Respiratory Flashcards
Lobes of the lung
Left has 2 (superior, inferior)
Right has 3 (superior, middle, inferior)
These are separated by the horizontal and oblique fissures
Define COPD
COPD describes progressive and irreversible obstructive airway disease. Consists of Chronic Bronchitis and Emphysema together.
Risk factors for COPD
- Age (>40)
- Smoking (biggest)
- Air pollution
Occupational exposure (coal, cement, dust, smelting) - Frequent respiratory infections
- Gender (men)
- Alpha 1 anti-trypsin deficiency- (young patients presenting with COPD!!)
O2 saturation targets for a normal person and for someone with an acute COPD exacerbation. And at what O2 sats is someone considered hypoxic
Normal: 95-100%
COPD exacerbation: 88-92% (normal COPD maintained above 92%)
Normal <94%
COPD exacerbation <88%
What 2 organisms usually cause infective exacerbations of COPD
H. influenza
S. pneumoniae
If a young patient presents with COPD symptoms without a smoking history, what should be suspected?
Alpha 1 Antitrypsin deficiency
Define chronic bronchitis
Inflammation of the bronchial tubes. Considered chronic when it causes a productive cough for at least 3 months a year for 2 years.
Pathophysiology of Chronic Bronchitis
Overall
- Hypersecretion
- Ciliary dysfunction
- Narrowed lumen
Explanations:
- Irritation of epithelium of bronchi causes inflammation. This leads to hypertrophy and hyperplasia of the bronchial mucous glands in bronchi, and goblet cells in bronchioles.
- Epithelial layer becomes ulcerated, eventually replacing the columnar epithelium with squamous (metaplasia), and smoking makes cilia shorter and less mobile
- Chronic inflammation causes infiltration of epithelium, narrowing lumen.
Why does Chronic Bronchitis increase infection risk
Even a small amount of mucus can block lumen, stopping clearance.
Cilia are also shortened and immobile.
Explain the lung spirometry tests (4)
1) FVC (Forced vital capacity) - Max air volume in 1 breath (<80%)
2) FEV1 (Forced Expiratory Volume in 1 second) - Max air 1 second (<80%)
3) FEV1:FVC Ratio (<0.7 obstructive)
4) TLC (total lung capacity) (increased in COPD due to air trapping)
Signs/symptoms of Chronic Bronchitis
Blue Bloater
- Chronic productive cough
- Cyanosis
- Dyspnoea on exertion
- Usually overweight
- Purulent sputum
- Crackles, wheezes when breathing
Hypoxia/aemia (insufficient oxygen in tissues/blood) and hypercapnia (high CO2)
What are some symptoms of CO2 retention? (as would be seen in COPD)
- Drowsiness
- Asterixis
- Confusion
- Cyanosis
Complications of chronic bronchitis
- Secondary polycythaemia vera
- Pulmonary HTN due to reactive vasoconstriction to hypoxaemia
- Cor pulmonale due to chronic pulmonary HTN
Define emphysema
Damage to/destruction of the alveolar air sacs. This causes the alveoli to permanently enlarge and lose elasticity. This means the lungs are unable to recoil, so patients have trouble exhaling
Pathophysiology of emphysema
Irritants trigger inflammation in lungs, releasing proteases (collagenases, elastases), which break down elastin. Normally, elastin prevents low pressure environment from collapsing. In emphysema, elastin is lost and airways collapse.
This causes:
- Air trapping distal to point of collapse
- Airways stretch during inhalation but cant breath out fully.
- Elastin loss also causes breakdown of thin alveolar walls (Septa), causing neighbouring alveoli to coalesce. This reduces the area for gas exchange.
Types of Emphysema
Centriacinar - most common. Damages central/proximal alveoli in each acinus, in the upper lobes of lungs. Seen in smokers.
Pan-acinar - Whole acinus affected. Seen in A1AT, affecting lower lobes.
Para-septal - Distal alveoli, can cause a pneumothorax when alveoli rupture
Irregular - Irregular acinar involvement. Scarring/fibrosis
Signs/symptoms of emphysema
Pink puffer
- Pursed lip breathing
- Barrel shaped chest
- Hyperresonance on percussion
- Downward displacement of liver
- Dyspnoea, cough, weight loss
Imaging signs of emphysema (3)
- Increased anterior-posterior diameter
- Flattened diaphragm
- Increased lung field lucency
Signs of COPD (6)
- Barrel chest
- Hyperresonance on percussion
- Cyanosis
- Pursed lip breathing
- Wheezing/crackling
- Productive cough with purulent sputum
What scale is used to assess breathlessness
MRC dyspnoea scale.
Breathlessness:
1 - on exercise
2 - on hurrying/slight hill
3 - walks slower than others/ has to stop to catch breath
4 - Stops to catch breath after 100m
5 - breathless on minimal activity (getting changed)
Investigations in COPD
Clinical diagnosis - Over 35, smoking history, signs/symptoms of COPD.
Spirometry
- FEV1<80% expected
- FEV1/FVC <0.7, with no bronchodilator reversibility
Chest X ray -
- Flattened diaphragm
- Hyperinflation
- Bullae
CHECK FBC - COPD causes chronic hypoxia -> polycythaemia vera.
Give the difference between type 1 and 2 resp failure. What investigation helps check this?
ABG
1 - low oxygen and normal/low CO2
2 - low oxygen and high CO2
How is COPD classified
GOLD classification
Goes down based on FEV1
e.g. FEV1>80% = 1 (mild),
FEV1 50-79 = 2 (moderate) etc
FEV1 49-30 = 3 (Severe)
FEV1 <30 = 4 (very severe)
Name all 5 drugs used in COPD treatment
Bronchodilators:
- Short acting Beta 2 agonist (salbutamol)
- Long acting Beta 2 agonist (salmeterol)
-
- Short acting muscarinic antagonists (Ipratropium bromide)
- Long acting muscarinic antagonists (Tiotropium)
Inhaled corticosteroid (Beclometasone)
Treatment algorithm of COPD (inhalers)
1) SABA or SAMA
2) LABA and LAMA regularly (ICS if asthma features)
3) LABA + LAMA + ICS
+ SABA at any stage (can still be taken as required)
Other treatments of COPD
Long term Oxygen if sats below 92 at rest
Oral Theophylline (bronchodilator)
Oral mucolytic
Prophylactic azithromycin!
