NZ Respiratory Flashcards
Respiratory abnormalities associated with T21
- Pulmonary hypertension
- Bronchial stenosis
- Subpleural cysts
- Alveolar simplification
Diaphragmatic Hernia
- 1: 2-3000
- Contralateral lung is usually affected
- Long term nutritional problems are common
- Malrotation occurs in 30-60%
- R sided in 12% of cases
Poor prognostic factors for CF
- Malnutrition
- Pseudomonas
- Burkholderia cepacia
- Diabetes
- Frequent exacerbations
- Female gender
Indications for lung transplant in CF
- FEV1 <30% predicted
- Poor nutritional status
- Poor exercise tolerance
- Rapid decline in lung function
- Major life threatening complications
- QOL issues
Stages of sleep in childhood
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, very regular breathing
REM: “dream sleep”, decreased tone, rapid eye movements, partial paralysis, vivid dreams, irregular breathing, increased upper airway resistance, decr. tidal volume
–> Occurs during the latter half of sleep
Stages of sleep in newborns
Different due to decreased myelination
- Active sleep: equivalent to REM sleep
- Quiet sleep: equivalent to N3
- Indeterminate sleep
Respiratory events: apnoeas
Apnoea >90% decrease in baseline flow for 2 or more respiratory cycles
- Obstructive: continued effort
- Central: absence of effort + desat >3% or arousal
- Mixed: starts central ends obstructive
Hypopnoea >30% decreased baseline flow for 2 or more resp cycles with desat or arousal
- More commonly seen in children with OSA, usually don’t have apnoeas, but partial obstruction or hypopnoea
Normal number of obstructive events per hour of sleep
<1/hr (<5/hr in adults)
Respiratory events on polysomnograph
- Drop in nasal flow
- Look at effort bands (thorax and abdo) to see if there is increased effort of breathing - obstructive vs central
- Confirm arousal or desaturation
Parasomnias
- Occur in N3 stage of sleep –> disturbance occurs, brain half awake
- -> To fully wake someone up and stop the event, need to go back go sleep. Waking someone up will prolong the event
- Includes confusional arousals, night terrors, sleep- walking
- Usually occurs 60-90min into sleep, usually 1 or 2 per night, positive FHx
DDx for parasomnias
Nightmares
Frontal lobe seizures - very stereotyped events, features of pointing, pelvic thrusting, more likely to stand, sudden offset
Night terror vs nightmare
- Night terror: N3 phase, occurs 60-90min into sleep (predictable), not awake!, unable to be settled/comforted, unable to recall the event (like a seizure!)
- If extreme, can trial clonazepam or zopiclone - Nightmare: REM phase, no specific timeframe, able to be comforted as they can wake up from event, takes ~20min to settle, can recall events
Anticipatory waking
Since parasomnias are predictable in their timing, wake up the child 30min before event to reset the sleep cycle
- Events may still occur
Periodic limb movement disorder
- Non-sleep stage specific disorder
- Part of restless legs syndrome
- Increased frequency of periodic limb movement during sleep –> disturbs pt from sleep
- Due to partial iron deficiency in basal ganglia
- Tx with Fe supp and aim for ferritin >50
Narcolepsy
- Hypersomnia disorder
- Genetics: HLA-DR2, DRB11501, DQA0102, DQB1*0602
- Hypocretin-1 level in CSF (low hypocretin/orexin)
- Features:
- -> Short latency (<8min) with REM sleep during the day
- -> Cataplexy: sudden loss of muscle tone
- -> Sleep paralysis and hypnagogic hallucinations
- Mx: good routine, scheduled naps, stimulants
- -> Stim: ritalin, modafinil
- -> Cataplexy: sodium oxybate, tricyclics, SSRIs, venlafaxine
Associations between sleep and obesity
Sleep deprivation associated w/ inc obesity
- Sleep dep –> for next 48hrs, increased hunger and caloric intake
- Other factors: altered thermoregulation and increased fatigue –> reduced energy expenditure
Behavioural insomnia
Mostly mixed phenotype
- Sleep association type i.e. children need to learn to fall asleep, need to have positive associations with bed time
- Limit setting disorder type i.e. naughty children with parents who can’t set limits
- Mx:
- -> Exclude physiologic causes for night waking e.g. OSA, GORD, asthma, eczema etc
- -> Sleep hygiene and better associations
- -> Sudden or graduated extinction: let them cry, parents don’t interact with children
- -> Fading with positive bedtime routines: 20min of positive, quiet activity before bed, move bed time backwards by 15min each night
ADHD and insomnia
Decreased sleeping, increased movement in sleep
Increased sleep latency, more restless sleep
More night-time wakings
Difficulty waking/irritability with daytime sleepiness
- Is stimulant the problem? Trial children on atomoxetine instead of ritalin, consider clonidine or melatonin
- Behavioural therapy
Autism and insomnia
- 44-83% have sleeping problems (significant)
- Issues: difficulty settling, waking during the night for hours, early morning waking
- Mx:
- -> Behavioural therapy: 50% find it helpful
- -> Melatonin: helps with sleep onset, but does not help decrease night time or early morning waking due to short half life
- -> Melatonin SE: binds receptors in gonads, in animals - affected puberty and fertility
Delayed sleep phase treatment for a petulant adolescent
- Sleep hygiene
- Dim light before bed, no texting, no computer/TV in room - Bright light when awake
- Advance bed time by 15min every 3 nights
- Melatonin can be used as adjuvant
N.B. Sunlight can move body clock by 2hrs, melatonin can move body clock by 20min!
