Respiratory Flashcards
1
Q
Natural Hx asthma
A
30-70% children with episodic asthma will have less severe of absent Sx by late adolescence
Severity in childhood determines severity in later life
2
Q
Most sensitive and specific symptom of asthma
A
Wheeze
3
Q
% of children with asthma who have allergies
A
66%
80% have positive SPT to dust mites
4
Q
Classification of wheeze in children 1-4 years
A
Infrequent preschool (viral) wheeze Frequent preschool (viral) wheeze Multi-trigger wheeze
5
Q
Diagnosing asthma in children (Aus asthma handbook)
A
- Symptoms and signs suggestive of asthma
(If not or suggestive of another diagnosis needds further Ix)
2a. Perform spirometry if child able => if FEV1 >12% of baseline 10-15 mins after bronchodilator Dx as asthma
(If not for further Ix eg. bronchial provocation test, cardiopulmonary exercise test => if these suggest asthma can still Dx asthma)
2b. If child not able to perform spirometry trial of treatment => if clear response to treatment Dx as asthma
(If not Dx as wheezing disorder, asthma not confirmed)
6
Q
True/False- normal spirometry in the absence of symptoms does not exclude asthma
A
True
7
Q
Spirometry pattern: low flow, normal volume
A
Fixed central/upper airway obstruction
8
Q
Spirometry pattern: normal inhalation, scooped out exhalation with decreased flow
A
Obstructive picture
9
Q
Spirometry pattern: Flow roughly normal, volume reduced
A
Restrictive picture
10
Q
Spirometry pattern: Normal flow and normal exhalation morphology but decreased volume
A
Incomplete exhalation
11
Q
Spirometry pattern: Normal exhalation, reduced flow in inhalation
A
Variable upper airway obstruction
12
Q
What is on the axes in the spirometry loop
A
X: volume
Y: flow
13
Q
What defines a bronchodilator response on spirometry
A
Salbutamol 4 puffs
Repeat spirometry 15 mins post
FEV1 increase >= 12% from baseline + 200mL (if FVC <1.5L, >100mL)
14
Q
Direct airway challenge test
A
Inhalation of increasing concentrations of histamine or methacholine
In asthma: will result in fall of FEV1 >20% => if normal asthma is excluded
Good sensitivity, poor specificity- positive test does not confirm asthma
15
Q
Indirect airway challenge test
A
Exercise challenge- in exercise-induced bronchospasm will result in FEV1 decrease 10-15%
Negative response is useful in excluding asthma in children with exercise-related breathlessness
16
Q
Serial peak expiratory flow monitoring
A
PEF varies throughout the day
Serial measurement shows poor concordance with disease activity- low specificity and sensitivity for asthma
17
Q
Fractional exhaled nitric oxide
A
Positive FeNO suggests eosinophillic inflammation and provides supportive, but not conclusive, evidence of asthma
Will also be raised in oesionphillic bronchitis, allergic rhinitis, eczema
Will be low in: smokers, during the early phase of an allergic response, neutrophillic asthma
18
Q
Stepwise Mx asthma in children
A
- SABA PRN
- Low dose ICS / montelukast / cromone
- High dose ICS / low dose ICS + montelukast / ICS/LABA combination*
- Referral
*>= 12 years
Review each step in 2-4 weeks if montelukast/cromone, 4 weeks if ICS
Ensure adherence and technique before stepping up
Step up if poor control
Step down if good control for 3 months
19
Q
Definition of good asthma control
A
Daytime sx <= 2x per week and rapidly relieved by SABA
No limitation of activities
No nighttime Sx
Need for relieved <= 2 x per week (does not include prophylactic before exercise)
20
Q
Definition of partial asthma control
A
Daytime sx >2x per week and rapidly relieved by SABA
Any limitation of activities
Any nighttime Sx
Need for relieved >2 x per week (does not include prophylactic before exercise)
21
Q
Definition of poor asthma control
A
