asthma

Question 1

what is asthma?

Answer 1

• chronic inflammatory disease of the airways
• reversible (not completely in some people), either spontaneously or with treatment
• increased airway responsiveness (Airway narrowing) to a variety of stimuli

Question 2

what is the difference between a wheeze and stridor?

Answer 2

• wheeze is expiratory
• continuous whistling sound
• suggests obstruction of lower respiratory tract
• stridor is inspiratory
• high pitched
• suggests obstruction of upper respiratory tract

Question 3

what are some differentials for a wheeze?

Answer 3

most common
- asthma

other

• pulmonary oedema
• PE
• vocal cord dysfunction
• GORD
• foreign body
• allergy
• hyperventilation/psychosocial
• cardiac disease

Question 4

what are the trigger factors for asthma?

Answer 4

• smoking
• upper respiratory tract infections, viral usually
• allergens e.g pollen, house dust mite, pets
• exercise, also cold air
• occupational irritants
• pollution
• drugs - aspirin, beta blockers
• food and drink
• stress
• severe asthma, consider inhaled heroin, pre menstrual, psychosocial aspects

Question 5

what is the pathophysiology of asthma?

Answer 5

• airway epithelial damage, shedding and sub epithelial fibrosis, basement membrane thickening
• An inflammatory reaction characterised by eosinophils, T lymphocytes (Th2) and mast cells. inflammatory mediators released include histamines, leukotrienes and prostaglandins.
• cytokines amplify inflammatory response
• increased number of mucus secreting goblet cells and smooth muscle hyperplasia and hypertrophy
• mucus plugging in fatal and severe asthma

Question 6

what indicates near fatal asthma exacerbations?

Answer 6

raised pCO2

Question 7

what are the signs of life threatening asthma exacerbations?

Answer 7

• Peak expiratory flow rate <33% of best or predicted
• Sats <92% or ABG pO2<8kPa
• cyanosis, poor respiratory effort, near or fully silent chest
• exhaustion, confusion, hypotension or arrhythmias
• normal pCO2

Question 8

what are the signs of a severe asthma attack?

Answer 8

• PEFR of 33-50% of best or predicted
• cannot complete sentences in one breath
• resp rate >25/min
• heart rate >110/min

Question 9

what is the management of an acute asthma attack?

Answer 9

• ABCDE approach
• aim for SpO2 94-98% with oxygen, ABG if sats <92%
• 5mg nebulised salbutamol, can repeat after 15 mins
• 40mg oral prednisolone (IV hydrocortisone if PO not possible)

Question 10

what is the management of a severe asthma attack?

Answer 10

• nebulised ipratropium bromide 500mg

- consider back to back salbutamol 5mg

Question 11

what is the management of life threatening or near fatal asthma attack?

Answer 11

• urgent ITU or anaesthetist assessment
• urgent portable CXR
• IV aminophylline
• consider IV salbutamol if nebulised route ineffective

Question 12

what is the criteria for safe asthma discharge after exacerbation?

Answer 12

• PEFR >75%
• stop regular nebulisers for 24hrs prior to discharge
• inpatient asthma nurse to review reassess inhaler technique and adherence
• provide PEFR meter and written asthma action plan
• at least 5 days oral prednisolone
• GP follow up within 2 working days
• resp clinic within 4 weeks
• for severe or worse, consider psychosocial factors

Question 13

what is eosinophilic inflammation?

Answer 13

some patients with asthma have eosinophilic inflammation which typically responds to steroids

get eosinophilia

Question 14

what are the differentials of eosinophilia?

Answer 14

• airway inflammation (asthma or COPD)
• hayfever/allergies
• allergic bronchopulmonary aspergillosis
• drugs
• churg-strauss/vasculitis
• eosinophilic pneumonia
• parasites
• lymphoma
• SLE
• hypereosinophilic syndrome