Respiratory Flashcards
What are the common obstructive airway diseases?
Chronic bronchitis
Emphysema
Asthma
What is the mechanism behind asthma?
Type 1 hypersensitivity in the airways to an allergen
Either specific IgE, stress, cold drugs or chemicals
What is the clinical definition of chornic bronchitis?
Cough productive of sputum most days in 3+ consecutive months for 2+ consecutive years
Exludes TB, bronchiestasis
What are the morphical changes in chronic bronchitis?
Large airways >Mucous gland hyperplasia >Goblet gland hyperplasia >Inflammation and fibrosis Small airways >Goblet cells appear Inflammation and fibrosis in long term disease
What is emphysema?
Increase beyond the normal size of airspaces distal to terminal bronchiole
Either due to dilatation or destruction
And without obvious fibrosis
What are the types of emphysema?
Centriacinar
Panacinar
Periacinar
Scar
What is centriacinar emphysema?
Loss of respiratory bronchioles in proximal portion with sparing of distal alveoli
Typical in smokers
What is panacinar emphysema?
Loss of all portions of acinus, from bronchiole to alveoli
Typical in apla-1-antitrypsin deficiency
What is type 1 respiratory failure?
Where PaO2 is less than 8kPa
With PaCO2 normal or low
What is type 2 respiratory failure?
Where PaCO2 is greater than 6.5 kPa
With PaO2 usually being low
What are the four states associated with hypoxaemia?
Ventilation/perfusion imbalance
Diffusion impairment
Alveolar hypoventilation
Shunt
What are the pulmonary vascular changes in hypoxia?
Pulmonary arteriolar vasoconstriction
>Occurs in all vessels in hypoaemia
Due to protective mechanisms
What is cor pulmonale?
Hypertrophy of the right ventricle resulting from disease affecting the function and/or structure of lung
What is asthma?
A disease characterised by increased responsiveness of trachea/bronchi to various stimuli
Manifested by widespread narrowing of airways
Changes in severity either spontaneously or as a result of therapy
What is the prevalence of asthma?
10-15% of children (boys>girls)
5-10% adults (girls>boys)
What are the risk factors for asthma?
Inherited tendency to IgE response to allergens
>Asthma, eczema, hayfever, food allergy etc family history
>Maternal most influential (3x that of father)
Occupation Obesity Diet Smoking (maternal during pregnancy) Indoor pollution, maybe outdoor
How is obesity linked to asthma/airway problems?
Positively associated with:
>Asthma
Wheezing
>Airway hyperactivity
Also more breathless
>obesity pro-inflammatory
How do you diagnose asthma clinically?
Wheeze (NO WHEEZE NO ASTHMA) Short of breath, with severity Chest tightness (/pain) Cough - usually dry, paroxysmal Sputum occasionally
Look for airflow obstruction + variability
What are the triggers for asthma?
Exercise Cold air Smoke Perfume URTIs Pets Tree/grass pollen Food Aspirin
What signs on examination indicate it might not be asthma?
Clubbing Cervical lymphadenopathy Stridor Assymetrical expansion Dull percussion note Crepitations
What tests can you do to confirm asthma?
Spiromitry
>If obstructed do full pulmonary function testing to exclude COPD
>If obstructed then check reversibility with B2 agonists/steroids
> If normal check peak flow monitoring
?If still okay, do bronchial provocation with nitric oxide
What are some useful investigations into asthma?
Chest X ray >Check for hyperinflaton/hyperlucent Skin prick testing Total/specific IgE Full blood count (for eosinophillia)
What indicated acute severe asthma?
Ability to speak inhibted Heart rate >110 Resp rate >25 PEF Oxygen sats down
What is a moderate asthma attack?
Increasing symptoms, however still able to speak and stats not as high as severe
What indicates life-threatening asthma?
Grunting Impaired conciousness, confusion / exhaustion Bradycardic OR HR >130 Hypoventilating Cyanosis
Raised PaCO2 is near fatal
What are the differentials of asthma?
Viral induced wheeze CF Immune deficincy Foreign body Possibly aspiration
How do you treat episodic wheeze with a cold?
Salbutamol
What are the differentials for an isolated cough in children?
Brocnhitis (2-3 years)
Pertussis
Habitual cogh (8-12 years)
Tracheomalacia (life long)
What are the clinical features of bacterial bronchitis?
Recurrent wet cough Tractor (darth vader sounding) Palpable fremitis Often first born + very well child Self limiting
What is the natural history of bacterial bronchitis?
Follows URTI
Lasts 4 weeks
First winter bad, progressively better. 3rd is often fine
Often caused by pneumococcus
What is pertussis?
Coughing fits (whoping cough) Often with vomiting, colour change + petechiae Vaccination available
What are the common URTIs?
Coryza (common cold) Sore throat syndrome Acute laryngotracheobronchitis (croup) Laryngitis Sinusitis Acute epiglottitis
What two organisms cause acute epiglottitis?
Group A beta-haemolytic streptococci
H. Influenzae (type B)
What are the LRTIs?
Bronchitis
Bronchiolitis
Pneumonia
+complications
What are the respiratory tract defence mechanisms?
Macrophage-mucociliary escalator system
General immune system
Respiratory tract secretions
What makes up the macrophage–mucociliary escalator system?
Alveolar macrophages
Mucociliary escalator
Cough reflex
What are the aetiological calssifications of pneumonia?