Daytime Sx >2x per week and not quickly and completely controlled by reliever
Any 3x partial control Sc within a week
22
Q
Inhaled corticosteroids for asthma- low and high doses (microg)
A
Beclometasone diproprionate (Qvar) - 100-200; 200-400 Beclomethasone dipropionate ultrafine - 100; 200 Budesonide (Pulmicort) - 200-400; 400-800 Ciclesonide (Alvesco) - 80-160; 160-320 Fluticasone propionate (Flixotide) - 100-200; 200-500
23
Q
Initial preventor choice by age group
A
<12 months: specialist referral
1-2 years: sodium cromoglycate PO for multi-trigger wheeze
2- 5 years with frequent intermittent asthma, mild persistent asthma, frequent viral wheeze or multi-trigger wheeze: montelukast PO
2-5 years with mod-severe persistent asthma or mod-severe multi-trigger wheeze: low dose ICS
>6 years frequent intermittent: montelukast or cromone
>6 years and mild persistent: monktelukast or cromone
>6 years and mod-severe: low dose ICS
24
Q
Patterns of asthma in 1-5 year olds
A
Infrequent intermittent - flare up less than every 6 weeks, Sx free in between
Frequent intermittent- flare up more often than every 6 weeks, Sx free in between
Mild persistent asthma- daytime Sx more than 1x per week but not daily, nighttime Sx >2x per month but not weekly
Mod persistent asthma- Daily daytime Sx, weekly nighttime Sx, restriction in activity or sleep
Severe persistent asthma- continual daytime Sx, frequent nighttime Sx, frequent restriction of activities or sleep
25
Patterns of asthma in 6 years and older
Infrequent intermittent - flare up less than every 6 weeks, Sx free in between
Frequent intermittent- flare up more often than every 6 weeks, Sx free in between
Mild persistent asthma- FEV1 >80% predicted + at least one of: daytime Sx more than 1x per week but not daily, nighttime Sx >2x per month but not weekly
Mod persistent asthma- Any of: FEV1 <80% predicted, dDaily daytime Sx, weekly nighttime Sx, restriction in activity or sleep
Severe persistent asthma- Any of: FEV <60% predicted, continual daytime Sx, frequent nighttime Sx, frequent restriction of activities or sleep, frequent flare ups
26
Inhaled devices recommended by age group
<2 years: small volume spacer and mask
2-4 years: small volume spacer, may transition to no mask
5-7 years: large volume spacer and no mask
8-15 years: large volume spacer and mask, dry powder device, breath-activated device
27
Low dose ICS acheives _% of maximum efficacy
80-90%
28
Effect of ICS on height
Small and temporary decreased height velocity- within first 2 years of treatment
Difference ~0.7% adult height
(Note that severe uncontrolled asthma will also reduce height)
29
Why is LABA monotherapy unsafe
Internalisation of the B2 receptors can result in paradoxical bronchospasm and no response to SABAs
Sensitisation risk is reduced when using with LABA
30
MOA cromones
MAST cell stabiliser
31
MOA montelukast
Leukotriene receptor antagonist
32
MOA omalizumab
Anti-IgE- given as a subcute injection every 2-5 weeks
33
MOA mepolizumab
Anti-IL5
34
Use of steroids in acute episodes asthma for children <5 years
Should only be used for those in hospital, on O2, with multi-trigger wheeze phenotype
35
Effect of sleep on respiratory physiology
Decreased muscle tone => airway resistance doubles, tidal volume halves
Therefore any impairment of ventilation will be worse in sleep (except laryngomalacia)
36
Stages of sleep
N1- transition to light sleep, easily roused
N2- light sleep (k complexes and spindles)
N3- deep sleep or slow wave sleep, still, very hard to rouse, regular breathing
REM- dream sleep, decreased tone, partial paralysis, vivid dreams, irregular breathing, increased upper airway resistance, decreased tidal volume
37
REM sleep