Adverse effects of OSA
- Causes defects of executive function (MC): impulsiveness, inattention/poor concentration, memory decrements
- Disrupts sleep - tiredness/irritability
- Hard to wake or daytime sleepiness
- HTN, elevated lipids, insulin resistance
- Severe: FTT, pulmonary HTN, cor pulmonale
Major features of OSA in Hx
- Most sensitive: Snoring - 50%
- Increased odds ratio: (strength of association)
- Frequent mouth breathing asleep + awake
- Witnessed pauses or apnoea
- Struggling to breath
- Parents feel they have to poke child - Ex-prem, FHx
- Minor features: restless sleep, sweating, cough or vomit in sleep, morning headache
Examination findings on OSA
Tonsil size and mouth breathing (increased OR)
Nasal patency: hyponasal speech
High arched or narrow palate
Investigations for OSA
Diagnosis = polysomnography
Risk stratification for adenotonsillectomy = oximetry
- Motion-resistant oximeter with 2 second averaging time
- 5 or more clusters of desats to <80%, associated elevated early AM CO2 on blood gas
Treatment options for OSA
- Adenotonsillectomy
- Nasal corticosteroids
- Halve PSG score and cure mild OSA (shrinks adenoids) - CPAP
- For moderate post-surgical disease, severe but on waitlist, surgical contraindication
Outcomes from T&As in OSA pts
- 80-85% of near or total cure
- 50% cure in obese or severe OSAs
- Benefits: improves behaviour and QoL, but not necessarily IQ and executive function
Risk factors for respiratory compromise (e.g. apnoeas, atelectasis) post-T&As
- Syndromes: T21, DMD
- Morbid obesity
- Severe OSA
- <3yo
- Complications of OSA present prior to T and As –> FTT or cor pulmonale
Which pt groups are at risk of developing OSA?
- Large tonsils/adenoids
- Obese children
- Floppy children: T21, NMD
- Narrowing/crowding of upper airway: craniosynostosis, Pierre Robin sequence, Crouzon syndrome
I.e. more at risk of obstructing upper airway
Obesity and pathophysiology of OSA
- Decreased lung volumes due to increased pressure on chest and diaphragm squashes from below
- Fatty deposit around pharynx narrowing airway further
- Combined effect –> small airway volume –> increased pharyngeal collapsibility and airway resistance –> obstruction
OSA in obese pts increases risk of…
- Metabolic syndrome and insulin resistance
- HTN (sympathetic surge)
- Stroke > MI (vibration of snoring of carotid arteries)
- Poor sleep –> increases appetite
- Pro-inflammatory state
ABG Rules: AG - HCO3
(Change in AG) - (Change in HCO3) in high anion gap metabolic acidosis to identify co-existing NAGMA and met alkalosis
= (Calc. AG - (N) AG) - (Measured HCO3 - (N) HCO3) = >6 is abnormal
- Remember: the ratio ofchange in acidic anion and HCO3 should be 1:1 i.e. addition of 1 acid –> decrease in 1 base (neutralisation)
- If change in AG > change in HCO3 = concurrent met alkalosis, there must have been more base to start with to have a smaller decr in HCO3 c.f. bigger increase in AG
- If change in HCO3 > AG = concurrent NAGMA, there must be another acidotic process going on, as change in AG alone can’t explain sig decrease in HCO3
ABG Rules: Compensation
- When PCO2 and HCO3 move in the same direction, compensation is present
- -> Metabolic compensation implies chronicity as renal comp takes hours/days to complete - Resp acid/alkalosis: every 10mmHg change in CO2 (40) –> HCO3 (24) to change by 1 (acute) or 4 (chronic)
- Metabolic acidosis:
- pCO2 = (1.5xHCO3) + 8 (+/-2) OR
- Last 2 digits of pH = CO2 (e.g. pH 7.19 = CO2 19) - Metabolic alkalosis: pCO2 ~50 is the max that can be expected for compensation, otherwise expect a second process
- (0.7 x HCO3) + 20
Exhaled ntric oxide (FeNO)
- NO usually exhaled in breath. In asthma, high levels of NO + high levels of inducible NO synthase on epithelial cells of airways
- High FeNO suggests up-regulation of airway inflammation and presence of eosinophilic inflammation
- FeNO can decrease with corticosteroid therapy –> non-invasive method to MONITOR response to anti-inflammatory Tx
- NOT conclusive for asthma diagnosis
- Asthma = >35ppb in school aged children
Ix for primary ciliary dyskinesia
- Nasal nitric oxide
- Abnormal = <250ppb or <75nL/min (incorporates flow)
- True PCD <100ppb - Ciliary biopsy/brushings - look at ultrastructure of cilia
- Genetic testing
DDx for nodular miliary pattern
= innumerable, small 1-4 mm pulmonary nodules scattered throughout the lungs
- TB
- PJP
- CMV
- Lymphocytic interstitial pneumonia
- Metastatic lesions (e.g. osteosarcoma)
- Sarcoidosis
When does the risk of pulmonary hypoplasia increase?
