Respiratory Flashcards
What is Chronic Obstructive Pulmonary Disease (COPD)?
Progressive irreversible airway obstruction and limitation of air flow caused by long term damage to lung tissue.
What are the conditions that are classed as COPD?
Chronic Bronchitis
Emphysema
What is the epidemiology of COPD?
1.2 million people with COPD in the UK
4th leading cause of death globally
Typically diagnosed >45 yrs
What are the risk factors for COPD?
Cigarette smoking
Air pollution
Occupational exposure to dusts, chemical agents, and fumes
A1AT deficiency
What are the risk factors for COPD?
Cigarette smoking
Air pollution
Define Chronic Bronchitis?
A inflammatory lung condition that develops over time in which the bronchi and bronchioles become inflamed and scarred.
What is the pathophysiology of Chronic Bronchitis?
Initial exposure to irritants and chemicals (cigarette smoke)
Hypertrophy and hyperplasia of bronchial mucinous glands and goblet cells. There is also ciliary destruction.
This increases the production of mucus in the lumen causing narrowing and obstruction
This causes air trapping causing poor exchange of O2 and CO2 and increases risk of infection.
This also stimulates immune cells causing inflammation of the bronchus and bronchioles.
What are the symptoms of chronic bronchitis?
Chronic Cough - high sputum production
Dyspnoea
Wheeze
Recurrent respiratory tract infections - due to mucus plugging
What are the Signs of Chronic Bronchitis?
Wheeze - narrowing of airway creates higher pitch sound.
Crackles - popping open of small airways
Hypoxaemia and Hypercapnia - mucus plugs block airflow and lead to partial pressures of CO2 to rise and subsequent decline of O2.
Cyanosis (if hypoxaemia is really bad leading to the term blue bloaters).
Pulmonary Hypertension - due to Hypoxic vasoconstriction leading to increased pulmonary vascular resistance
What is Emphysema?
A lung disease characterised by dilatation and destruction of the lung tissue causing enlarged air spaces distal to the terminal bronchioles
What is the Pathophysiology of Emphysema?
Occurs in the ACINUS
Irritants/chemicals lead to damage and destruction of the alveoli wall.
Causes and inflammatory reaction and immune cell infiltration releasing Leukotriene B4, IL-8 and TNF-a
Proteases (elastases and collagenases) are also produced which break down alveolar wall structural proteins.
This leads to permanent enlargement of the alveoli and loss of their elasticity.
Alveolar wall septa break down reducing the total surface area. This leads to gas exchange dysfunction.
Loss of elasticity in the airways means that the airways collapse upon exhalation causing air trapping distally.
What are the different types of Emphysema?
Centriacinar Emphysema
Panacinar Emphysema:
Paraseptal Emphysema:
What is Centriacinar Emphysema?
Most common
Damage to central/proximal acini due to smoking
Typically affects upper lobes
What is Panacinar Emphysema?
Entire acinus affected
Due to A1AT Deficiency (protease inhibitor deficiency) cannot prevent breakdown.
Typically affects Lower lobes
What is Paraseptal Emphysema?
Affects peripheral lung tissue.
Peripheral ballooned alveoli can rupture causing pneumothorax
How is Chronic Bronchitis and Emphysema classified differently?
Chronic Bronchitis is defined by clinical features
Emphysema is defined by structural changes (enlarged alveoli)
What are the symptoms of Emphysema?
Dyspnoea - diminished gas exchange
( can improve this by exhaling slowly through pursed lips giving the name pink puffers)
Hypoxaemia
Weight loss
Cough - with some sputum
Pulmonary HTN
How does Emphysema lead to pulmonary hypertension?
Widespread Hypoxic vasoconstriction.
Too many blood vessels are constricted increasing the pressures in others.
Leads to pulmonary hypertension.
What is the cause of the barrel shaped chest in COPD?
Both chronic bronchitis and emphysema leads to air trapping within the Bronchi/acini.
This leads to Hyperinflation of the lungs giving a barrel chest appearance.
What are the main complications of COPD?
Recurrent Respiratory Tract Infections:
S. pneumoniae
H. influenzae
Cor Pulmonale
What is a the most serious complication of COPD?
