, pH)
- Physiology (spirometry, pulmonary function tests)
- Bronchoscopy +/- biopsy and lavage
what is the lungs function?
to facilitate transfer of O2 to blood and CO2 in the other direction
What is type 1 respiratory failure?
decreased arterial pO2
What is type II respiratory failure?
decreased arterial pO2 plus increased arterial pCO2
which is worse of the two respiratory failures?
Type II - pulmonary function is terminal
What does decreased Pa O2 lead to?
• Dyspnoea and increased respiratory rate
• Pulmonary vasoconstriction (and pulmonary
hypertension)
• Eventually right sided heart failure
What can cause airway narrowing /obstruction?
- Muscle spasm
- Mucosal oedema (inflammatory or otherwise
- Airway collapse due to loss of support
- (Localised obstruction due to tumour or foreign body)
What are the main categories of obstructive disease?
- Asthma
* Chronic obstructive pulmonary disease (COPD/COAD/COLD)
What is bronchial asthma?
A chronic inflammatory disorder characterised by hyperreactive airways leading to episodic reversible bronchoconstriction
What is extrinsic asthma?
response to inhaled antigen
What is intrinsic asthma?
non-immune mechanisms (cold, exercise, aspirin)
What is type I hypersensitivity ?
Allergen binds to IgE on surface of mast cells
what effects does type 1 hypersensitivity have?
• Degranulation (histamine)
– muscle spasm
– inflammatory cell influx (eosinophils)
– mucosal inflammation/oedema
• Inflammatory infiltrate tends to chronicity
Name the types of pathology.
- Narrowed oedematous airways
- Mucus plugs
- Inflammatory cells (lymphocytes, plasma cells, eosinophils)
- Epithelial cell damage
What is mucosal oedema?
airways narrowed and blocked by mucous
Name 2 types of chronic obstructive disease.
- Chronic bronchitis
* Emphysema
what do symptomatic patients have?
Often have both chronic bronchitis and emphysema
What is the epidemiology of COPD?
- Smoking
- Atmospheric pollution
- Genetic factors
what is the epidemiology definition of chronic bronchitis?
Cough productive of sputum on most days for 3 months of at least 2 successive years
what does chronic bronchitis not imply?
airway inflammation
What is emphysema?
• Increase beyond the normal in the size of the airspaces distal to the terminal bronchiole
• Without fibrosis
-The gas-exchanging compartment of the lung
What is emphysema due to?
“Dilatation” is due to loss of alveolar walls (tissue destruction)
• Appears as “holes” in the lung tissue
Discuss the diagnosis and treatment of emphysema.
• Difficult to diagnose in life (apart from in
extremis)
• Radiology (CT) can show changes in lung
density
• Correlation with function known from autopsy studies
what is panacinar emphysema?
Tissue destructtion-extreme -big dilated airspaces, loss of tissue between gives illusion of dilation
what do emphysema impair?
respiratory function
How does emphysema impairs respiratory function?
- Diminished alveolar surface area for gas exchange
* Loss of elastic recoil and support of small airways leading to tendency to collapse with obstruction
What causes restrictive lung disease?
- Decreased lung volumes due to scarring +/- inflammation in the alveolar walls
- Many causes (idiopathic pulmonary fibrosis, sarcoidosis, farmer’s lung, asbestosis)
Name 3 pulmonary infections.
- Pneumonia
- Chronic infection – abscess/bronchiectasis
- Tuberculosis
what is pneumonia?
Infection involving the distal airspaces usually with inflammatory exudation (“localised oedema”)
-fluid filled spaces lead to consolidation
what is bronchopneumonia?
Common in older people -after flu - common terminal cause of death
what is the clinical context of bronchopneumonia?
- COPD
- Cardiac failure (elderly)
- Complication of viral infection (influenza)
- Aspiration of gastric contents
Name 4 complications of pneumonia.
- Scarring
- Abscess
- Bronchiectasis
- Empyema (pus in the pleural cavity)
Describe lung abscess.
- Localised collection of pus •Tumour-like
* Chronic malaise and fever •Context - aspiration
what is tuberculosis?
- Mycobacterial infection
* Chronic infection described in many body sites – lung, gut, kidneys, lymph nodes, skin
what is tuberculosis pathology characterised by?
delayed (type IV) hypersensitivity (granulomas with necrosis)
what are the 2 types of lung neoplasm?
- Primary
- Metastatic
What are the 2 types of primary lung neoplasms.
– benign (rare)
– malignant (very common)
What is metastatic?
coming from somewhere else in the body
what is the commonest cause of cancer death in men?
33% in men
what is the mortality rate 1 year after diagnosis?
90%
What does tobacco smoke contain?
- polycyclic hydrocarbons
- aromatic amines
- phenols
- nickel
- cyanates
What percentage of smokers die of lung cancer and what do they also suffer from?
- 20% of smokers die of lung cancer
- (also suffer laryngeal, cervical, bladder, mouth, oesophageal, colon cancer)
What is the clinical presentation of a primary neoplasm?
Local effects:
- obstruction of airway (pneumonia)
- invasion of chest wall (pain)
- ulceration (haemoptysis
What is the clinical presentation of metastases?
– nodes
– bones
– liver
– brain
How many common smoking -associated lung tumours are there (heterogenous)?
4: – adenocarcinoma (35%) – squamous carcinoma (30%) – small cell carcinoma (25%) – large cell carcinoma (10%)
what other classification of lung tumours are there?
- Neuroendocrine tumours
* Bronchial gland tumours
what is different about different type of tumours?
Prognosis
what is the most simple classification of lung cancer?
- Small cell lung cancer (SCLC)
- Non-small cell lung cancer (NSCLC)
What is the treatment of small cell lung cancer?
- Small cell known to be chemosensitive but with rapidly emerging resistance
- Surgery the treatment of choice in other types. “Non-small cell” regimens have also been developed in chemotherapy/radiotherapy
What are new development in chemotherapy?
- Differing NSCLC regimens for squamous cell and adenocarcinoma (e.g. pemetrexed contraindicated in squamous carcinoma)
- Molecular abnormalities, particularly in adenocarcinoma, can define susceptibility to new targeted drug treatments
Describe the molecular pathology and targeted treatment (epithelial growth signalling in lung epithelium.
- Specific point mutations render the EGFR gene active in the absence of ligand (epidermal growth factor) binding
- These mutations can be identified in DNA extracted from biopsy or cytology samples
- Mutation seen almost exclusively in adenocarcinoma (esp. non-smokers and in Asian populations)
- These tumours respond to tyrosine kinase inhibitors (erlotinib)
- EML4-ALK fusion oncogene also identifies a target for specific drug treatment (crizotinib)
