Respiratory medicine Flashcards
Define Acute respiratory distress syndrome
Acute lung damage leading to non-cardiogenic pulmonary oedema
It’s due to diffuse alveolar damage with hyaline membrane formation, endothelial disruption and leakage of fluid into the alveoli from pulmonary capillaries
The Berlin criteria are used to determine if a pt has ARDS, they need to have all of the following:
1) Acute onset <1wk
2) CXR showing bilateral opacities
3) Decreased ratio of arterial to inspired O2 concentration (PaO2/FiO2) <300
Causes of Acute respiratory distress syndrome
Common:
- Sepsis
- Pneumonia
- Aspiration
- Pancreatitis
- Major trauma
Other:
- Fat embolism
- Drowning
- Burns
- TRALI
- Drug overdose
- DIC
Acute respiratory distress syndrome features
- Severe dyspnoea
- Tachypnoea
- Confusion and presyncope secondary to hypoxia
- Appear in respiratory distress
- Critically unwell
- Diffuse crepitations on auscultation
Acute respiratory distress syndrome investigations
- Resp viral swabs = COVID19, influenza
- Sputum, blood and urine cultures = septic screen
- ABG
- Serum amylase = pancreatitis is a common cause
- CXR = bilateral alveolar infiltrates w/out features of HF (cardiomegaly and Kerley B lines)
- CT chest
Acute respiratory distress syndrome management
- Identify and treat underlying cause
- Intubation and ventilation on ICU
Define Asbestosis
Chronic fibrotic lung disease that typically manifests 10-20 years following exposure to asbestos fibres
Asbestosis features
Symptoms:
- Progressive dyspnoea manifesting over months-years
- Dry cough
- WL
- Fatigue
Signs:
- Bilateral fine end-expiratory crepitations, predominantly basal
- Finger clubbing
- Cyanosis
Asbestosis investigations
- Exposure Hx
- PFTs = reduced FVC and TL w/ normal FEV1/FVC
- CXR = bilateral shadowing, often at the bases
- High resolution CT = may show honeycombing, traction bronchiectasis and parenchymal bands esp in the lower zones
Asbestosis management
No specific treatment to reverse the lung damage - aim for supportive therapy and reducing the risk of LC:
- Smoking cessation
- Pulmonary rehab
- O2 therapy if significant hypoxaemia
- Influenza and pneumococcal vaccines
Define Aspiration pneumonia
Inflammation of the lungs after an irritating substance is inhaled (commonly gastric or oesophageal secretions)
This causes pneumonitis, and may lead to infection caused by the normal flora found in the oropharynx entering the LRT
Causes of Aspiration pneumonia
- Swallowing difficulties = stroke, bulbar palsy, oesophageal strictures, MS, achalasia
- Impaired consciousness = seizures, GA, alcohol/drug intoxication
- Tracheooesophageal fistulae
Aspiration pneumonia features
- Cough - may be productive of purulent sputum
- SOB
- Chest pain
- Fever
- Malaise
Aspiration pneumonia investigations
- Sputum culture
- Bloods
- CXR = look for consolidation - more likely to be right sided due to the more vertical orientation of the right main bronchus
Aspiration pneumonia management
- Initial abx as per local guidelines - BTS suggest co-amoxiclav
- Supportive care
Asthma pathophysiology
Type 1 hypersensitivity reaction leading to inflammation
This inflammation leads to airway hyperresponsiveness which in turn causes bronchospasm, mucus hypersecretion and airway obstruction
Over time in severe asthma, airway remodelling mediated by fibroblasts causes chronic obstruction and thickening of smooth muscle
Asthma investigations
- Spirometry w/ bronchodilator reversibility testing for all pts >5
- FeNO testing in adults to confirm eosinophilic airway inflammation = +ve if >40 parts per billion
If there is diagnostic uncertainty following the tests, pts may be asked to monitor their peak flow twice a day for 2-4 wks and keep a dairy, this is to assess peak flow variability - variability >20% is +ve
If still uncertain then can do direct bronchial challenge testing = histamine or metacholine is inhaled to trigger bronchoconstriction, airway hyperresponsiveness is assessed by looking at the concentration of the triggering medication required to causes a 20% decrease in FEV1 - 8mg/mL or less is +ve
Management ladder for chronic asthma
1) SABA (salbutamol) +/- low dose ICS (betamethasone) for pts using their SABA 3x a week or more
