Respiratory Flashcards
Pathophysiology of asthma
Chronic inflammation (due to IgE release from mast cells) of the airways causing episodic bronchoconstriction leading to reversible airflow limitation.
Describe the chronic remodelling/histological changes of airways seen in asthma
Thickening of sub-basement membrane
sub epithelial fibrosis
airways smooth muscle hypertrophy + hyperplasia
Mucus gland hyperplasia + hyper secretion
Common triggers in asthma
Cold air
Exercise
NSAIDs / Aspirin
Beta-blockers
Infection
Animals
Dust
Moulds
Clinical Features of asthma
Episodic symptoms + Diurnal variation
Bilateral widespread polyphonic wheeze
Dry cough
History of atopy / exposure to trigger
1st line investigations for asthma
Fractional exhaled NO + Spirometry
>40 parts NO is diagnostic + spirometry must demonstrate 12% increase in FEV1 or PEFR following bronchodilator use
2nd line investigations for asthma
PEFR diary or Bronchial provocation test
Management of Asthma (Age >12yrs)
- SABA prn
- SABA + low dose ICS
- SABA + low dose ICS + LTRA
- SABA + low dose ICS + LABA (+/- LTRA if helped)
- SABA + MART (ics + laba)
- SABA + Med dose ICS + LABA
- Refer - for consideration of high dose ICS or adding in Theophylline/Aminophylline
MOA and Example of LTRA
Montelukast
MOA = Leukotreine antagonist. reduces inflammation, bronchoconstriction and mucus secretions.
What monitoring is needed for theophylline
Plasma levels 5 days after initiation and 3 days after each dose change (due to low therapeutic index)
Definition of COPD
Progressive, irreversible long term airflow obstruction caused by damage to lung tissue.
What are the 2 conditions outlined by COPD
Emphysema + Chronic Bronchitis
RF for COPD
Smoking
Age
FHx
A1AT deficiency
Exposure to dust
Sulphur dioxide exposure
Histological changes in COPD
Narrowing of airways
Airways remodelling (pseudo stratified columnar epithelium –> Squamous cell)
Increased number of goblet cells
Mucus gland hyperplasia
Vascular bed changes –> Pulmonary HTN
What is emphysema?
Enlargement of alveolar airspace due to breakdown of elastin and destruction of alveolor walls leading to loss of lung elastic recoil + small airways collapse resulting in air trapping.
What is chronic bronchitis
Chronic productive cough due to goblet cell hyperplasia and fibrosis + thickening of airways resulting in airflow limitation
How to differentiate between Emphysema + Chronic bronchitis subtypes
Emphysema = ‘Pink puffers’ - barrel chest, SOB, pursed lip breathing, weight loss, accessory muscle use
Bronchitis = ‘Blue bloaters’ - chronic cough, ascites, ankle oedema, cor pulmonale, cyanosis, polycythemia
Clinical Signs of COPD
Hypoxemia
Asterixes
Distant breath sounds
Tachypnoea
R sided HF signs
MRC dyspnoea scale
1 = Breathless on strenuous exercise
2 = Breathless on walking uphill
3 = Breathless that slows on walking flat
4 = Needs to stop + catch breath after walking 100m on flat
5 = unable to leave house due to SOB
Investigations for COPD
Clinical Features + Spirometry (Obstructive pattern reduced FEV1:FVC)
Classification of COPD severity
Mild = FEV1 >80%
Moderate = FEV1 50-79%
Severe = FEV 30-49%
Very severe = FEV1 <30%
CXR findings in COPD
Lung hyperinflation, bullae, flattened diaphragm
Special tests in suspected COP
Echocardiogram + ECG (if suspecting cor pulmonale)
TLCO = decreased
Genetic testing (for A1AT deficiency)
Management pathway for COPD
- SABA or SAMA (e.g ipratropium)
- If steroid responsive/asthma features = LABA +ICS
- If not steroid responsive = LABA + LAMA (make sure to stop SAMA)
- LABA + LAMA + ICS
- Add theophylline / azithromycin / Carbocystine
- Consider LTOT or lung volume reduction surgery
What monitoring is needed prior to azithromycin treatment
LFTs
ECG - can cause prolonged QT interval (tdp)
Indications for long term oxygen therapy in COPD patients
2 ABGs at least 3 weeks apart showing SpO2 < 7.3
FEV1 <30%
Polycythemia
Peripheral oedema
Raised JVP
Sp02 < 92% on air
Which condition is characterised by Bronchiectasis + emphysema + Liver cirrhosis
Alpha-1 Antitrypsin deficiency
What is the inheritance of A1AT deficiency
Autosomal recessive mutation to the SERPINA1 gene on chromosome 14
Which type of lung cancer is most common
NSCLC - Squamous cell
Which type of lung cancer has the strongest associated with smoking?
