Resp/ENT/Sleep Flashcards
Definition of chronic cough
Ddx
persistence of cough >4 weeks
Most common 3:
- Protracted bacterial bronchitis
- Bronchiectasis
- Asthma
Aspiration
Atypical infx
Inhaled foreign body
Post viral
ILD
Cardiac disease
Ear disease
Oesophageal disease
Medications
Somatic/habit cough
- What is protracted bacterial bronchitis
- What are the most common bacteria found in these cases?
- What should you be suspicious of if the cough doesn’t respond to 4 weeks abx?
- Cough lasting >4 weeks that is WET in nature with response to 2 weeks abx tx (ADF) with no other features to indicate another cause
- H. influenzae, Moraxella catarralis, Strep pneumonia
- Bronchiectasis
Asthma management step wise approach
- Reliever (salbutamol) PRN
- low dose ICS preventer (eg fluticasone, budesonide, ciclesonide) or montelukast or cromeo
- higher dose ICS OR low dose ICS plus montelukast OR LABA plus low dose ICS
- Refer resp physician
Wait 4 weeks after starting ICS or cromones to assess for sx resolution and 2 weeks after montelukast before stepping up
Bronchiectasis
Definition
Adults vs children
ADULT DEFINITION
Irreversible dilatation of one or more bronchi (bronchi larger than accompanying blood vessel) w failure of bronchi to taper in periphery of lung
Bronchoarterial ratio >1
Radiological diagnosis - seen on CT.
CHILDREN
- Reversible with early treatment
- Bronchoarterial ratio >0.8
- Bronchiole normal tubular -> cyclindrical/follicular (dilated) = ‘tree in bud appearance’ on CT -> varicose -> cystic
- Up to cylindrical point it is reversible in children but beyond this it is not.
FEATURES
- CT changes + chronic wet/productive cough
- Frequent resp exacerbations
Spectrum of chronic suppurative lung disease
Underlying pathogenesis
Mildest end of spectrum
Protracted bacterial bronchitis (can occur in healthy well children)
-> repeated infections ->
Chronic suppurative lung disease (CT scans normal)
->
Radiological bronchiectasis
Pathophys:
- Insult to lung (infection) -> inflammatory response with cytokines, nests, elastase and bacterial byproducts -> impairs lungs normal mucociliary clearance -> incr mucus production/decr clearance -> blocks small airways -> incr propensity for microbial colonisation -> bacteria cause more inflammation -> cycle continues
Treatment bronchiectasis
Antibiotics
Maximise airway clearance (chest PT)
Diet optimisation/nutrition
Minimise environmental pollutants (smoking)
Exercise
Classic bugs that cause infection in children with CF bronchiectasis
PSA
Staph aureus
Non typable haemophilis influenza
- what is its mode of pathogenicity?
- what condition has increased susceptibility to this bug?
Secretes biofilm (ECM protecting against host immune response and abx, helping to prolong existence in airways)
Incr susceptibility in PBB and CF
Worsens inflammation cycle
Abx therapy (abx + duration) in exacerbation of bronchiectasis
- mild-mod
- vs mod-severe
Initial empiric tx
Mild-mod: PO Augmentin DF (amoxicillin) or Azithromycin. Cipro if PSA in recent culture.
Mod-Severe: IV ampicillin, cefotazime, ceftriaxone. Tazocin or ceftaz and tobra if PSA in recent cultures.
Minimum 10-14 days or cough free for 2 days
Start with oral abx, if not effective then will need IV abx
Indication for long term abx in bronchectasis
3+ exacerbations in previous 12 months
Aims for suppression rather than eradication
Decr exac and hospitalisation rate BUT risk of resistance
Benefits of macrolides in CF
Risks
Example of a macrolide
ex: Azithromycin
BENEFITS
Antimicrobial and anti-inflammatory
Routinely used in CF
Inhibits biofilms (PSA, NTHI)
Decr exac rate
RISKS
1. BUT macrolide resistance (staph aureus specifically) and risk of GI side effects
Exclude NTM prior to starting tx to avoid induction of resistance to macrolides
2. QTc prolongation (need to perform baseline ECG prior to starting tx)
What conditions have evidence for inhaled abx
CF
Non-CF BE with PSA only
Features of salbutamol toxicity
what do u see on blood gas
Tremor, tachycardia, tachypnoea Metabolic acidosis (lactate high)
Pathophys of asthma
Two major components to airway obstruction
i. Chronic Airway inflammation
ii. Reactive airways = bronchoconstriction and airway hyperresponsivness
Pathology
i. Smooth muscle hyperplasia of bronchial and bronchiolar walls
ii. Thick tenacious mucous plugs
iii. Thickened BM
iv. Mucosal edema
v. Eosinophilia of the submucosa and secretions
vi. Increased mast cells in smooth muscle
Results in
Mucosal edema, bronchospasm and mucus plugging -> airflow obstruction -> increased resistance to airflow -> decreased ability to expel air -> hyperinflation
Explain VQ mismatch in asthma
Explain how ventolin can affect this
Airway inflammation and resulting airflow obstruction is NOT uniform throughout the tracheobronchial tree – distribution of inspired air is uneven, uneven circulation to the alveoli, uneven ventilation (VQ mismatch)
Ventolin
Can cause a paradoxical worsening in VQ mismatch (and thus spO2) early in treatment (first 30min). May need supplemental O2 for this short period of time.
Innervation of bronchial smooth muscle
Parasympathetic nervous system -> bronchoconstriction (M3 receptors) = cholinergic
Sympathetic nervous system -> bronchodilation (B2 receptors) = beta adrenergic
Spirometry findings in asthma
Define the values of abnormality for each
Airway obstruction defined as
- FEV1 <80% (predicted)
- FEV1/FVC <75% (varies with age)
- MMEF 25-75 <67% (predicted)
Bronchodilator reversibility = improvement of FEV1 of 12% in absolute values
How many actuations in a ventolin inhaler?
