Respiratory Flashcards
Asthma
- chronic reversible obstructive airway disease -> inflammation / bronchospasm
- non/eosinophilic
Asthma RFs
- atopy
- maternal smoking, low birth weight, formula fed
- air pollution
- allergens, eg dust mites
Triggers
- infection, nighttime, exercise, animals, cold/damp air, strong emotions
Occupational
- workplace triggers - eg flour…
Asthma Px
- episodic sx
- diurnal variation - worse at night
- SOB
- chest tightness
- dry cough
- wheeze - widespread, polyphonic
- reduced PEFR
Asthma Ix
Measure eosinophil count or fractional nitric oxide (FeNO)
Diagnose asthma, without further investigations if:
Eosinophil is above reference range
FeNO is ≥ 50 ppb
If asthma is not confirmed by the eosinophil count or FeNO
measure bronchodilator reversibility (BDR) with spirometry
diagnose asthma if:
the FEV1 increase is ≥ 12% and 200 ml or more from the pre-bronchodilator measurement, or
the FEV1 increase is ≥ 10% of the predicted normal FEV1
if spirometry is not available or it is delayed, measure peak expiratory flow (PEF) twice daily for 2 weeks
diagnose asthma if:
PEF variability (expressed as amplitude percentage mean) is ≥ 20%
If asthma is not confirmed by eosinophil count, FeNO, BDR or PEF variability but still suspected on clinical grounds:
refer for consideration of a bronchial challenge test
diagnose asthma if bronchial hyper-responsiveness is present
Asthma Dx
Initial Ix
- FeNO
- spirometry with bronchodilator reversibility
If dx uncertain
- peak flow diary
If still uncertain
- direct bronchial challenge
Asthma new joint guidelines
Step 1: a low-dose inhaled cordicosteroid (ICS)/formoterol inhaler to be taken as needed for symptom relief (anti-inflammatory reliever (AIR) therappy
If the patients presents highly symptomatic or with a severe exacerbatiion-
Start treatment with low-dose MART
Treat the acute symptoms as appropriate (a course of oral corticosteroids may be indicated)
Step 2:
A low dose MART- (ICS/formoterol combination for maintenance therpay as needed ie regularly and as required)
Step 3:
A moderate-dose MART
Step 4:
Check the fractional exhaled nitric oxide (FeNO) level if available, and the blood eosinophil count-
If either raised- specialist case
If neither raised- trial LTRA or a LAMA in addition to MART
If control has not improved stop LTRA or LAMA and start the alternative (LTRA or LAMA)
Step 5-
Reder people to a specialist in asthma care when asthma is not controlled despite treatment with moderate-dose MART, and trials of an LTRA and a LAMA
Asthma further Mx
- ?occupational - refer to resp
- yearly flu jab
- yearly asthma review
- consider stepping down tx every 3mo or so
- reducing ICS dose - only by 25-30% at a time
- regular exercise, avoid smoking, avoid triggers
Asthma drugs
SABA - salbutamol
LABA - salmeterol, formoterol
SAMA - ipratropium
LAMA - tiotropium
ICS - beclometasone / budesonide
MART - Fostair - beclometasone + formoterol
Trimbow - beclometasone + formoterol + glycopyrronium
LTRA - montelukast
Theophylline
Acute exacerbation of asthma
- rapid deterioration in sx in asthma
- triggers as chronic, may be infection
Acute asthma Px
- SOB
- Cough
- Accessory muscle use
- Tachypnoea
- Global wheeze
- Reduced air entry
Acute asthma grading
Moderate
- PEF 50-75%
Acute severe
- PEF 33-50% best
- RR>25
- HR>110
- Unable to complete sentences
Life-threatening
- PEF <33%
- Sats <92%
- Silent chest, cyanosis
- Bradycardia, low BP
- Exhaustion, confusion, coma
(Near fatal)
- Raised pCO2
- mechanical ventilation, raised inflation pressures
Acute asthma Ix
- ABG - resp alkalosis -> hypoxic -> normal pCO2
- bloods, CXR
Acute asthma admit if
- Life-threatening grade
- Acute severe grade + unresponsive to tx
- Previous near-fatal attack
- Pregnancy
- Occurring despite oral corticosteroid
- Px at night
Acute asthma Mx
- abx
- O2
- salbutamol - inhaler / nebs
- PO prednisolone 40-50mg / IV hydrocortisone 5d (3d in paeds)
- ipratropium - nebs
- IV Mg
- IV salbutamol
- IV aminophylline
- Intubation/ventilation, ECMO
Acute asthma criteria for discharge
- Stable on discharge medication (no nebs / O2) for 12-24hrs
- Inhaler technique checked + recorded
- PEF >75%
COPD
- Chronic irreversible progressive condition involving airway obstruction, emphysema, chronic bronchitis
Causes
- smoking, A1AT deficiency, coal, cotton, cement…
COPD Patho
- bronchitis - airway inflammation, fibrosis, mucus production
- emphysema - parenchymal destruction, loss of elastic recoil, reduced SA for gas exchange
- V/Q mismatch, lack of oxygenation, CO2 retention
- increased pulmonary artery pressure -> PAH, RHF
- some pts CO2 retainers
COPD Px
- SOB, cough, sputum, wheeze
- recurrent infections
- minimal diurnal variation
- accessory muscles
- hyperinflation
- decreased cricosternal distance
- decreased expansion, hyperresonant
- pursed lips
- cyanosis, cachexia
- cor pulmonale - peripheral oedema, raised JVP, SOBOE, syncope, chest pain
- PP/BB
MRC SOB scale
- SOB on marked exertion
- SOB on hills
- Slow or stop on flat
- Exercise tolerance 100-200 yards on flat
- Housebound / SOB on minor tasks
COPD vs asthma
- Younger onset in asthma
- Smoking - in most with COPD
- Asthma - sx vary, less so in COPD
- Nocturnal sx in asthma
- Persistent productive cough - COPD
COPD Ix
- spirometry - FEV1/FVC<70%
- CXR - hyperinflation, flat hemidiaphragms, bullae
- FBC - anaemia/polycythaemia
- ECG / ECHO
- CT thorax
- transfer factor for CO (TLCO)
- ?A1AT levels
COPD severity
Stage 1 / mild - FEV1>80%
Stage 2 / moderate - FEV1 50-79%
Stage 3 / severe - FEV1 30-49%
Stage 4 - very severe - FEV1 <30%
COPD Mx
- stop smoking, pneumococcal/flu jabs
- pulm rehab
- inhalers
- oral theophylline
- prophylactic abx - azithromycin
- mucolytics
- PDE-4 inhibitors - roflumilast
- furosemide for cor pulmonale
- LTOT - long-term O2 therapy
- surgery - lung volume reduction surgery, bullectomy, lung transplant
COPD Inhaler Mx
1st step
- SABA / SAMA
2nd step
Asthma/steroid-responsive features
- previous dx asthma/atopy
- variation FEV1 >400mls
- diurnal variation PEF >20%
- raised eosinophils
- if no features -> LABA + LAMA (anoro ellipta)
- if features - LABA + ICS (fostair)
3rd step
- LABA + LAMA + ICS (trimbow)
- do not prescribe LAMA with SAMA (change to SABA)