Respiratory Flashcards
(101 cards)
1
Q
Which organisms most commonly colonise the airways of adolescent patients with cystic fibrosis?
A
Staph aureus (50-80% and Pseudomonas aeruginosa (70-80%)
2
Q
Interaction between meconium and surfactant?
A
Meconium deactivates surfactant and may also inhibits surfactant synthesis
3
Q
Bronchiolitis obliterans overview
A
Occurs following an insult to the lower respiratory tract from infectious or non-infectious causes, leads to chronic obstructive lung disease from fibrosis of the lower airways
4
Q
Clinical features of bronchiolitis obliterans
A
Cough, fever, dyspnoea, cyanosis, chest pain, respiratory distress
Chronic symptoms include chronic cough, dyspnoea, sputum production and wheeze
5
Q
Spirometry findings in bronchiolitis obliterans?
A
Obstructive pattern, with variable response to inhaled bronchodilators
6
Q
Management of bronchiolitis obliterans
A
Supportive
Antibiotics for secondary infection
Supplemental oxygen if required
Corticosteroids
Immunomodulatory agents in post transplant patients
7
Q
Postnatal clinical presentation of CPAM?
A
Respiratory distress in the newborn period, due to pulmonary hypoplasia, mediastinal shift, spontaneous pneumothorax and/or pleural effusions secondary to hydrops
8
Q
Causes of acquired bronchiectasis
A
Arises from obstruction of the airways, due to repeated infections, inflammation, impacted mucus and poor ciliary clearance, leading to the airways being susceptible to colonisation
9
Q
Pathophysiology of bronchiectasis
A
A cycle of a chronic inflammatory response is triggered and leads to bronchiole remodelling (dilation and increased wall thickness).
The cycle of chronic infection, inflammation and difficulty clearing secretions propagates airway injury and remodelling
10
Q
Clinical features of bronchiectasis
A
Chronic cough with copious purulent sputum, crackles, wheeze, clubbing, anorexia, poor weight gain
11
Q
What is the main determinant of intrathoracic airway resistance in normal children?
A
Lung elastic recoil
12
Q
Best investigation to evaluate CPAM postnatally (if not visible on CXR?
A
High resolution CT of the chest
13
Q
After CF, what is the next most common disease affected by allergic bronchopulmonary aspergillosis?
A
Persistent asthma (1-2%)
14
Q
NAVA: with flow triggered ventilation and volume guarantee of 3ml/kg, what will occur if there is a decrease in the baby’s lung compliance?
A
If lung compliance decreases, the breaths will require a higher peak inspiratory pressure to be able to achieve the same volume
15
Q
CXR findings of subglottic narrowing and a ragged appearance of the trachea suggest?
A
Bacterial tracheitis
16
Q
Most common pathogens causing bacterial tracheitis
A
Staph aureus, haemophilus influenza and moraxella catarrhalis
17
Q
Physiological changes seen in bacterial tracheitis?
A
Obstructive airway disease due to the formation of a pseudomembrane, pus and mucosal sloughing
18
Q
‘Thumb print sign’ on lateral neck XR is suggestive of?
A
Epiglottitis
19
Q
The most common CF gene mutation is a result of?
A
The most common is change in F508, which is a codon deletion on the CFTR gene (class II defect)
Accounts for 70% of all mutations and results in severe disease
20
Q
What is the most likely morbidity for patients with moderate chronic upper airway obstruction?
A
Decrements of memory and attention (leading to poor school performance)
21
Q
Overview of subglottic haemangioma
A
Rare cause of stridor in children
Strongly associated with cutaneous haemangiomas
Usually present after the first few weeks of life due to development of symptoms with enlargement of the haemangioma
22
Q
Effect of carbon monoxide on the oxyhemoglobin dissociation curve?
A
Shifts to the left - further hypoxia as the Hb is unable to offload oxygen
23
Q
Overview of toxic effects of carbon monoxide
A
Displaces oxygen from Hb binding site, decreasing O2 carrying capacity of the blood:
- CO has 250 fold increased affinity for Hb than oxygen
- CO shifts dissociation curve to the left
- reacts with myoglobin to further impair oxygen uptake by reducing facilitated diffusion of oxygen into muscle
24
Q
Presentation of pertussis in older children?
A
Prolonged, persistent, paroxysmal cough often confused with acute bronchitis
- associated with leukocytosis due to lymphocytosis
25
Overview of congenital lobar emphysema
Presents in neonatal period, many noted prenatally
Clinical features - range from mild tachypnoea and wheeze to severe dyspnoea and cyanosis
Affects upper and middle lobes, left upper lobe most common
Affected lobe is nonfunctional due to over distension, which may cause atelectasis of the ipsilateral normal lung
Mediastinal shift is due to overdistension
26
Which interleukins are markedly increased during COVID-19 infection?