Cor Pulmonale:
Both Chronic bronchitis and Emphysema will lead to pulmonary hypertension due to excessive hypoxic vasoconstriction.
This causes R sided ventricular hypertrophy which will eventually lead to RHF and “Cor Pulmonale”
Who typically presents with COPD?
Older Px
Long term smokers
Occupational exposure: such as dust, cadmium (in smelting), coal, cotton, cement and grain
What are the Symptoms of COPD?
Chronic cough - often with sputum
Constant Dyspnoea - not episodic
What are the Signs of COPD?
Tachypnoea
Barrel Chest
Wheeze/Crackles
Hyperresonance on percussion
Evidence of Cor Pulmonale
Do patients with COPD typically present with Chronic Bronchitis or Emphysema?
Often Px will present with both conditions as COPD due to the same triggers causing both.
Who typically presents with COPD?
Older Px
Long term smokers
Occupational exposure: such as dust, cadmium (in smelting), coal, cotton, cement and grain
How is COPD Diagnosed?
Clinical Dx with Spirometry Test
Spirometry shows Obstruction:
FEV1/FVC ration <0.7
Negative Reversibility Testing: <12% Inc FEV1
Obstruction does not show good response to salbutamol.
CXR - Lung hyperinflation + Bullae
How does Asthma respond to Reversibility testing?
Bronchodilator (salbutamol) will increase FEV1 by >12%
What is FVC?
Forced Vital Capacity:
The total amount of air forcibly expired
What is FEV1?
Forced Expiratory Volume in 1 second
What is an Abnormal FEV1?
- The result is compared with the predicted values, if the FEV1 is 80% or
greater than the predicted value = NORMAL - Thus is the FEV1 is less than 80% of the predicted value = LOW i.e
abnormal
What is an Abnormal FVC?
- The result is compared with the predicted values, if the FVC is 80% or
greater than the predicted value = NORMAL - Thus is the FVC is less than 80% of the predicted value = LOW i.e
abnormal
What does a low FVC suggest?
Airway Restriction
What does a Low FEV1/FVC ratio suggest?
<0.7 = Airway Obstruction
If FEV1/FVC ratio is high/normal but FVC is low (<80%) then airway restriction.
Do patients with COPD typically present with Chronic Bronchitis or Emphysema?
Often Px will present with both conditions as COPD due to the same triggers causing both.
What other tests may be done to look for the cause of COPD?
DLCO (diffusing capacity of CO across lung):
Low in COPD, Normal in Asthma
Genetic testing for A1AT Def.
ABG - may show T2RF
ECG - heart function
CXR - flattened diaphragm
Bloods - anaemia
How is the severity of COPD and airflow graded?
Stage 1: FEV1 >80% of predicted
Stage 2: FEV1 50-79% of predicted
Stage 3: FEV1 30-49% of predicted
Stage 4: FEV1 <30% of predicted
What is the treatment of COPD?
Stop risk factors - smoking
Prophylactic Vaccines - Pneumonia
Medication:
1. SABA (Salbutamol) OR SAMA (Ipratropium Bromide)
- LABA (Salmeterol) + LAMA (Tiotropium
(if they have asthmatic/steroid responsive features then LAMA + inhaled corticosteroid beclometasone)
What management can be provided for severe COPD?
Nebulisers - Salbutamol and/or ipratropium
Long term Oxygen therapy
What is an Exacerbation of COPD?
worsening of symptoms such as cough, shortness of breath, sputum production and wheeze. It is usually triggered by a viral or bacterial infection.
How are Exacerbations of COPD treated?
At Home:
Prednisolone 30mg once daily for 7-14 days
Regular inhalers or home nebulisers
Antibiotics if there is evidence of infection
In Hospital:
Nebulised Bronchodilators
Prednisolone 30mg once daily for 7-14 days
Antibiotics if there is evidence of infection
Physiotherapy
What is the main risk of COPD exacerbations?
Respiratory Failure:
COPD patients are chronic retainers of CO2 and therefore their kidneys adapt to produce extra HCO3 to compensate the acidotic state.
In acute exacerbations the kidneys cannot produce enough HCO3 quickly leading to RF.