Indications of oxygen in COPD
- If O2 Sats <92% at rest (88-92 is during exacerbation)
- Cyanosis
- Polycythaemia
- Raised JVP
- If FEV1<30%
Oxygen targets in patients on oxygen
88-92% if retaining CO2
>94% if not retaining CO2
How do Beta 2 agonists and Muscarinic antagonists work
B Agonist - Bind to and activate Beta 2 receptors (which are normally activated by NAd)
M antagonist - Bind to M3 muscarinic receptors. Prevents acetylcholine from binding, preventing bronchoconstriction
Complications of COPD (4)
- Cor pulmonale (RH failure secondary to pulmonary HTN)
- Pneumothorax
- Type 1/2 resp failure and respiratory acidosis
- Infections
How does pulmonary hypertension cause cor pulmonale, and what are its clinical manifestations
Pulmonary vasoconstriction and HTN means right heart must pump against high pressures, eventually failing.
Causes peripheral oedema, raised JVP, hepatomegaly
Define COPD exacerbation with ABG finding
Acute worsening of symptoms, usually due to infective cause (H influenza, S pneumoniae).
Shows respiratory acidosis (low pH and high CO2). Increased bicarbonate (HCO3-) shows compensation by kidney
Treatment of COPD exacerbation
Amoxicillin
What are the criteria for bronchodilator reversibility
> 12% increase in FEV1
AND volume increase >200ml post bronchodilator
Define asthma
Chronic airway disease characterised by reversible airway obstruction, airway hypersensitivity and inflamed bronchioles, causing recurrent episodes of dyspnoea, wheezing and a productive cough.
This can be allergic/IgE mediated, or non IgE mediated (exercise, cold air and stress)
Define Atopy
Predisposition to respond immunologically to a diverse range of allergens, leading to CD4+ Th2 production, and overproduction of IgE.
The 3 atopic diseases are atopic dermatitis, allergic rhinitis and asthma
Risk factors for asthma
- History of atopy
- Family history
- Allergen exposure (tobacco, pets, outdoor air pollution, dust, grass, pollen)
- Viral URTI
- Growing up in a clean environment (Hygiene hypothesis)
Pathophysiology of asthma
Allergen picked up by dendritic cells and presented to Th2 cells, which respond by releasing cytokines, releasing IgE which bind to mast cells, causing mast cell degranulation. This releases histamine, leukotrienes, prostaglandin.
This causes chronic airway inflammation causing:
- Bronchoconstriction and smooth muscle spasm
- Mucus hypersecretion
After a few hours, immune cells release chemical mediators that damage the lung. At first this is reversible, however over time, this causes thickening of epithelial basement membrane, permanently reducing airway diameter.
Precipitating factors of asthma
- Pollen, dust mites, grass
- Cold air
- Exercise
- Pets
- Tobacco smoke
- Occupational allergens (bakers, manufacturers, lab work, welding)
Signs/symptoms of asthma
Episodic shortness of breath, usually after trigger exposure.
- Diurnal PEFR variation (worse at night/early morning)
- Usually dry cough (but can be productive)
- Expiratory wheezing/dyspnoea/chest tightness
What might microscopy of an asthma patients sputum look like?
Will contain spiral mucus plugs - casts from small bronchioles.
Investigations in asthma
Spirometry:
- FEV1/FVC <70%
- Bronchodilator shows improvement
Fraction of exhaled nitric oxide (FeNO): >45ppb
Peak Expiratory Flow Rate (PEFR) GOLD. Multiple times a day for 2-4 weeks. Variability >20% throughout day diagnostic
Allergy testing
What is Samter’s triad
Inflammation and swelling of airways in response to aspirin/NSAIDs. Leads to:
- Chronic Asthma history
- Recurrent nasal polyps
- Aspirin intolerance/hypersensitivity
Management algorithm of asthma
1) SABA (Salbutamol)
2) SABA + low dose ICS (beclomethasone)
3) SABA + low dose ICS + LTRA (leukotriene receptor antagonist) (montelukast)
4) SABA + low dose ICS + LABA (salmeterol), + LTRA in adults, - LTRA in children
5) SABA + MART (Maintenance and reliever therapy - fast acting LABA and ICS)
What does stepwise management mean in asthma?
- Aim to use lowest effective doses possible
- Only step up treatment if previous doesn’t work
- Step down treatment every 3 months
- Annual asthma reviews for stable asthma
Define asthma exacerbation
acute/subacute episode of progressive worsening of asthma symptoms (SOB, wheezing, cough, chest tightness)
What suggests severe asthma exacerbation/episode
Any of
- PEFR 50-33%
- Resp Rate >25
- Heart rate >110
- Inability to complete sentences in one breath
Signs of life threatening asthma exacerbation
Cyanosis
Reduced GCS
Exhaustion causing silent chest
Arrhythmia
Hypotension
PEFR <33%
SpO2 <92%
PO2 <8kPa
Normal PaCO2
Acute management of asthma exacerbation
Moderate
- Salbutamol + 5 days prednisolone
Severe/life threatening - hospital
1 - Oxygen (aim for SpO2>94%)
2 - Nebulised bronchodilators (SABA, SAMA)
3 - Oral Prednisolone
3 (if not conscious) - IV bronchodilator (Magnesium sulphate)
At what PEFR can a patient be discharged
When it falls back into moderate range, PEFR>75%
Define Tuberculosis
Granulomatous infection caused by Mycobacterium tuberculosis. Present in 1.7b people worldwide in latent stage. Common in South Asia and sub saharan Africa
Risk factors for TB
- Recent active TB contact
- Endemic region travel
- Homelessness
- Immunosuppression
- Alcohol/drug abuse
Pathophysiology of TB
Macrophages struggle to clear M tuberculosis due to waxy mycolic capsule, which confers protections and prevents stain binding (acid fast!).
Spreads via respiratory droplets from active disease patients.