Longer in the second half of the night - more obstruction and hypoxia in the second half of the night
38
Babies sleep patterns
50:50 REM and quiet sleep
39
Identifying sleep stages on sleep study
```
N2:
- Chin EMG medium movement
- EEG: quiet, k complexes, spindles
N3:
- Chin EMG small
- EEG: big slow waves
REM:
- Chin EMG smallest
- Quiet EEG, eye movements, no Ks or spindles
```
40
ADHD and sleep
Decreased sleeping
| Increased movement in sleep
41
Parasomnias
Partial awakening from N3 sleep
Usually 6-90 mins in to sleep- end of first cycle of deep sleep
Consider and underlying cause of arousal eg. OSA/periodic limb movement disorder
42
Treatment of night terrors
Clonazepam if frequent
43
Treatment f periodic limb movement disorder
Can be from partial iron deficiency in the basal ganglia- treat with iron to keep ferritin >50
44
Narcolepsy
Lack of neurotransmitter orexin (AKA hypocretin)- usually autoimmune disorder that attacks cells that secrete orexin
HLA for DR2
Ix: hypocretin-1 levels in CSF, multiple sleep latency test (REM sleep during the day)
Assoc with cataplexy 70%- drop attack with extreme emotion
Mx:
- Sodium oxybate, TCAs or SSRI for cataplexy
- Modafinil
- Methylphenidate or dexamphetamine
- Scheduled naps
45
Lung volumes
- Tidal vol
- TLC
- Vital capacity
- Residual vol
- Insp capacity
- Exp reserve vol
- FRC
Tidal vol: normal insp to normal exp (6-7mL/kg)
Total lung capacity
Vital capacity: forced insp to forced exp
Residual vol: air left after forced exp
Insp capacity: normal exp to full insp
Exp reserve vol: normal exp to forced exp
Functional residual capacity: exp reserve vol + residual vol
46
Change in lung volumes with restrictive disease
Smaller TV, FRC, insp capacity
47
Change in lung volumes with obstructive disease
Larger RV, exp reserve vol
48
Normal FVC, reduced FEV1, reduced FEV1/FVC
Obstructive
49
Obstructive spirometry pattern
Normal FVC, reduced FEV1, reduced FEV1/FVC
50
Low FVC, low FEV1, normal FEV1/FVC
Restrictive or failure to inhale or exhale completely
51
Spirometry: Restrictive
Low FVC, low/normal/increased FEV1, normal/increased FEV1/FVC
52
Spirometry: Failure to inhale or exhale completely
Low FVC, low FEV1, normal FEV1/FVC
53
Low FVC, normal or increased FEV1, normal or increased FEV1/FVC
Restrictive or inadequate effort
54
Low FVC, low FEV1, low FEV1/FVC
Mixed, severe obstruction, or obstruction with inadequate effort
55
Reference values for spirometry
```
FVC <80% predicted
FEV1 <80% predicted
FEV1/FVC <76-78% (actual value)
TLC <80% predicted
FEF25-75% <66% predicted
```
56
FEF25-75%
Most sensitive for airway obstruction
| Effort independent
57
Relationship between chest wall compliance and FRC
```
Unusually low (restrictive) or high (obstructive) FRC causes decreased lung compliance
FRC is primarily determined by chest wall compliance (FRC is the point at which outward recoil of the chest wall is equal to the inward recoil of the lungs)
```
58
How does restrictive lung disease cause hypoxaemia
Restrictive lung disease = reduced FRC
FRC is the volume available for gas exchange at all times - if reduced then have reduced volume available for gas exchange in expiration = hypoxia in expiration
59
Poiseuille's law
Resistance is the amount of pressure required to general flow
R= (8 x length x viscosity) / (pi x radius^4)
60
Compliance
= change in volume/change in pressure
61
Principles of ventilating conditions associated with decreased lung compliance
Eg. pneumonia, pulmonary oedema, atelectasis
| Relatively smaller tidal volumes and faster RR
62
Principles of ventilating conditions associated with increased airway resistance
Eg. asthma, bronchiolitis, aspiration
| Slower RR with higher IT to allow pressures to equalise, larger tidal volumes