Community Acquired Pneumonia Hospital Acquired (Nosocomial) Pneumonia Pneumonia in the Immunocompromised Atypical Pneumonia Aspiration Pneumonia Recurrent Pneumonia
What are the patterns of pneumonia?
Bronchopneumonia
Segmental
Lobar
Hypostatic
Aspiration
Obstructive, Retention, Endogenous Lipid
What is the bronchopneumonia pattern?
Often bilateral basal opacification
Due to focal nature of consolidation
What are the possible complications of pneumonia?
Pleurisy, Pleural Effusion and Empyema Lung Abscess Bronchiectasis Constrictive bronchiolitis Pneumonia is still a potentially fatal disease
What can cause lung abcesses?
Tumours - leading to obstructed bronchus
Asipiration
Particular organisms - Staph A, some pneumococci
Necrotic lung (sencondary to infection)
What is bronchiectasis?
Pathological dilatation of bronchi due to >Severe infection >Recurrent infections >Proximal bronchial obstruction >Lung parenchymal destruction
What is the clinical picture of bronchiectasis?
Cough Abundent foul sputum!!! Haemoptysis Signs of chronic infection Coarse crackles Clubbing
How do you treat bronchiectasis?
Postural drainage
Antibiotics
Surgery
What are the causes of aspirational pneumonia?
Vomiting Oesophageal Lesion Obstetric Anaesthesia Neuromuscular Disorders Sedation
What are opportunistic infections?
Infection via organism not usually capable of producing disease
However able to in patients with existing lung disease
What are examples of opportunistic infections?
Low grade bacterial pathogens
CMV
Pneumocystis jirovecii
Other fungi and yeasts
Why do you get hypoxaemia in pneumonia?
Ventilation mismatch due to bronchitis
Shunt in severe bronchipneumonia - leads to no ventilation of abnormal alveoli
What is a shunt?
Blood passing from right to left side of heart without contacting ventilated alveoli
Lung shunts respond poorly to increased fractional oxygen intake
What can cause pathological shunt?
AV malformations,
congenital heart disease
and PULMONARY DISEASE
What are the causes of COPD (Emphysema + chronic bronchitis)?
Smoking (85%) Chronic asthma Passive smoking Maternal smoking Air pollution Occupation (Dusts, vapours/fumes: coal mining, concrete, farming, plastics, textiles etc) Rare: alpha1-antitrypsin deficiency
What are the clinical features of COPD?
Cough Sputum Dyspnoea Wheeze Weight loss
Tachypnoea Prolonged expiratory pahse Hyperinflation (barrel chest) Cynaosis Inspiratory crackles Cor pulmonale
What indicates emphysema?
Emphysema (pink puffers) >Increased alveolar ventilation - pink but breathless >Normal PaO2 Normal/low PaCO2 T1 respiratory failure
What indicates chronic bronchitis?
Chronic bronchitis (blue bloaters)
>Decreased alveolar ventilation - cyanosed not breathless
>Decreased PaO2 + increased PaCO2
>Type 2 respiratory failure + cor pulmonale
How do you investigate COPD?
CXR (look for hyperinflation, prominent pulmonary arteries + peripheral oligaemia)
ECG (R Atrial hypertrophy)
Spirometry
What are the causes of lung cancer?
Tobacco Asbestos Environmental causes Radiation Pulmonary fibrosis
What are the four main types of cancer in the lungs?
Adenocarcinoma
Squamous cell carcinoma
Small cell carcinoma
Large cell carcinoma
What genes cause adenocarcinoma of the lungs?
KRAS (35%) = smoking induced
EGFR = 15% (not smoking)
BRAF, HER2, ALK
Why is a primary lung cancer often fatal?
Symptoms don’t show until late in disease
By that time often too late to cure
What are the local effects of lung cancer?
Bronchial obstruction (through collapse or otherwise) Pleural issues of inflammation/malignancy
What are the effects of a cancer invading the following nerves? Phrenic L recurrent laryngeal Brachial plexus Cervical sympathetic
Phrenic - Diapragmatic paralysis
L recurrent laryngeal - Hoarse, bovine cough
Brachial plexus - Pancoast T1 damage
Cervical sympathetic - Horners syndrome
Where can a lung cancer locally spread to?
Chest wall
Nerves
Mediastinum
Lymph nodes
Where can a lung cancer distally spread to?
Liver Adrenals Bone Brain Skin
What hormones does a small cell cancer affect?
ACTH
siADH
What hormones does a squamous cell lung cancer affect?
PTH
What non-metastatic effects do you get from lung cancer?
Finger clubbing Hypertrophic pulmonary osteoarthropathy Endocrine disruption Acanthosis nigricans Nehprotic syndrome
How do you investigate lung cancer?
CXR
Bronchoscopy
FNA
Pleural effusion
Maybe CT, MRI etc
What is the prognosis of lung cancer?
7% 5 year survival Mostly dependant on stage If operable then better: >Stage 1 60% >Stage 2 35%
What is the prognosis of small cell carcinoma of lungs?
4% - median survival is 9 months
What are the two main thromboembolic diseases?
DVT
PE - pulmonary embolism
What is virchows triad?
Decreased blood flow
Abnormal vessels
Hypercoagulable state
> States risk factors for thromboembolic disease
What causes decreased blood flow?
Immobility Travel Bed bound Obesity Heart failure