Oligohydramnios prior to 26 weeks gestation
Lung development: pseudoglandular stage
Weeks 6-16: development of lower conducting airways
- By this stage all major elements of the lung have formed, EXCEPT for those involved in gas exchange
- Aberrant development: bronchogenic cysts, congenital lobar emphysema, CDH
Lung development: canalicular stage
Weeks 16-26: formation of acini
- Bronchial lumen and terminal bronchials become larger
- Lung tissue becomes highly vascular, pulm capillaries occur
- Terminal bronchioles form respiratory bronchioles –> divide into primordial alveolar ducts
- -> The alveolar sacs allow beginning of gas transport
Lung development: terminal sac stage
Weeks 26-36: refinement of blood-air barrier & surfactant
- Many more alveoli develop and epithelium become very thin (type I pneumocytes)
- Capillaries begin to bulge into sacs - increases alveolar-blood barrier surface area
- Development and maturation of surfactant system
Lung development: alveolar phase
Weeks 36 to 3yrs: alveolar proliferation + development
- Saccules become alveoli and alveoli attain polyhedral shape
- Thinning of acinar walls, dissipation of interstitium and invagination of alveoli by pulmonary capillary
Role of betamethasone
Increases surfactant production
Lung development: embryonic phase
Weeks 3-6: development of proximal airways
- Laryngotracheal groove develops caudal to fourth pair of pharyngeal pouch
- Lung bud (laryngotracheal diverticulum) arises from foregut day 21 to 26
- Aberrant development:
- -> Laryngeal web or atresia: failure to recanalise the larynx after 10th week
- -> Tracheal agenesis, tracheal stenosis: usually assoc. w/ variants of tracheo-oesophageal fistula
- -> TOF: incomplete division of cranial foregut into resp and oesophageal parts during 4th wk
- -> Pulmonary sequestration (accessory lung bud)
Gurgling upper airway noises
DDx:
- Lingual cyst
- Pharyngeal airway abnormality
Pulmonary hypoplasia
- Usually associated with congenital abnormality or pregnancy Cx that prevents adequate development of lung, airways and alveoli
- Causes:
- Physial constraint: CDH (can cause hypoplasia on contralateral side if squashed), CCAM, pleural effusions due to hydrops, thoracic dystrophy
- Oligohydramnios: foetal renal insuff, PROM
- Isolated - Presentation:
- Resp insufficiency
- PPHN
- Tachypnoea/distress with viral infections in infancy - mild presentations
Management of pulmonary sequestration
Risk of complications from unresected sequestration outweighs risks of surgery
- With extralobar seq, if infected, may require lobar resection
- Very small risk of cancer in remaining abnormal lung tissue
- Thorascopic resection
Where are pulmonary sequestrations located?