63
VQ mismatch
Ventilation of a poorly perfused lung (eg. PE, hypovolaemia) results in dead space ventilation = higher PaCO2 than PACo2
Perfusion of a poorly ventilated lung (eg. asthma, pneumonia, RDS) = intrapulmonary R-> L shunting/venous admixture = lowed PaO2 than PAO2
64
Pa vs PA
```
a = arterial
A= alveolar
```
65
Minute volume
MV = Vt x RR
66
What determines PaCO2
PaCO2 is inversly proportional to alveolar ventilation
| Alveolar ventilation = Vt- anatomic dead space
67
Alveolar and arterial gases in disorders that affect the alveolar capilary barrier
Decreased diffusion
CO2 20x more diffusible than O2
Therefore in decreased diffusion, will have a significant alveolar-arterial oxygen gradient, but no significant arterial-alveolar CO2 gradient/elevation of PaCO2
68
Choanal atresia
MC congenital anomaly of the nose
Bony 90%, membranous 10%
Unilateral or bilateral (uni more common)
F:M 2:1
50-70% have other anomalies:
- CHARGE, Treacher-Collins, Kallmann syndrome, VACTERL
Cyanosed at rest, improves with crying (mouth breathing)
Dx with failure to pass NGT, CT
69
Piriform aperture stenosis
Bony abnormality of the anterior nasal aperture
Can be associated with holoprosencephly, hypopiuitarism, cardiac and urogenital malformations
Severe nasal obstruction noted after birth
Nasal decongestant, NPA, Mx reflux, may need surgery
70
Nasal polyps
1% of the populaton, increases with age
CF MC cause in childhood= 50% of patients will experience obstructing polyposis
Rx: decongestants, steroid spray cause shrinkage, doxycycline improves size, nasal Sx, mucosal and systemic markers of inflammation, surgery
71
ABG in central airway obstruction
Causes uniform alveolar hypoventilation- early increase in PaCO2
72
ABG in depressed respiration
Causes uniform alveolar hypoventilation- early increase in PaCO2
73
ABG in neuromuscular disease
Causes uniform alveolar hypoventilation- early increase in PaCO2
74
ABG in obstructive lung disease (intrapulmonary)
```
Causes VQ mismatch/venous admixture
Mild: type 1 resp failure
Mod: normal PaCO2, low PaO2
Severe: very high CO2, very low O2
Responds well to supplemental O2
```
75
ABG in alveolar-interstitial pathology
Causes R -> L shunt
Early decrease in PO2, low/normal CO2 until fatigue develops
Only moderate response to supplemental O2 at best
76
Primary cilial dyskinesia
AKA Kartagener syndrome
Impaired ciliary function leading to chronic sinopulmonary disease, persistent middle ear effusion, laterality defects (eg. situs inversus totalis, heterotaxy), infertility
3 types of cilia:
- Motile cilia (9+2 arrangement on EM)
- Sensory cilia (9+0)
- Nodal cilia (during embryonic development) (9+0)
MC abnormality is shortening or absence of dynein arms
Usually AR
Usually slower resp decline than CF patients- near normal lifespan
77
OSA- causes
8% of paediatric population
Due to anatomically or functionally narrowed upper airway
MC adenoid/tonsillary hypertrophy (size does not correlate with degree of obstruction)
Chronic rhinitis, craniofacial anomalies, GORD with pharyngeal odema, nasal septal deviation, neuromuscular disease, reduced resp drive eg. Arnold-Chiari malformation, T21 (70%), obesity
78
OSA metabolic and cardiovascular complications
Insulin resistance, systemic hypertension- due to upregulation of inflammatory pathways
79
OSA Dx and Rx
Polysomnography- apnoea-hypopnoea index (number of events per hour of sleep)
Normal children <1.5, older adolescents <5
Rx: A&T, CPAP, weight loss, nasal steroids
80
Bronchiolitis obliterans
Chronic obstructive lung disease of the bronchioles and smaller airways due to fibrosis, secondary to an insult to the LRT
81
Bronchiolitis obliterans causes
Transplant patients- bronchiolitis obliterans syndrome (BOS)
