Respiratory Flashcards
When and where does the lung bud develop from
What are the stages of lung development and when do they occur
When is surfactant formed
Week 4 from the endoderm Embryonic- Pseudoglandular- from 6 weeks Canalicular- from 16 weeks Saccular- from 24 weeks Alveolar- from 36 weeks
What forms at each stage of lung development
Embryonic- bronchial buds Pseudoglandular- bronchioles Canalicular- terminal sacs Saccular- surfactant Alveolar- alveoli
What shifts the o2 affinity curve left?
What does this do to oxygen affinity Examples?
Increased affinity for o2
Fetal hb
LESS h, temp,co and 2,3 DPG
What shifts the o2 dissociation curve right
What does it indicate
2 examples
Increased affinity to o2
Raised H, CO 2,3 DPG and temp
Adult hb and sickle cell
What is the role of 2,3 DPG
when it increases what does it do
How does it correlate to the o2 binding curve?
Controls o2 release from hb
Lowers affinity to o2
Increases- reduces affinity- shifts curve right
Lowered- increases affinity- shifts curve left
What process causes most toxic effects from carbon monoxide poisoning?
Reversible binding to cytochrome A3
From bottom to top what 4 volumes are seen in the spirometry curve
What capacity do all 4 make up?
Reserve vol Exp reserve Tidal vol Insp reserve Total lung capacity
What makes up the forced vital capacity (3 volumes)
IRV
TV
ERV
What makes up the functional residual capacity?
What does it signify?
Reserve vol
Exp reserve vol
Everything left after a normal breath out
What is changed more in obstructive disease; Inspiration or expiration
How do the volumes and capacities change
How does FEV1 change. How and why does this change the ratio?
Expiration becomes poor- air trapping Increased RV and ERV increased FRC and TLC Reduced FEV1 FEV1 reduces more than fvc therefore ratio decreases
Why can spirometry not diagnose restrictive disease reliably?
Cannot measure the RV therefore can’t measure TLC
How does the spirometry flow loop change in obstructive disease
Concave curve in exp.
normal curve in insp.
moves slightly left
What changes in restrictive disease
How does the ratio change
All volumes decrease
Increased or normal as all volumes and FEV1 reduce in proportion
In central/small airways obstruction how does a fixed obstruction look
How would a variable extrathoracic defect change the curve and why? Give an example
How would a variable intrathoracic curve look and why? Give an example
Boxed shaped curve- both insp and exp change
Extrathoracic airways have the smallest lumen in inspiration- flattening of the insp curve.
Vocal cord dysfunction
Intrathoracic have the smallest volume on exp- flattening of the exp curve.
Tracheomalacia
What is FEF 25-75
What does it indicate
What value is abnormal
Average flow rate in the middle of the FVC
Medium airway disease
<66%
What two shapes will you see in a normal flow volume curve
Will the upper or lower bit be inspiratory or expiratory
Triangle above a semi circle
Upper- exp
Lower- Insp
How does the spirometry flow loop change in obstructive disease
How does it change in restrictive disease
Moves left, scalloped exp portion
Generally smaller
What object does fixed upper airway dysfunction look like on a flow volume curve. What causes it
Post box
Tracheal stenosis
How does a variable intrathoracic obstruction look on a flow volume loop?
What causes it
Flattening of the exp curve
Tracheomalacia or foreign body
How does a variable extrathoracic obstruction look on flow volume loop?
Give an example
Flattened insp curve
Laryngomalcia or vocal cord palsy
What 2 volumes make up the inspiratory capacity
Reserve volume
Insp reserve volume
What happens FEV1:FVC ratios in obstructive disease and restrictive disease
Obstructive- FEV1 reduces more than fvc therefore ratio reduces
Restrictive- both reduce so ratio is normal or increased
What would be seen on spirometry with poor technique
Everything reduces in proportion
Which gene in CF is potentially treated
What class of defect is it
What is the medication
G5116D
Class 3
Ivacaftor
Where are the central chemoreceptors found. What do they sense?
