Dr Rickbir Singh Randhawa FY1. Definition: Asthma Chronic inflammatory airway disease characterised...
-
Upload
joshua-hubbard -
Category
Documents
-
view
228 -
download
0
Transcript of Dr Rickbir Singh Randhawa FY1. Definition: Asthma Chronic inflammatory airway disease characterised...
Respiratory Medicine:Asthma and COPD
Dr Rickbir Singh Randhawa
FY1
Definition:Asthma
Chronic inflammatory airway disease characterised by reversible airway obstruction, airway hyper-responsiveness and bronchial inflammation.
Three factors contribute to reversible airway narrowing:1. Bronchial smooth muscle contraction triggered by a
variety of stimuli2. Mucosal swelling/inflammation caused by mast cell
and basophil degranulation- release of inflammatory mediators
3. Increased mucus production
Definition:COPD
Chronic progressive lung disorder characterized by airway obstruction with little or no reversibility. It includes the following:
Emphysema: defined histologically as permanent destructive enlargement of air spaces distal to the terminal bronchioles
Chronic Bronchitis: defined clinically as a chronic cough with sputum production on most days for 3 months per year over 2 successive years.
AetiologyAsthma
Genetic factors-+VE family Hx, atopic (eczema, allergic rhinitis),
linkages to multiple chromosomal locations genetic heterogeneity
Environmental triggers-Allergens (House dust mite, pollen, pets (fur)), cigarette
smoke, viral URTI, occupational allergens (isocyanates-spray paints, epoxy resins-adhesives/fibreglass fabrics)
Aetiology/Risk factorsCOPD
Bronchial and alveolar damage due to environmental toxins- smoking (cigarette smoke)
Indoor air pollution (such as solid fuel used for cooking and heating)
Outdoor air pollutionOccupational dusts and chemicals (vapours, irritants, and
fumes)Frequent lower respiratory infections during childhood.Rare cause is α1-antitrypsin deficiency (<1%) consider in
non smokers or in younger patients
HistoryAsthma
Intermittent wheezeBreathlessness (dyspnoea)Cough (often nocturnal)Occasionally sputumDiurnal variation in symptoms/ peak flow- morning dips
of peak flow recordings
HistoryAsthma: Precipitating factors
Cold airExerciseAllergens (house dust mite, pollen, pets-animal fur)EmotionsSmoking/passive smoking exposureViral URTIHx of atopy (eczema/hayfever-allergic rhinitis)FHxDrugs (Beta blockers, NSAIDS- ask OTC meds)-
OSCE !
HistoryAsthma: things to also ask!
Precipitating factors if presentCompliance with medicationReliever usage (inhaler) – gauge severityOccupational Hx-causeSleep- interference? SeveritySmoking HxEczema/hayfever- atopyDays off school/work – gauge severityRemember CROSSED mnemonic!
HistoryCOPD
Chronic breathlessnessChronic Cough/sputum productionWheezeSmoker!Minimal diurnal variation in symptoms compared to
asthmaAge of onset >35 years (Rare cause is α1-antitrypsin
deficiency (<1%) consider in non smokers or in younger patients)
Clinical signs O/EAsthma COPD
TachypnoeaUse of accessory muscles of
respirationHyper inflated chest (reduced
chest expansion)Hyper resonant percussion noteReduced air entryPolyphonic wheeze
TachypnoeaUse of accessory muscles of
respirationPurse lip breathingHyper inflated chest (reduced chest
expansion)Hyper resonant percussion noteReduced air entry-prolonged
expirationWheeze, crackles if infective
exacerbation cyanosis
Severity of AsthmaModerate exacerbation:Increasing symptomsPEF >50-75% of best or predictedNo features of severe asthmaSevere exacerbation:Unable to complete sentences in one breathPEF 33-50% of best or predictedRR ≥ 25/minHR ≥110/min
Severity of AsthmaLife threatening attack: Any ofPEF <33% of best or predictedSilent chestCyanosisFeeble respiratory effortHypotensionExhaustion/confusion/coma (CO2 retention)ABG: normal or high CO2 (normal PaCO2 4.6-6.0 kPa) PaO2 <8kPa/O2 sats <92%Low pH <7.35 acidosis (CO2 retention)
Severity of COPDSeverity FEV1 (% predicted)
Mild ≥80%But FEV1/FVC <70%
Moderate 50-79%
Severe 30-49%
Very Severe <30%
InvestigationsAsthma
Acute exacerbation:Peak flow- PEF reading to classify the severityBasic Obs include pulse oximetry- classify severityABG-respiratory failureCXR- exclude differentials i.e. pneumothorax, pneumoniaBloods- FBC (raised WCC infective exacerbation),
U+E’s, CRPBlood culture (febrile)Sputum culture
InvestigationsAsthma
Chronic Asthma:PEF monitoring with peak flow diary- diurnal variation >20%
on ≥3days a week for 2 weeks with morning dips in readings.Pulmonary function test- obstructive defect with
improvement of FEV1 usually >15% improvement after a trial of a Beta 2 agonist.