Most commonly, LLL - 90% extralobar, >60% intralobar
Complications associated with pulmonary sequestrations
Receives blood supply from systemic circulation (thoracic or abdo aorta)
- Recurrent infections and pneumonia
- Respiratory distress
CPAM
- Benign hamartomas or dysplastic tumours (mixed w/ N lung tissue) –> overgrowth of terminal bronchioles in glandular pattern
- Communicates with lung, normal pulmonary arterial and venous supply
- Lower lobes > upper lobes, R=L, rarely multilobar
- Antenatal USS: polyhydramnios, mediastinal shift, pleural effusion, hydrops (IVC comp)
- Macrocystic dz assoc w/ better prognosis (type I)
- Presentation: severity depends on degree of mediastinal compression and secondary pulmonary hypoplasia
- Main risks: PTX, infection and bronchiectasis, small risk of malignant transformation –> all determined by size + degree of compression
- Tx: plan with HRCT, surgical resection <12mth, TRUE spont resolution rare (can get smaller/disappear on XR)
Congenital lobar emphysema
- Secondary to bronchial obstruction (other pathology) –> distension –> irreversible destruction of alveolar septae
- Expiratory air trapping within affected lobe –> overdistension of affected lobe + compression of adjacent structures
- -> Atelectasis of ipsilateral normal lung, mediastinal shift
- Normal lung parenchyma, assoc. bronchial collapse
- Main clue: lungs are NOT inflated on antenatal scans as air trapping occurs postnatally
- Presentation: MC incidental finding on CXR for neonates with RDS
- LUL (40-50%), RML (30-40%), RUL (20%)
- Screen with echo as 15% associated with CHDs
- Mx depends on Sx and lung function: observe vs surgical excision
Bronchgenic cysts
- Abnormal budding from tracheobronchoeal diverticulum before 16 wks –> can be found anywhere along conducting airways
- Single, unilocular, R is MC
- Presentation: incidental finding vs tachypnoea, wheezing +/- FTT if compression of adjacent structures + lobar collapse
- -> Older children: infections
- Cx: infection, if ruptures –> PTX or haemoptysis, malignant transformation
- Mx: Surgical resection
Airway abnormalities and syndromes
Choanal atresia
CHARGE syndrome
Airway abnormalities and syndromes
Down Syndrome
Subglottic stenosis
Tracheal stenosis
Airway abnormalities and syndromes
Velocardiofacial syndrome
Submucosal clefts
Laryngeal webs
Airway abnormalities and associations
Tracheal stenosis
Tracheo-oesophageal fistula - pre and post-operatively
CFSPID
CF sweat test positive, inconclusive diagnosis
- 2 genes positive, normal sweat test
- 1 gene positive (hetero) or no genes, indeterminate/borderline sweat test
At risk of “delayed” CF
CF Genetics: Class 1
- Chromosome 7q
- Lack of CFTR synthesis
- Premature stop codon due to nonsense mutation –> truncated protein synthesised in nucleus
- W1282X, G542X, R553X
CF Genetics: Class 2
- Chromosome 7q
- 90% in Australia
- Defect in protein processing
- Deletion of phenylalnine at position 508 - CFTR protein degraded in ER and does not reach the membrane
- Del508, N1303K
CF Genetics: Class 3
- Chromosome 7q
- Gating mutation
- CFTR transported to apical membrane, but defect in intracellular arms of the protein, does not respond to stimulus –> lack of channel opening
- G551D
CF Genetics: Class 4
- Chromosome 7q
- Protein defect - missense mutation changes structure of protein pore
- CFTR transported to membrane, but restricts the movement of Cl- across the pore –> conductance defect
- R117H, R347P
CF Genetics: Class 5
- Chromosome 7q
- Reduced protein synthesis
- Very small number, most do not cause significant lung disease
- 278+5G –> A, A455E
CF Genetics: Class 6
- Chromosome 7q
- Increased protein turnover
- Functional protein, but unstable structure –> quickly degraded
- 120del 23, N287Y
PFTs in CF
- Decreased FEF25-75: indicates early obstructive disease
- FEV1: predictor of survival, monitor of disease progression
- -> FEV1 <30% - lung transplant, expected 50% 2yr mortality
- RV and FRC increased early in course of lung disease
Bacteria most commonly responsible for exacerbations in very young pts
- S. aureus
- P. aeruginosa (non-mucoid)
- Hib
- S. pneumoniae
- E. coli
Organisms associated with rapid decline in PFTs, increased morbidity and mortality
- Chronic pseudomonas infection (mucoid type)
- MRSA
- Burkholderia cepacia
- -> Cepacia syndrome: significant hypoxia + rapid resp failure, haemorrhagic pneumonia with rapid progression to death, overwhelmin sepsis
What sort of reaction is ABPA due to?