2) Add a leukotriene receptor antagonist e.g. Montelukast
3) Add LABA e.g. salmeterol
4) Low dose ICS + maintenance and reliever therapy inhaler (MART) +/- LTRA
- MART = combination inhaler of beclomethasone + formoterol (Fostair) which can be used as both a reliever therapy and maintenance treatment
5) Increase ICS dose and refer to secondary care
6) High dose ICS, oral corticosteroids
7) Biologics e.g. omalizumab which targets IgE
Grading of acute asthma exacerbation severity
Moderate:
- PEFR >50% of predicted or best
- No features of severe/life-threatening asthma
Severe:
- PEFR 33-50% of predicted or best
- HR >110
- Resp rate >25
- Unable to complete sentences in one breath
- Accessory muscle use
Life-threatening:
- PEFR <33% of predicted or best
- O2 sats <92% or cyanotic
- Altered consciousness/confusion
- Exhausted/poor resp effort
- Cardiac arrhythmia
- Hypotension
- Silent chest
Acute asthma management
- ABCDE
- Titrate O2 to maintain sats 94-98%
- Nebulised salbutamol (10 puffs outside of hospital)
- Add ipratropium bromide if no response
- Give prednisolone 40-50g orally, or IV hydrocortisone if pt unable to swallow
- Consider IV magnesium sulphate and/or aminophylline if no response to nebulisers
- If pt continues to deteriorate then intubation and ventilation in ICU
Follow pt up 2 wks after an acute attack
Chronic asthma management ladder in paediatrics
Under 5’s:
1) SABA
2) 8 week trial of moderate paediatric dose ICS if symptoms >3x a week or disturb sleep
4) If symptoms reoccur w/in 4 wks then paediatric low dose ICS, if reoccur after 4 wks repeat the trial
5) Add LTRA
6) Refer to secondary care
5-16:
1) SABA
2) Add paediatric low dose ICS
3) Add LTRA
4) Swap LTRA for LABA
5) Swap to MART inhaler e.g. Fostair
6) Refer to secondary care
What are the 2 types of pneumococcal vaccine?
1) Pneumococcal polysaccharide vaccine = 1 off dose that covers 23 variants - revaccinated every 5 years
2) Pneumococcal polysaccharide conjugate vaccine = part of the childhood vaccination schedule, 2 doses are given at 12 weeks and 1 year - covers 13 serotypes
Who is given the Pneumococcal polysaccharide vaccine?
Pts aged 65+ and pts aged 2+ in an at risk group:
- Splenic dysfunction or asplenia
- COPD
- Chronic HF
- CKD stage 4/5
- Chronic liver disease
- DM requiring medication
- Immunosuppressed pts
- Cochlear implant
- Pts at risk of CFS leak
- Pts exposed to metal fumes at work (e.g. welders)
Causes of Bilateral hilar lymphadenopathy
- Inflammation = sarcoidosis
- Infective = TB, mycoplasma, histoplasmosis
- Malignancy = lymphoma (HL more common than NHL), carcinoma
- Pneumoconiosis = silicosis, berylliosis
Define Bronchiectasis
A chronic lung disease where inflammation and obstruction causes damage to the bronchial walls leading to their permanent dilation
The damage may affect the whole lung or only one lobe
Causes of Bronchiectasis
- Idiopathic (40%)
- Previous severe LRTI (most common identifiable cause)
- Immunodeficiency = HIV, CVID
- Defective mucocilliary clearance = CF, PCD
- AI = RA, SLE, IBD
- Airway obstruction = inhaled foreign body, bronchial carcinoma, severe COPD/asthma
- Chronic aspiration
- Congenital defects of the large airways = Marfan’s, tracheobronchomegaly
Bronchiectasis features
Symptoms:
- Productive cough lasting at least 8 weeks
- Copious production of purulent sputum
- Dyspnoea
- Haemoptysis
- Chest pain
- Fatigue
- WL
Signs:
- Coarse crackles on auscultation
- Wheeze
- Rhonchi = snoring sound caused by secretions in the large airways
- Finger clubbing
Bronchiectasis investigations
- Sputum culture
- Spirometry
- Bloods
- CXR = increased lung markings, tram-track opacities and ring shadows
- High-resolution CT = diagnostic -shows lack of tapering of airways, increased ratio of bronchi to adjacent pulmonary arteries, bronchial wall thickening and impacted mucus
- Investigate underlying cause
Bronchiectasis management
Conservative:
- Pt education on sputum clearance chest exercises
- Smocking cessation
- Pulmonoral rehan
- Influenxa and pneumococcal vaccines
Medical:
- Treat infectious exacerbations
- Long-term abx prophylaxis should be considered in pts w/ 3+ exacerbations per year, or exacerbations causing significant morbidity - these should be tailored to sputum cultures
