Asthma Flashcards
1
Q
What is asthma?
A
- Chronic inflammatory condition of airways causing episodic exacerbations of bronchoconstriction
2
Q
What are the 3 factors that causes airway narrowing?
A
- Bronchial muscle contraction
- triggered by stimuli
- Mucosal swelling
- mast cell & basophil degranulation
- Increased mucus production
3
Q
What are the typical triggers of asthma?
A
- Smoking, pollution
- Infection - mainly viral
- Night time or early morning
- Exercise
- Animals
- Cold/damp
- Dust
- Stress
- NSAIDs
- B-blockers
- Pollution
- Occupational asthma (flour, latex, isocyanates, wood dust)
4
Q
What are the RF for asthma?
A
- Personal history of atopy.
- Family history of asthma or atopy.
- Inner city environment; socio-economic deprivation.
- Obesity.
- Viral infections in early childhood.
- Smoking.
- Maternal smoking.
- Early exposure to broad-spectrum antibiotics
5
Q
What are the sx of Asthma?
A
- Wheeze
- SOB
- chest tightness
- Cough
6
Q
What features of the sx increase the probability of asthma?
A
- Diurnal variation
- response to exercise, allergen, cold air
- present after taking aspirin or b-blocker
- History of atopic disorder.
- Family history of asthma and/or atopic disorder.
- Widespread wheeze heard on auscultation of the chest.
- unexplained low forced expiratory volume in one second (FEV1)
- unexplained peripheral blood eosinophilia.
7
Q
What signs will you find on examination for asthma?
A
- Inspection
- Tachypnoea
- Hyperinflated chest
- Expiratory wheeze
- Prolonged expiration
- Harrison’s sulcus seen in children with chronic asthma
- palpation
- Hyper-resonant percussion note
- Auscultation
- Reduced air entry
- widespread polyphonic wheeze
8
Q
What are the 3 characteristics of Asthma?
A
- Reversible airflow limitation
- Airway hyperresponsiveness
- Inflammation of bronchi
9
Q
How would you diagnose Asthma?
*this is for intermediate asthma probability
A
- First line
- Fractional exhaled nitric oxide (FeNO>40ppb)
- Spirometry c bronchodilator reversibility
- If diagnostic uncertainty
- Peak flow variability - measured several times/day
- Methacholine challenge test
- Additional
- TLCO - raised
10
Q
What are the differentials for asthma in adults?
A
- COPD
- Asthma-COPD overlap syndrome
- persistent airflow limitation with several features of asthma and COPD
- Acute asthma
- Acute Bronchitis
- Heart Failure
- CHD
- Malignancy
- GORD
11
Q
What affects peak expiratory flow rate?
A
- Sex
- Age
- Height
12
Q
Why is spirometry preferred over PEFR?
A
- offer clearer identification of airway obstruction
- less effort-dependent
- more repeatable
13
Q
How does FeNO work?
A
- Measures level of nitric oxide in the breath
- Increased levels - lung inflammation and asthma
14
Q
What are the list of medications used for asthma?
A
- SABA - salbutamol
- ICS - beclometasone
- LABA - salmeterol
- LAMA - tiotropium
- LRA - montelukast
- Phosphodiesterase inh. - Theophylline
- Maintenance And Reliever Therapy (MART)
- low dose ICS + fast acting LABA
15
Q
What is the BTS/SIGN Stepwise ladder for mx of chronic asthma?
A
- SABA PRN. If use >3 times/week > step up
- Add low dose ICS (200-800mcg/day)
- Add LABA (Fostair - contains both ICS and LABA)
- Medium dose ICS/Montelukast
- Specialist referral
16
Q
A
17
Q
What are the cx of asthma?
A
- Pneumonia.
- Pneumothorax.
- Pneumomediastinum.
- Respiratory failure and arrest
18
Q
What is brittle asthma?
A
- Unstable/unpredictable asthma
19
Q
What are the features of moderate asthma?
A
- PEFR 50-75% best or predicted
- Speech normal
- RR < 25 / min
- Pulse < 110 bpm
20
Q
What are the features of severe asthma?
A
- PEFR 33 - 50% best or predicted
- Can’t complete sentences
- RR > 25/min
- Pulse > 110 bpm
21
Q
What are the features of Life-threatening asthma?
A
- PEFR < 33% best or predicted
- Oxygen sats < 92%
- Silent chest, cyanosis or feeble respiratory effort
- Bradycardia, dysrhythmia or hypotension
- Exhaustion, confusion or coma
22
Q
What are the features of near fatal asthma?
A
- Respiratory arrest
- Raised PaCO2
- Altered conscoiusness
- Required mechanical ventilation
23
Q
What does TLCO measure?
A
- gas transfer for the lungs from the alveoli into the capillaries
- reflects how much oxygen is taken up into the red cells
24
Q
Aspirin can induce asthma and cause Samter’s triad. What is this triad?
A
- asthma
- aspirin sensitivity
- nasal polyps
25
What are the features of mild asthma?
* PEFR \>75%
26
What are the causes of eosinophilia?
* Asthma/COPD
* Hayfever / allergies
* Allergic Bronchopulmonary Aspergillosis
* Churg-Strauss
* Drugs (allopurinol)
* Eosinophilic Myalgia Syndrome
* Lymphoma
* Parasite - Ascariasis
* SLE
27
What is the pathophysiology of Asthma
1. Airway epithelial damage - shedding and subepithelial fibrosis, basement membrane thickening
2. Inflammatory reaction - eosinophils, Th2, mast cells
3. Inflammatory mediators release - histamine, leukotrines, prostaglandins
4. Cytokines amplify inflammatory response
5. Increase mucus secreting goblet cells, smooth muscle hyperplasia, hypertrophy
6. Mucus plugging in fatal and severe asthma
28
What are the criteria for safe asthma discharge after exacerbation?
* PEFR \>75%
* Stop regular neb for 24hrs prior to discharge
* Reassess inhaler technique and adherence - by inpatient asthma nurse
* Provide PEFR meter and written asthma action plan
* 5 days oral prednisolone
* GP follow up within 2 days
* Resp clinic follow up within 4 weeks
29
Asthma can be classified into moderate, severe, life threatening and near fatal. Describe the features of each category
\*think sx, vitals, sat, PEFR
30
What parameters would you wan to maintain control in chronic asthma?
1. **Clinical:** make sure no daytime symptoms, night-time waking or activity limitation
2. **Acute:** make sure no asthma attacks and no need for rescue medication
3. **Medications:** make sure no need for rescue medication, ensure minimal side-effects from medication
4. **Lung function**: normal (PEF/FEV1)
31
32
How would you diagnose occupational induce asthma?
* Serial peak flow measurements at work and at home
33
What factors should be considered when considering asthma?
* **recurrent episodes of symptoms:** may be triggered by viral infection, allergen exposure, NSAIDs/beta-blockers and/or exacerbated by exercise, cold air and emotion/laughter in children
* **recorded observation of wheeze:** due to varying use of language this usually means wheeze documented by a clinician
* symptom variability: asthma is generally **worse at night or early in the morning**
* **personal history of atopy**: e.g. eczema/allergic rhinitis
* **absence of symptoms of alternative diagnosis**: e.g. COPD, dysfunctional breathing or obesity\*
* historical record of variable peak flows or FEV1