Hypersensitivity Type 1 and 3
- Aspergillus cell wall Ag causes allergic response
Risk factors for developing ABPA
- Inhaled antibiotic use
- Atopy
- Male
- Chronic infection
- Previous pseudomonas infection
- Poor lung function
- HLA-DR2 and DR5
5 Criteria for ABPA diagnosis
- Acute or subacute deterioration of lung function with chronic cough, wheeze, reduced ET, decline in PFTs, increased sputum not attributable to other cause
- IgE >1000 (unless receiving steroids)
- Immediate cutaneous reactivity to aspergillus (>3mm with surrounding erythema)
- Precipitating Abs to aspergillus or serum IgG to asper
- New findings on CXR or CT not improving with physio and ABx
Management of ABPA
- Oral prednisolone 1-2mg/kg or methylpred pulses
- Antifungal agents: itraconazole, vori or posi for 6/12 with steroids
- If resistant to steroids, omalizumab - Anti-IgE
- Treat asthma-like Sx with ICS
- Monitor progress with serial IgE levels
Importance of Scedosporium apiospermum infection in CF
= Fungus with poor sensitivity to antifungal drugs
- Its presence can PREVENT transplant
Genetic defects in CF can confer protection against which bug?
Salmonella Typhi
Prophylactic macrolide therapy in CF (Azithromycin)
- Very effective anti-inflammatory agent esp in pts with chronic P. aeruginosa
- Increase in FVC and FEV1 in pts with chronic pseudo
- Reduce rate of pulmonary exac requiring IV therapy
- Reduced hospital admissions
- Resulted in small increases in weight
- Azithromycin has long intracellular half life –> thrice weekly dosing
Pulmozyme
- Breaks down sulphide bond in mucus molecules
- Improves lung function and reduce exacerbation rates, maintains effectiveness for >2yrs
- <5yo: strict criteria
- -> Severe course with >3 admissions
- -> Sig. bronchiectasis, severe bronchiolitis with wheeze, severe impairment on spirometry
- > 5yo: 1mth trial showing 10% increase in FEV1 for continued therapy
Neb Hypertonic Saline 3-7%
- Cough stimulant, can induce bronchospasm
- Salbutamol 15min before therapy
- Discontinue if tachypnoea, wheeze etc
Side effect of high dose pancreatic enzyme replacement therapy or “overdosing”
High doses > 6000u lipase/kg: Fibrosing colonopathy, predispose to DIOS
Most common microangiopathic Cx of CFRD
- Neuropathy 55%
- Gastropathy 50%
- Retinopathay 16%
- Microalbuminuria 14%
Do CF pts go into DKA?
No - persistance of endogenous insluin production and impaired glucagon response prevents DKA
CFRD is more severe with concomitant…
CF-related liver disease
Clues to CFRD
- Delayed puberty, decreased growth velocity/failure to gain weight
- Worsening PFTs
- Polyuria and polydipsia
- Presence of significant hyperglycemia may indicate P. aeruginosa or Burkholderia infection/colonisation
RIsk factors for CF-related liver disease
- Hx of meconium ileus
- Pancreatic insufficiency
- Male gender
- Mutations class I-III
Cholestasis –> focal biliary cirrhosis –> multifocal biliary cirrhosis
Neonatal cholestasis in CF pts
Presents with conjugated hyperbili and hepatomegaly
- Usually resolves and is not a predictor of later CFLD
- However, this may change if prolonged TPN or surgery related to meconium ileus
CF related liver disease
- Focal biliary cirrhosis (20-40%): asymptomatic, persistently elevated LFTs, hepatomegaly, develops within first 12yrs of life
- Multilobar biliary cirrhosis (5-10%): cirrhosis, Cx by portal HTN, GI bleed, varices and nutritional deficiencies
- Hepatic steatosis (10-60%): relationship btwn steatosis and FBC is unclear; usually thought to be benign - inflammatory features of steatohepatitis don’t develop
RF for hepatic steatosis
- Malnutrition
- Essential fatty acid deficiency
- Alcohol ingestion
Pancreatic insufficiency and CF
- 60% are pancreatic insufficient at time of diagnosis
- At 1yr post-Dx, 95% are insufficient
Symptoms more likely to suggest asthma
- Wheeze (most sensitive and specific Sx of asthma)
- Chest tightness
- Nocturnal cough
- Breathlessness
Particularly if:
- Worse at night or early morning
- Obvious triggers e.g viral infection (MC 85%), exercise, cold air, allergen, stress, aspirin
- Seasonal or recurrent
Other features: personal Hx of atopy or FHx of asthma
Objective testing that is more likely suggestive of asthma
- Obvious response to bronchodilators
- Raised blood eosinophilia and FeNO
- Bronchial hyper-responsiveness on challenge testing
- Obstructive pattern on spirometry (low FEV1, low FEV1/FVC, low FEF25-75%)
Features NOT suggestive of asthma
- Isolated cough without wheeze
- Wet, productive cough
- No wheeze or repeatedly normal exam during an “exacerbation”
- No response to trial of asthma treatment
- Normal spirometry or peak expiratory flow when SYMPTOMATIC
LABAs
A B2-receptor genotype (Arg16 polymorphism in the B2-receptor gene) pre-disposes children with asthma to down-regulation/internalisation of the B2-receptor –> tolerance and paradoxical bronchospasm –> SABA will not provide desired response
- Increased risk of mortality with LABA monotherapy
What determines disease severity in adolescence and adulthood?
