Asthma Flashcards
What is asthma
Chronic hyper responsiveness of airway - type I
Reversible bronchospasm = obstruction
Smooth muscle contraction
Inflammation + mucous = narrowing
What are the types of onset of asthma
Early infant / VIW Childhood Adult Exertional Occupational - normal peak flow when not at work (refer to specialist)
What causes asthma / RF
Genetic factors - to be hyper allergic / responsiveness
Environment - childhood exposure to allergens / maternal smoking
Familial atopic tendency / atopy - tendency to be hyper allergic and produce IgE
Occupation - smoke decreased FEV1 and increases wheeze
Other
- LBW
- Not breast
What is atopy and what happens in atopy
1st exposure sensitises T cells, B cells produce IgE which binds to mast cells
2nd exposure mast cells release contents
What do mast cells release and what does this cause
Histamine, leukotrienes and inflammatory cells
Oedema, mucous and smooth muscle contraction
What triggers asthma
What drugs should be avoided
Exercise Cold air Aspirin BB NSAID Sedatives Allergies - Pets, Pollen, Food Smoke / parenteral smoking URTI / infections Poor inhaler technique
What are the symptoms of asthma
VARIABLE + REVERSIBLE
Often worse at night - diurnal variation
Expiratory wheeze - narrow airways = turbulent
SOB - more effort to inflate hyper inflated lungs
Cough - dry, exertion, nocturnal
Chest tight - voluntary contract muscles
Haemoptysis
What are the signs of asthma
Tachycardia Tachypoea Hypercpania + hypoxaemia Cyanosis Reduced PEFR Hyperinflated CXR as air is trapped Acccessory muscles
What are complications of asthma
Pneumothorax - parenchyma ruptures due to increased alveolar pressure
What is a delayed eosinophil response
Atopic triad - Conjunctivitis 'Hayfever' - Allergic Rhinitis - Dermatitis Bronchiole constriction
How does asthma present in children
NO WHEEZE = NO ASTHMA Dry nocturnal cough Respiratory difficulty / obstruction Sooking in of ribs - recession <18 months = more infection
What suggests its not asthma
Dizzy Productive cough Smoking Hx Cardiac disease Normal PEFR when symptomatic Clubbing Stridor - harsh vibrating Asymmetrical expansion Dull percussion Crepitations No response to RX Unilateral Sx
What is suggestive of asthma
Wheeze / SOB / tight chest Diurnal variation Exercise / allergic / cold air worsens Aspirin / BB worsens Evidence of atopy FH atopy Low FEV1 / PEF Blood eosinophilia
How do you investigate asthma
Spirometry with bronchodilator reversibility = 1st line
FeNO - released by eosinophil and show atopy
Peak flow variability over 2 weeks
What does spirometry look at
Amount of air and speed during exhalation
FEV1 <70% = suggestive
FVC = normal
Ratio reduced
What does bronchodilator reversibility show
Large increase in FEV1 >12%
What are other investigations
CXR - old / smoking HX PEFR for 2 weeks - >15% variability = suggestive + diurnal variation >2% PFT to exclude COPD - Helium dilution - CO gas transfer = normal Bronchial hyper responsiveness Skin prick for allergen Total IgE FBC
What do you do if >17
Spirometry
BDR
FeNO
What do you do 5-17
Spirometry + BDR
FeNO if normal but still suspect
What do you do in <5
Clinical
Trial of Rx
If unsuccessful = refer
What do you do for occupational asthma
Serial peak flow
Exposed and unexposed periods
If Sx better on holiday
Refer to occupational health
What should you ask about in the Hx
Variation - Diurnal / Weekly variation / better in holiday / annual - pollen ? Triggers - inc drugs that worsen Childhood asthma / bronchitis / hay fever / excema FH Days of work Sleep disturbance Acid reflux - Rx improves spirometry
What drugs are CI in asthma
BB NSAID Aspirin Sedatives Esp if nasal polyps
How do you treat asthma
Different depending on SIGN vs NICE SABA Consider adding therapy every 4-8 weeks SABA + ICS - Budenoside Add LTRA - Montelukast Add LABA - Salmeterol Stop LABA / LTRA if no benefit Consider starting MART (low dose ICS + LABA) - Seratide Increase ICS
