Respiratory Flashcards
Allergic bronchopulmonary aspergillosis
ABPA
incidence: 2-15% of all CLD (2-32% asthmatics, 7% CF)
cause: exaggerated response of the immune system to aspergillus
pathophysiology: hypersensitivity response causing damage to lung parenchyma with subsequent bronchiectasis/fibrosis
clinical:
- acute/subacute deterioration in respiratory function
- fever, malaise, brown mucous plugs, haemoptysis, eosinophilia
- should be consider if deterioration does not respond to AB in 1 week
diagnosis: serum IgE>1000IU, positive skin test reactivity to aspergillus, positive IgE anti-aspergillus
CXR: tram line shadows due to ectatic bronchi, ring shadows, gloved finger shadows, branched tubular radiodecities extending from hilum
CT: proximal cylindrical bronchiectasis (UL>LL)
treatment: glucocorticoids 14 days and taper 3-6 months, itraconazole
Alveolar Gas Equation
PAO2= PIO2- oxygen consumed
PAO2= PIO2 - (PaCO2/RQ)
where PIO2= (PATM-PH2O)xFIO2
* PATM at sea level is 760
* PH2O= 47
*FIO2 RA is 0.21
Asthma
incidence: 15% children (1 in 6)
classification: 75% have infrequent episodic asthma
- see table
- intermittent infantile wheeze: no hx atopy
- persistent wheeze: hx atopy, later decrease lung function
pathophysiology:
- viral in 85% exacerbations
negative factors: ICU admission, poor compliance/control, interval sx, salbutamol use ++, exac by food
deaths: 33% mild, 33% no previous admission, 36% severe
Asthma
-medications-
Relievers
short acting beta2 agonist: salbutamol, terbutaline
inhaled CS/long beta2 agonist: budesonide
anticholinergic bronchodilators: ipratropium
theophylline: aminophylline (methylxanthine: PDE inhib, adenosine antagonist)
Preventers
inhaled CS: beclomethasone, budesonide, fluticasone
inhaled CS/long beta2 agonist: budesonide, fluticasone
leukotriene receptor antagonist: montelukast
cromones (mast cell stabilisers): sodium cromoglycate
Asthma
-preventer treatment-
Atelectasis
pathophysiology:
- more common in children (increased compliance/decreased collaterals)
- RML/RLL most common to collapse together (common supply)
types:
- Obstructive (most common) eg. asthma, CF
- Reabsorptive eg. pneumonia, NMD, post anaethetics
- Relaxation eg. pleural effusion, pneumothorax
- Compressive eg. space occupying lesion
diagnosis:
- RUL: triangle opacity, elevated right hilum, tenting diaphragm
- RML: (common) little impact, 10% volume
- RLL: prominent horizontal fissue, wedge opacity
management: fix cause, physio, IPPV?, mucolytics
Bordetella pertussis
organism: gram negative encapsulated coccobacillus
incidence: 20-40% school children with prolonged cough
incubation: 7-10 days
clinically 3 phases:
- Catarrhal (1-2wks): mild cough and coryza
- Paroxysmal (2-6wks): coughing attacks with inspiratory whoop and post-tussis vomiting
- Convalescent (wks-mths): gradual resolution
complications: apnoeas, seizures (2%), death (< 6 months)
atypical (young/vaccinated):
- infants: minimal catarrhal, feeding difficulties, cyanosis, apnoea, NO whoop
- vaccinated/older: milder, less apnoea/cyanosis
diagnosis: cough >14 days with paroxysms or whoop or vomits
treatment indicated if early, cough< 14 days, admission, complications
- clarithomycin (syrup), azithromycin (tablet)
contact treatment: aimed to decrease spread to <6 months
- same AB as above with DTPa
unimmunised contacts: exclude from school for 14 days OR after 5 days AB
pregnancy prophylaxis: At weeks 27-35 or immediately postpartum
Breathing mechanics
Pleural pressure resting= -5cm H20
Alveolar pressure: inspiration=-1cmH20 expiration=1cmH2O
Transpulmonary pressure= pleural-alveolar pressure
Compliance= change in vol./change in pressure (VIP)
Airway resistance=(8xlengthxviscosity)/(3.14radius4)
Bronchiectasis
definition: radiological evidence of bronchial dilation with chronic productive cough
causes:
- primary immune deficiencies: SCID, X-linked agammaglobulinaemia, CVID
- genetic defect: ciliary dyskinesia, CF