Disease severity in childhood
Natural history of asthma
- Children who lose overt Sx still have persistent signs of airway obstruction on PFTs and history
- Recurrence of asthma after years of freedom from overt Sx can occur
- Airway inflammation can persist in the absence of Sx
- -> Airways still show significant abnormalities and evidence of active inflammation
Low dose vs high dose ICS
- Daily dose that achieved 80-90% of maximum efficacy is low doses (Fluticasone 100microg/day/Budesonide 200microg/day/Beclomethasone 200microg/day)
- More evidence to suggest that adding an extra agent provides increased benefit in Tx rather than increasing ICS dose
Low dose ICS and growth
- Can have small, temporary effect on growth that is NOT progressive and or cumulative
- Esp seen in pre-pubertal children in first 1-2yrs of Tx
- Long-term outcomes showed a difference of 0.7% in adult height (~1cm)
- Severe, poorly controlled asthma can also affect growth!
Montelukast
Leukotriene receptor antagonist
- Psychiatric side effects
Cromones
Mast cell stabilisers
- Sodium cromoglicate, nedocromil sodium
Omalizumab
Anti-IgE - prevents IgE binding to mast cells
- Subcut 2-5 weekly depending on response
Mepolizumab
Anti-IL 5
Tiotropium bromide
Long-acting muscarinic antagonist
Best predictor for severe asthma exacerbation
Hospitalisation or ED visit for severe exacerbation of asthma in last year
Features associated with increased risk of severe asthma exacerbation and/or death from asthma
Symptoms:
- Poorly controlled asthma
- Hospitalisation/ED for exac of asthma in last yr
- Extreme SABA use (>1 cannister/mth)
- ICU admission or intubation ever
- Requirement for long-term oral steroids
- Personal Hx of severe food allergy and anaphylaxis
Medication adherence:
- Poor technique or poor adherence to preventer use
Social:
- Alcohol/drug abuse in family, tobacco use, poor health literacy, low SES/financial hardship, poor follow up, unhealthy housing
Protracted bacterial bronchitis
- May be precipitated by URTI, prolonged to chronic cough (>2-8wk) that is wet with sputum production
- On examination, WELL, no wheeze or atopy, no added sounds
- Sputum/BAL: bacterial counts of >10^4 cfu/mL, Haemophilus influenzae (non-typable)
- Normal CXR
- Responds to prolonged course of PO augmentin 4-6/52, with resolution seen in 2/52
Most significant predictor of lung function (FEV1) decline in bronchiectasis
Frequency of hospital exacerbations
- Predicted FEV1 decline of 1.95% per admission
Characteristic findings on HRCT for bronchiectasis
- Enlarged internal bronchial wall diameter relative to adjacent pulmonary = signet ring sign
- Lack of bronchial tapering as it reaches periphery
- Bronchi seen in lung periphery
- Bronchial wall thicking, mucous plugging or impaction
- Mosaic perfusion defects
- Air trapping on expiration
Most common bacteria isolated on sputum/BAL for bronchiectasis
- Non-typeable Haemophilus influenzae
- Streptoccocus pneumoniae
- Moraxella catarrhalis
Definition of chronic suppurative lung disease
- Disease spectrum: PBB –> CSLD –> Bronchiectasis
- Respiratory Sx and signs that are seen in bronchiectasis without bronchial abnormalities seen on HRCT
- Recurrent (3 or more eps) chronic wet, productive cough (>4wks)
- Variable responses to prolonged courses of POABx
- Exertional dyspnoea, wheeze and other Sx of airway hyperresponsiveness
- Recurrent chest infection
- Growth failure
- Clubbing
- Hyperinflation or chest wall deformity
Central apnoeas in infancy
- Occur frequently, especially during active (REM) sleep, upon body movement and during transition between wakefulness to sleep
- Frequency of central apnoeas decrease after 1st yr of life
Complications of OSA
- Cardiovascular abnormalities secondary to increased sympathetic drive (as a result of repetitive partial/complete upper airway obstruction)
- RVH
- Systemic HTN
- Pulmonary HTN and cor pulmonale - Defects in executive function, behavioural and learning disabilities
- Poor growth or obesity
- T2 respiratory failure
Definition of respiratory failure
- Type 1: arterial PaO2 <60mmHg
- Causes of hypoxaemia: hypoventilation, diffusion impairment, shunt, V/Q mismatch - Type 2: arterial PCO2 >55mmHg
- Causes of hypercarbia: hypoventilation, V/Q mismatch
Gas exchange during sleep
- Decreased hypoxic and hypercapneic drive during sleep
- Normal child experience increase in PaCO2 (4-6mmHg) and small decrease in arterial oxyhaemoglobin saturation PaO2 (2mmHg) in sleep
- Changes in gas exchange are exaggerated in children with underlying lung disorders, upper airway abN and NMDs
NMDs associated with progressive respiratory muscle weakness and development of chronic respiratory failure. What are the causes?