What do you do if still not controlled
High dose ICS >800 Theophylline LAMA - titropium bromide (not in children) Oral daily steroid Refer
What are lifestyle measures
Smoking cessation Weight loss Inhaler technique PEF 2x daily Asthma action plan Flu vaccine Yearly review
What are steroid sparing agents
Omalizumab
Mepolizumab
What should you consider every 3 months
Step down of maintenance Rx
What is a SABA
Salbutamol (Ventolin) - either accuhaler or easy breath
Reliever
Relax smooth muscle
What are the SE
Tremor Cramp Headache FLushing Palpitations Tachycardia Hypokalaemia so monitor U+E
When do you start ICS (preventer) or LTRA in <5
SABA 3x
Waking one night
Oral steroids for exacerbation in past 2 years
What does ICS do
Betaclometesone (Flixodide or QVAR)
Reduce inflammation
What are the SE
Adrenal crisis
Dysphona
Oral candidiasis
Stunted growth in children
LTRA
Montelukast
LABA
Salmeterol or Severent
What are SE of LAMA
Anti-cholinergic SE Dry mouth / eyes Headache Glaucoma GI
How do you measure control
S- SABA used 1+ a week
A- Absence from school or work
N- Nocturnal Sx
E- Exertional Sx
What is Ddx of asthma
Pulmonary oedema COPD Obstruction - foreign body / tumour SVC obstruction - wheeze and SOB (not episodic) Pneumothorax PE Bronchiectasis Bronchiolitis
DDX for wheeze
Tumour
FB
Localized obstruction
What is low dose ICS
<400
High dose = >800
Diff for children
What is a moderate asthma attack
Wheeze with stethoscope HR <110 RR <25 PEF 50-75% SaO2 >92% PaO2 >8
What is a severe attack
Can't speak sentences Use of accessory muscle Audible wheeze >110 >25 PEF 33-50 SaO2 and Pao2 normal
What is life threatening
Silent chest / no wheeze as so constricted Cyanosis Poor response effort Exhaustion Impaired consciousness Coma HR >130 Brady / arrhythmia / hypotension EF <33% Sats <92% O2 <8 Normal PaO2 = life threatening as should be low as hyperventilating
What is fatal
Raised PaCO2
What are symptoms of asthma attack
SOB Wheeze Cough Accessory muscles Not responding to salbutamol
What should you ask in HX
Usual and recent Rx
Previous attacks
Best PEF
Any ICU
What investigations should you do
PEF if can - before and after nebuliser ABG if sats <92% CXR if suspect pneumothorax / infection FBC, U+E, CRP Blood / sputum culture
How do you monitor
Sats
RR and effort
HR
When should you always admit
If previous life threatening
What do you do for mild attack
Check RR, HR, sats, PEFR, chest
Oral prednisone 40mg 5 days for all attack
Possibly cover with Ax
SABA
MDI with spacer 10 puffs
Step up ICS dose
Can use nebuliser if PEFR half of expected or look unwell
What do you do for severe
Admit to hospital
Oxygen 15l NRB to maintain sats
Burst therapy - back to back neb (prescribe all doses)
Nebuliser
- Salbutamol 5mg with O2 - 3 doses
- Ipratropium bromide 500mg (SAMA) - 2 doses
- Hydrocortisone 100mg IV 1 dose or prednisone 40mg PO
Other
Add theophylline - not much role
What do you do if not responding
ITU - always if raised PaCO2 IV magnesium sulphate 2g/20 minutes next step IV theophylline 5mg / kg IV salbutamol IV steroid / hydrocortisone = final step NIV Intubation ECMO in extreme
What do you need to monitor with theophylline
ECG - can cause arrytmhia
DDX asthma attack
Exacerbation COPD PE anaphylaxis Pulmonary oedema Obstruction
When do you discharge
PEF >75% within 1h of Rx Stable 24 hours Chek inhaler technique Steroid and bronchodilator therapy Written management plan
What do you organise for patient
GP in 2 days
Asthma clinic 4 weeks
If a patient with asthma has a chest infection what should you give
Antibiotic + increase steroid
What do you do if suspect theophylline toxicity
Activated charcoal
Haemodialysis = definite
Supportive
What is supportive
IV crystalloid for hypo
Diazepam for seizure
IV BB for SVT