200
Asthma severity levels
Infrequent intermittent asthma (Symptom-free for at least 6 weeks at a time (flare-ups up to once every 6 weeks on average but no symptoms between flare-ups)
Frequent intermittent asthma (Flare-ups more than once every 6 weeks on average but no symptoms between flare-ups, normal exam and PFT between flares)
Persistent asthma
• Daytime symptoms >2 days/week
• Nocturnal symptoms >1 night/week
• Attacks <6 weeks apart
• May have abnormal lung function
• Multiple presentations to ED
Montelukast
Mechanism of action
Age cut off
Indication
Mechanism of action = LT receptor antagonist
Can be used in children >= 2 years of age
Main indication = alternative to ICS in children with Frequent intermittent asthma or Mild persistent asthma
Trialed first IF:
- The child is unable to use inhaled therapy
- The child also has significant allergic rhinitis
- The parents have strong concerns about adverse effects of ICS
Risk of LABA use and limitations of use in asthma
LABA also results in phosphorylation and internalisation of beta 2 receptor – results in increased mortality
No evidence for children <5 years
Should not be started when child is clinically unwell and should not be used as monotherpay (always with ICS)
Mepolizumab
Omalizumab
Mepo
i. Humanised anti-IgE Monoclonal Ab
ii. Prevents binding of free IgE to high affinity receptors on basophils and mast cells
iii. Approved for moderate to severe allergic asthma in children 12 years or older
iv. Delivered by SC every 2-4 weeks
Omal
i. An add-on maintenance therapy for severe asthma with an eosinophilic phenotype in patients age 12 years and older
ii. Anti-IL-5 Mab injected SC every 4 weeks
iii. Decreases the production an survival of eosinophils, a major inflammatory cell involved in asthma pathogenesis
Diagnosis of CF
New born screening test looks for elevated IRT (‘immunoreactive trypsinogen’ produced by stressed pancreas)
- screens for the most common 12 genotypes in the state although over 900 exist
Gold standard is the ‘Sweat Test’ (elevated Cl, Na, sweat weight)
However there is a risk of false negatives
Any child w evidence of pancreatic insufficiency (Steattorrhoea, fat globules or crystals in stool) +/- FTT should be considered for CF
CF gene (most common)
Delta 508 most common (90% of patients in australia)
Pathophys CF
Mutation in the CF transmembrane regulator gene (CFTR transports Cl across the cell wall)
Results in abnormal CFTR protein processing
- Impaired Cl secretion from airway epithelial cell
- > incr Na and H20 into cell resulting -> causes dehydration of airway surface liquid of cell resulting in THICK mucous and impaired clearance of mucous - Impaired HCO3 secretion from cell -> airway surface liquid pH becomes more acidic -> inhibits antimicrobial fxn -> impaired killing of pathogenic bacteria entering lung
Cycle of CFTR dysfunction -> viscous secretions -> infection and inflammation -> lung damage and abnormal lung function
Ultimately results in death due to resp failure
Classic bugs causing infection in CF
Most common early on:
- S aureus
- Non typable haemophilus influenza
Most common later on (adolescence):
- Pseudomonas is a bad prognostic indicator (becomes more predominant older you get)
Uncommon
- MRSA (if present in resp tract, almost pathopneumonic of CF)
- Steno maltophilia
- B cepacia least common but can cause very aggressive lung disease and death in some children
Need abx prophylaxis for first 2 years of life to prevent colonisation especially w Staph
ABPA in CF
Prevalence
What is the pathophys
Diagnostic features
Treatment
Risk to CF patients (1-15% prevalence)
Type 1 Hypersensitivity reaction - Exaggerated TH2 CD4+ immune response to aspergillus
Diagnosis requires 5 features
- Acute or subacute clinical deterioration (BROWN sputum characteristic) often w wheeze
- Serum IgE >1000 IU/ml
- Immediate cutaneous reactivity to Aspergillus on RAST skin prick
- Pos Aspergillus précipitans IgG
- New or recent abnormalities on chest XR or CT (pulmonary infiltrates)
- Aspergillus in sputum culture
Treatment
- Oral steroids (or pulse IV methyl predictive if noncompliant)
- Oral antifungals (itraconazole)
Abx against pseudomonas in CF
Tobramycin (IV or nebulised)
Ciprofloxacin
Cayston (nebulised Aztreonam)
2 month initial eradication course (2 weeks IV Tobra then 2 months nebulised Tobra)
If unsuccessful, for intermittent cycles of abx to try to lessen bacterial load
Indication, effect and MOA of azithromycin in CF patients
Indication: patients with chronic PSA infection -> used as a three times a week dosing regime to stabilise chronic lung disease in CF pts w PSA
Effects:
- Improvement in lung function
- reduced pulmonary exacerbations (PEx)
- improvement in nutritional status
MOA:
Azithromycin suppresses alginate production (PSA produces a gene that codes for alginate when it progresses from acute to chronic infection)
Anti neutrophilic and anti inflammatory cytokine production
What is the purpose of cross infection prevention practises in CF patients?