- Chronic rejection of heart or lung transplant, or GVHD assoc with BMT
Resp infection- adenovirus (types 3, 7, 21) MC
Inflammatory diseases eg. JIA, SLE, scleroderma, SJS
Inhalation of toxic fumes or particulate exposure
82
Bronchiolitis obliterans organising pneumonia (BOOP)
Histological features of BO with extension of the inflammatory process in to the alveoli and proliferation of fibroblasts
83
Clinical features bronchiolitis obliterans
Cough, fever, cyanosis, dyspnoea, chest pain, resp distress
Then initial improvement
Then increasing dyspnoea, chronic cough, sputum, wheeze
Spiro: obstruction +/- bronchidilator response
CXR: normal, hyperlucent, patchy infiltrates
84
Bronchiolitis obliterans treatment
Corticosteroids
Immunomodulation is BOS post transplant
BOOP- oral corticosteroids for a year
85
Bronchiolitis obliterans prognosis
BO- can rapildy deteriorate and die within weeks
BOS higher mortality rate
BO (non-transplant) will usually survive with chronic disability
BOOP recovery 60-80%, although can relapse
86
Dry/plastic pleural effusion
Secondary to acute LRTI, connective tissue disorder eg. RF
Secretion of small amounts of serous fluid from the visceral pleura
Pain, pleural rub, dullness to percussion and decreased breath sounds
Rx: treat the underlying infection
87
Serofibrinous or serosanguinous pleural effusion
Fibrinous exudate on the pleural surface and exudative serous fluid in to the pleural cavity
Causes: LRTI, inflammatory conditions of the abdomen/mediastinum, connective tissue disorder, malignancy
Can progress from plastic pleurisy
Dx: thoracocentesis
Rx: Treat underlying infection, drain a large effusion (note: if rapidly draining >1L, may be associated with development of re-expansion pulmonary oedema), supportive cares
88
Empyema
Pus in the pleural space
MC assoc with pneumonia- strep or staph
MC infants and preschool children
Empyema on thoracocentesis: bacteria seen on gram stain, pH <7.2, >100 neuts
Note: pneumococcus on positive from pleural culture 60% of the time, better yield from BC or using PCR
Rx: VATS, Abs
89
Timing of sinus development
Ethmoidal sinuses pneumatised from birth
Maxillary sinus present from birth, pneumatised 4 yo
Spenoidal 5yo
Frontal 7yo-adolescence
90
Causes of bacterial sinusitis
```
Strep pneumo 30%
Hib 20%
Moraxella 20%
Immunosupression: mucor, aspergillosis
Predisposing factors: URTI, smoke exposure, CF, ciliary dysfunction, GORD, anatomic defects, nasal polyps, nasal foreign bodies
```
91
Differentiation URTI from bacterial sinusitis
Peristsence of nasal congestion, rhinorrhoea and daytime cough >10 days without improvement
Severe Sx: T >39 + purulent discharge present for 3 days
Worsening symptoms
Recurrent of symptoms afetr initial improvement
92
Rx bacterial sinusitis
50-60% will recover without treatment
Abs to prevent suppurative complications (amox --> augmentin if not improving, cef if not tolerating orals)
IV ceftriaxone intially in frontal sinusitis- can rapidly progress to serious intracranial complications
93
Retropharyngeal/lateral pharyngeal abscess
MC <4 years (retropharyngeal nodes involute after 5 years)
60% Hx recent ENT infection
Usually polymicrobial - GAS, oropharyngeal anaerobic bacteria, S. aureus
94
Lemierre disease
Septic thrombophlebitis of the internal jugular vein and embolic absccess of the lungs
Caused by fusobacterium necrophorum
95
Gastrointestinal complications of CF
```
Mec ileus/mec plug (Mex ileus present in 1/7 infants with CF)
Distal intestinal obstruction syndrome (non-neonatal)
Rectal prolapse
Pancreatitis
Billiary cirrhosis
Neonatal obstructive jaundice
Hepatic steatosis
Cholelithiasis
Inguinal hernia
Fat soluble vitamin deficiency
Malnutrition
Diabetes