Disease has 4 stages (more detail in other cards)
- Primary
- Latent (dormant, asymptomatic)
- Secondary (reactivation)
- Miliary (systemic spread)
Stages of TB infection
Primary - TB phagocytosed but resists killing. Focal, caseating granuloma forms in upper part of lung, called a Ghon focus. If there is hilar lymph nodes involvement, it becomes a Ghon complex.
Latent - Bacteria dormant, patient is asymptomatic. Sputum test will be negative but Mantoux will still be positive
Secondary - Immunocompromised patients. Latent TB reactivates, patient is infectious and symptomatic.
Miliary - Lymphatogenous spread to other organs, causing systemic symptoms
Signs/symptoms of TB
- Fever
- Night sweats
- Weight loss
- Cough with haemoptysis
- Lymphadenopathy
- Crackling on auscultation
- Dyspnoea
- Clubbing if long standing
Extrapulmonary TB symptoms
TB Meningitis
TB back/spine pain (Pott’s disease)
TB pericarditis
TB cystitis
Miliary TB (disseminated)
Investigations in latent TB
Mantoux screening - Intradermal injection of purified protein derivative tuberculin, causes type IV hypersensitivity reaction. >55 induration positive
Interferon gamma release assay - Blood mixed with TB. If previous contact, interferon gamma released
Causes of false positive TB test results (3)
Previous BCG vaccine
Non tuberculous mycobacteria infection
Incorrect tuberculin administration
Causes of false negative TB test results (4)
Recent infection (<8 weeks)
HIV
Lymphoma
Sarcoidosis
Investigations in active TB
Chest X ray (specific signs, in separate card)
- Sputum stain/culture - 3 deep cough sputum samples. Will stain red with Ziehl-Neelsen stain. Mycobacterium culture positive.
- Nucleic-acid Amplification Test (NAAT) - Test conducted on urine or sputum. Done if patient has HIV, or is under 15.
CXR signs in TB
Primary
- Patchy consolidations
- Pleural effusion
- Hilar lymphadenopathy
Latent
- Ghon complex
Secondary
- Nodular consolidation with cavitation (gas filled spaces) in upper lung
Miliary
- “Millet seeds” uniformly distributed throughout lung fields
What vaccine helps prevent against TB
BCG vaccine
Treatment of active TB
RIPE - two months course
Rifampicin
Isoniazid (+ Pyridoxine)
Pyrazinamide
Ethambutol
Then R and I for 4 further months
What is prescribed with isonazid and why?
Pyridoxine (vitamin B6)
Helps prevent peripheral neuropathy
Treatment of latent TB
RI for 3 months
Rifampicin
Isoniazid (+Pyridoxine)
OR Isoniazid for 6 months
What should be done immediately in active TB patient
- Notify UKHSA
- Isolate patients, ideally in negative pressure room
- Contact tracing
Side effects of TB treatment drugs
R- rifampicin –> red urine/sweat
I- isoniazid –> peripheral neuropathy
P- pyrazinamide –> gout, hepatitis
E- ethambutol –> optic neuritis
All can also cause hepatitis
MoA of TB drugs
Rifampicin - inhibits bacterial RNA polymerase
Isoniazid - Inhibits mycolic acid synthesis
Pyrazinamide - Inhibits Fatty Acid Synthetase, disrupting bacterial membrane function
Ethambutol - Inhibits cell wall synthesis
What is the continuation phase of TB Treatment
After initial treatment, Rifampicin and Isoniazid may be given for 4 further months
What are the effects of rifampicin and isoniazid on CYP450
R - Liver enzyme inducer
I - Liver enzyme inhibitor
3 ways lung defends itself
- Coughing
- Mucociliary escalator
- Alveolar macrophages
Pathophysiology of pneumonia
Microorganisms enter lungs triggering immune response. Inflammation and fluid accumulation in alveoli of lung occurs (exudate)
Causes of pneumonia
CAP - Community Acquired Pneumonia (typical)
- S. pneumoniae (MC)
- H. influenzae
HAP - Hospital Acquired Pneumonia (most g- aerobic bacilli)
- Pseudomonas aeruginosa
- E. coli
- Klebsiella
Atypical CAP causes
- Mycoplasma pneumoniae (Milder disease, rash called erythema multiforme and includes neurological symptoms)
- Chlamydophila pneumoniae
- Legionella pneumonia/ legionnaires’ disease (typically due to infected water supplies or AC units. Causes SIADH/hyponatraemia. Suspect if recent cheap hotel holiday to a place with AC units + hyponatraemia!)
Stages of lobar pneumonia
- Congestion - Blood vessels and alveoli fill with fluid. Few RBCs and neutrophils in lung
- Red Hepatisation - Infiltration of exudate, including RBC, neutrophils, fibrin, filling air spaces, making them look “solid” on imaging. Has red, liver like appearance.
- Grey hepatisation - RBCs break down, changing it to grey colour
- Resolution
Other types of pneumonia
- Ventilator Associated Pneumonia - microbes on endotracheal tube
- Aspiration pneumonia - food, drink, saliva, vomit goes into lung, carrying microbes with it. (right lower lobe)
- Bronchopneumonia - bronchioles affected
- Atypical - Interstitium of alveoli
- Lobar - Complete consolidation of lobe
Signs/symptoms of pneumonia
- Productive, coloured sputum cough. Can include haemoptysis
- Fever and chills
- Pleuritic chest pain (worse breathing/coughing)
- Bronchial breathing and coarse crepitations
- Dullness to percussion
- Fatigue, confusion and hypoxia
Examination signs of pneumonia
- Dullness to percussion
- Focal coarse crackles
- Bronchial breathing sounds
- Tactile vocal fremitus (more vibrations from person’s chest/back when they talk)
Presentation of atypical pneumonia
- Gradual onset
- Milder flu like symptoms (cough/dyspnoea)
- Low/No fever
- Dry cough
- Sore throat and myalgia (not really present in typical)
1st and GOLD investigations of pneumonia
1st Chest X ray
- Consolidation within alveoli and bronchioles, can be lobar. Air bronchograms visible (air-filled bronchi against background of consolidated lung tissue)
- Consolidation is well defined. Diffuse/nodular in atypical
GOLD Sputum culture
How is CRP used in pneumonia
<20 no antibiotics
20-100 consider antibiotics
>100 definitely offer
What classification system is used in Pneumonia
CURB 65
Confusion (abbreviated mental test score <8 or disorientation)
Urea (kidney function) - >7mmol/L
Respiratory rate - >30/min
Blood pressure - Systolic <90 or diastolic <60
Age >65
How is CURB 65 score used?
