Lung disease

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  • Created by: z
  • Created on: 12-03-16 13:21

Asthma

  • bronchospasm (rapid onset)
  • symptoms:
    • wheeze
    • SOB
    • chest tightness
    • cough
  • onset:
    • anytime, mostly infancy/childhood
    • late onset - consider other causes e.g. COPD, CCF
  • v common:
    • 20-30% of infants wheeze
    • 10% of children have asthma
    • 1 in 12 adults (8%) have current asthma
    • on average 3 people die a day of asthma
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Asthma diagnosis in adults- is it likely to be ast

  • factors that incr chance that it's asthma:
    • wheeze, chest tightness, SOB or cough
      • esp if worse at night, during exercise or in response to cold
    • history of atopic disorder (eczema, rhinitis)
    • FHx of asthma or atopy
    • widespread wheeze on auscultation
    • unexplained low FEV1 or PEFR
    • unexplained eosinophilia
  • decr chance that it's asthma
    • dizziness, light-headedness, peripheral tingling
    • chronic productive cough w/o wheeze or SOB
    • normal examination and PEFR when symptomatic
    • voice disturbance
    • symptoms only with cold
    • smoking Hx (>20 pack year)
    • cardiac disease
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Common asthma triggers

  • allergens
    • dust mites
    • pollen
  • drugs
    • aspirin
    • beta-blockers
  • occupational
    • isocyanates (paint, plastic manufactoring)
    • wood resin
    • dyes
  • envirornmental
    • cold air
    • emotional
    • exercise
  • normally a mix!
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Asthma management

  • principles:
    • avoid triggers
    • steroids for inflammation
    • leukotriene antagonists for inflammatory mediators
    • B2 agonists/anticholinergics/theophylline for bronchospams
  • "control" defined as:
    • no daytime symptoms
    • no night time awakening (due to asthma)
    • no need for rescue meds
    • no acute exacerbations
    • no limitations on any activity (including exercise)
    • normal lung function (FEV1 or PEF >80% predicted)
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Stepped treatment of asthma

  • start at most appropriate level
    • step 1 - SABA
    • step 2 - SABA + mild ICS
    • step 3 - SABA + ICS + LABA
    • step 4 - SABA + ICS + LABA + theophylline/leukotriene antagonist
    • step 5 - all above + oral steroids up to 2000mcg
  • common reasons for poor response to Rx
    • poor compliance
    • poor inhaler technique
    • presence of triggers (esp smoking)
    • wrong diagnosis (GORD, COPD, bronchectasis)
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SABA + ICS

  • BA
    • effect= bronchodilation
    • rapid relief when inhaled (though technique important)- action w/in 20-30 mins, lasting > 4 hrs
    • main drugs: salbutamol (ventolin) and terbutaline
    • forms: inhaler, neb, IV, tablet/syrup (but incr s/e)
    • a/e - tremor, tachycardia, hypokalaemia (Rx for hyperK)
  • ICS
    • inhaled for step 2 and above
      • add on if exacerb in last 2 yrs, SABA used >2x/week, night time symtpoms
    • main drugs: beclometasone, fluticasone, budesonide
    • preventers rather than relievers
    • use 2x daily
    • up to max daily does of 800mcg beclometasone (or equal)
    • a/e - sore throat/oral thrush (common, decr risk by washing out mouth after use, RX w/ antifungal lozenge), osteoporosis (adults), growth suppression
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LABA + LRA + xanthine derivative

  • LABA
    • salmeterol or formeterol
    • duration ~12 hours
    • step 3 in asthma and COPD
    • often in combo e.g. seretide (selmeterol + fluticasone)
  • LRA
    • prophylaxis (esp exercise or aspirin induced)
    • montelukast or zafirlukast
    • oral, taken ODS
    • s/e - hypersensitivity reactions, GI upset
  • Xanthine derivative
    • modified release theophylline
    • problems: interactions, narrow therapeutic index w/ variation in liver metabolism (c450)
    • a/e cardiac arrythmias, seizures
    • can be used IV for acute relief but only under a specialist
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Acute severe asthma

  • cannot complete full sentences
  • quiet chest
  • HR > 110 bpm; RR > 25
  • PEFR <50% predicted
  • fatigue and dehydration
  • Rx
    • hospitalise
    • oxygen
    • oxygen driven neb of salbutamol/terbutaline (repeat if necessary)
    • prednisolone 50mg oral/hydrocortisone 100mg IV
    • if poor response:
      • inhaled ipotropium bromide 500mg every 4-6hrs by oxygen driven nebuliser
      • IV BA, aminophylline or magnesium sulphate
    • nebs and steroids over next few days + find cause of exacerbation + f/u in GP
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COPD

  • middle/old age
  • smoking Hx
  • productive cough
  • increasing dyspnoea
  • assess degree of:
    • bronchospasm
    • infection
    • RHF
    • emphysema
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Management of COPD

  • inhaled bronchodilators
    • SABA - salbutamol
    • LABA - salmeterol
    • antimuscarinics
      • SAMA- ipatropium
      • LAMA- tiotropium (glycopyrronium, aclidinium)
  • ICS 
  • oral bronchodilators - theophylline
  • antibiotics if indicated
  • vaccination (influenza yearly, pneumococcal)
  • mucolytics (carbocisteine)
  • heart failure Rx (diuretics)
  • long term oxygen for RF
  • smoking cessation
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Smoking cessation- pharmacological Rx

  • Nicotine replacement therapy (NRT)
    • doubles chance or quitting
    • reduces symptoms of withdrawal
    • many forms
  • Prescription only
    • Bupropion (zyban)
      • antidepressant w/ smoking cessation effect
      • contra-indicated if seizure Hx
    • Varenicline (champix)
      • selective nicotine receptor partial agonist
      • caution if Hx of psychiatric illness
    • both contrindicated if <18yrs, pregnancy, breastfeeding
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Drug delivery by inhalation

  • partial size
    • >10ym - mouth to large airway
    • < 5ym - small airways
    • ~2ym alveoli
    • <1ym may be exhaled again
  • delivery methods
    • MDI
    • spacer devices (used w/ MDIs)
      • don't have to coordinate breathing
      • decr a/e w/ ICS
    • nebuliser 
      • ~10% dose gets to lungs
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