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Medicine Notes Respiratory Notes

Asthma Notes

Updated Asthma Notes

Respiratory Notes

Respiratory

Approximately 35 pages

Complete set of notes covering the respiratory system. Includes pathophysiology, aetiology, presenting symptoms, management and relevant pharmacology. Concise bullet points, colour coded by topic. Includes tables and summary charts. All you need to pass respiratory module at medical school....

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The following is a more accessible plain text extract of the PDF sample above, taken from our Respiratory Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:

Asthma

An inflammatory condition causing reversible airway obstruction

Epidemiology

  • 2000 deaths a year in UK

  • Prevalence 10-15%

  • Classified as

    • Extrinsic (childhood, associated with atopy, remits in teens)

    • Intrinsic (develops later in life, doesn’t respond to rx well)

    • Occupational (relates to workplace allergen)

Aetiology

  • Genetic predisposition

    • Runs in families with atopy (eczema, hayfever, asthma, conjunctivitis)

  • Environmental factors

    • Drugs (aspirin, B blockers)

    • Allergens (dust, pollen, animal hair)

    • Occupational (wood, dust, dye)

    • Environmental (cold air, exercise, emotion)

Pathophysiology

3 factors contribute to airway narrowing

  1. Bronchial muscle contraction + hypertrophy

  2. Mucosal inflammation caused by mast cells + basophil degranulation, resulting in release of inflammatory cytokines

  3. Increased mucus production

Clinical features

Symptoms (all INTERMITTENT) Signs

Dyspnoea

Wheeze

Nocturnal cough

Sputum

Diurnal variation of peak flow + symptoms (worse in morning)

Decreased exercise tolerance

Tachpnoea

Audible wheeze

Hyperinflated chest

Hyperresonant percussion note

Decreased air entry

Widespread, polyphonic wheeze

Assessing the severity of an asthma attack

  • Moderate

    • PEFR < 65% predicted (admit)

    • Low pO2, low pCO2 (normal or low pH)

  • Severe

    • PEFR < 50% predicted (alert ITU)

    • Pulse > 110bpm

    • Resp rate > 25

    • Inability to complete sentences

    • Wheezy chest

    • Alert/mild confusion

    • Very low pO2, normal pCO2, normal pH

  • Life threatening

    • PEFR < 33% predicted (alert ITU)

    • Bradycardia

    • Exhaustion

    • Can’t talk

    • Silent chest

    • Cyanosis

    • Feeble resp. effort

    • Confusion/coma

    • V low pO2, raised pCO2, low pH

Investigations

  • Acute asthma attack

    • Bloods

      • FBC, U+E, CRP

      • ABG

    • Imaging

      • CXR (exclude infection/pneumonia)

    • Bedside tests

      • PEFR

      • Sputum culture

  • Chronic Asthma

    • PEF monitoring

    • Spirometry (obstructive defect)

    • CXR (hyperinflation)

    • Skin prick test for allergens

    • Histamine/metacholine challenge

Management

  • Chronic asthma

    • Lifestyle

      • Stop smoking

      • Avoid precipitants

      • Education re. inhaler technique, PEF monitoring, alteration of medication according to symptoms

Drug management

Step 1 (mild) Short acting B2 agonist (inhaled) – when required
Step 2 (regular) Inhaled corticosteroids
Step 3

Add-on therapy

Long-acting B2 agonist +/- inhaled corticosteroid
Step 4

Increase inhaled steroid dose

Long acting B2 agonist

Leukotriene receptor agonist/ theophylline
Step 5

Daily oral steroid

Daily high dose inhaled steroid

Referral for specialist care (asthma clinic)

  • Acute/severe

    • O2 high flow (100% in non-rebreathe mask)

    • Sit patient up

    • Nebulised salbutamol + ipratropium bromide with O2

    • Hydrocortisone IV/prednisolone po (both if very ill)

    • CXR to exclude pneumothorax

  • Life threatening

    • Inform ITU + seniors

    • Add IV magnesium sulfate

    • Repeat nebs (15 minutes...

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