HAP
>2 = hospital care
CAP (urea not measurable in primary care etc)
0-1 (low severity) - community care
2 (moderate) - hospital care
3 - intensive care
Management of pneumonia
Depends on CURB65
CAP
low (0-1) - 5 day Oral amoxicillin or doxycycline.
Moderate (2) - Oral amoxicillin and clarithromycin if atypical. 5 day course
High (3+) - IV co-amoxiclav and clarithromycin
HAP
Low - oral co-amoxiclav
High - IV ceftriaxone
Treatment of Legionnaire’s pneumonia
Legionella needs clarithromycin
Also Legionnaire’s is NOTIFIABLE
What is the most common pneumonia in HIV patients
Pneumocystis pneumonia
Fungal infection caused by Pneumocystis jirovecii
Presentation of Pneumocystis pneumonia
HIV patient
Chest exam mostly normal
Pyrexia, dry cough, fever.
Shows lymphadenopathy, hepatosplenomegaly, choroid lesions (benign naevi back of eye)
Management of pneumocystis pneumonia
Co-trimoxazole (trimethoprim and sulfamethoxazole)
Define cystic fibrosis, with how its caused.
Autosomal recessive inherited disease, causing secretions from mucus glands to become thick. Respiratory and pancreatic problems most prominent
Phenylalanine deletion on CFTR (Cystic Fibrosis Transmembrane conductance Regulator) gene on chromosome 7.
General pathophysiology of Cystic Fibrosis
Phenylalanine deletion on CFTR gene on chromosome 7. CFTR is a channel protein that pumps chlorine into secretions, drawing water into them. Mutated CFTR misfolds, and is unable to migrate to cell membrane. Hence, secretions are thicker than usual.
Respiratory pathophysiology in Cystic Fibrosis
Dry airways/ impaired mucociliary clearance
Thick immobile secretions harbour bacteria and cause infection. This can lead to chronic inflammation and bronchiectasis, which can lead to respiratory failure and death
Pancreatic pathophysiology in cystic fibrosis
Thick pancreatic and biliary secretions block ducts. This causes pancreatitis, cholangitis and a lack of digestive enzymes in GI tract, which can lead to malabsorption. Causes failure to thrive, steatorrhoea, and endocrine dysfunction e.g. CF diabetes.
Signs/symptoms of cystic fibrosis
- Failure to thrive
- Chronic, thick sputum cough
- Crackles/wheeze on auscultation
- Recurrent URTI
- Loose, greasy, smelly stools
- Nasal polyps and finger clubbing
- Salty tasting child
Main sign in neonates of cystic fibrosis
Meconium ileus
Meconium usually passed in first 48 hours, but becomes thick and mucusy, causing obstruction.
Investigations of cystic fibrosis
Screened for in all babies in Guthrie heel prick (Immunoreactive trypsinogen)
GOLD: Chlorine sweat test - Pilocarpine induces sweating. Increased chlorine in sweat (>60mmol/L)
Genetic testing for CFTR gene
Faecal elastase - Pancreatic insufficiency
Lifestyle advice for cystic fibrosis
- High calorie, high fat diet
- No smoking
- Regular exercise
- Regular chest physiotherapy
- Regular flu vaccination
Respiratory management of cystic fibrosis
Chest physiotherapy and exercise
Bronchodilator (SABA - Salbutamol)
Mucolytic - Dornose alfa
Nebulised Tobramycin for Pseudomonas infection
Prophylactic Flucloxacillin always
Digestive management of cystic fibrosis
High calorie high fat diet
Fat soluble vitamins (ADEK)
Pancreatic enzyme replacement (Creon tablets)
PPI - omeprazole (aid pancreatic enzyme absorption)
Ursodeoxycholic acid (make bile more soluble)
Complications of cystic fibrosis (7)
- Life expectancy ~40 yrs
- Pancreatic insufficiency
- CF related diabetes
- Infertility
- Recurrent URTI/Lung disease
- Malabsorption, leading to delayed puberty, osteoporosis, infertility
- Liver cirrhosis
Define Sarcoidosis
Idiopathic systemic granulomatous inflammation. Granulomas are non caseating (no necrotic core). Lungs most prominently affected
Type 4 hypersensitivity reaction
Pathophysiology of sarcoidosis
T cell mediated immune response to antigenic stimulus causes formation of non caseating granulomas. This occurs systemically.
Macrophages can fuse together forming Langhans giant cells.
Mostly affects hilar lymph nodes near where bronchi meet lungs.
Signs/symptoms of sarcoidosis
- Cervical and submandibular lymphadenopathy
- Lupus pernio (type of rash)
- Erythema nodosum (red nodules on shins)
- Non productive cough
- Uveitis (red-eye, photophobia)
- Polyarthralgia, swinging fever, fatigue, weight loss
Associated syndromes with sarcoidosis
Lofgren’s - Subset of sarcoidosis. Triad of bilateral hilar infiltration, erythema nodosum, acute polyarthritis
Heerfordt’s - Facial nerve palsy, parotitis/mumps (inflammation of salivary glands)
Investigations in sarcoidosis
CXR - Bilateral hilar lymphadenopathy and pulmonary infiltrates, used to stage.
Serum calcium - Raised
ACE - Raised
Bronchoscopy and mediastinal lymph node biopsy GOLD - Non caseating granulomas with epithelioid cells
CXR staging of sarcoidosis
CXR - Bilateral hilar lymphadenopathy (staged 1-4)
0 = normal
1 = Just bilateral hilar lymphadenopathy
2 = + interstitial infiltrates
3 = Pulmonary infiltrates, no lymphadenopathy
4 = Diffuse fibrosis
CT signs of sarcoidosis
Hilar lymphadenopathy and pulmonary nodules.