- Treat comorbidities
Surgical:
- Lung resection in severe localised disease
- Lung transplant in severe diffuse cases
COPD GOLD gradeing system
Grade 1) Mild COPD = FEV1 >80% of predicted, FEV1/FVC <0.7
Grade 2) Moderate COPD = FEV1 50-79% of predicted , FEV1/FVC < 0.7
Grade 3) Severe COPD = 30-49% of predicted, FEV1/FVC <0.7
Grade 4) Very severe COPD = FEV1 <30% of predicted or <50% w/ resp failure or RHF, FEV1/FVC <0.7
COPD features
Symptoms:
- SOB worse w/ exertion
- Reduced exercise tolerance
- Chronic productive cough
- Recurrent LRTI
- Wheeze
Signs:
- Wheeze or crackles on auscultation
- Accessory muscle usage
- Pursed lip breathing
- Cyanosis
- Hyperinflation of the chest
- Cachexia
- Raised JVP and pulmonary oedema (indicates cor pulmonale)
COPD investigations
- Spirometry = FEV1/FVC <0.7
- Bloods = look for polycythaemia (chronic hypoxia) or anaemia (of chronic disease)
- CXR = hyperinflation, flattened hemidiaphragms, bullae
Chronic COPD management
Conservative:
- Smoking cessation
- Annual influenza and 1 off pneumococcal vaccines
- Pulmonary rehab
Medical:
- SABA or SAMA (ipratropium) inhaler for all pts who’s activates are limited by breathlessness
- Next step depends on if they have features of asthma or steroid responsiveness - if they do then add LABA (formoterol) and ICS, if not then add LABA and LAMA (tiotropium)
- Then all 4 inhalers = SABA/SAMA + LABA + LAMA + ICS
- Oral mucolytics
- Prophylactic abx = azithromycin 3x a week
- Long-term O2 therapy for at least 15 hrs a day if they meet the criteria (in another flash card)
Surgical = Lung volume reduction surgery = removal of emphysematous areas of the lung so the healthy lung can expand:
- Surgical resection
- Bronchoscopic insertion of a one-way valve in one of the larger airways to collapse the diseased lung
why
How are COPD pts assessed for long-term O2 therapy?
Pts should be referred if:
- Oxygen saturations <92% in air or cyanosis
- FEV1 <30% predicted (consider referring if <49%)
- Polycythaemia
- Peripheral oedema or raised jugular venous pressure (suggesting cor pulmonale)
Pts are assessed to ensure they are medically optimised and their COPD is stable (not recovering from a recent exacerbation) and to ensure they dont smoke (O2 is a fire hazard)
Pts then have 2 ABGs in air at least 3 weeks apart and the following pts are offered LTOT:
- PaO2 below 7.3kPa
- PaO2 7.3-8kPa w/ any of; secondary polycythaemia, peripheral oedema or pulmonary HTN
Acute exacerbation of COPD management
- If clinically well = increase in usual inhaler usage, 30mg prednisolone for 5 days, oral abx if bacterial suspected
- If unwell then admit for IV steroids and abx
Causes of Croup
- Parainfluenza virus (most common)
- Adenovirus
- RSV
- Rhinovirus
- Influenza
These viruses causes inflammation of the subglottic and laryngeal mucosa which partially obstruct the airways - leads to resp distress and stridor
Croup management
Depends on severity:
- No stridor or chest recessions = treat at home w/ single dose of oral dexamethasone 0.15mg/kg
- Stridor or chest recessions or systemically unwell = admit, O2 therapy, oral dex/prednisolone or nebulised budesonide
- Nebulised adrenaline for temporary symptomatic relief
- Anaesthetics +/- ENT input if concerns regarding airway
Cystic fibrosis features
Resp:
- Bronchiectasis (chronic productive cough, dyspnoea)
- Frequent LRTIs
- Chronic sinusitis
- Nasal polyps
- Increased incidence of pneumothoraces
GI:
-Meconium ileus
- Distal intestinal obstruction syndrome = SBO due to thickened secretions
- Rectal prolapse
- Pancreatic insufficiency = DM and steatorrhea
- Cirrhosis and portal HTN
- Gallstones
- Failure to thrive
- Prolonged neonatal jaundice
Reproductive:
- Congenital absence or blockage of vas deferens = obstructive azoospermia
- Thickened cervical mucus and menstruation disruption due to malnutrition can impact female fertility
MSK:
- Finger clubbing
- Osteopenia/porosis due to malnourishment
- Short stature
- Non-specific joint and muscle pain
Cystic fibrosis investigations
- Heel pick test at birth
- Chloride sweat testing = if sweat Cl level >60mmol/L
- Genetic testing
Cystic fibrosis management
Conservative:
- Pt education