Define Asthma?
Chronic reversible inflammatory airway condition characterised by reversible airway obstruction, airway hyperresponsiveness and inflamed bronchioles
What are the types of Asthma?
Allergic (70%) - Extrinsic IgE mediated T1 Hypersensitivity
Non Allergic (30%) - Intrinsic non IgE mediated.
Explain the pathophysiology IgE mediated asthma?
Environmental trigger against specific allergens.
This leads to an immune system activation and activation of Th2 cells.
Th2 cells produce cytokines such as IL3, 4, 5, 13.
IL-4 leads to IgE production and degranulation of mast cells releasing histamine and leukotrienes.
IL-5 leads to eosinophil activation and release of proteins
This leads to a Hypersensitivity Rxn which causes Smooth muscle bronchospasm and increased mucus production leading to narrow airways and airway obstruction.
What happens to the airways in chronic asthma?
Initially asthma and inflammation of the airways is reversible.
Over chronic asthma the inflammation in the airways causes irreversible damage such as scarring and fibrosis causing thickening of the epithelial BM causing permanent narrowing of the airways.
What is the cause of asthma
Causes are unknown:
Genetics may play a factor
Environmental Factors:
Hygiene hypothesis
What is the Hygiene Hypothesis?
Reduced early exposure of bacteria and viruses when young leads to an altered proportion of immune cells.
This can subsequently lead to later onset asthma
What are the risk factors for asthma?
History of Atopy
FHx of asthma
Allergens - pollen, fur, smoke
What are some triggers for asthma?
Infection
Night time or early morning
Exercise
Animals
Cold/damp
Dust
Strong emotions
Drugs
What drugs can trigger asthma?
Aspirin
Beta blockers
How can aspirin trigger asthma?
Aspirin inhibits COX1/2
Shunts more arachidonic acid down LPOX pathway.
Produces leukotrienes (LTB4, 5, 6)
These are proinflammatory
What is the epidemiology of asthma?
A very common condition affecting 10% of the US.
More common in children/young people compared to COPD
What are the symptoms of asthma?
Chest tightness
Episodic Dyspnoea/SOB
Wheeze
Dry Cough (typically but can be wet)
What are the signs of asthma?
Diurnal PEFR variation
Dyspnoea and Expiratory Polyphonic wheeze
Samter’s Triad: Nasal polyps, Aspirin sensitivity, Asthma
What may be found in sputum from an asthmatic?
Curschmann spirals:
Mucus plugs that look like casts of the small bronchi
Charcot-Leyden crystals:
From break down of eosiophils.
How may a patient present indicating asthma?
Episodic symptoms
Diurnal variability. Typically worse at night.
Dry cough with wheeze and shortness of breath
A history of other atopic conditions such as eczema, hayfever and food allergies
Family history
Bilateral widespread “polyphonic” wheeze
How may a patient present indicating a different diagnosis to asthma?
Wheeze related to coughs and colds more suggestive of viral induced wheeze
Isolated or productive cough
Normal investigations
No response to treatment
Unilateral wheeze. This suggests a focal lesion or infection.
What are the signs of asthma?
Diurnal PEFR variation
Dyspnoea and Expiratory Polyphonic wheeze
Samter’s Triad: Nasal polyps, Aspirin sensitivity, Asthma
Atopic Triad: Atopic Rhinitis, Asthma, Eczema
What is Samter’s Triad
Nasal Polyps
Asthma
Aspirin sensitivity
What is Atopic Triad?
Atopic Rhinitis
Asthma
Eczema
How is asthma classified?
According to:
Frequency of symptoms (night/early morning)
FEV1
PEFR (peak expiratory flow rate)
Frequency of medication use
What are the classifications of asthma?
Intermittent
Mild Persistent
Moderate Persistent
Severe Persistent
What are the primary investigations for asthma?
NICE advise to carry out tests and not make a clinical Dx:
1st Line Ix:
Fractional Exhaled NO
Spirometry w/ Bronchodilator Reversibility
(shows reversible obstruction)
2nd Line:
PEF variation measurements - 2-4 weeks
Direct bronchial challenge test with histamine or methacholine
What is the Treatment algorithm for Chronic asthma?