Ground glass appearance - reversible
Cystic distortion - irreversible
Management of sarcoidosis
- Corticosteroid - Oral prednisolone
- Immunosuppression - methotrexate
IV corticosteroid and ventilation support if resp failure
Complications of sarcoidosis (6)
- Pulmonary fibrosis/ HTN
- Cor pulmonale
- Liver cirrhosis
- Kidney stones, interstitial nephritis
- Encephalopathy, nerve palsy (facial)
- Optic neuritis
Risk factors for idiopathic pulmonary fibrosis
- Age
- Male
- Smoking
- Family history
- Dust exposure
Pathophysiology of pulmonary fibrosis
Type 1 pneumocytes release transforming growth factor beta 1, which gets type 2 pneumocytes to stimulate fibroblasts to proliferate into myofibroblasts which lay down reticular and elastic fibres.
In IPF there is type 2 pneumocyte overproliferation, causing fibrosis of the lung. This causes problems with ventilation and oxygenation, decreasing FEV1 and FVC.
Also leads to loss of alveoli
Signs/symptoms of IPF
Mostly affects lower lobes
- Bibasal fine end inspiratory crackling in lower zones
- Clubbing
- Cyanosis
- non productive cough
Investigations in IPF
CXR - Bilateral shadowing (ground glass appearance, progressing to honeycombing), mainly in lower zones
Spirometry - restrictive pattern (FEV1 decreased FVC greatly decreased, FEV1/FVC >80%)
High resolution CT thorax GOLD - shows reticulation and honeycombing
Management and complications of IPF
Supportive care - oxygen and vaccinations against pneumococcus and influenza
Antifibrotic agents (nintendinib and pirefenidone)
Can lead to pulmonary HTN and cor pulmonale
Define bronchiectasis
Permanent dilation of the bronchi due to the destruction of elastic and muscular components of the bronchial wall.
Obstructive condition, as inflammation causes mucus plugs in airways
Pathophysiology of bronchiectasis
Usually due to chronic inflammation. Over time, cytokines damage ciliated epithelial cells and destroy elastin fibres in walls of airway, so airway becomes clogged with mucus and permanently dilated. Stiff, mucus filled airways make it a struggle for passage of air. This can cause hypoxia over time, causing the pulmonary arterioles to constrict. This causes pulmonary hypertension, which can lead to cor pulmonale.
Signs/symptoms of bronchiectasis
- Productive cough with lost of sputum
- Dyspnoea
- Chest pain
- Inspiratory crepitations
(usually has post infection, CF etc history)
Long standing hypoxia can cause clubbing!
Investigations of bronchiectasis
CXR/CT scan - Thickened, dilated bronchi and bronchioles
Spirometry shows obstructive disease
Management of bronchiectasis
Antibiotics for infections
Chest physio
Mucolytics - dornose alfa
Explain how Primary ciliary dyskinesia and cystic fibrosis cause bronchiectasis. Give 2 other causes also
PCD - Cilia dont move, allowing mucus and bacteria to stay and fester. Bacteria multiplies causing a pneumonia. Recurrent, can cause chronic inflammation
CF - Mucus is sticky and hard to sweep. Causes stagnation and build up of bacteria -> recurrent pneumonias
- Post infection (TB, measles, HIV)
- Airway obstruction (tumour or foreign object) blocks mucociliary escalator (same pathology as aspiration pnuemonia)
Define Pleural Effusion
Fluid collects between in pleural space (space between visceral and parietal pleura)
parietal pleura - stuck to chest wall, covers mediastinum, diaphragm, ribs etc
visceral pleura - envelopes all lung surfaces
Pathophysiology of pleural effusion
Can be transudate or exudate
Transudate - <30g/L protein
Exudate - >30g/L protein
Normally fluid is drained by lung lymphatics, but disease which increase filtration rate from vasculature or decrease absorption from lymphatics will result in fluid build up in pleural space.
What causes transudative effusion
Increased hydrostatic pressure or low oncotic pressure causes fluid movement from capillaries to pleural space. Hence, no/low protein.
Causes include
- Congestive heart failure
- Hypoalbuminaemia (liver problem)
- Hypothyroidism
- Peritoneal dialysis
What causes exudative effusion?
Inflammation, infection and malignancy cause increased vessel permeability, so fluid and protein leak out of tissues into pleural space.
Causes include
- Malignancy
- Infection
- Trauma
- PE
- Autoimmune/connective tissue disorders
Symptoms of pleural effusion
Dyspnoea
Cough
Pleuritic chest pain
Signs of pleural effusion (5)
- Reduced chest expansion and reduced breath sounds on affected side
- Decreased tactile and vocal fremitus
- One sided dullness to percussion
- Pleural friction rub (raspy breathing) and bronchial breathing at most superior part of effusion
- Tracheal deviation from effusion if big effusion
Underlying features indicative of cause of pleural effusion
Peripheral oedema -> Heart failure
Ascites/jaundice -> Liver cirrhosis
Productive cough/fever -> pneumonia
Weight loss (malignancy)
What is a chylothorax?
Lymphatic effusion
Thoracic duct disrupted, so drainage inefficient. This causes leakage of the lymphatic fluid into the pleural space.
Investigations of pleural effusion
Chest X ray first
- Blunting of costophrenic angle
- Fluid in lung fissures
- Meniscus in larger effusions
- Tracheal and mediastinal deviation
Pleural fluid and analysis
- Conducted on lateral site, above the ribs
What are the following fluid appearances suggestive of in pleural effusion:
- Pale yellow
- Red
- Milky
- Pus
- Food
Pale - Transudate
Red - Blood (malignancy, PE, TB)
Milky - Chylothorax
Pus - Empyema
Food - Oesophageal rupture
What lab tests are conducted on aspirated pleural effusion?
pH
Glucose
Protein (transudate/exudate)
LDH (high in exudate)
Gram stain/culture
Acid fast/Ziehl Neelsen
Amylase (pancreatitis)
What criteria is used to classify if effusion is transudative or exudative?
