Block 13 Flashcards
What are the sudden causes of breathlessness?
Pulmonary oedema (additional nocturnal dyspnoea)
Pneumothorax (additional pluritic chest pain)
PE (additional syncope)
Anaphylaxis (additional swelling, itch, urticaria)
Foreign body inhalation (onset whilst eating)
What are the rapid (hour onset) causes of breathlessness?
Acute asthma
Pneumonia
Pulmonary oedema
Acute hypersensitivity pneumonitis
What are the subacute (week onset) causes of breathlessness?
Heart failure
Anaemia
Pleural effiusion
Lung cancer
What are the slowly progressive causes of breathlessness?
COPD
Interstitial lung disease
Pneumoconiosis
Pulmonary arterial hypertension
What are some causes of cough?
Infection Left heart failure Lung cancer Foreign body inhalation ACE inhibitors Asthma COPD GO reflux disease
What are some factors to note about sputum?
Colour:
Mucoid? Purulent? Bloodstained?
Volume:
Large volume in bronchiectasis and bonchioalveolar carcinoma
Odour:
Putrid in anaerobic infection
What are the causes of haemoptysis?
Lung cancer TB Bronchiectasis Pulmonary oedema Pulmonary embolism Pneumonia
What are the causes of wheeze?
What is the difference between wheeze and stridor?
Wheeze = expiratory sound produced by air moving through narrowed airways.
Acute bronchitis
Asthma
COPD
Large airway obstruction
Stridor = an inspiratory sound in: whooping cough, epiglottitis, foreign body obstruction, laryngeal obstruction
What are the causes of chest pain?
Pleuritis
Pneumonia (sharp, stabbing, worse on inspiration)
PE (sharp, stabbing, worse on inspiration)
Pneumothorax (sharp, stabbing, worse on inspiration)
Tracheitis
Mediastinal tumour (retrosternal pain)
Rib mets (bony pain)
Spinal root pain
Herpes zoster (dermatomal)
What are the causes of wheeze - heard on auscultation?
Asthma = polyphonic and high pitched Monophonic = large airway obstruction
What are the causes of crackles - heard on auscultation?
Clearing with coughing = consolidation - lots of causes. Main being pneumonia.
What is the incidence of lung cancer?
The 2nd most common cancer in the UK ~45000
The leading cause of cancer death ~35000
What is the survival rate for lung cancer?
Poor.
1yr survival = 50%
5yr survival = 10%
What are the risk factors for developing lung cancer?
FHx
Environmental factors (asbestos, chemical dust, radiation)
Smoking
What are the main forms of lung cancer?
Small cell
Adenocarcenoma
Squamous cell carcinoma
Large cell carcinoma
Describe the features of small cell carcinoma.
The most malignant form of lung cancer
Metastasises early and widely
Histologically - lots of small, highly nucleated cells. Very fragile = crush artefacts
Closely associated with smoking
Necrosis is usually present and extensive throughout the lung
Common mutations (p53, KRAS, 3p)
Commonly associated with a PARANEOPLASTIC syndrome.
Describe the features of a lung adenocarcinoma.
Most common form of lung cancer
Not associated with smoking. (Usually found in young, non-smoking females)
Slow growing but can metastasise early
Usually sound in the periphery of the lung
Atypical adenomatous hyperplasia –> adenocarcinoma in situ.
Describe the features of squamous cell carcinoma.
As with small cell carcinoma, strongly associated with smoking rates.
Usually found in large, main, bronchi.
Squamous metaplasia –> dysplasia –> CIN –> neoplasm
Describe the features of large cell carcinoma.
Uncommon form of lung cancer (5-10%)
Linked with smoking - not as much as SCC and SCC
Undifferentiated, epithelial tumours.
What is a pancoast tumour?
An apical lung tumour which impinges on nerves in the mediastinum - particularly: recurrent laryngeal, vagus, sympathetic trunk.
Causes: Horners syndrome (enopthalmos, ptosis, miosis, anhidrosis)
What are the early –> late symptoms found in lung cancer?
Early:
Productive cough w/ blood, chronic cough, weight loss
Mid:
Chest pain, SVC syndrome, effusion, pneumonitis, atelectasis
Late:
Bone pain, heptaomegaly, neurological change, Addisons.
What percentage of heavy smokers develop lung cancer?
~11%
Suggesting that there is a strong genetic involvement
Give some examples of the common 2˚ pathology that can arise from lung cancer?
(10)
Partial lung obstruction = focal emphysema
Total lung obstruction = atelectasis
Venous blockage = pulmonary oedema
Invasion of pleura = pleuritis / pleural effusion
Vascular compression = superior SVC syndrome
Pericardial spread = pericarditis / tamponade
Recurrent laryngeal nerve = hoarsness
Sympathetic trunk = horners syndrome
Oesophageal invasion = dysphagia
Chest wall invasion = rib pain / destruction
What are the common clinical presentations of lung cancer?
Chronic cough
Weight loss
Chest pain
Dyspnea (SOB)
What are the main treatments for lung cancer?
Lobectomy
Pneumonectomy
Chemotherapy and radiotherapy (little effect on small CC)
EGFR inhibitors (adenocarcinoma)
What is the incidence of TB?
Extremely common cause of morbidity and mortality worldwide (>1.7billion infected)
2nd most common cause of deaths worldwide
UK incidence ~10/100,000
What are the main risk factors for TB?
Overcrowding Poverty Poor hygiene Concurrent chronic illness HIV infection
What organism causes TB?