- Airway physio = twice daily airway clearance ant home
- Dietitian input
Medical:
- Orkambi (CFTR modulator) can be given to pts w/ 2 copies of the F508 gene
- Other precision medication used for 1 copy
- Dornase alpha daily nebuliser = is a mucoactive agent which reduces the viscosity of the mucus and makes sputum clearance easier
- Creon and insulin for pancreatic insufficiency
- Flucloxacillin should be given from diagnosis till ages 3-6 as prophylaxis against infections
- Oral azithromycin can be used as an immunomodulator in pts w/ declining lung function or frequent exacerbations - oral steroids 2nd line
Surgical:
- Organ transplant - lung or liver
Differentials for haemoptysis
Bleeding from the trachea or bronchi:
- Malignancy
- Bronchitis
- Bronchiectasis
- Airway trauma
Bleeding from the lung parenchyma:
- Pneumonia = rust coloured in pneumococcal, red current jelly coloured in klebsiella
- TB
- Lung abscess
- Granulomatosis w/ polyangiitis
- Goodpasture’s syndrome
Vascular bleeding:
- PE
- AV malformation
- Mitral stenosis (due to pulmonary venous HTN)
- Iatrogenic
Causes of Horner’s syndrome
Central lesions:
- Vertebral artery dissections
- Ischaemic stroke (lateral medullary syndrome)
- Syringomyelia above T1 (can be bilateral)
- Demyelination
- Neoplasm of the brainstem
Preganglionic:
- Cervical rib
- Pancoast’s tumour (apical LC that invades the surrounding soft tissue)
- Thyroid or mediastinal tumour
- Iatrogenic (birth trauma)
Postganglionic:
- Carotid artery dissection
- Cavernous sinus thrombosis
- Injury of the superior cervical ganglion
- Cluster headache
- Neoplasms of the nasopharynx, pituitary or skull base
Serotypes of Influenza
- Influenza A = capable of causing pandemics and epidemics, no animal reservoir
- Influenza B = capable of epidemics only, animal hosts includes pigs and birds
- Influenza C = only found in cattle
Influenza features
Incubation period of 1-4 days and pts can remain infectious for 7-21 days
- Fever
- Non-productive cough
- Myalgia
- Headache
- Malaise
- Sore throat
- Rhinitis
Influenza management
- Largely supportive
- If w/in 48hrs and pt at great risk of complications - can give Tamiflu (neuraminidase inhibitor)
Causes of Interstitial lung disease
Upper zone predominant (BREAST):
- Bronchopulmonary aspergillosis
- Radiotherapy
- Extrinsic allergic pneumonitis
- Ankylosing spondylitis
- Sarcoidosis/silicosis
- TB
Lower zone predominant (RAIDS):
- RA
- Asbestosis
- Idiopathic pulmonary fibrosis (most common)
- Drugs (amiodarone, nitrofurantoin, bleomycin, methotrexate, phenytoin)
- Scleroderma/SLE
Define Idiopathic pulmonary fibrosis
A progressive, fibrotic lung disease of unknown cause that is more common in males and smokers
Imaging usually shows interstitial pneumonitis, and there is characteristic basal honeycombing on high resolution CT scan
Median survival of 3yrs from diagnosis
Define Hypersensitivity pneumonitis
A hypersensitive reaction in the lungs due to inhalation of specific environmental agents - e.g. chemicals, agricultural dusts, plants, animals and fungal proteins
One-off exposure can cause acute onset flue-like symptoms, but repeated exposure results in ongoing inflammation - this leads to interstitial fibrosis
Define Farmers lung
A type of hypersensitivity pneumonitis triggered by mould spores of hay or straw
Interstitial lung disease features
Symptoms:
- Dry cough
- SOB
- Reduced exercise tolerance
- Fatigue
- WL
- Anorexia
Signs:
- Cyanosis
- Clubbing
- Cachexia
- Fine end-inspiratory crackles that don’t clear on coughing - location depends on the type of ILD
Interstitial lung disease investigations
Bloods:
- FBCs may show eosinophilia in hypersensitivity pneumonitis
- U&E, LFTs, bone profile
- CRP
- AI screen
- Serum precipitins to specific antigens
- Serum ACE if suspecting sarcoid
Imagine:
- CXR = usually shows reticular and nodular shadowing
- Bilateral hilar lymphadenopathy = sarcoidosis
- HRCT = gold standard - typical findings are honeycombing, ground-glass changes and traction bronchiectasis (where contracting fibrosis pulls the bronchioles apart)
Other:
- Spirometry = FEV1/FVC >0.7, decreased total lung capacity, decreased TLCO
- Bronchoscopy to find predominant cells in the lung
- Lung biopsy