Squamous cell
Which type of lung cancer is most common in non-smokers
Adenocarcinoma
Which type of lung cancer originates in neuroendocrine cells - APUD/Kulchitsky cells?
SCLC
Which lung cancer is caused by undifferentiated tumour cells?
Large cell
Cavitating lesions with central necrosis on CXR is indicative of which type of lung cancer?
Squamous cell
What are the paraneoplastic extramanifestations of pancoast tumours
- Recurrent laryngeal nerve palsy
- Phrenic nerve palsy
- SVC obstruction
- Brachial plexus palsy
- Horner’s syndrome
Signs + Symptoms of SVC obstruction
Facial swelling
SOB
Distended neck veins
Pemberton’s sign - facial congestion + cyanosis when hands raised above head
Hypercalcemia, Hyperthyroidism and Hypertrophic pulmonary osteoarthropathy are parenoplastic manifestations of which type of lung cancer?
Squamous cell carcinoma
Gynaecomastia is associated with which type of lung cancer?
adenocarcinoma
What are the paraneoplastic manifestations associated with SCLC?
- SIADH
- Cushing’s
- Hypercalcemia
- Lambert-eaton syndrome
- Limbic encephalitis
Management of SCLC
Radiotherapy + Chemotherapy
Management for NSCLC
Surgery (Lobectomy) + neoadjuvant chemotherapy
Contraindications to surgery in Squamous cell lung cancer
Stage IIIb or IV
FEV1 <1.5
Malignant pleural effusion
Tumour near the hilum
Vocal cord paralysis
SVC obstruction
Clinical Features of mesothelioma
History of asbestos exposure
SOB
chest pain
SOB
Clubbing
Painless pleural effusion
1st line investigation for mesothelioma
CXR: shows pleural effusion / pleural thickening / pleural plaques
Next step = Pleural CT and consider a pleural aspirate if effusion is present
Most common cause of pneumonia in general population
Streptococcus pneumoniae
Most common cause of pneumonia in COPD patients
Haemophilius influenzae
Main cause of Hospital acquired pneumonia
Staph aureus
Which patients tend to get Morazella catarrhalis pneumonia?
Immunocompromised patients or those with chronic lung diseases
Which organism causes pneumonia in cystic fibrosis patients
Pseudomonas auerginosa
Cause of pneumonia in a patient with red current jelly sputum + Epyema + Cavitating lesions in upper lobes
Klebsiella
Klebsiella pneumonia is common in which patients
Chronic alcoholics
Diabetics
Aspiration pneumonia
Which type of pneumonia is commonly caused by air-con or infected water
Legionella
Clinical Signs / Features of Pneumonia
Sx = Productive cough + purulent sputum / SOB / Pleuritic chest pain / fever
Signs = Bronchial breath sounds / Focal coarse crackles / Dullness to percussion / Whispering pectroloquy
Severity assesment in pneumonia
CURB 65
Confusion
Urea >7
RR >30
BP <90
Age >65
Management of pneumonia
CURB score 0-1 = Amoxicillin 5 days at home (or doxy/clarith/eryth)
2 = Amoxicillin + Macrolide for 10 days (in hosp)
3-5 = IV Co-amoxiclav + fluids + O2
What monitoring is required in patients with pneumonia to indicate recovery
WBC + CRP
Complications of pnuemonia
Sepsis
Pleural effusion
Respiratory failure
Lung abscess
Empyema
Symptoms of Legionairres disease
Flu like symptoms + Dry cough + SIADH + Confusion + deranged LFTs
Investigation for legionairres disease
Urinary antigen
Psittacosis
Often caused by contact with birds
Sx = pneumonia + severe headache
Invx = CXR + Atypical pneumonia screen
Atypical causes of pneumonia
Legionella
Psittacosis
Mycoplasma pneumoniae
Chlamdoyphilia pneumonia
Coxiella (Q fever)
Which cause of atypical pneumonia has a prolonged & gradual onset and causes erythema multiforme / erythema nodosum
Mycoplasma pneumoniae
Cold aha / Guillian barre / Bullous myringitis / Pericarditis and GN are complications of which atypical pneumonia?