Prevent cross infection of NTM between carriers
No 2 CF patients should ever come into contact w each other
Mucolytic therapies in CF
Examples
Effect on disease
Pulmozyme (dornase alpha), neb Hypertonic saline (6%), neb Inhaled mannitol (dry powder delivery device)
Pulmozyme reduces number of resp exacerbations
Shown to improve lung function with patients with severe lung disease but in patients with normal lung function their lung function continued to decline
ALL:
Get a transient increase in FEV1 then stability in lung function
Not disease modifying agents
Ivacaftor
- What is it used for
- What does it do
- For class 3 (G551D) and 4 mutations in CF pts over age of 2
- *Potentiator*
- Disease modifying agent: partially corrects the channel defect allowing Cl transport
- Initial FEV1 increase then stability
- Decr in sweat chloride to almost non CF levels
- Improvement in nutrition
What disease modifying agents can you use in delta 508 homozygous (class 2) CF patients
What effects do these have on CF
Orkambi in >2yo (ivacaftor and lumicaftor)
- *corrector*
- For Class 2 mutations (delta 508 homozygous) in CF in pts >12yo
- -> improves protein folding and incr trafficking to cell surface
- 3-4% incr in LFT and 34% decr in pulmonary exacerbations
- No incr in nutrition or improvement in QOL
Symdeko (Tezacaftor + ivacaftor) in >5yo
- *corrector*
- Incr FEV1, reduce pulm exacerbations
Trikafta (elexacaftor, texacantor and ivacaftor)
- *amplifier*
- improved/partially corrected protein folding and Cl passage through channel
- reduces exacerbations, sweat Cl and QOL
- improves FEV1 and BMI (incr)
CF complications
Pancreatic insufficiency
fat soluble vitamin deficiency
Malabsorption
Growth failure/delay/pubertal delay
CF-related diabetes (yearly OGTT and HBA1C > 10yo to detect this). Signs incl reduction in weight and RFT in 2 yrs leading up to diagnosis. Assoc w reduction in life expectancy.
Cancer of small bowel, colon, biliary tract (NOT stomach or rectum)
C diff
Crohns disease
Osteoporosis (Dexa scans yearly over age of 10 to detect this) - sec to malabsorption of vit D, Ca
Infertility (95% men infertile)
CF related liver disease (starts w mild transaminitis -> progress to cirrhosis and portal HTN). can start URSO to improve bile drainage.
CF arthropathy
Pseudo-bartters syndrome (metabolic alkalosis w low K and Na and dehydration)
Anxiety and depression
ChILD
Definition
Presentation
Remodelling of lung interstitium and distal airways leading to abnormal gas exchange
Presents w 3/4 of the following
- Resp sx (cough, SOB, exercise tolerance)
- signs (tachypnoea, creps, clubbing, FTT, resp failure, incr WOB)
- hypoxia
- diffuse abnormalities on cxr/ct
Tachypnoea and hypoxia soon after birth
CT and biopsy below
Diagnosis? Tx?
Pulmonary interstitial glycogenosis
Type of congenital ILD
Histological ddx from lung biopsy
- round glycogen laiden mesenchymal cell
Tx w corticosteroids
- good long term outcome
Otherwise healthy infants during the first months to year of life with persistent tachypnea, crackles, and hypoxemia
Diagnosis?
Tx?
Neuroendocrine cell hyperplasia of infancy
Form of ILD - histological or radiological diagnosis
bx- neuroendocrine cell bodies in interstitium or bronchioles
HRCT - ground glass opacities in RML and lingual and air trapping in lower lobes
Tx is supportive
Pulmonary symptoms and hypoxemia tend to improve with time but may persist for years.
Surfactant dysfunction
Causes/genes
presentation
treatment
Genetic disorder
- 4 genetic defects
–> SPB: lethal neonatal RDS in homozygous individuals (AR)
–> SPC: AD, causes interstitial lung disease of varying severity and age of onset
–>ABCA3: lethal neonatal respiratory distress OR ILD in those surviving and presenting at older ages
P/w persistant tachypnoea, hypoxia
time of presentation depends on specific genetic defect
Treatment
- Chronic ventilation
- Lung transplant
- Corticosteroids, hydroxyquinolone, azithromycin
- nutritional supplementation due to incr WOB
Hypersensitivity pneumonitis
pathophys
presentation
ix
tx
IE ‘Extrinsic Akllergic Alveolitis’
Type 4 (and 3) HS reaction to inhaled organic particles -\> granuloma formation in the lungs
- Commonly to bird Ag ('Bird fancier or breeder's lung') and mould (Aspergillus; 'ABPA')
- also spray paints, glues, insecticides, dusts
Diagnosis - mean age 10yo
Presentation
- Acute (fever, cough, body aches)
- Subacute: chronic cough w weight loss, dyspnoea, fatigue
- Chronic - as above but with fibrosis (ILD) on CT
Ix
- CXR, CT (micronodules, ground glass opacities)
- BAL (lymphocyte infiltration, granulomas, multinucleated giant cell)
- Lung bx
- Ag challenge
Tx
- remove Ag
- corticosteroids
Connective tissue diseases with lung involvement
- pathophys
- causes
AutoAb to pulmonary parenchyma and vasculature
Nonspecific interstitial pneumonia most common histological finding
Lead to chILD
Causes
SLE
Systemic sclerosis
Dermatomyositis/polymyositis
Sjogrens syndrome
Ix for chILD
Pulse oximetry
Lung function (restrictive pattern, decr lung compliance and lung volumes)
- spirometry
- plethysmography
- DLCO
- Exercise testing
HRCT (findings depending on underlying cause of ChILD)
Genetic testing
Bronchoalveolar lavage (findings depending on underlying cause of ChILD)
Lung biopsy (gold standard)
Management of chILD
Supportive tx
Nutritional support
Immunisations
Lung PT, exercise programs
Avoid smoke exposure
Family support, education
+/- O2 support
+/- If pulm HTN -> sildenafil
+/- steroids for certain conditions
+/- steroid sparing agents /immunomodulators
+/- other specific tx
+/- lung transplant
What cells produce surfactant, when does this occur in-utero?
What does surfactant do?
Type II alveolar epithelial cells around 20-24 weeks, produce surfactant around 30 weeks gestation
Decr surface tension of the alveolar, facilitating expansion/keeping them patent.
Tracheomalacia
DEfinition
Sx
Absence/deficiency/malformation or softness or tracheal cartilage
Congenital/acquired, primary or secondary types
Sx
- intrathoracic compression = collapse on exp -> retained lower airway secretions, wheeze
- extrathoracic -> collapse on inspiration -> chronic brassy barking or seal-like cough, stridor
- Resp distress
Tracheo-oesohageal fisutla
what is it
how common is vacterl assoc
what are the diff types and which is most common?
complications
Defective separation of developing trachea from developing oesophagus
50% have VACTERL assoc
type C is most common ~ 85%
Complications
- tracheomalacia at level of fistula
- TOF-cough
- GORD, dysphagia
- Recurrent aspiration
- associated anomalies (laryngeal cleft, other fistulas_
Vascular rings
What is most common type?