Where are the two peripheral ones found? What do they sense?
Medulla- high co2
Carotid and aortic bodies- low o2
On spirometry testing how much variation is allowed?
5%
What will increase DLCO
Pulmonary haemorrhage
How will a lateral neck X-ray differentiate between bacterial tracheitis and retro pharyngeal abscess
What is seen on presentation with the 2
Bacterial tracheitis- toxic with hoarse voice. Steeple sign and indentations along the trachea
Retropharyngeal abscess- widened RP space. Sick with sore neck and unable to open mouth
Which chromosome is involved in developing CF What are the three most common gene defects and what class of mutations are each
Chromosome 7
1-G542X. Non sense mutation- no protein
2- delta F508- missense mutation- deletion of phenylalanine- trafficking defect. Single phenylalanine deletion.
3- G551D- gating defect
How is screening carried out for CF
what happens next
How is a definitive diagnosis made
Look for IRT and genetic testing
Sweat test and stool test
Positive sweat test- cl >60 and/ or two positive genes
What can cause a false negative sweat test
What 3 things can cause a false positive
Oedema
DI, adrenal al insufficiency, dermatitis
What is the pattern of infection seen over time in CF
Staph and haemophillus
Pseudomonas and stenoprophomonas
Burkholderia
Non TB mycobacterium
What defines a transudate?
What are 4 examples
What defines an exudate?
Give 4 examples
Exudate: Low protein and high glucose
Heart failure, cirrhosis, nephrotic syndrome, dialysis
Transudate: High protein and low glucose
Pneumonia, TB, chylothorax, cancer
What happens to the cilia mostly in primary ciliary dyskinesia
What will exhaled NO show
Absent dyenin arms
Low NO- diagnostic
What 2 tests in spirometry help a diagnosis of asthma.
How much and how does the FEV1 change?
Bronchodilator response- should increase by>12%
Histamine- should reduce by 20%
When should a mask be used in asthma
All under 2s
What are the steps in managing asthma- under 5s
Over 5s
Under 5s 1) preventer 2) add low ICS 3) add monteleukast 4) refer
Over 5s 1&2 same 3) consider LABA/ICS combo 4) add minteleukast 5) increase dose of combined and refer
Why are LABAS never used alone
Which age group should they never be given to
Increases mortality by down regulating the beta 2 receptors
Under 5s
What is a low dose and standard dose of
- beclomethasone
- beclomethasone ultra fine
- fluticasone
- budesonide
What makes up a high dose
- 200/400
- 100/200
- 100/200
- 200/400
Twice a standard dose
What do SMART and air therapy use
What is the regime?
Symbicort- eformoterol and budesonide
(Rapid onset LABA) and ICS
AIR- use it PRN
SMART- use it BD
How does omalizumab work
What is the caveat
What is the alternative and how does it work?
Binds to free igE
IgE needs to be less than 1300
Mepolizumab- binds to IL5
What may a bronchial cast show
Underlying asthma or CF
What happens REM sleep during the sleep cycle
More towards the end so more in the mornings
What is the genetic association with narcolepsy
What is deficient
HLADQ1B
Orexin neuropeptide
What is congenital central hypoventilation syndrome associated with (2 things)
Increased neural crest tumours and hirschsprungs
When is BIPAP use in neuromuscular weakness- at night? Day and night?
FVC <60%
FVC <20%
Which test in TB can be affected by the vaccine
Which is more specific
TST
IGRA
If a less than 5 year old is exposed to TB what should be done
If results are negative what should be done
If results are positive what should be done
Treat for 3 months, do IGRA and CXR
Stop treatment and give vaccine
If symptoms and positive cxr- samples and treat for active disease
If no symptoms and negative cxr- treat for latent TB
What two waves are seen in non REM sleep
What owe wave is seen on REM sleep
Sleep spindles and k complexes
Delta waves
What percentage of kids snore?
How many have OSA
10-20
3%