Mycoplasma pneumoniae
When to suspect Q fever
Pt with pneumonia symptoms + working as a farmer/in an abattoir
Management of Pneumocystosis jiroveci (PCP)
Co trimoxazole
Clinical Presentation of Bronchiectasis
Productive cough
Daily production of sputum (often thick, foul smelling green mucus)
Haemoptysis
Wheeze
Clubbing
CT chest showing thickened dilated bronchi + cysts at the end of bronchioles (bunch of grapes pattern) is indicative of what respiratory disease
Bronchiectasis
Causes of Upper zone fibrosis
C - Coal workers pneumoconiosis
H - Hypersensitivity pneumonitis / Histiocytosis
A - Ankylosing spondylitis
R - Radiation
T - TB
S - Silicosis / Sarcoidosis
Causes of lower zone fibrosis
B - Bronchiectasis
I - Intersitial pneumonia / infection
S - Systemic sclerosis / SLE / RA
A - Aspiration / A1AT deficiency / Asbestosis
M - Medications (BANS ME)
Medications causing lower zone fibrosis
Bleomycin
Amiodarone
Nitrofuantoin
Sulfalazine
Methotrexate
Clinical Presentation of Fibrosis
Insidious onset
Progressive exertional dyspnoea
Weight loss
Clubbing
Bi-basal fine end-inspiratory crackles
CXR showing reduced lung volume, bilateral interstitial shadowing + lung honeycombing is indicative of what
Lung fibrosis
Ground glass appearance on CT is indicative of what
Lung fibrosis
Features of sarcoidosis
Erythema nodosum
Bilateral hilar lymphadenopathy
Swinging fever
Polyarthralgia
Fibrosis (SOB + Cough + Weight loss)
Lupus pernio
Hypercalcemia
Non-caseating granulomas
Management of Sarcoidosis
Oral prednisolone - should be stated when stage 2/3 or hypercalcemia
Lofgren’s syndrome
Acute form of sarcoidosis characterised by BHL + Erythema nodosum + Fever + polyarthralgia
Hereford’s syndrome
Parotid enlargement + fever + uveitis (associated with Sarcoidosis)
Causes of Hypersensitivity pneumonitis (Extrinsic allergic alveolitis)
Farmers lung - wet hay
Bird-fanciers lung - bird droppings
Malt workers lung - mould on barley (aspergillus)
Mushroom lung
Clinical presentation of Hypersensitivity pneumonitis
SOB + dry cough + fever acutely.
After weeks/months = Lethargy + SOB + Anorexia + weight loss
Investigations + Special tests for hypersensitivity pneumonitis
FBC = No eosinophilia
Imaging = Upper/mid zone honeycomb lung/fibrosis
Special tests = bronchealveolar lavage shows raised lymphocytosis + mast cells
Pt presents with a new wheeze + cough + SOB.
The patient has a PMH of bronchiectasis.
FBC shows eosinophilia
CXR shows new infiltrates
+Ve RAST test
Diagnosis?
Allergic bronchopulmonary aspergillosis
CT scan findings in Allergic bronchopulmonary aspergillosis
Bronchocoeles
(finger in glove appearance)
Special tests for allergic bronchopulmonary aspergillosis
RAST test to aspergillus
IgE raised
+ve IgG precipitans
Management of Allergic bronchopulmonary aspergillosis
Oral prednisolone
Idiopathic pumonary fibrosis + Features
Essentially fibrosis without any other clear cause.