Most commonly mycobacterium TB (can be mycobacterium bovis)
Acid fast bacillus (Zhiel Neilson stain)
Spread by droplet infection
What is the pathophysiology of 1˚ TB?
Droplets into the lungs - usually effects lung apices as M.tb is an aerobic organism.
Taken up by alveolar macrophages + phagocytosis
TB released substance which prevents lysosome fusion
Replication and proliferation within macrophages
Causes a 1˚ infection which generally goes unnoticed (subclinical or flu-like infection)
After 3w antigens are taken to lymph and cell-mediated immune response begins.
T-cells release INF-gamma which causes macrophages to coagulate and form fibrous capsule around the infected area GHON FOCUS
GHON COMPLEX is formed with lymph nodes become involved.
What is the pathophysiology of 2˚ TB infection?
Reactivation of a latent ghon focus due primarily to immunosuppression (drugs, disease, age).
Causes a severe - localised inflammatory reaction.
Cavitation when the necrosed centre of the lesion erodes into a bronchiole and has a method of escape.
Haemoptysis, pleural effusion, emphysema, pleuritis
GHON COMPLEX is formed with lymph nodes become involved.
Miliary TB = seeding of other organs with lesions of TB (particularly the liver) causing widespread infection.
What component of the cell wall causes TB to be acid fast?
Myocolic acid
What are the two forms of drug resistant TB?
Multidrug resistant = ioniazid and rifampicin resistant
Extensively drug resistant = as MDR +1 of: ethambutol, streptomycin, pyrazinamide
What are the main components that are seen in spirometry?
Vital capacity = max inhalation to max expiration. Should be >80%. Is decreased in restrictive airway disease
FEV1 = max air expelled in 1 sec. Decreased in both restrictive and obstructive
FEV1:FVC = proportion of vital capacity expelled in 1 sec. Decreased in obstructive disease.
What FEV1:FVC ratio is indicative of obstructive lung disease?
<70%
What spirometry pattern is seen in obstructive lung disease?
Normal FVC
FEV1 reduced >70%
What spirometry pattern is seen in restrictive lung disease?
FVC reduced
FEV1 reduced
As both reduced by same quantity ratio is normal
What spirometry pattern is absolutely indicative of asthma?
A 15% improvement of FVC1 after administration of Beta agonists.
What is the test for infection with TB?
Mantoux = subcutaneous PPD
No differentiation between infection and disease?
What is the difference between TB infection and disease?
Infection = latent infection after 1˚ TB disease
Disease = current, active infection and inflammation.
What is respiratory failure?
Failure of the lungs and respiratory system to provide the oxygen requirements and CO2 secretion required by the body.
Can be type 1, type 2 or somewhere between the two extremes.
What is type 1 respiratory failure?
‘pink puffer’
Hypoxia without hypercapnia.
Hunched over, struggling to breathe, pursed lip breathing, barrel chest, accessory muscles of inspiration, hyperventilation
What is type 2 respiratory failure?
‘blue bloater’
Hypoxia and hypercapnia
Cyanosis, hypoventialtion, diminished drive
What are the two forms of emphysema?
Panacinar = total alveolar enlargement. Mainly caused by congenital disease (alpha-1 amitrypsin deficiency)
Centriacinar = enlargement at the levels of respiratory bronchioles. Caused by damage from smoking.
Define emphysema.
Lung parenchyma destruction without fibrosis and insufficient wound repair.
Describe the pathophysiology of emphysema.
A combination of genetic and environmental factors - mainly smoking.
Causes inflammation of the lung parenchyma (anti-inflamamtories a-1 amitrypsin deficiency)
Activation of proteases, elastases, cytokines, oxidants.
Causes: necrosis, apoptosis, ECM destruction
What are the major symptoms of COPD?
Progressive dyspnea (SOB) Chronic cough Wheezing Weight loss (misconstrued as neoplasia) FEV1:FVC <70%
Describe the pathophysiology of chronic bronchitis.
A cough lasting longer than 3 consecutive months in two consecutive years.
Mucus hyper secretion caused by hyperplasia of goblet cells within the large bronchial walls - caused by excessive chemical stimulation.
Hypersecretion of mucus –> outflow obstruction –> mucus plugs, inflammation, fibrosis –> 2˚ microbial infection
What are the main features of asthma?
Reversible airflow obstruction SOB - particularly brought on by exercise Diurnal variation Wheeze (possibly stridor) Inflammatory airway obstruction Eosinophil infiltrate
What is the main difference between COPD and asthma
COPD is irreversible whereas asthma is reversible (time and medication)
What are the common airway irritants in asthma?
Dust + dust mites, mould, pet dander, chemicals, pollen, shellfish, nuts
What is the main piece of legislation that has decreased occupational asthma in the last 50 years.
Clean air act (1950)
What is the difference between occupational asthma and workplace asthma?
Occupational asthma = caused by work
Workplace = current asthma exacerbated by the workplace.
What are the main diseases of the airway?
Occupational asthma Occupational COPD Pneumoconiosis Toxic pneumonitis Occupational infections (TB) Malignancies (lung and pleura)
What are the most common allergens to cause occupational asthma?
Flour (bakers asthma)
Solder
Isocyanates
How can occupational asthma be distinguished from ‘normal’ asthma?
- Are the symptoms worse at work
- Do the symptoms get better when away from work - at weekend and on holiday.
- Peak flow diary to measure this