- other: aspiration syndrome, post infective, obstructive (FB, TB, tumour)
pathophysiology: neutrophilic inflammation cause dilated airways, mucous gland hyperplasia, loss of cilia, destruction of airway wall and tortuous bronchial vessels
clinical: chronic moist cough, dyspnoea, wheeze, clubbing
CXR: signet ring size (bronchi>vessel)
treatment: AB, physio, nutrition, exercise, mucolytics
Bronchiolitis obliterans
definition: rare chronic lung disease of bronchioles/small airways due to injury
pathophysiology: tissue repair with large amounts of granulation causing airway obstruction and obliteration
etiology:
- infection: adenovirus**, pertussis, mycoplasma, influenza, measles
- drugs: penicillamine (Cu chelator)
- AI: connective tissue disease, GVHD, lung transplant
clinical: cough, tachypnoea, cyanosis
diagnosis:
bronchography: obstruction of bronchioles
VQ: moth eaten appearance with matched defects
biopsy: confirms diagnosis
PFT: obstructive then restrictive
treatment: transplant
prognosis: some die within weeks, otherwise chronic disability
Carboxyhaemoglobin
pathophysiology: Hb contact CO forming stable compound preventing delivery of oxygen to body
- CO binds same site as O2 but 200x more strongly
- decreased ability to offload other Hb bound oxygen
- 15% bound myoglobin/cytochromes/NADPH impairing oxidation in mitochondria and can cause myocardial stunning
- also inactives cytochrome oxidase impairing peripheral oxygen use
- half life 4-6hours
source: combustion of carbon fuels
clinical: normal 3%
carbon monoxide poisoning
- lethargy, dizziness, LOC
treatment: oxygen, hyperbaric chamber
CPAM
(Congenital Pulmonary Airway Malformation)
incidence: 2/100,000 births
pathogenesis: imbalance cell proliferation/apoptosis in organogenesis
pathology:
- unilateral single lobe: usually lower lobe
- hamartomatous lesions of cystic and adenomatous elements arising from the tracheal, bronchial, bronchiolar or alveolar tissue
- can compromise growth of adjacent normal tissue
- blood supply from pulmonary circulation
type 1 (60-70%): thin-walled cysts 2-10cm in diameters
type 2 (15-20%): multiple 0.5-2cm cysts and solid areas that blend into adjacent tissue
type 3 (5-10%): very large and involve entire lobe
clinical:
- 2/3 diagnosed prenatally: can develop hydrops
- 1/4 symptomatic at birth: respiratory distress
diagnosis: CXR then CT at 6 weeks even if CXR normal
treatment: surgical
survival: >95%
Chlamydia pneumonia
clinical: mild disease common with wheeze/hyperactive airways
- extrapulmonary: meningoencephalitis, guillan-barre, reactive arthritis, mycocarditis
diagnosis: sputum
treatment: erythromycin <8yrs, doxycycline >8yrs
Chlamydia psittaci
-psittacosis-
transmission: birds
clinical: fever, headache, myalgia, dry cough, pulmonary sx
complications: respiratory failure, hepatitis, endocarditis, encephalitis
diagnosis:
- CXR: lobar changes
- CT: nodular changes with ground glass opaciites
- serum: Ab testing
treatment: doxycycline/tetracycline
Choanal atresia
incidence: 1/7000 girls>boys
definition: obliteration/blockage posterior nasal aperture
clinical:
- unilateral (2/3): unilateral nasal discharge/obstruction
- bilateral: upper airway obstruction, noisy breathing, cyanosis worse in feeding
diagnosis: catheter through nose then CT
associations: Treacher-Collins, CHARGE, heart/GU defects, VATER, Pfeiffer
Chronic suppurative lung disease
definition: chronic endobronchial suppuration with or without bronchial dilation
clinical: productive cough worse on waking, haemoptysis, FTT, RTI
Eosinophilic granulomatosis
(Churg Strauss)
pathophysiology: necrotising vasculitis small/medium arteries
onset: 20-30s with pulmonary opacities
clinical:
- chronic rhinosinusitis, asthma and peripheral blood eosinophilia
- asthma cardinal feature (90%)
- lung and skin (tender subcutaneous nodules) most commonly affected organs
- prodromal phase, eosinophilic phase then vasculitis phase