Light’s criteria - used when protein 25-35g/L
Essentially high protein or high LDH suggests exudative cause
Treatment of pleural effusion
Small, non infective effusions can be managed through underlying cause.
Chest tube drainage if infective cause
Thoracentesis for symptomatic, non red flag effusion
Indications of chest tube drainage (3)
- Purulent or cloudy pleural fluid
- Positive gram stain/culture
- pH <7.2
Treatment of recurrent effusion
- Pleurodesis: Scarring pleural space causing adhesion of visceral and parietal pleura
- Indwelling pleural catheter: Allows for long term repeated drainage
Complications of pleural effusion
- Empyema (infective effusion)
- Pneumothorax
- Lobar lung collapse
- Trapped lung/fibrosis
Define Empyema
Collection of pus in the pleural space, usually due to infection
Causes of Empyema
Bacterial pneumonia
Recent thoracic surgery
Lung abscess
Chest trauma
Immunodeficiency
Define Pneumothorax
Abnormal accumulation of air within pleural space (basically pleural effusion for air)
Pathophysiology of Pneumothorax
Normally intrapleural pressure is lower than both atmospheric and alveolar pressure. This means gases can follow pressure gradients. building up in the pleural space.
Normally, the thoracic cavity is below its resting volume, and the lung is greater than its resting volume. Hence, when a pneumothorax forms, the thoracic cavity enlarges and the lung shrinks.
The more air that builds up, the greater the intrathoracic pressure, the smaller the lung becomes, and the larger the tracheal and mediastinal deviation that occurs.
The 3 types of pneumothorax and their main causes
Primary Spontaneous - No underlying cause, subpleural bleb rupture in healthy, tall male, possibly whilst playing sports
Secondary Spontaneous - Underlying disease, middle aged COPD patient with sudden onset breathlessness and chest pain
Tension Pneumothorax - Usually occurs secondary to penetrating chest injury (surgery, trauma etc)
Risk factors for Primary Spontaneous Pneumothorax
- Tall, slender, young (20-30)
- Smoking
- Marfan
- Rheumatoid arthritis
- Family history
- Driving/flying
risk factors of Secondary Pneumothorax, and how they form
Ruptured bleb or bullae (air filled sacs) in a patient with underlying disease. Bullae form when there is a small leak in the alveoli which allow air to leak out and form an air filled sac. Bullae can break into visceral pleura, forming a pneumothorax/
- Underlying lung disease (COPD, asthma, lung cancer)
- TB
- Pneumocystis Jirovecii
Formation of Tension Pneumothorax with risk factors
Penetrating chest wall injury rips into parietal pleura from outside, allowing air to enter. Forms a ONE WAY VALVE, meaning air can enter but not leave. Air enters during inspiration but can’t leave. Tracheal deviation small in spontaneous, large in tension
Medical emergency, requires emergency decompression.
- Recent chest wall trauma
- Recent penetrative surgery
- Intubation
- Mechanical ventilation
Signs/symptoms of Pneumothorax
Sudden onset breathlessness, pleuritic chest pain, haemodynamic instability, sweating/cyanosis
- Ipsilateral hyperresonance
- Ipsilateral reduced breath sounds
- Ipsilateral hyperexpansion
- Contralateral tracheal deviation and circulatory shock in tension
Investigations in pneumothorax
1st - Erect CXR
- Visible visceral pleural edge
- Contralateral mediastinal shift and tracheal deviation
- Collapsed lung
GOLD - CT Chest
No investigations in Tension, go straight to decompression
Management of spontaneous pneumothorax
No SOB, less than 2cm air on CXR - discharge and follow up
If SOB, >2cm - Needle aspiration or chest drain at 5th intercostal space, mid axillary line
Management of tension pneumothorax
Immediate emergency large bore cannula in 2nd intercostal space, mid clavicular line. Needle decompression then chest drain.
Definitive management of pneumothorax
Pleurodesis. Create inflammatory reaction between pleural layers, making them stick together
Pleurectomy
Driving and flying rules in pneumothorax
Driving - avoid indefinitely, or until bilateral pleurectomy
Flying - 1 week after check X ray after resolved pneumothorax
Causes of chronic interstitial lung diseases
- Granulomatosis
- Hypersensitivity pneumonitis
- Pulmonary fibrosis
- Scleroderma, RA
- Amiodarone
- Goodpastures
Define pulmonary hypertension
Pulmonary blood pressure greater than 25mmHg (BP in lungs usually much lower than rest of body)
Give 5 causes of pulmonary hypertension
1 - Congenital heart defects (left to right shunt)
2 - Connective tissue disease
3 - Left heart failure
4 - Chronic lung disease (COPD etc)
5 - Pulmonary vascular disease (embolism)
How do connective tissue disorders cause pulmonary HTN
Damage to endothelial cells causes release of chemicals such as serotonin and thromboxane which constrict pulmonary arterioles and cause hypertrophy of surrounding muscle.
No compensatory nitric oxide and prostacyclin production
How does left heart failure cause pulmonary HTN
Left heart unable to pump efficiently, causing backing up of blood into the pulmonary circulation.
How does chronic lung disease cause pulmonary hypertension
Hypoxic vasoconstriction
Lung area diseased, cant deliver oxygen to blood, so pulmonary arterioles constrict. If widespread (e.g. in COPD), widespread constriction increases pulmonary vascular pressure.
How does pulmonary hypertension cause right heart failure
Pulmonary hypertension makes it harder for the right heart to pump blood into pulmonary circulation, causing the right ventricle to hypertrophy. Eventually, oxygen demand exceeds supply causing right heart failure
(When chronic lung disease causes this -> Cor pulmonale)
How does right heart failure cause its symptoms
Right heart failure causes backing up of blood into venous circulation.
This causes fluid buildup (peripheral oedema), elevated jugular vein pressure and hepatomegaly. Left ventricle must compensate, causing it to pump faster
Why does pulmonary HTN cause lung symptoms
Fluid is squeezed out of pulmonary vessels, causing pulmonary oedema, making gas exchange difficult.