Sx
Which syndrome is associated?
Most commonly double aortic arch completely encircles trachea and oesophagus, causing compression
Sx - stridor, resp distress, cough/wheeze, frequent infection, feeding difficulties/dysophagia/vomiting
Associated anomalies (often cardiac such as ASD, syndromes such as De George)
Congenital pulmonary airway malformations (CPAM)
What is it
What is it caused by
Where is the blood supply from
Clinical features
Mx
Cx
Multicystic masses of segmental lung tissue with abnormal bronchial proliferation. Non-functioning.
Due to abnormalities of branching morphogenesis of lung.
Blood supply is from pulmonary circulation
Clinical features
- Can be detected antenatally (ultrasound) with pressure effects with hydrops foetalis, mediastinal shift, pleural effusions, polyhydramnios
- present with neonatal distress
- can be asymptomatic (carries small risk of malignany)
Cx
- Cancer risk (Pleuropulmonary blastoma (PPB))- particularly common in type 4 CPAM
- Infection
- Pneumothorax
- Compression of mediastinal structures/mass effect -> resp distress
Mx - depends on sx or malignancy risk but often would be surgical excision
Pulmonary sequestration
What is it
Where is the blood supply from?
How is it classified
Mx
=’accessory lung’
Non functioning mass of lung tissue that doesn’t contribute to gas exchange (not communicating with normal tracheobronchial tree)
Predominantly affecting lower lobes (LLL 60% > RLL 40%)
Blood supply from systemic circulation
Classified based on pleural covering
- Intralobar (75%) - does not have its own pleura
- Extra lobar - has own pleura separating it from rest of lung; more commonly assoc w other congenital malformations (CDH most common, CPAM 15-20%, bronchogenic cysts, CHD)
Presentation
- in newborns as respiratory distress, cyanosis, or infection
- later in life with r_ecurrent pulmonary infections_ , persistant cough, exercise intolerance
- If large can present as CCF due to R -> L shunting
- Occasionally p/w pulm haemmhorage
Mx - surgical excision
Congenital lobar overinflation
What is it
Which areas of lung does it most commonly affect
Clinical presentation
Associations (1x)
Hyperinflation of 1 or more lobes, can cause compression of adj lung and mediastinal structures
Most often affects LUL followed by RUL
Presents postnatally with resp distress in neonatal period to first 6mo
Possible wheeze, decr breath sounds, mediastinal shift, hyper resonant percussion note
Assoc w cardiac disease (VSD, PDA, TOF) -> screening echo
Congenital diaphragmatic hernia
What is it
Presentation
Mx
Defect within the diaphragm where it doesn’t have an associated membranous sac so the abdominal contents can herniate into thorax, inhibiting lung development
Affects left side > right side (liver protective)
Scaphoid abdomen, funnel shaped chest
Contralateral deviation of trachea and mediastinum +/- collapse of contralateral lung
Resp distress
Stabilise baby
Surgical mx
Diaphragmatic eventration
What is it
Causes
Diagnosis
Mx
Abnormal elevation of all or part of diaphragmatic dome
(congenital - incomplete development of the muscular portion of the diaphragm or innervation)
Acquired (more common) - phrenic nerve injury from instrumental delivery, insertion of intercostal catheters or from cardiac surgery
Diagnosed by USS -> paradoxical movement of diaphragm
Mx - conservative. Only surgical mx if severe resp distress
Pectus Excavatum
What is it
How does it present
Mx
Depression of sternum and anterior chest
- due to defect in sternal cartilage OR overgrowth of costal cartilage of ribs
60% cases assoc with shallow chest
Presentation - generally asymptomatic. ?reduced exercise tolerance. Cosmetic concerns.
Mx - Conservative. Surgical for cosmetic concerns but is a big surgery!
Effects of scoliosis on respiration
Management options
Respiratory effects = restrictive lung disease
- Rigid thoracic cage not allowing full expansion
- Decr insp muscle strength
- Reduced lung growth
Mx
- Bracing
- Spinal implants/distraction devices (rods allowing for growth)
- Spinal fusion (for severe scoliosis in adolescents)
Pre op assessment prior to scoliosis surgery
Lung function (FVC)
Sleep study
Multidisciplinary clinic to optimise other issues (aspiration, constipation, medication rationalisation)
Establishment of pre-operative resp support (Bipap)
REM sleep
rapid eye movement
slow muscle tone
dulled airway reflex
irregular brathing and decr tidal volume
dreaming
More REM sleep in 2nd half of the night (more NREM, or lighter sleep, in the first 1/2 of the night)
What is sleep disordered breathing
Continuum from primary snoring (sleep study) to severe obstructive apnoea (OSA can be clinical diagnosis but severity stratification requires sleep study)
OSA
- Definition
- Causes
- Diagnosis
- Mx
Recurrent oropharyngeal upper airway collapse during sleep leading to multiple cycles of hypoxic episodes followed by blood reoxygenation. Often worse in REM sleep (reduced muscle tone)
Causes
- Adenotonsillar hypertrophy
- Chronic rhinitis/hayfever
- Laryngomalacia (<1)
- Obesity
- Anatomical
- Syndromes (T21, PWS, BWS, Pierre-Robin)
- Abnormal muscular tone (CP, hypotonia, muscular dystrophy)
- Mucopolysaccharoidosis, Achondroplasia
- *Diagnosis via**
- Overnight oximetry (good PPV, but poor NPV) -> look for clusters of desaturations assoc w rise in HR
- Polysomnography (sleep study)
- *Mx in children**
- *Mild**
- IN steroids (nasonex)
- Weight/allergy mx
- Positional
- Watchful waiting (CHAT study)
- Adenotonsillectomy if medical tx not successful
- *Severe**
- Adenotonsillectomy
- Turbinectomy, septoplasty, other jaw distracting surgeries
- CPAP
- Rarely tracheostomy
Indications for PSG in neonates
Periodic desats during sleep
ALTE w history of SDB
Sydromes w compromised airway
Quantification of impact of upper airway lesions (laryngomalacia)
Assess for residual OSA post-op if clinical concern
?Congenital hypoventilation syndrome
CPAP vs BIPAP
Continuous/constant raised pressure applied to airway
Pneumatic splint to upper airway
- maintains airway potency, prevents collapse and reduces insp work of breathing
BiPap
- application of 2 different pressures for inspiration (assists ventilation) and expiration (maintains airway patency)
- re-expands collapsed/poorly ventilated alveoli, decr WOB
- improves O2, decr CO2
- resets chemoreceptors
Nocturnal hypoventilation
Presentation
Risk factors
Children with NM disease are at risk (muscular dystrophies most at risk - peripheral >central neurological abnormalities)
IDENTIFIED VIA
- daytime hypercapnia
- nocturnal desaturation
Cx of Restrictive lung dsiease in patients w NM disease - reduced FVC
Starts with REM disordered breathing, then progresses to NREM and REM disordered breathing
Mx w BiPAP -> reduces morbidly, mortality
Congenital central hypoventilation syndrome
What is it
Genetic mutaiton involved
Presentation
Associated conditions
Mx
Cannot produce ventilatory response to hypercapnia. response to hypoxia is variable.
