Case 2- Asthma Flashcards
Community asthma treatment
- SABA
- ICS
- LTRA
- LABA
- MART regime (low dose ICS and a LABA) + SABA + LTRA
- Increase ICS (or change to moderate ICS and LABA)
- Increase ICS, theophylline, LAMA
- Specialist
NB- if well controlled (eg. not using blue inhaler for a year), you can trial step down of treatment eg. aim for a reduction of 25-50% in the dose of inhaled corticosteroids
Additional asthma treatment
Flu jab/ pneumococcal vaccine
Yearly asthma review
Advise exercise and avoid smoking
Treatment of a primary non-tension pneumothorax
Asymptomatic and less than 2cm rim of air- conservative treatment. Follow up in 2 weeks (CXR)
Symptomatic and more than 2cm rim of air- needle aspiration
If aspiration fails twice- chest drain
Unstable patients/ bilateral- chest drain
Life long scuba diving ban
Treatment of a tension pneumothorax
Needle aspiration and chest drain- CXR to check for correct placement
Life long scuba diving ban
Typical asthma Sx
Persistent dry cough that worsens at night, with exercise, cold or exposure to irritants, exploratory wheeze, dyspnoea, chronic allergic rhinitis with nasal congestion
Asthma differentials
CF, bronchiectasis, COPD, PE, pneumothorax
Investigations for suspected asthma
Observations and physical exam
Fractional expired NO- increased (check this.. )
Spirometry with bronchodilator reversibility testing- value of at least 200ml and 12% increase (no bronchodilators when assessing baseline)
PEFR- diary for 2-4 weeks (diurnal variation- 20% variation)
FBC- neutrophilia and eosinophilia
CXR- exclude another pathology
NB- don’t routinely use spirometry on its own to diagnose asthma as patients won’t show any abnormality when asymptomatic (if spirometry is normal, you cant exclude asthma, you have to do further tests ie. FeNO)
Blood gas
Consider in any acute respiratory situation
Gives good insight into patients respiratory function- ABG favoured over VBG
In asthma- if sats below 92%
Forced vital capacity (FVC)
Total volume expelled without time limit from maximal inspiration to forced maximal expiration (calculated as a % of predicted value)
Restrictive- less than 80%
Obstructive- normal
Total lung capacity (TLC)
Low in restrictive disorders
High in obstructive disorders
Graph interpretation (time vs volume expired)
Normal- rapid increase in volume of air expired and then curve forms a plateau
Obstructive- prolonged increase (air cannot be expired as quickly due to airway resistance) but ends at same point as the FVC is normal
Restrictive- rapid increase as normal, but curve forms a plateau much sooner (total air volume in lungs is much smaller)
Graph interpretation (volume expired vs exploratory flow rate)
Normal- rapid increase in flow rate, then gradual decrease until the end of expiration
Obstructive- decreased peak exploratory flow rate with steeper reduction in flow rate after it peaks causing a characteristic dip in curve (collapse of small airways)
Restrictive- curve is normal in shape but smaller due to proportionally reduced flow rates (volume in the lungs is reduced)
Long term oxygen therapy
pO2 of <7.3 or pO2 7.3-8.0 and one of the following;
-polycythaemia
-peripheral oedema
-pulmonary HTN
Raised TLCO
Asthma
Pulmonary haemorrhage
Left to right cardiac shunt
Polycythaemia
Hyperkinetic state
Male gender
Exercise
Reduced TLCO
Pulmonary fibrosis
Pneumonia
Pulmonary embolism
Pulmonary oedema
Emphysema
Anaemia
Low cardiac output