diagnosis: clinical with eosinophilia >5000, ANCA +ve (60%)
treatment: systemic GC, cyclosphosphamide
Community acquired pneumonia
- pathogens-
Neonates:
<1 month: GBS, E.coli, Listeria, CMV, HSV
1-3 months: viral, S.pneumoniae, afebrile pneumonitis, S.aureus
Children:
3months-5 years: viral, S.pneumoniae, S.aureus
>5years: viral, Mycoplasma, S.pneumoniae, Chlamydia pneumoniae
Community acquired pneumonia
-lobar versus bronchopneumonia-
lobar: large portion of entire lobar
- usually strep pneumonia or klebsiella in young healthy people
- pathology: congestion, hepatisation and resolution
bronchopneumonia: centred on bronchi and surrounding alveoli
- wider variety or organisms: staph, strep, H.influenza, P.aeruginosa
- in individuals with commorbidities
- pathology: diffuse areas of acute exudate may resolve with fibrous scarring
Cough
definition:
acute: < 3 weeks
chronic:> 4 weeks
classification:
non-specific: no abnormal findings on CXR/PFTs
post viral: pre-school, paroxysmal cough night>day, trigger URTI, lasts 2-4 wks, NO wheeze/SOB
protracted bronchitis: prolonged wet cough <5yrs, trigger URTI, well child
psychogenic: adolescent F>M, throat clearing, ABSENT night, URTI
treatment: reassurance, reevaluation, trial bronchodilators if wheeze
- NO antitussives: assoc deaths
Cystic Fibrosis
- genetics-
incidence: 1/2,500
genetics: single gene chromosome 7 encoding CFTR (CF transmembrane conductance regulator)
- ABC (ATP binding cassette) family of proteins
- regulated chloride channel: phosphorylation R domain and presence of ATP
mutations: over 1300 identified
- delta F508: 70% mutations in caucasians
5 classes of mutations (1-3 more severe)
Class I: defective protein production
- premature termination mRNA with absent CFTR
Class II (included delta F508): defective protein processing
- abnormal post-translation processing so not transported to right location
Class III: defective regulation
- altered ATP response with decreased Cl channel activity
- response to CFTR modulators (ivacaftor)
Class IV: defective conduction
- reduced rate of ion flow and duration of opening
Class V: reduced amounts of CFTR
- altered stability CFTR protein or mRNA
gene modifiers: account for difference in phenotype with genotypes
- eg. TGF-beta 1, MBL
incomplete phenotype: 10% mild phenotype or limited to one organ
Cystic fibrosis
-clinical-
pulmonary:
- features: clubbing, barrel chest, anorexia, malaise
- airway hypersensitivity: 50% wheeze, 50% respond SABA
- complications: pneumothorax, haemoptysis
- CXR: hyperinflation, prominent vascular markings UL>LL, bronchiectasis, cysts, peribronchial cuffing, tram tracking
sinus: panopacification of sinuses
pancreatic:
- incidence: 2/3 pancreatic insufficiency
- clinical: FTT, stetorrhoea, fat soluble vitamin deficiency
- treatment: enzyme replacements, ADEK
- complications: pancreatitis 10%, CF DM (20% by 20yrs)
GIT:
- meconium ileus: 90% babies
- distal ileal obstruction: 15% adults
- rectal prolapse rare
- GOR: transient relaxation LOS, increased abdominal pressure
reproduction:
- males: >95% infertile due to sperm transport failure (absent vas deferens)
- females: less fertile due to malaborption/thick cervical mucous
bones: decreased mineral density
renal: nephrolithiasis/nephocalcinosis due to enteric hyperoxaluria/hypercitraturia
DVT: often in presence CVC
Cystic fibrosis
-diagnosis-
Newborn screen (3 steps): 1. IRT, 2. Gene testing, 3. Sweat Cl
NBST: tests for immunoreactive trypsinogent (IRT)
- 80% sensitivity
Sweat chloride test: abnormal >60mmol/L
Screening asymptomatic individuals:
- partners known carriers
- family hx CF
- Ashkenazi Jews
Cystic fibrosis
-lung transplant-
indications:
- FEV1<30% or rapidly declining
- increasing exacerbations
- recurrent/refractory pneumothoraces
- recurrent haemoptysis not managed embolisation
contraindications: B.cepacia, respiratory failure/intubation, symptomatic, osteoporosis
prognosis: better outcome than other indications