Signs/symptoms of pulmonary hypertension
- Shortness of breath (orthopnoea if caused by LEFT HEART FAILURE)
- Chest pain
- Raised JVP
- Hepatomegaly
Investigations of pulmonary hypertension
- Echocardiogram measures pulmonary hypertension
- ECG (RV hypertrophy shows as large R waves in V1-3)
- CXR (Dilated pulmonary arteries, RV hypertrophy)
Treatment of pulmonary hypertension
Oxygen
Decrease BP (CCB)
Endothelin receptor antagonist can be used if CCB contraindicated
What is a restrictive lung disease
Disease that restricts the lung from filling. FEV1/FVC is usually normal (>0.8 - person can exhale 80% of their FVC in first second)
Examples include:
- Idiopathic pulmonary fibrosis
- Sarcoidosis
- Systemic sclerosis (scleroderma)
- Hypersensitivity pneumonitis
Define hypersensitivity pneumonitis
Restrictive lung disease. AKA extrinsic allergic alveolitis (but NO IgE involvement). Usually caused by known organic antigen
Type 3 hypersensitivity reaction. Antibody-antigen complex deposition causes inflammation of lung tissue.
Over time, chronic exposure can cause type 4 to occur due to T cell involvement. This leads to non caseating granuloma formation
Risk factors for hypersensitivity pneumonitis
- Pre existing lung disease
- Regular hot tub usage
- Occupations (farmers, cattle workers, ventilation systems, chemicals, coffee, tobacco)
- Bird keeping)
Signs and symptoms of hypersensitivity pneumonitis
Dyspnoea
Cough
Headache
Fever and rigors
Chronic can lead to cyanosis, clubbing and respiratory failure
Treatment of hypersensitivity pneumonitis
Remove trigger
Steroids can be given
Define pneumoconiosis
A group of lung diseases caused by inhaling certain types of dust or particles, usually in a workplace environment. These cause inflammation, scarring and damage over time.
Substances that cause occupational lung diseases
- Coal/carbon dust
- Asbestos
- Silicon dioxide
- Beryllium
5 at risk jobs for occupational lung disease
- Quarry worker
- Miner
- Cotton mill worker
- Plumbers
- Construction workers
Signs/symptoms of occupational lung disease
Fine crackles, wheezing and clubbing, weight loss, haemoptysis that develops over time in at risk worker.
Cough that may be productive of black sputum if progressive massive fibrosis
What job is at risk of berylliosis and what does berylliosis lead to
Aerospace industry and beryllium miners
- leads to non caseating granuloma formation, upper zone fibrosis and risk of lung cancer
What job is at risk of silicosis and what does it lead to
Sandblasters, quarry miners, silica miners
- Increased TB risk, eggshell calcification in hilar lymph nodes.
What job is at risk of asbestos and what can it lead to
Construction workers, plumbers, shipyard workers
- Pleural plaques and lower zone fibrosis
- Leads to increased risk of mesothelioma! and lung cancer
Risk factors for lung cancer
- Age
- Smoking
- Asbestos
- Arsenic
- Air pollution
- Radiation
What are the types of lung cancer and from where do they arise?
- Mesothelioma (arises from pleura) (asbestos)
- Small cell lung cancer (from neuroendocrine Kulchitsky cells)
- Non small cell (adenocarcinoma MC non smokers, squamous cell carcinoma MC smokers)
- Large cell
- Carcinoid tumours
Define Mesothelioma with its main cause
Malignancy of the pleura
Main cause is asbestos, but doesn’t present until decades post exposure. Usually occurs in men aged 60+
Signs/symptoms of mesothelioma
Chronic (>3 weeks) cough, breathlessness, weight loss, fatigue, night sweats
Finger clubbing
Reduced breath sounds
Haemoptysis
Pleuritic chest pain
Investigations of mesothelioma
CXR - Lower zone fibrosis, pleural thickening, pleural effusion, reduced lung volume
Contrast CT - Pleural plaques and enlarged lymph nodes if metastasis
Management of mesothelioma
Usually inoperable, as has metastasised by the time it is found.
Operable - Extrapleural pneumonectomy, pleurectomy
Inoperable - Chemotherapy (cisplain, pemetrexed)
Complications of Mesothelioma
Pneumothorax
Local invasion causing dysphagia, hoarseness, cord compression
Metastasis to
- Other lung
- Peritoneum
- Brian
- Hilar lymph nodes
What are primary bronchial carcinomas
Cancers of the lung that affect lung parenchyma.
These are categorised into small cell lung cancer (15%) and non small cell lung cancer (85%)
Define small cell lung cancer
Fast growing, late presenting tumours derived from neuroendocrine cells at central lesions near main bronchus.
These cells usually release ectopic neuroendocrine hormones. E.g.
- ADH = SIADH (and hyponatraemia)
- Cortisol = Cushings
Also cause Lambert Eaton syndrome!!
Define Non small cell lung cancer
All other lung cancers. Consist of squamous cell carcinoma, adenocarcinoma, carcinoid tumour, large cell tumour
Summarise Squamous cell lung cancer
RF: Smoking
Usually arises from lung epithelium. Central lesion that produces keratin and can also produce PTH related protein, causing hypercalcaemia.
Causes hypertrophic pulmonary osteoarthropathy (HPO)
Summarise lung adenocarcinoma
RF: Asbestos
Usually peripheral lesion, arising from mucus producing glandular cells. Causes gynaecomastia and can cause HPO
Metastasis common - Bone, brain, adrenal gland, lymph nodes, liver
Summarise carcinoid tumour
Genetic Association! MEN1
Arise from mature neuroendocrine cells, causing carcinoid syndrome.
What do large cell tumours secrete
B-HCG (pregnancy marker!)
Signs/symptoms of lung cancer
Weight loss, cough, breathlessness, haemoptysis, pleuritic chest pain, fever night sweats fever.
Lymphadenopathy and pneumonia possible and stony dull percussion if pleural effusion.
Clubbing, facial plethora, hoarseness are extrapulmonary manifestations
Investigations in lung cancer
CXR
- Lung consolidation
- Circular opacity (visible lesion)
- Lung collapse
- Hilar node enlargement
- Pleural effusion (unilateral)
CT with Contrast GOLD
PET scan to check for metastasis.