Rare autosomal dominant condition of primary alveolar hypoventilation (mutation PHOX2B gene at 4p12)
- all subjects heterozygous for a mutation
Typical presentation is
- in infancy with hypoventilation during sleep but normal when awake.
- NREM worse than REM.
- P/W Protracted RTIs and unable to be weaned from ventilator.
- Severe forms hypoventilate awake and asleep.
- Also incr risk during exercise as well.
Assoc - hirshsprungs, tumours of neural crest cell origin, arrhythmias etc
Mx - lifelong
- tracheostomy/IPV
- NIV
- Phrenic nerve/diaphragmatic pacing for severe forms
Monitoring
- 72 hr holter monitor
- echo
- formal neurocog assessment
- barium enema or rectal bx for those w hx constipation
- imaging/annual review for monitoring of neural crest tumours
What is minute volume?
Same as minute ventilation
TV x RR
Volume of gas inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a person’s lungs in one minute
Dead space
Anatomical
vs pathological
vs physiological
Anatomical dead space – air required to fill conducting airways not involved in gas exchange
i. Usually about 150ml
Pathological dead space – air not involved in gas exchange due to pathology
Physiological dead space = Anatomical + Pathological
i. Volume of gas that does NOT eliminate CO2
Alveolar ventilation
- definition
- formula
- how does this relate to CO2 concentration
= (TV – physiological dead space) x RR
Volume of atmospheric air entering alveoli
Concentration of CO2 in alveolar gas and arterial blood is INVERSELY related to the alveolar ventilation
Round pneumonia
- most common age group
- most common pathogen
- pathogenesis
Strep pneumonia
Age 5 most common (<8 majority)
Pathogenesis
- Inter-alveolar communication and collateral airways (pores of Kohn and canals of Lambert) develop as children age and allow air-drift between the parenchymal subsegments
- In adults, these allow lateral dissemination of infection throughout a lobe, leading to lobar pneumonia
- In children, where these have not developed, the limited spread of infection results in round pneumonia
Definition of pneumonia
What is complicated pneumonia?
Aetiology
CLINICAL diagnosis when there a signs of a lower respiratory tract infection + wheeze excluded
i. Presence of persistent or repetitive fever, cough and tachypnoea at rest
‘Complicated’ pneumonia = parapneumonic effusion, empyema, lung abscess or necrotising
What pathogens are associated with the following types of pneumonia?
- Lobar
- Bronchopneumonia
- Necrotising
- Caseating
- Interstitial and peribronchiolar
- HAP
- Immunocompromised
- Aspiration
- Lobar pneumonia = S. pneumoniae pneumonia.
- Bronchopneumonia = primary involvement of airways and surrounding interstitium -> Streptococcus pyogenes and Staphylococcus aureus pneumonia.
- Necrotizing pneumonia = associated with aspiration pneumonia and pneumonia resulting from S. pneumoniae, S. pyogenes, and S. aureus)
- Caseating granuloma = tuberculosis
- Interstitial and peribronchiolar with secondary parenchymal infiltration – typically occurs when a severe viral pneumonia is complicated by bacterial pneumonia
- Hospital acquired: GNR (Klebsiella pneumoniae, E.coli, Pseudomonas aeruginosa), S. aureus
* *(MRSA)** -
Immunocompromised pneumonia:
* *Klebsiella, Pneumoncystis jiroveci, M. tuberculosis, aspergillosis** - Aspiration pneumonia: Klebsiella, E.coli, S. aureus, gastric bacteria
Tx of pneumonia
Mild-mod
Severe
Progression desipite empirical abx
Admission is required for oxygenation, fluid therapy or moderate to severe work of breathing
Administer oxygen to maintain O2 saturations >92%
If giving NG or IV fluids limit to half or 2/3 maintenance
Antibiotics
-
Non-severe pneumonia
- Amoxicillin 30 mg/kg TDS
- IV benpen 60 mg/g Q6H – if unable to tolerate oral intake/vomiting -
Severe pneumonia
- IV ceftriaxone + flucloxacillin
- Consider IV vancomycin if MRSA suspected - Consider IV azithromycin if pneumonia progressing despite antimicrobial therapy (?atypical)
Indications for IV vanc in pneumonia
Concurrent skin infection due to MRSA
Indigenous or Torres Strait Islander
Necrotising pneumonia
Previous MRSA colonization)
How does Osteltamivir work?
When is this indicated?