- 5yr survival 65%
Cystic fibrosis
-organisms-
S.aureus 64% (most common)
- MSSA 52%, MRSA 19% (assoc decline FEV1)
- airway inflammation additive effect with P.aeruginosa
Pseudomonas
- hypoventilation/hypoxia which promotes biofilm and defect CFTR allow binding
- assoc decline FEV1/survival
- conversion of P.aeruginosa to mucoid phenotype worse prognosis
Burkholderia cepacia 3%
- accelarated decline PFT/survival
- highly resistant to multiple AB
- lung transplant in infected assoc recurrent infection (CI)
- treatment: bactrim, doxycycline, ceftazidime, meropenem
Haemophilus influenzae 20-30%
Cystic fibrosis
-pathophysiology-
pathophysiology:
pulmonary
defect: inability to secrete NaCl/water causes thick secretions and chronic infections and defects in FA metabolism increase arachidonic acid causing inflammation
colonisation: S.aureus, P.aeruginosa, Burkholderia cepacia, H.influenzae, Stenotrophomonas maltophilia, Achromobacter, Non TB mycoplasma, Aspergillus
progression: chronic infection/neutrophils produce elastase and cause tissue destruction with air trapping/bronchiolitis/bronchitis/bronchiectasis
GIT
- impaired bile/pancreatic secretions with maldigestion/malabsorption
- CF related DM
- intestinal obstruction/intussusception/rectal prolapse
skin
- decreased NaCl absorption from skin
Flow-volume curve
obstructive: scooping of descending limb of curve on expiration only
restrictive: narrow based curve on inspiration/expiration
variable intrathoracic obstruction: expiratory defect
- reduced FEF50%/FIF50%
- eg. tracheomalacia, bronchogenic cysts, tumour
variable extrathoracic obstruction: inspiratory defect
- elevated FEF50%/FIF50%
- eg. laryngomalacia, tracheomalacia, vocal cord defect
fixed upper airway obstruction: reduced insp/exp flow
- FEF50%/FIF50%=1
- eg. tracheal stenosis, goitre
Laryngomalacia
incidence: most common cause laryngomalacia 50-75%
sex: M>F 3:1
assoc other pathology 30%: tracheomalacia, subglottic stenosis, VC palsy
pathophysiology: surrounding structural malformation
- 50% large floppy arytenoids, 25% floppy epiglottis, 25% short aryepiglottic folds
- prolapse over larynx during inspiration
clinical: stridor 2weeks- 18months, abnormal voice, resp distress, poor feeding, FTT
- causes GORD due to increased intrathoracic pressure to overcome obstruction
investigation: fluoroscopy, laryngoscopy/bronchoscopy
management:
- 99% conservation
- surgery if severe
Lung abscess
pathophysiology: necrosis of pulmonary parenchyma by infection
causes: aspiration pneumonia, post tricuspid valve endocarditis (S.aureus), Lemierre’s syndrome, pharyngitis
organisms:
- usually anaerobes from mouth: peptostreptococcus, prevotella, bacteroides, fusobacterium
- others: S.aureus, K.pneumonia, nocardia, fungi
clinical: indolent symptoms weeks-months
CXR: infiltrates with cavity +/- ring enhancement
diagnosis: transtracheal/bronchoscopic aspirates (sputum contaminated)
treatment: IV AB
Lung volumes
Lymphocytic interstitial pneumonitis
incidence: most common form paediatric ILD
pathogenesis: cause unknown ?EBV
2 patterns:
perinatal HIV: 25-40% children by 2-3yrs
- insidious onset cough, dyspnoea, clubbing
- LN, HSM, salivary gland enlargement
- hypergammaglobulinaemia
- can spontaneously resolve or progress to respiratory failure
others: idiopathic, AI associated
- tachypnoea, cough, respiratory infections, crepitations
- LN rare
diagnosis:
- biopsy
- CXR: diffuse reticulonodular pattern with hilar adenopathy, ground glass
PFTs: restrictive
treatment: steriods, hydroxychloroquinolone
prognosis: high long term mortality
Mixed obstructive/restrictive
diagnosis: FEV1 out of proportion to decreasd FEV1/FVC
Mycoplasma pneumonia
incubation: 3 weeks
incidence: 50% pneumonia in adolescence
clinical: headache, malaise, low grade temp, resp sx, pharyngitis
- extrapulmonary: haemolysis, rash, CNS involvement (transverse myositis, PN), GI, polyarthritis