16+:
- SABA (salbutamol)
- SABA + ICS (beclomethasone)
3a. Before adding more drugs assess inhaler technique and compliance
3b. SABA + ICS + Leukotriene Receptor Antagonist (LTRA = montelukast)
4. SABA + ICS + LABA (Salmeterol) +/- LTRA
5. Consider change to MART (maintenance and reliever therapy)
6. Increase ICS Dose
What is the treatment for acute asthma Exacterbations?
OSHITME:
O2
Saba (nebulised)
Hydrocortisone (ICS)
IV MgSO4
Theophyline (IV) - MgSO4 / Escalate
What are the complications of Asthma?
Asthma Exacerbation
Pneumothorax
What are the main conditions that are caused by Lower respiratory Tract Infections (LRTL)?
Tuberculosis
Pneumonia
What is Tuberculosis?
An infectious disease caused by Mycobacteria characterised by caseating granulomas.
What are the organisms classified as Mycobacterium Tuberculosis Complex (MTC)?
MTC organisms = TB causing:
M. tuberculosis
M. africanum
M. microtis
M. bovis (from unpasteurised milk)
What is the morphology of M. TB?
Gram Positive Rod Bacilli
Non motile + non spore forming
Mycolic acid capsule: Acid fast staining (w/ ZN)
Resistant to phagocytic killing.
Slow growing (15-20 hrs)
What is the epidemiology of TB?
1.7Bn people have latent TB
Affects immunocompromised more
More common in South Asia (India, China, Pakistan) and Sub-Saharan Africa
How is TB infection spread?
Via airborne transmission
What are the risk factors for TB infection?
Contact with someone w/ active TB
Country/recent travel to associated countries
Immunocompromised (HIV etc)
IVDU
Homelessness
Smoking and alcohol
Increased age
What are the different types of TB?
Active TB - active infection
Latent TB - Previous infection where the immune system has encapsulated and prevented progression of TB
Secondary TB - When Latent TB reactivates
Miliary TB - Where immune system cannot control the infection and it becomes disseminated
Extrapulmonary TB - where TB infects other areas
What Extra-pulmonary sites can TB infect?
Lymph nodes
Pleura
Central nervous system
Pericardium
Gastrointestinal system
Genitourinary system
Bones and joints
Cutaneous TB affecting the skin
What is the pathogenesis of TB?
Infection of TB via droplets/aerosol
TB phagocytosed (but resistant to killing)
Granulomatous formation (typically in hilar lymph nodes)
T cells recruited and Centre of granuloma undergoes caseating necrosis (1’ Ghon Focus)
Ghon Focus spreads to nearby lymph nodes forming a Ghon Complex
Latent TB:
In most people TB is contained within granuloma and becomes latent TB.
Miliary TB:
If TB spreads from Ghon complex
systemically then it becomes Miliary TB
Is latent TB symptomatic?
No - ASx as bacteria is contained within granuloma and causes no Sx
What are the symptoms of active TB?
Systemic Sx:
Fatigue
Fever + night sweats + weight loss (characteristic of TB)
Lymphadenopathy
Cough w/haemoptysis
Dyspnoea
Erythema Nodosum
What are the signs of TB?
Auscultation - often normal (may have crackles)
Clubbing
What may be symptoms of Extrapulmonary TB?
Meningism
Skin rash
TB pericarditis Sx
Join pain
Spinal Pain (spinal TB)
What are the primary investigations for TB?
Latent Disease - Mantoux Test
Interferon Gamma release assay
CXR - patchy consolidation, pleural effusions
Sputum culture - AFB bright red on ZN stain.
NAAT
What is the management of latent TB?
Doesnt necessarily need Tx
If risk of reactivation then:
Isoniazid and rifampicin for 3 months
Isoniazid for 6 months
What is the Treatment for Active TB?
RIPE:
R – Rifampicin for 6 months
I – Isoniazid for 6 months
P – Pyrazinamide for 2 months
E – Ethambutol for 2 months
What are the side effects of TB treatment?