- Airway obstruction
- Bulbar obstruction –> hypoventilation
- Atelectasis due to hypoventilation - Increased lung damage
- Increased secretions due to ineffective cough
- Aspiration due to bulbar weakness
- Recurrent chest infection - Restrictive disease
- Scoliosis –> smaller lung volume
- Stiff chest wall –> reduced compliance
- Resp muscle fatigue/weakness
Manifestations of respiratory insufficiency and failure in NMDs
- Sleep disordered breathing –> hypoventilation in REM
- Desaturations, but normal CO2 - Hypoventilation throughout sleep
- CO2 >50
- Need to start NIV - Respiratory failure with high CO2 while awake
- CO2 >55
- Headache, exhaustion
Which of the following has NIV NOT been shown to improve in NMD? A. Episodes of chest infection B. QoL C. Blood gas abnormalities D. Survival E. Spirometry
E. Spirometry
- Increasing ventilation decreases CO2
- Increases survival - gains 5yrs
What’s the indicator to start investigating NMDs for consideration of NIV?
Abnormal pulmonary function tests –> start assessment by doing PSG
What are the indications for starting NIV in NMD
- Sx of chronic nocturnal hypoventilation or daytime respiratory failure/hypercapnoea
- -> I.e. hypoventilation during entire sleep, not just REM
1. Sleepiness
2. Fatigue/lethargy
3. Headaches
4. Increased night time waking - Recurrent chest infections –> preventing recurrent admissions
Approximate FVC when NMD pt starts hypoventilating throughout entire sleep
40%
Approximate FVC when NMD pt is in chronic respiratory failure
25%
Which is the best indicator of the need for NIV in NMDs? A. FVC <60% B. FEV1 <40% C. Nocturnal CO2 higher than awake CO2 D. Nocturnal CO2 >50mmHg E. Max mouth pressure <30cmH2O
C. Nocturnal CO2 higher than awake
D. Nocturnal CO2 >50mmHg
FVC predictors: <60%, 40% and 25%
- FVC <60%: predicts sleep disturbed breathing/REM hypoventilation
- FVC <40%: predicts nocturnal hypoventilation
- FVC <25%: predicts daytime hypercapnoea and chronic respiratory failure
- FVC <1L: 8% 5yr survival
What prolongs survival in NMD?
- Scoliosis repair
- Commencement of NIV
Other predictors of disease progression in NMD
- Cough
- Ineffective cough with cough peak flow <270L/min
= Vulnerable to resp failure with minor LRTI
- <160L/min: unable to clear own secretions - Mouth and Sniff Inspiratory Pressures (SNIP):
- MIP <30mmHg predicts SDB
- MIP <19mmHg predicts nocturnal hypoventilation
What is SNIP testing for?
- Inspiratory muscle strength (i.e. respiratory muscle function) in pts with neuromuscular disease, ineffective cough, dyspnoea, reduced vital capacity
- Monitors whether known respiratory muscle weakness has improved/stabilised/worsened
Ondine’s Curse
- PHOX2B gene repeat expansion - polyalanine repeats proportional to severity
- -> Normal = 20 alanines on both alleles
- -> Mild = 20/24 and 20/25
- -> Severe = 20/27 and 20/33
- Autonomic dysregulation and arrhythmias >27
- Neural crest tumours (e.g. neuroblastoma) >29
- Presents in newborns as:
1. Hypoventilation, monotonous RR and shallow resps in sleep and awake, apnoeas + cyanosis
2. Autonomic dysregulation
3. Altered development of neural crest cell structures (e.g. Hirschprung’s) or neural crest tumours
When is self ventilation better in Ondine’s Curse?