Malignancy
```
96
Endocrine complications of CF
```
Infertility
Delayed puberty
Diabetes mellitus
Short stature
Hyponatremia
```
97
Ortho/derm complications of CF
Clubbing
Hypertrophic osteoarthropathy
Aquageni palmoplantar keratoderma (skin wrinkling)
98
CF genetics
AR mutation of CFTR
1/3500 lives births in white population
1/30 carriers in white population
>1900 CFTR polymorphisms
MC- F508del: 50% homozygous, further 30% heterozygous
CFTR: chloride channel, adneosine triphosphate-binding vassette superfamily of proteins
99
CF classes
I: lack of protein production- no CFTR present
II: defect in protein trafficking with degradation in endoplastic reticulum/golgi body- basically no CFTR present = dF508
III: defective regulation- CFTR not activated by ATP or cAMP- no CFTR present
IV: reduced chloride transport through CFTR at the apical membrane
V: splicing defect with reduced production of CFTR
100
What disease are you less likely to get with a CFTR mutation
Cholera
101
CF diagnosis
Positive sweat test (Cl >60mEq/L) + one of:
- Typical chronic obstructive pulmonary disease
- Documented exocrine pancreatic function
- Positive FHx
Genetic testing
102
Indications for sweat test:
```
Sig FHx
Congenial intestinal atresia
Meconium ileus
DIOS
FTT
Recurrent and chronic pulmonary disease
Chronic sinus disease
Obstructive azoopermia
Acute or chronic pancreatitis
Malabsorption
Rectal prolapse
Pseudo-Bartter syndrome
```
103
rhDNase
Mucoactive agent unsed in CF
AKA pulmozyme
Cleaves DNA
104
Staphylococcal infections CF
Flucloxacillin/Augmentin from diagnosis until age ?1 ?3 as prophylaxis
If colonised than continue as prophylaxis, and if unwell change to another anti-staph AB for 2 weeks
105
Pseudomonas in CF
First infection- Eradication therapy (PO eg. cipro or IV eg. timentin and tobra + inhaled eg. tobra) and then extended course of oral and inhaled antibiotics
If eradication not successful (3 consecutive cultures 1 month apart positive) continue inhaled antibiotic- eg. neb colistimethate sodium (colistin), neb tobi as a second line if ongoing deterioration
106
Non-tuberculous mycobacteria in CF
Initially repeat test for confimation
Chest CT to look for changes consistent with non-tuberculous TB
Consider Abs if perisstently positive, clinically unwell/CT consistent with NTBM, and not responding to other treatments
107
Aspergillus found in sputum in CF patients
If stable pulmonary function do not routinely need AB treatment
If ekevated aspergillus IgG or IgE and declining pulmonary function, treat for ABPA esp if consistent changes on CXR or CT
108
Burkholederia and CF
New diagnosis - treat with ABs even if clinically well
Usually asymptomatic, or slow decline in lung function
Rare: cepacia syndrome- rapid decline with necrotising pneumonia
Gram neg
Often resistant to beta-lactams, fluroquinolones and aminoglycosides
ABs- chloramphenicol, bactrim, cipro, neb ceftazidime
109
Haemophilus and CF
New diagnosis- treat with Abs even if clinically well (eg. augmentin) for 2 weeks
If chronic infection consider long term prophylaxis
110
Azithromycin use in CF
Used as an immunomodulatory agent- indications including declining lung function or repeated pulmonary exacerbations
Long term treatment
111
Pancreatic insufficiency in CF- Dx
Fresh faecal elastase
112
Distal intestinal obstruction syndrome
Acute onset peri-umbilical or RLQ pain +
- Palpable mass RLQ
- Faecal loading RLQ esp if associated with air-fluid levels
- Clinical features of complete or partial obstruction
Rx: gastrograffin (PO or NGT), second line PEG
Prevention: adequate fluid intake, optimise pancreatic enzyme replacement, regular stool softeners
113
Liver disease in CF
Annual LFTs