Biopsy for peripheral lesions and bronchoscopy and ultrasound for central.
Management of lung cancer
NSCLC can be fixed surgically, SCLC less so as presents late.
Lung cancer complications
Paraneoplastic syndromes
- Cushings
- SIADH
- Hypercalcaemia
- Lamber Eaton syndrome
Nerve palsy/obstruction
- Laryngeal - hoarse voice
- Phrenic - Diaphragm weakness (breathless)
- Horners syndrome (due to pancoasts tumour)
- Superior vena cava obstruction (presents with pembertons sign)
Metastasis to adrenal gland, liver, bone, brain
What bacteria most often causes pharyngitis and otitis media, and what antibiotic is used against this
Streptococci (Group A/pyogenes)
Amoxicillin
Define pharyngitis
Pharyngeal inflammation causing sore throat, usually due to a viral infection
Causes of pharyngitis
Viral (most common):
Adenovirus
Rhinovirus
Coronavirus
EBV
Bacterial:
Group A Strep (“Strep throat”)
Causes of tonsilitis
Viral (most common)
Rhinovirus
Coronavirus
Adenovirus
Bacterial
Group A beta haemolytic strep (pyogenes)
H influenzae
Staph aureus
Most common cause of recurrent tonsillitis
Staph aureus and MRSA
Signs/symptoms of tonsillitis and pharyngitis
Red, inflamed, throat/tonsils (with exudate/pus = bacterial)
Anterior cervical lymphadenopathy
Sore throat
Fever
Malaise
How is pharyngitis and tonsillitis diagnosed
Usually clinical
Can also do throat culture and rapid group A strep test
When should tonsillectomy be considered?
If
- Recurring tonsillitis and complications
- Obstructive sleep breathing in children
Define otitis media
Inflammation of the middle ear. Can be bacterial or viral
Bacterial:
- strep pneumoniae
- H influenzae
- Staph aureus
Viral
- Rhinovirus
- Adenovirus
- Influenza
Otoscopy findings in otitis media
Red tympanic membrane
Bulging tympanic membrane
Middle ear efffusion
Presentation of otitis media
general symptoms (fever malaise, headache etc), with ear pain, reduced hearing in children
Define Sinusitis
Inflammation of paranasal sinuses.
Acute can last up to 4 weeks, subacute 1-3 months, chronic 3+
Presentation of sinusitis
- Purulent rhinorrhoea
- Facial pain
General symptoms (headache, fever, malaise, cough)
Treatment of sinusitis
Acute is usually self resolving
If no improvement: Penicillin V for 5 days
What major condition are otitis media and sinusitis associated with?
Meningitis
Disease spreads contiguously to paranasal sinuses and ears.
Define epiglottitis
Inflammation of the epiglottis, causing potentially life threatening airway obstruction. Mostly in children
Pathophysiology of epiglottitis
Normally, epiglottis prevents food from getting into trachea.
Bacterial infection (H influenzae B (MC), Strep pneumoniae and pyogenes) causes it to inflame. Less common now due to HiB vaccine
Symptoms of epiglottitis
- Tripoding (Child sat forwards with knees up, mouth open and tongue out to breathe)
- Drooling
- High fever
- Dysphagia
- Septic/unwell looking child (STRONG association with septicaemia)
Investigations of epiglottitis
Investigations should not be done, could distress child and cause catastrophic airway occlusion and respiratory arrest.
Lateral neck radiograph may be appropriate - shows thumb sign, helps to exclude foreign body
Treatment of epiglottitis
Important to not distress child.
Intubation to secure airway.
Once airway secure, cultures can be done for antibiotics.
IV Ceftriaxone
Define whooping cough with its causative organism
NOTIFIABLE DISEASE
URTI in which child has severe coughing fits with loud whooping sound, in which child struggles to take air in between coughs.
Caused by Bordetella pertussis - a gram negative coccobacilli
What factors enable the virulence of Bordetella pertussis
- Filamentous Haemagglutinin (aids adherence)
- Adenylate Cyclase Toxin (ACT) (inhibits phagocyte chemotaxis/T cell activation)
- Tracheal cytotoxin (paralyses cilia)
- Pertussis toxin (makes blood vessels and resp tissue more sensitive to histamine = greater exudate = harder to breathe)
Disease course/symptoms of whooping cough
Incubation - 1 week
Catarrhal phase - 2 weeks (extremely contagious)
- low grade symptoms, fever, rhinorrhoea, cough.
Paroxysmal phase 1-6 weeks
- Uninterrupted “whooping” coughing that can result in vomiting, collapsed lung, broken ribs and apnoea
- O2 decrease can cause death
Convalescent phase (2-3 weeks)
- Healing
Investigations of whooping cough
Nasopharyngeal swab
PCR testing
Anti-pertussis toxin IgG present 2 weeks after cough onset
Management of whooping cough
Notify UKHSA (health security agency) (formerly Public Health England)
- Azithromycin for older than 1 month
- dTap Vaccine
Possible complications of whooping cough
Symptoms usually resolve in 8 weeks but severe cough can cause damage:
Bronchiectasis
Pneumonia
Seizures
Rib fractures
Encephalopathy
Define Croup
Laryngotracheobronchitis - swelling of larynx, trachea, large bronchi
Viral upper resp tract infection caused by parainfluenza
Usually in children under 3
Signs/symptoms of Croup
Characteristic barking cough
Hoarse voice
Stridor (noisy breathing through obstructed airway)
Intercostal and subcostal recession if respiratory distress
Fever
Investigations of Croup
Do NOT distress child, could worsen symptoms
Clinical diagnosis.
Westley score can be used to assess severity
Management of Croup
Simple supportive treatment is usually enough, starts to get better in 48 hrs
If severe, or stridor or chest recession do not improve,
- Oral dexamethasone or prednisolone. OR
- Nebulised steroids OR
- Nebulised adrenaline
What indicates a need for hospital admission in croup
Moderate/severe croup
Haemodynamically significant congenital heart disease
<3 months old
Inadequate fluid intake