Rifampicin - Haematuria
Isoniazid - Peripheral Neuropathy
Pyrazinamide - Hepatitis
Ethambutol - Optic neuritis/eye problems
What is Pneumonia?
Infection of the lungs leading to inflammation of the lung tissue and fluid exudation (sputum) collecting in the alveoli.
What are the classifications of Pneumonia?
Community Acquired Pneumonia
Hospital Acquired Pneumonia
Aspiration Pneumonia
Define Community Acquired Pneumonia (CAP)?
Pneumonia that develops out in the community or <48hrs after hospital admission
Define Hospital Acquired Pneumonia (HAP)?
Pneumonia that develops more than 48 hours after hospital admission.
Define Aspiration pneumonia?
Pneumonia that develops as a result of inhaling foreign material (food etc)
What is the main type of organism that causes pneumonia?
Bacterial infection
Can also be Viral (Influenza/CMV) or fungal (P. jirovecii)
What are the main cause of CAP?
S. pneumonia (50%)
H. influenzae (20%)
Mycoplasma pneumoniae (Atypical pneumonia)
What are some less common causes of CAP?
S. aureus
Legionella (atypical)
Moraxella
Chlamydia pneumoniae (atypical)
Where is legionella caused pneumonia typically from?
Often from Spain.
Recent Travel Hx and staying in hotels with air conditioning.
What are the main causes of HAP?
P. aeruginosa
E. coli
S. aureus
Klebsiella
What is the concern of treating HAP?
Most of the causative organisms have multi drug resistance
What is the main cause of aspiration pneumonia?
Klebsiella
What is atypical pneumonia?
How are they Tx?
pneumonia caused by an organism that cannot be cultured in the normal way or detected using a gram stain.
They dont respond to penicillins
Tx with Macrolides, Fluoroquinolones and tetracyclines.
What are the causes of atypical pneumonia?
Legionella
Chlamydia psittaci
Mycoplasma pneumoniae
Chlamydophila pneumonia
Q fever (Coxiella)
What is the main cause of fungal pneumonia?
Pneumocystis jiroveci (PCP)
Occurs in immunocompromised Px
AIDS defining illness
How is PCP treated?
Co-trimoxazole
(combination of Trimethoprim and Sulphamethoxazole)
What are the risk factors for pneumonia?
Extremes of age
Preceding infection (viral)
Immunosuppressed
IVDU
Respiratory conditions - asthma, COPD, CF
What is the pathogenesis of typical pneumonia?
Bacteria invades
Infection and inflammation
Exudate forms inside alveolar lumen
Sputum production
What is the pathogenesis of atypical pneumonia?
Bacteria invades
Infection and inflammation
Exudate forms in interstitium of alveoli
Dry cough
What are the symptoms of pneumonia?
Productive cough w/purulent sputum
Fever - due to infection
Pleuritic chest pain
Dyspnoea
May cause confusion in elderly
Dry cough in atypical pneumonia
What are the signs of pneumonia?
Reduced breath sounds
Bronchial Breathing w/ coarse crepitations
Hypoxia
Tachycardia
Pyrexia
What are the primary investigations of pneumonia?
1st Line:
CXR (diagnostic) shows consolidation
FBC - Raised WCC
U&E - urea
CRP - raised due to inflammation
Sputum sample and culture to ID organism
How is pneumonia assessed for severity?
CURB65:
C – Confusion
U – Urea > 7
R – Respiratory rate ≥ 30
B – Blood pressure < 90 systolic or ≤ 60 diastolic.
65 – Age ≥ 65
Score 0/1: Consider treatment at home
Score ≥ 2: Consider hospital admission
Score ≥ 3: Consider intensive care assessment
What organisms may show multi-lobar pneumonic lesions on CXR?
S. pneumoniae
S. aureus
Legionella
What organisms may show Multiple abscess pneumonic lesions on CXR?
S. aureus
What organisms may show upper lobe pneumonic lesions on CXR?
Klebsiella
(but first exclude TB)
What is the treatment for pneumonia?
Antibiotics:
Mild CAP: Amoxicillin 5 days
Moderate-severe CAP: Amoxicillin + Macrolide 7-10 days
If legionella (notify PHE) and Clarithromycin
What are the major complications of pneumonia?