Bloods- eosinophilia, raised IgE levels in atopic asthma. Skin prick tests- help identify any allergensAspergillus antibody titres- for allergic aspergillus lung
disease
InvestigationsCOPD
Acute exacerbation:ABG- respiratory failureBloods- FBC (raised WCC infection),U+Es, CRPBloods cultures if febrileSputum culture CXR –exclude differential i.e. pneumothorax, pneumoniaECG- cor pulmonale right axis deviation (RVH)
InvestigationsCOPD
Chronic COPD:Spirometry/pulmonary function tests- obstructive defect
FEV1/FVC <70% also with FEV1<80% predicted CXR- normal or show lung hyperinflation( >6 anterior ribs seen,
flat hemi-diaphragms), large central pulmonary arteries, decreased peripheral vascular markings
ABG- hypoxia and/or hypercapniaBloods- FBC (increased Hb and PCV due to secondary
polycythaemia secondary to hypoxia).ECG and echocardiogram- cor pulmonale, pulmonary hypertensionα1-antitrypsin levels- in young patients or with minimal smoking
Hx
Obstructive vs Restrictive defectSpirometry/PFTFEV1 FVC FEV1/
FVCObstructive lung
diseaseDecreased (<80%) Decreased Decreased
(<0.7)
Restrictive lung disease
Decreased Decreased (<80%) Normal (>0.7) or increased
ManagementAcute life threatening Asthma
Start Rx before Ix ABCDE!Oxygen 15L NRB- sit patient up, 02 sats 94-98%/intubateSalbutamol- 5mg Nebulised, back to back Nebs Hydrocortisone 100mg IVIpratropium bromide 0.5mg nebulisedTheophylline (aminophylline) IVMagnesium sulphate 2mg IV if no improvementRemember OSHIT! Mnemonic Normal or high CO2 is a very worrying sign- get early
anaesthetic/ITU r/v
Management Chronic AsthmaChronic Asthma
Chronic Asthma ManagementAsthma Management The BTS Stepwise ApproachRx started at the step most appropriate to the severitySTEP 1: SABASTEP 2: Step 1 + ICSSTEP 3: Step 2 + LABA &/or ↑ ICS doseSTEP 4: Step 3 + leukotriene receptor antagonist
(montelukast)/theophyllineSTEP 5: Step 4 + oral steroids- refer to asthma clinicStep down Rx if symptom control is good for >3 monthsEducate on proper inhaler techniques and routine
monitoring of peak flow.Develop an individual Mx plan to avoid triggers
Management Acute exacerbation COPD
ABCDE approach!Controlled oxygen therapy 24-28% Venturi mask vary
according to ABG- target sats 88-92%Nebulized bronchodilators- salbutamol 5mg (back to back
NEBS) and ipratopium bromide 0.5mg (4-6 hourly)Steroids- IV hydrocortisone 200mg or PO prednisolone
40mg (7-14 days)Abx- if evidence of infection see local guidelinesNIV- if severe respiratory acidosis or medical Rx shows
no improvement e.g. BIPAP- type 2 respiratory failure
Management Chronic COPD
Non Pharmacological MxSmoking CessationNutrition- Rx poor nutrition e.g. fortisipsObesity- healthy diet/lifestyle, regular exercisePulmonary Rehabilitation- graded exercise therapy to
increased exercise tolerance
Chronic Management COPD
Chronic Management COPDMucolytics- aid chronic productive coughCBT/Antidepressants- chronic illnessCriteria for LTOT:Only for those stopped smoking- fire risk!PaO2<7.3 kPa clinically stable- this value should be stable on
two occasions >3 weeks apartPaO2 7.3-8.0 kPa with signs of pulmonary hypertension/cor
pulmonaleTerminally ill patientsSurgical Mx- bullectomy (recurrent pneumothoraces), lung
volume reduction surgery
Inhalers-Quick run throughSABA-e.g. salbutamol (ventolin) “blue inhaler”LABA-e.g. salmeterol (serevent)SAMA- e.g. ipratopium bromide (atrovent)LAMA-e.g. tiotropium bromide (spiriva)IC Steroids:Becotide (beclometasone), Pulmicort (budesonide),
Flixotide (fluticasone)Combination ICS:Seretide (fluticastone + salmeterol)Symbicort (budesonide + formoterol)
Inhaler: Explaining how to use it
1. Remove the dust cap from the inhaler device. 2. Shake the device. Remember the canister holds a suspension of drug, and this needs to
be shaken to ensure a uniform distribution of the drug particles. 3. If you have not used the inhaler for a week or more, or it is the first time you have
used the inhaler, spray it into the air before using it to check that it works. 4. Hold the inhaler upright with you forefinger on the top of the canister. 5. Breathe out as far as is comfortable. 6. Place the mouthpiece in your mouth between your teeth, and close your lips around it. 7. Start to breathe in slowly and deeply, and at the same time, activate the inhaler by
pressing down on the canister. When the canister is pushed down, a valve delivers a measured dose of drug in a fine mist.
8. Hold your breath for as long as is comfortable, then breathe out as normal. 9. If you are instructed to take 2 puffs, wait for about 30 seconds and repeat this process. 10. Do not release two puffs at the same time. This will increase the likelihood of
deposition at the back of the throat and reduce the amount of drug reaching the lungs. 11. Finally, replace the cap on the inhaler.
Clinical scenarioA 64 year old gentleman presents to A&E with increasing
SOB over the last 3 days. This is associated with a cough productive of thick, green sputum. He has a past medical history of “asthma”, but he has smoked 50 cigarettes a day for the past 40 years. On examination he is tachypnoeic, tachycardic, O2 sats 85% on air, he is using his accessory muscles to breathe. Auscultation reveals bilateral diffuse coarse crepitations and widespread wheeze
QuestionsWhat are your main differential diagnoses for this gentleman?How would you investigate this gentleman?Initial management in acute setting?Long-term management?Can you tell me about the pathophysiology of COPD? ie.
Clinical and histopathological definitionsCan you tell me some risk factors for COPD? What are the criteria for mild, moderate, severe and very severe
COPD? What are the criteria for use of long term oxygen therapy (home
oxygen)?
THANK YOU FOR LISTENING
ANY QUESTIONS?