If abnormal for US +/- ursodeoxycholic acid- may result in improvement of LFTs, and may be able to cease medication
Most patients will not show clinical signs of liver disease even in the presence of significant cirrhosis
114
DM in CF
Annual test after 10 years of age, or in pts receiving corticosteroids or enteral feeds
Signs of DM:
- Unexplained weight loss
- Deterioration in spirometry
- Increased frequency pulmonary exacerbations
- Excessive tiredness
115
Ivacaftor (aka Kalydeco)
Greatest effect in patients with G551D mutation (4-5% of patients)- class 3
Approved for any heterozygous class 3 mutation
Enhances chloride transport by potentiating the action of the CFTR protein
Improvements in FEV1, sweat chloride concentration, weight gain
Metabolised by CP450
Tablets should be taken with fatty food
116
Stenotrophomonas maltophilia in CF
Not usually associated with a decline in lung function
| No evidence for cross infectivity
117
URTI in CF
Treat with oral antibiotics- anti-staph and anti-Hib cover for 2 weeks (eg. augmentin), or cipro if known pseudomonas
118
ABPA
5-10% of patients
Wheezing, increased cough, SOB, marked hyperinflation
New focal infiltrates on CXR
Rust coloured sputum
Ix: aspergillus on sputum MCS, positive SPT/RAST for Aspergillus, eosinophils in sputum, high serum IgE
Oral corticosteroids 1st line, antifungals second line
119
Nutrition CF
Pancreatic eynzyme replacement
Fat soluble vitamins
High caloric intake
Infants should not be on soy formula- do not use this protein well, can present with sig hypoproteinaemia
120
Laryngomalacia
MC congenital laryngeal anomaly, MC cause of stridor in infants
Decreased laryngeal tone leads to supraglottic collapse during inspiration
Onset within first 2/52 of life, may increase in severity up until 6/12
Worse if associated with GORD or neurological disease
Ix: laryngoscopy to confirm diagnosis, CXR/broncoscopy if mod-severe WOB (15-60% have associated synchronous airway anomalies)
Mx: expectant, agressive Mx GORD, surgical supraglottoplasty
121
Congenital subglottic stenosis
2nd MC cause of stridor
Clinical features: biphasic/insp stridor, resp distress, recurrent or peristent croup esp <6 months
XR- airway narrowing, confirmed by direct laryngoscopy
Stenosis >50% requires surgical Rx
122
Vocal cord paralysis- bilateral
Assoc with congenital CNS lesions eg. hydrocephalus, Chiari malformation
Unable to fully open glottis
High-pitched insp stridor, can have a normal cry
Flexible laryngoscopy, further neuro work up
Usually self resolves by 12 months, may require temporary tracheostomy
123
Vocal cord paralysis- unilateral
Usually iatrogenic after ToF repair, PDA repair etc
Unable to close glottis
Aspiration, choking, weak/breathy cry, stridor less common
Flexible laryngoscopy
Can inject laterally to the vocal cord to move it medially to reduce aspiration
124
Congenital laryngeal web
Usually glottic with subglottic extension and subglottic stenosis
Assoc with 22q11
DIagnosed on direct laryngoscopy
Mx- inscision or dilation
Laryngeal atresia- complete web, assoc with tracheal agenesis and TOF
125
Congenital subglottic hemangioma
Airway obstruction within 1st 2 months of life
Biphasic stridor, or sx of peristent/recurrent croup
1% of children with a cutaneous hemangioma will have a subglottic hemangioma
50% of children with a subglottic hemangioma will have a cutaneous hemangioma
126
Laryngocele
Abnormal air-filled dilation of the laryngeal saccule that arises vertically between the false vocal cord, the base of the epiglottic and the inner surface of the thyroid cartilage
Communicates with the laryngeal lumen and, when intermittently filled with air, causes hoarseness and dyspnoea
127
Vascular causes of stridor
Abberant innominate artery- wheeze, cough, apnoea, self limiting