Typically men aged 50-70yrs
Features = exertional SOB + Weight loss + Bibasal fine end-inspiratory crackles
Reduced TCLO
Fibrosis on CXR
Risk Factors for PE
- Vessel wall damage (Surgery / Previous DVT / Trauma)
- Venous stasis (Age >40 / Bed rest / long haul flight / General anesthetic / Paralysis)
- Hypercoagulability (Pregnancy / COCP / HRT / Cancer / Polycythemia / SLE / Obesity)
Clinical Presentation of PE
SOB + Pleuritic chest pain + Haemoptysis
Tachycardia + Tachypnoea + Hypotension + Pleural rub
Causes of Transudative Pleural effusion
= < 25g/L protein + Low LDH
Heart failure
Renal failure
Constrictive pericarditis
Liver disease / Hypoalbuminemia
Hypothyroidism
Meig’s syndrome
Meig’s syndrome
Ovarian cancer + R sided pleural effusion
Causes of Exudative Pleural effusion
> 30g/L protein + High LDH
Pneumonia
Lung cancer / TB
Connective tissue disease (RA/SLE)
Acute pancreatitis
Dressler’s syndrome
Mesothelioma
Light’s Criteria
Useful for when protein is 25-30g/L
An exudative is likely if:
> Pleural fluid protein/Serum protein is >0.5
> Pleural fluid LDH/Serum LDH is >0.6
> Pleural fluid LDH is >2/3rds more than normal serum LDH
Examination findings in a patient with a pleural effusion
Stony dullness to percussion
Quiet breath sounds
Reduced chest expansion
Decreased/absent tactile vocal fremitus
If pleural fluid aspirate shows heavy blood staining what are the most likely causes of the pleural effusion
Mesothelioma
PE
TB
Empyema
= Purulent fluid in the pleural space (infected pleural effusion)
Pleural aspirate = Pus, pH <7.2, Low glucose, High HDL
Diagnostic test for OSA
Polysomnogrphy
Management of acute bronchitis
Consider doxycycline (if systemically unwell or CRP >100)
Kartagner’s syndrome
Dextrocardia + Bronchiectasis + Recurrent sinusitis + Subfertility
Small volume complexes in lateral leads or Quiet heart sounds may indicate what?
Dextrocardia
Wegners vasculitis - features + Invx
Granulomatosis with polyangitis
Features = Epistaxis + sinusitis + nasal crusting + saddle shaped nose deformity + haemoptysis + SOB + Glomerulonephritis + vasculitic rash
Invx = cANCA +ve
Renal biopsy = Epithelial crescents in the bowman’s capsule
Management of Wegner’s granulomatosis
Steroids + Cyclophosphamide + Plasma exchange
Churg-Strauss vasculitis - Features & invx
Eosinophilic granulomatosis with polyangitis
Features = asthma + paranasal sinusitis + mononeuritis multiplex
Bloods = eosinophilia
Invx = pANCA +Ve
May be precipitated by montelukast
Red staining with ziehl-nielson stain on sputum sample indicates what organism
TB
CXR findings in TB
Upper zone consolidation
Bilateral hilar lymphadenopathy
Ghon focus (in primary infection)
Gold standard investigation for TB
Sputum culture
Rapid diagnostic test for TB
NAAT
TB Screening
Mantoux test - used among high risk population.
<6mm induration = consider BCG vaccine
>6mm induration = DO NOT GIVE BCG VACCINE!
If >15mm = active infection
Management of TB
Rifampicin - 6 months
Isoniazid - 6 months
Pyrazinamide - 2 months
Ethambutol - 2 months
Rifampicin
MOA = Inhibits bacterial DNA dependent RNA polymerase
CYP450 inducer
SE’s = Hepatitis, Red-orange secretions , Flu-like symptoms
Isoniazid
MOA = inhibits mycolic acid synthesis
SEs = Peripheral neuropathy / Hepatitis / Agranulocytosis / Sideroblastic anemia
CYP450 inducer
*Prescribe pyroxidine (B6) with it to prevent neuropathy
Pyrazinamide
MOA = Inhibits fatty acid synthesis
SEs = Gout / arthralgia / hepatitis
Ethambutol
MOA = inhibits arabinosyl transferase
SEs = Optic neuritis
Acute mountain sickness
Sx start around 2500-3000m and last a few days
Sx = Headache / Nausea / Fatigue
Which drug can prevent acute mountain sickness
Acetazolamide - works by causing a metabolic acidosis and compensatory respiratory alkalosis which increases the RR.
Management of acute mountain sickness
descent
High altitude pulmonary oedema
develops > 4000m
SOB + Orthopnoea + Haemoptysis + PND
Management = descent + dexamethasone
High altitude cerebral oedema
Develops >4000m
Sx = Headache + ataxia + papillodema
Management of HACE (High altitude cerebral oedema)
Descent
Nifedipine + Dexamethasone + Acetazolamie + Sildenafil + Oxygen
Egg shell calcification of hilar lymph nodes
Silicosis
Management of pneumothorax
< 2cm and no SOB = discharge + review in 2-4weeks
> 2cm or SOB = Aspirate + reassess. If aspiration fails or patient is >50yrs insert chest drain
If a secondary pneumothorax (i.e there is existing lung disease) = Aspirate if < 2cm + Chest drain if >2cm.
Recurrent ones = Pleurodesis +/- Bullectomy
Most common cause of occupational asthma
Isocyanates - spray painting