- Neuraminidase inhibitor
- Blocks the function of viral neuraminidases of the influenza virus, by preventing its reproduction by budding from the host cell
- Consider for patients w complicated disease thought to be related to influenza or patients at high risk of complications (CHD, resp disease, immunosuppression)
- Use within 48 hrs of sx
- shortens duration of sx
Features of severe pneuonia
>/= 2 of
- severe resp distress
- severe hypoxaemia or cyanosis
- marked tachycardia
- altered mental state
OR empyema
Pleural fluid analysis, findings of empyema
- pH
- glucose
- LDH
- Protein
- serum protein ratio
- pH <7.0
- Glucose <40 mg/DL
- LDH >1000 IU
- Protein level > 3.0 g/dL
- Pleural fluid: serum protein ratio >0.5
Features of adenovirus infection
Can be asymptomatic
Acute respiratory distress = bronchiolitis, pneumonia
o May have features typical of bacterial disease (lobular infiltrates, high fever, parapneumonic effusions)
o Pharyngitis, coryza, sore throat, fever
Follicular conjunctivitis
o Pharyngoconjunctival fever = high temperature, pharyngitis, non-purulent conjunctivitis, lymphadenopathy
Gastrointestinal infection = diarrhoea, usually self-limiting
Haemorrhagic cystitis
Penicillin susceptibility iV vs oral
MIC (intermidiate)
IV
Sens – MIC <2; intermidiate 2-4 mcg/mL
NOTE use ceftriaxone if intermediate sensitivities
Oral
Sensitive if MIC <0.05; intermediate 0.05-1
Natural history of Tb in children vs adults (risk of progression to Tb disease)
- why do we treat latent disease in children?
Tb exposure -> 70-90% no infection vs 10-30% become infected
- Of those infected, in 90% Tb will remain dormant (not infectious, never develop Tb) vs 10% will develop active tb at some stage
NOTE the rate of Tb disease in children infected is INCREASED in younger children compared w adults
- This is why we treat latent infection in children (also because young children are at higher risk of extra-pull disease and have more years to potentially develop TB disease)
TB definitions:
Latent Tb infection
Tb disease
Uninfected
Latent - Asymptomatic but positive TST and normal CXR
Tb disease - Positive TST, symptomatic and/or abnormal CXR or with ACB or MTB cultured
Uninfected, TST negative and clinically well
hypersensitivity in children w Tb
- what type of HS?
- when does it occur
- how does it present
Type 4 HS
Occurs 3–8 wk after primary infection and may be heralded by (or may be asymptomatic):
- prolonged (‘Wallgren’s) fever
- formation of a visible primary complex on chest radiograph (CXR)
- hypersensitivity reactions such as erythema nodosum and tuberculin skin test (TST) conversion.
Inferferon I Release Assays in Tb
How do these work
Examples of such assays (2)
Advantages and disadvantages
Indications for IRA
Test for 2 or 3 Ag only:
ESAT-6, CFP10, TB7.7
- Quantiferon gold assay
- T cells from individuals infected w Tb become sensitised to ESAT-6 or CFP-10 Antigens
- When T cells encounter these Ag in vitro, they release cytokine IFN-gamma
- Assay measures the amount of IFN-gamma released - T-spot Tb
Positives
- Unaffected by BCG vaccine
- Unaffected by non-Tb mycobacteria (highly specific)
- Only one patient visit
- Simple yes/no - less subjectivity in terms of measuring
- not affected by ‘booster’
Disadvantages
- Expensive
- Requires blood test
- Technically more difficult than skin prick
Indications
- If family cannot return for TST reading
- If TST boosting likely to occur
- Taking blood for other reasons
- TST is borderline in lower risk ppl
- TST positive but past BCG vaccination
- If increased sensitivity required
Diagnosis of M Tb
Sx + CXR evidence + TST or IRA
Specimen
- sputum (limited in children as unable to expectorate, swallow sputum instead)
- gastric washings (NG)
- BAL
- Other tissue (LN, CSF, urine etc)
Stain - Zeil Neilson for AFB
Culture takes 6-8 weeks
PCR
Tb treatment regime
- Isoniazid
- Rifampicin
- Ryrazinmide
- Ethambutol (SE = optic neuritis -> eye check prior to starting this)
Generally well tolerated in kids w minimal SE
Use just Isoniazid for 6mo for latent Tb w post TST OR 6-12 weeks if recent exposure but Neg TST
Pulmonary Tb disease
- just 3 of the drugs for 6 months + contact tracing +/ pred if any bronchial obstruction
Military and extra-pulmonary Tb (spread via lymphatics/blood)
- 3 drugs for 2 mo then Isoniazid/rifampicin for 10 mo (total 12 mo)
- contact tracing
- Pred if Tb meningitis
Isolation until smear negative if disease present
Bronchogenic cyst
What is it
Where is it found
PResentation
Cx
CXR features
Tx
- Congenital malformations of the bronchial tree
- Arise from anomalous budding of the foregut during development (cannalicular stage, usually days 30-40)
- Most common = middle mediastinal
Presentation
o Typically present during the second decade of life with recurrent coughing, wheezing (which may simulate asthma), and pneumonia
o Newborns with rapidly enlarging central cysts can develop respiratory distress, cyanosis, and feeding difficulty (mass effect/compression)
CXR features
• Usually fluid filled (lined with ciliated epithelium, produces mucous) -> may have air fluid levels
• Usually appear as paratracheal soft-tissue density rounded structures
Cx
- Superinfection
- Haemmhorage
- Rapid grow in size
- Rare malignant transformation
Tx
- Some authors advocate surgical excision of all cysts given their tendency to become infected or rarely, to undergo malignant transformatio
Pneumocystis pneumonia (PJP)
RFs
Presentation
CXR features
Tx
RFs
- HIV infection (low CD4 cell count)
- post-transplant
- cancer (especially haematologic)
- Immunosuppressive medications (incl chemo, steroids)
Presentation - fever + dry cough (can be asymptomatic in pts w HIV)
CXR - bilateral diffuse interstitial infiltrates
Tx - Cotrimoxazole (trimethoprim-sulfamethoxazole)
What is the normal pulmonary circulation MAP?
what is pulm HTN defined as?