Vascular ring
Pulmonary artery sling
128
Vascular ring
Abnormal development of the aortic arch
MC- double aortic arch encircling the trachea and oesophagus and causing compression
Sx by age 3 months- stridor, dysphagia
Dx by barium oesophagram - posterior indentation of the oesophagus by the vascular ring
MC incomplete vascular ring is aberrant R subclavian artery- common but usually asymptomatic
129
Sites of airway foreign body
R main bronchus 58%
| Larynx 10%
130
Alveolar gas equation = in an ideal environment, the amount of gas available for exchange within the alveolus
PAO2 = PiO2 - (PACO2/R)
PACO2 (in the absence of diffusion issues) = PaCO2
R = resp quotient = 0.8
PiO2 = FiO2 x (partial pressure of the barometric air = PH2O)
- pH20 = 47
- At sea level partial pressure of the barometric air = 760
Therefore (at sea level):
PAO2 = FiO2 x (PPBA-47) - PaCO2/0.8
131
Congenital cystic malformation
Hamartomatous or dysplastic lung tissue mixed with normal lung
Generally confined to 1 lobe
1-4/100 000 births
Can be detected antenatally- can regress throughout gestation
CT after birth
Can undergo malignant transformation- needs surgical resection by age 1 year
132
Pulmonary sequestration- pathology, associations
Lung tissue that does not connect to a bronchus, and receives its arterial supply from the systemic circulation (commonly off aorta)
Extralobar- venous return to the IVC
Intralobar- venous return to the pulmonary veins
Functionally a space occupying lesion
Can have gastric or pancreatic tissue in the lesion, or cysts
Assoc with: CPAM, diaphragmatic hernia, oesophageal cysts
133
Pulmonary sequestration clinical features
Dullness to percussion and decreased breath sounds
Continuous or systolic murmur over the back
Intrapulmonary sequestration:
• Generally lower lobe
• Does not have its own pleura
• Patients usually present with infection
Extrapulmonary sequestration
• MC in boys, L lung
• Lesions enveloped in pleura, assoc with diaphragmatic hernia, colonic duplication, vertebral anomalies, pulmonary hypoplasia
• Incidental discovery, or present with resp symptoms or heart failure
134
Bronchogenic cyst
Abnormal budding of the tracheal diverticulum of the foregut before 16th week gestation
Enlargement can cause airway compression
Can become infected
135
Congenital pulmonary lymphangiectasia
Greatly dilated lymphatic ducts throughout the lungs
Can be associated with generalised lymphangiectasia (also affects the intestines) eg. Noonan syndrome
Chylous pleural effusions common
Decreased diffusion and pulmonary compliance - dyspnoea and cyanosis as a newborn
136
Normal PaO2
80-100
137
Normal PaCO2
35-45
138
Normal PvO2
35-45
139
Normal PvCO2
40-50
140
FiO2 of different O2 devices
NP - 0.24-0.44
Mask- 0.35-0.55
Non-rebreather - 0.7-1.0
141
Sats vs PaO2
```
95% = 80mmHg
90% = 60mmHg
80% = 45mmHg
70% = 35mmHg
```
142
Hyperinflation on CXR
>6 ant or 10 post ribs at MCL
143
1-2-HCO3-4-5
For every 10mmHg PaCO2 deviates from 40:
Acute resp acidosis: HCO3 +1
Acute resp alkalosis: HCO3 -2
Chronic resp acidosis: HCO3 +4
Chronic resp alkalosis: HCO3 -5
HCO3 deviates from 24
(Chronic = 3-5 days)
144
Orkambi (lumacaftor/ivacaftor)
Orkambi not PBS approved- available on compassionate grounds only (FEV1<40% for 6 months, transplant list)
FDA for homozygous dF508
Lumacaftor = CFTR corrector (more available at the surfance) + ivacaftor = CFTR potentiator (more Cl through the channels)
Main sig AE- worsening liver disease
Take with fatty food
Benefits: improvement in FEV1 ~4% and reduction in exacerbations, admissions and antibiotic use
145
Current CF drugs in phase III development
Symdeco - tezacaftor + ivacaftor
| Inhaled levofloxacin for pseudomonas