Sepsis
Pleural effusion
Empyema
Lung abscess
Death
What is Cystic Fibrosis?
An autosomal recessive condition that affects the mucus glands multi-systemically
What are the genetics for CF?
autosomal recessive mutation on Chromosome 7 affecting the AFTR protein.
There are multiple mutations but Delta-F508.
(phenylalanine is deleted)
This affects chloride channels.
What is the prevalence of CF?
1 in 25 are carriers of the gene
1 in 2500 are affected by CF
What are the risk factors for CF?
FHx
Known parental carriers
Caucasian (CF is the most common inherited condition in caucasians)
What is the CFTR protein?
CFTR is an epithelial cAMP regulated chloride channel that normally actively secretes Cl- ions and passively secretes Na+ ions along with water into ductal secretions
This makes the ductal secretions thin and watery
What is the pathophysiology of CFTR protein?
Mutation in CFTR causes it to become dysfunctional.
CFTR has reduced function meaning that less Cl-, Na+ and water are released into ductal secretions leading to the thickening of the mucus secretion.
What is the pathophysiology of a CFTR dysfunction in relation to the lungs?
CFTR mutation leads to thick mucus secretions.
This causes impaired mucociliary clearance as the mucus is extra thick.
This leads to stagnation of mucus that contains pathogens which leads to increased infection risk.
The thicker mucus causes difficulty breathing
Trapping of mucosal pathogens can cause a inflammatory reaction which leads to an increased risk of bronchiectasis
What is the pathophysiology of a CFTR dysfunction in relation to neonates?
Can lead to Meconium Ileus:
Stool becomes too thick to pass through the bowel leading to bowel obstruction.
Failure to thrive
What is the pathophysiology of a CFTR dysfunction in relation to the GI Tract?
Thick secretions from the pancreas can lead to pancreatic duct obstruction.
Pancreatic insufficiency and malabsorption of foods.
Bowel obstructions
What is the pathophysiology of a CFTR dysfunction in relation to the Hepatobiliary system?
Thicker biliary secretions leads to an increased risk of biliary obstruction.
Could lead to liver cirrhosis
How can CF lead to male infertility?
CFTR mutation can cause atrophy of the vas deferens leading to infertility
What are the symptoms of CF?
Chronic cough w/Thick sputum production
Recurrent respiratory tract infections
Loose, greasy stools (steatorrhoea) due to a lack of fat digesting lipase enzymes
Abdominal pain and bloating
Parents may report the child tastes particularly salty when they kiss them, due to the concentrated salt in the sweat
Poor weight and height gain (failure to thrive)
What are the signs of CF?
Low weight or height on growth charts
Nasal polyps
Finger clubbing
Crackles and wheezes on auscultation
Abdominal distention
What are the primary investigations for CF?
New-born Blood spot test
Sweat Test (gold standard)
Genetic testing for CFTR mutation)
What is the CF Sweat test?
Pilocarpine and electrodes placed on skin make it sweat.
Tested for Chloride Concentration.
A result of > 60 mmol/L (sweat chloride) is positive and requires referral to a cystic fibrosis specialist (normal value < 40 mmol/Ll)
Why are people with CF at a massively increased risk of recurrent respiratory tract infections?
Patients with cystic fibrosis struggle to clear the secretions in their airways.
This creates a perfect environment with plenty of moisture and oxygen for colonies of bacteria to live and replicate.
What are the key microbial organisms that colonise the respiratory tract in CF?
S. aureus
P. aeruginosa
+Haemophilus influenza
Klebsiella pneumoniae
Escherichia coli
What is the management of CF?
Non curative:
Conservative:
Chest physiotherapy
Exercise
No smoking
Medication:
Anti-mucolytics
Prophylactic Flucloxacillin (prevent S. aureus)
Bronchodilators (SABA)
Vaccinations
Systemic Tx:
Pancreatic enzyme replacement
Vitamin Supplements
High calorie diet.
What is Bronchiectasis?
Bronchiectasis is a chronic, debilitating lung disease characterised by the permanent dilation of the bronchi.
(Also have lots of mucus within them)