- Awake
- REM sleep due to cortical inputs
- Worst in N3 sleep (deep)
Respiratory findings in CCHS
- Absent or near absent CNS response to hypercarbia or hypoxia awake or asleep
- -> Absent arousal from sleep
- -> Absent perception of asphyxia - Markedly reduced tidal volume during sleep –> hypercarbia
Effects of hypoxic injury in CCHS
- Developmental delay from repeated hypoxic injury
- Low IQ
- -> Well-ventilated child can have normal IQ
Autonomic manifestations in CCHS
- Failure to mount fever during infection
2. Cardiac arrhythmias and sudden death
Light’s Criteria: Pleural effusion (transduate) vs Empyema
1. Pleural effusion
Appearance: clear
- Cell count: <1000
- Cell type: lymphocytes, monocytes
- LDH: <200
- Pleural:serum LDH: <0.6
- Protein >3g: uncommon
- Pleural:serum protein: <0.5
- Glucose: normal
- pH: normal
- Gram stain: negative
- Cholesterol: -
- Pleural:serum chol: <0.3
Light’s Criteria: Pleural effusion (transduate) vs Empyema
2. Empyma
Appearance: cloudy/purulent
- Cell count: >50,000
- Cell type: polymorphonuclear leukocytes
- LDH: >2/3 ULN for serum LDH
- Pleural:serum LDH: >0.6
- Protein >3g: common
- Pleural:serum protein: >0.5
- Glucose: low
- pH: low <7.10
- Gram stain: occasionally positive (less than 1/3)
- Cholesterol: >55
- Pleural:serum chol: >0.3
Management of empyema
- IV antibiotics (MC S. aureus and S. pneumo)
- Nutritional status: consider NG, monitor albumin - low due to protein loss into pleural space
- Chest tube drainage, if pleural fluid septae with loculations detected on USS - fibrinolytics
- Chest tube: large amt of fluid, compromised lung function, failure to respond to IVABs 48-72hrs, purulent - VATS - debridgement of fibrinous pyogenic material , break down loculations and drain pus
Fibrinolytics
- Only useful for loculations
- Streptokinase (higher risk of anaphylaxis) or urokinase
- -> SE: haemorrhage
- Does not: improve mortality, hospital stay, need for surgery, length of stay, reduce pus viscosity
- Does: breakdown loculations
VATS
Use of early VATS (<48hrs after admission) vs. late VATS (>48hrs) signficantly decreased length of hospitalisation
Reliable marker of pleural inflammation
LDH
Complications from empyema
- Staph: bronchopleural fistulas, pyopneumothorax
- Local: purulent pericarditis, pulmonary abscesses, peritonitis from extension, OM of ribs
- Effusion may organise into thick peel: restrict lung expansion, persistent fever, temporary scoliosis
Conditions predisposing to lung abscess
- Chronic aspiration e.g bulbar weakness, tracheo-oesophageal fistula, GORD, seizures
- FB aspiration
- Haematogenous seeding
- Pneumonia
- Immunodeficiencies
- Conditions with impaired mucociliary clearance
Anaerobic organisms causing lung abscess
Bacteroides spp.
Fusobacterium spp.
Peptostreptococcus spp.
Negative prognostic indicator for lung abscess
Presence of aerobic organisms esp secondary lung abscess
- Streptococcus spp., S. aureus, E. coli, K. pneumoniae, P. aeruginosa
- -> Have predilection on L side of lung
Pneumatocoele vs lung abscess
- Pneumatocoele:
- Complication of bacterial pneumonia
- Thin, smooth wall, localised air collection
- Cystic appearance with or without air-fluid level
- Resolves spontaneously - Lung abscess:
- Thick walled
- Low density centre progressing to air-fluid level
What can hasten the recovery and shorten course of IVABx in lung abscesses?
Early CT-guided percutaneous aspiration or drainage of abscess
Granulomatosis with polyangiitis
- Systemic vasculitis with necrotising granulomas
- Sinus, lungs, kidneys (necrotising glomerulonephritis)
- Epistaxis, purulent nasal discharge, sinusitis, haemoptysis with pulmonary vasculitis, non-productive cough, haematuria
- c-ANCA is 90% sens and spec; PR3-ANCA is absent in other granulomatous diseases
- Mx: cyclophosphamide +/- steroids
Goodpasture syndrome
- Antiglomerular basement membrane antibody
- Adolescent/young adult males
- Lung, kidneys
- Pulmonary haemosiderosis - abrupt haemoptysis or chronic, progressive dyspnoea, Fe deficiency anaemia, fatigue and recurrent cough. Restrictive pattern with pulmonary fibrosis
- Lung Sx precedes renal Cx - glomerulonephritis with linear deposition of IgG and C3 on basement membranes
- ANCA negative
- Mx: immunosuppressives, plasmapheresis