Pulmonary circulation MAP10mmHg
Pulm HTN > 25mmHg
What do your central and peripheral chemoreceptors respond to and where are they located?
Central chemoreceptors
i. Situated on ventral surface of medulla, surrounded by CSF
ii. Respond to CSF [H+]
iii. CSF [H+] is a reflection of CO2 in cerebral capillaries
iv. ↑ PaCO2 → ↑ CSF [H+] → ↑ ventilation
v. Do NOT respond to PaO2
Peripheral chemoreceptors
i. Situated in carotid bodies at bifurcation of common carotid arteries in neck, and aortic bodies around arch of aorta
ii. Rapid response
iii. Respond to ↓ PaO2, ↓ pH, ↑ PaCO2 → ↑ ventilation
VQ
ratio
What is the normal value?
VQmismatch
The ratio of ventilation (V) and perfusion (Q) in any lung unit
Normal = 0.8 (higher in upper portions of lung and lower at base)
- This is due to gravity reducing blood flow (perfusion) to lung areas above the heart
ii. In pathological conditions, blood flow or ventilation can be impaired resulting in mismatch
- Pneumonia, asthma, pulmonary oedema -> blocked airways/alveoli -> reduce ventilation -> reduce V/Q ratio (0=shunt)
- PE -> blocks blood vessels -> reduced perfusion -> incr V/Q (infinity = deadspace)
iii. In hypoxic conditions, pulmonary arteries constrict (opposite to systemic) and redirect to other alveoli to reduce perfusion
iv. In hypoxia, airways bronchodilate to increase ventilation
A-a gradient
How does fiO2 affect Aa gradient?
- The alveolar to arterial (A– oxygen gradient is a common measure of oxygenation (“A” denotes alveolar and “a” denotes arterial oxygenation)
- It is the difference between the amount of the oxygen in the alveoli (ie, the alveolar oxygen tension [PAO2]) and the amount of oxygen dissolved in the plasma (PaO2)
A-a oxygen gradient = PAO2 - PaO2
Higher fiO2 -> incr A-a gradient
Bacterial tracheitis
invasive soft tissue infection of bronchi
bacterial - staph aureus
preceding viral illness common
common <6yo
TOXIC presentation
essentially a ‘bacterial croup’
Complex airway - may need airway support.
IV vancomycin + cef
neb adrenaline for stridor
mechanism of ventolin
why do you get a paradoxical worsening
beta2 agonist - bronchodilator
initial hypoxaemia due to bronchospasm
signs of ventolin toxicity
tachycardia, tachypnoea and metabolic acidosis
Diagnosis of narcolepsy
Features
multiple sleep latency test (following normal sleep study)
Ft
- Sleepiness
- Cataplexy (sudden involuntary muscle weakness/’drop attacks’)
- Hallucinations before and for sleep
- Sleep paralysis
How might CF present/be picked up?
Majority picked up on NST
GI
- Mec ileus in ~15%
- DIOS
- adhesive small bowel obstruction
- GORD (often need fundoplication)
Respiratory: chronic productive cough, bronchiectasis, bronchitis, nasal polyps and sinusitis
Pancreatic insufficiency w fat soluble vitamin malabsorption and FTT
Pancreatitis
Dehydration w hyponatraemia
Infertility
where is the CFTR gene located
what is the mutation?
Large arm (q arm) of chromosome 7
Point mutation - Is a deletion (D) of Phenylalanine (‘F’)
CF gene mutation classes
Class (1-4 most common in caucasian populations; 1-3 are severe, 4-6 are milder forms)
1. No protein/defective protein synthesis (G542X, 2nd most common)
2. No traffic: misfolded protein -> not trafficked to cell surface (delta508del, most common)
3. No function: channel doesn’t open/gating defect (G551D, 3rd most common)
4-6. Some protein reaches the surface but
4 - less function (less Cl can move through channel due to structural problem)
5 - less protein produced
6 - less stable -> quick turnover of protein
G551D
Class 3 CF mutation
DF 508 del
Class 2 CFTR mutation
G542X
Class I CFTR mutation
Lung volume definitions
Vital capacity
Residual volume
tidal volume
FRC
Vital capacity : vol of air expired following maximal inspiratory breath/effort
residual volume: vol of air left in lungs following max insp/exp effort
*never reduced in any paediatric conditions*
Functional residual capacity: amt of air left in lungs following normal in/out breath (vital volume)
tidal volume: normal insp and exp volumes
What type of defect is this?
Obstructive
- PEF reduced
- FVC may be reduced
- Inspiratory curve normal
- Exp curve CONCAVE
what is this lung defect ?
suggestive of Restrictive lung disease
- FVC reduced and flow is higher than expected at a given lung volume
HOWEVER spirometry cannot strictly diagnose restrictive lung disease as cannot measure TLC (RV)
- normal VC rules out restrictive lung disease
- need body plesmysthography to measure TLC
what does this spirometry loop show? ddx?
Shows relative flattening of inspiratory loop
= variable (not fixed) EXTRA- thoracic (central or upper) airway obstruction (ex: laryngeal paralysis, vocal cord dysfuncton )
what does this show? ddx?
relative flattening of exp flow loop compared w insp flow loop
Variable (not fixed) INTRA-thoracic (central or upper) airway obstruction
ddx: tracheomalacia
what does this loop show? ddx?
flattening of insp and exp flow curves
FIXED central or upper airway obstruction
ddx tracheal stenosis, subglottic stenosis
what is the answer?
D)
obstruction w positive bronchilator response
what is the defect?
MIXED: definite obstruction and restriction cannot be ruled out without body plethysmography
what is the defect?
Could either be EARLY obstruction (normal FEV1/FVC but low FEF25-75%) or NORMAL
Negative BD response
Mx foreign body
Mx of croup
Diagnosis?
Sore throat
Fever
Neck pain and stiffness or torticollis
Fullness and redness of posterior pharyngeal wall; may be midline but can be laterally behind tonsil
Dysphagia and drooling
Retropharngeal abscess
lateral neck xray - paravertebral soft tissue swelling
Diagnosis?