associations: common in HIV
diagnosis:
- serum: haemolysis, neutrophilia, elevated titres (7-9 days)
CXR: peribronchial pneumonia with areas of atelectasis and interstitial infiltration
- pleural effusion 20%
Parapneumonic effusion/empyema
incidence: 5-10% all children with pneumonia
organisms: S.pneumonia, S.aureus, mycoplasma (20%), viral (10%)
pathophysiology: collection of pus in the pleural cavity
- 3 stages: exudative, fibrinopurulent, organization
clinical:
- as for pneumonia with dullness to percussion, fever, malaise, chest pain
- consider in anyone febrile or unwell post IVAB
complications: bronchopleural fistula, pyo-pneumothorax
CXR: white out +/- mediastinal shift
US: to confirm if loculated or simple
diagnosis: fluid (MCS, exudate vs transudate)
treatment:
- small <5 days: IVAB
- large/distress/>5 days: thoracocentesis or chest drain
- persistent: VATS, chest tube
Pneumocystis jirovecci pneumonia
clinical: insidious onset fever (80-100%), cough, dyspnoea, crepitations, HSM
- also weight loss, chills, fatigue
CXR: diffuse alveolar infiltrates, pleural effusions
Primary ciliary dyskinesia
incidence: 1/10,000, M=F
definition: congenital impairment of mucociliary clearance
pathophysiology: defect in airway cilia causing immotility/aplasia
- deletion dynein (commonest), absence radial spokes, abscent central tubule
- defect in nodal cilia controlling normal position of heart/viscera
genetics: AR, heterogenous, defective central cilia, flagella, matrix etc.
clinical: cough/rhinitis/sinusitis +/- nasal polyps/agenesis frontal sinus
- pulmonary: URTIs, chronic cough, wheeze, obstruction
- rhinosinusitis: nasal congestion, polyposis
- otitis: defective ciliary function middle ear causing recurrent OM
- situs inversus: 50% PCD
- fertility: males immotile sperm, women<50% change pregnancy
diagnosis: nasal nitric oxide, measure mucociliary clearance, nasal/bronchial brushings, EM (absence dynein arms)
monitoring: PFTs, CXR, HRCT
management: physio, mucolytics, AB, vaccinations, sinus surgery, lung transplant
prognosis: slower decline than CF
Pulmonary bronchogenic cysts
incidence: most common LRT malformation
pathogenesis: arise from anomalous budding of foregut during development at any part of the tracheobronchial tree
clinical: infants with rapidly enlarging cysts may become symptomatic
- more commonly present 2nd decade with coughing, wheeze, pneumonia
diagnosis:
- CXR: round water-density mass
- CT: marginated cystic mediastinal mass with water attenuation
management: surgical excision
Pulmonary Hypoplasia
pathogenesis: failure of lobe or lung to develop
imaging: mimics lobectomy
associations: spinal abnormalities
Pulse oximetry
Falsely high: carboxyhb, methb, sick cell
Falsely low: hypoperfusion, anaemia, venous congestion
Left shift (increased binding):
- fetal Hb, low H+/CO2/temp/2,3 BPG
Right shift (decreased binding):
- high H+/CO2/temp/2,3 BPG
Respiratory function in achondroplasia
pathophysiology: abnormal development base of skull forming small foramen magnum that can compress cervicomedullary region causing apnoeas
clinical: apnoea, cyanosis, feeding issues, quadriparesis, death
Spirometry
FEV1: most reproducible
FEV25-75 (MMEFR): most accurate for small airway obstruction but variability
PEFR: monitor disease progression
Poor effort: usually problem with sustaining adequate exp
Variation: require 3 attempts within 5% of each other
Staphylococcal pneumonia
clinical: acute and rapid course
CXR:
- early illness: lobar changes with pleural effusions
- late illness: wides opacifications, large pleural effusions, displaced intrathoracic structures, abscesses, airleaks (highly specific)
Subglottic stenosis
incidence: 2nd most common cause neonatal stridor
pathophysiology:
- primary: congenital
- secondary: intubation, silent GOR, diptheria, burns
clinical: biphasic/inspiratory stridor
investigation: laryngoscopy
management: improves with age but surgery may be required