Severe sore throat (often unilateral)
Hot potato/muffled voice
Trismus
Swollen posterior palate and tonsil, with medial displacement of tonsil and deviation of the uvula
Peritonsillar abscess (quinsy)
Causes
- Strep pyogenes, staph aureus, HIB, neiseria
- fusobacterium (anaerobic)
tx
- clindamycin or third gen cephalosporin (due to incr presence of beta lactamase producing oranisms resistant to penicilins)
- or amox + metronidazole
Diagnosis?
Inadequate Hib immunisation or immunocompromised
High fever and systemically unwell
Muffled voice
Hyperextension of neck
Dysphagia
Pooling of secretions, drooling
Absent cough
Low pitched expiratory stridor or stertor
Epiglottitis
Stages of lung development inutero
Embyronic
Pseudoglandular (from 4-6wks)
Cannalicular (from 16wk)
Saccular = surfactant (from 24 weeks)
Then alveolar from 36wk
Ddx biphasic stridor
FIXED obstruction/lesion needs to be at level of vocal cords or glottis
- Laryngeal web or laryngeal mass
- Subglottic haemangioma or subglottic stenosis
- B/L vocal cord paralysis (assoc w FTT, feeding difficulties)
- Other vocal cord lesion
Stertor
vs stridor
stertor - UPPER airway noise - noises produced nasal cavities, pharynx, tonsil
stridor
- middle airway noise (supra glottis, glottis, sub glottis)
Ddx inspiratory stridor
Obstruction at level of glottis/supra glottic/sub glottis
- Laryngomalacia
- Subglottic stenosis
- Other subglottic pathology (FB etc)
Ddx expiratory stridor/wheeze
Obstruction at level BELOW subglottis ie trachea or below
- tracheomalacia
- lower tracheal or bronchial foreign body
- vascular ring
weak or absent cry
biphasic stridor
may be present at birth
What’s the diagnosis?
What syndrome is this assoc with?
Laryngeal web
Could also be assoc w di george syndrome
Inspiratory stridor with FTT/feeding difficulties in child that improves when nursed prone
Vallecular or epiglottic cyst (between tongue and epiglottis)
- presents first 2 weeks of life
- Thyroglossal duct origin
- complete excision is required to obtain long lasting cure.
Tracheo and bronchomalacia - presentation
ix
tx
Excessive tracheal or bronchial collapsivity
Clinical presentation includes early-onset EXP stridor or fixed wheeze, recurrent infections, brassy cough and even near-death attacks, depending on the site and severity of the lesion.
ix - definitive/gold standard diagnosis w flexi bronchoscopy. radiological diagnosis w cxr or CT
Laryngeal web
what is it? why/how did it form
presentaiton
mx
A rare malformation consisting of a membrane-like structure that extends across the laryngeal lumen close to the level of the vocal cords
Due to incomplete recanulisation of larynx
Mostly seen between the vocal cords and has a concave posterior margin
presentation - airway obstruction (biphasic stridor) weak cry or aphonia from birth
mx - excision
what sort of hearing loss does a cholestatoma give?
Usually unilateral conductive hearing loss
mixed only if it goes into inner ear
Stages of sleep
NREM
- N1: transition to light sleep, easily roused
- N2: light sleep (K complexes and spindles)
- N3: deep sleep (slow wave sleep = delta waves), very hard to rouse, very regular breathing
REM: dream sleep. more common in 2nd half of night.
- decr tone
- rapid eye movements
- partial paralysis
- irregular breathing
- incr upper airway resistance
- decr tidal volume
- easily rousible
what stage of sleep?
N2 (NRem)
What stage of sleep?
REM
Can see no chin movements (paralysed) and eye movements in opposite directions
Presentation of bronchogenic cyst
Asymptomatic at birth, often incidental finding on CXR (mediastinal mass +/- Air fluid level on CXR)
Present when secondarily infected or they enlarge in size and compromise an adjacent airway
Tx: surgical resection
What is this cxr of?
what are the features?
Bronchiologitis
Features
- Hyperinflation (horizontal ribs, flattened diaphragm)
- patchy atelectasis (often RUL)
- peribronchial thickening
What is this condition based on the path shown?
What is the classic triad of features
Causes?
Pulmonary haemosiderosis: chronic diffuse alveolar haemorrhage
- brown lung tissue with haemosiderin laden macrophages
Triad
- Iron def anaemia (low Hb and haematocrit, low iron; incr relics and bilirubin)
- Haemoptysis
- CXR: multiple alveolar infiltrates
Causes
- primary; goodpastures
- secondary: vasculitis (SLE, Wegeners, HSP), HUS, PPHN
MOA Mepolizumab and Reslizumab in asthma
Bind to IL-5 (monoclonal Ab)
Inhibit proliferation/activation of eosinophils and B cells
MOA Benralizumab in asthma
monoclonal Ab that Binds IL-5 receptor
prevents activation/proliferation of eosinophils and B cells
Congenital lobar emphysema/overinflation
- Characterized by respiratory distress due to overexpansion of one or more pulmonary lobes of the histologically normal lung without the destruction of alveolar walls with compression of surrounding lung parenchyma
- The affected lobe is essentially non-functional because of overdistention and air trapping.
- LUL > RUL and RML > lober lobes
Aetiology
- 50% idiopathic/unknown
- Paucity/underdevelopment of cartilage in airways leading to airtrapping
Presentation
- Almost 50% of the patients are symptomatic at birth and another 50% present within the first six months of life
- Resp distress, wheezing, retractions, and cyanosis
- Difficulty in feeding
- history of chronic cough and recurrent respiratory infections
Ix
- CXR - overinflation, hyperlucency of affected lobe; may push mediastinal structures over to contralateral side due to mass effect
- CT is gold standard
Tx
- Conservative tx if mild-mod sx
- Lobectomy if severly sx-atic