Cytokines IL6 and IL10 are known to increase during COVID-19 infection, as part of the proinflammatory immune response
27
SpO2 of 90% equal what PaO2?
60mmHg
PaO2 40mmHg = SpO2 70%
PaO2 50mmHg = SpO2 80%
PaO2 60mmHg = SpO2 90%
28
How is diagnosis of latent TB made?
Positive tuberculin skin test or Interferon Gold and no evidence of TB disease
These patients are not unwell or infectious but are at risk of reactivation, therefore need treatment
29
Decreased serum IgG, +/- decreased IgA and IgM in infants >6 months?
Transient hypoglammaglobulinaemia of infancy (B cell deficiency)
- normal to near-normal antibody responses to protein immunisations
30
Which measure on spirometry is the most sensitive in children with small airways disease?
Forced expiratory flow 25%-75% (FEF 25%-75%)
- also known as maximum mid-expiratory flow rate, considered to represent flow in smaller airways
- the most effort independent portion of the curve
- useful measurement of milder obstruction
- can be reduced when patient is symptom free and in the presence of normal FEV1/PEFR
31
Which measure on spirometry correlates well with the severity of obstructive diseases?
FEV1
32
Pulmozyme (dornase alpha) indication and MoA?
= highly purified solution of recombinant human deoxyribonuclease I, an enzyme which selectively cleaves DNA
Inhaled solution used for CF
Anti-neutrophil, reduces gas trapping, improves airway clearance and improves CT findings
33
Characteristic features of primary ciliary dyskinesia?
Chronic bronchiectasis
Nasal polyposis
Recurrent otitis media
Recurrent sinusitis
Infertility/subfertility
34
What is Kartagener's syndrome?
Occurs in 50% of patients with PCD
- visceral situs inversus, chronic sinusitis and bronchiectasis
35
At what stage of lung development is the earliest time when surfactant is produced?
Canalicular (weeks 16 to 24) - bronchioles are produced, cells lining respiratory structures begin to differentiate to form type I and type II pneumocytes. Once the cells have differentiated, they begin to secrete small amounts of surfactant
36
Order of lung development?
Embryonic (weeks 4-7)
Pseudoglandular (weeks 7-16)
Canalicular (weeks 16-24)
Saccular (weeks 24-40)
Alveolar (weeks 36 to 8 years postnatally)
37
Lung development - embryonic stage?
Weeks 4-7
Lung buds originate as an outgrowth from the ventral wall of the foregut, where lobar division occurs
At the end of this stage, the first segments appear in the five lobes of lung
38
Lung development - pseudoglandular stage?
Weeks 7-16
Conducting epithelial tubes surrounded by thick mesenchyme are formed. Lungs have the appearance of a gland-like structure, this stage is critical for the formation of conducting airways.
39
Lung development - canalicular stage?
Weeks 16-24
Bronchioles are produced, increasing numbers of capillaries are in close contact with cuboid epithelium and the beginning of alveolar development
Cells lining respiratory structures begin to differentiate to form type I and type II pneumocytes. After the cells have differentiated, they begin to secrete surfactant
40
Lung development - saccular stage?
Weeks 24-40
Major growth and maturation of the respiratory system occurs from week 24. More alveolar precursors develop and larger quantities of surfactant are produced. Alveolar ducts, air sacs and pulmonary capillaries are developed, to create a large SA for gas exchange.
At about week 28, enough alveolar precursors have matured, which increases the chance of survival of a baby born prematurely at this stage
41
Lung development - alveolar stage?
Week 36 to postnatally 8 years
At 1-3 years postnatally, the alveoli continue to develop through separation, increasing gas exchange surface area
42
Genetics of CF?
AR disorder caused by mutations in a single gene on the long arm of chromosome 7
Mutations lead to abnormal functioning of CFTR gene
Most common mutation is F508
43
What is the effect of the F508 mutation on the function of CFTR?
Abnormal protein folding, and therefore poor transport to the cell membrane
- occurs due to a deletion of one amino acid at position 508 in the CFTR protein
44
In children who snore/have OSA, what is the predominant cause of hyperaemia without hypercapnoea?
Ventilation-perfusion (V/Q) imbalance
45
Which pathogen is most commonly associated with bronchiolitis obliterans?
Adenovirus (types 7 and 21 are the most concerning)
46
Pneumothorax, hypertrophic osteoarthropathy, cor pulmonale and delayed puberty are complications of which respiratory condition?
Cystic fibrosis
47
CF patient with asthmatic symptoms of episodic bronchial obstruction (wheeze, cough, SOB, hyperinflation) with rust coloured sputum?
Allergic bronchopulmonary aspergillosis
- complication affecting 5-10% of CF patients (also seen in steroid dependent asthmatics)
48
Common infective organisms in patients with CVID?
Haemophilus, Streptococcus, moraxella catarrhalis and Staph aureus
49
Spirometry features of large airway obstruction?
Flattened curve on expiration and inspiration
May have a sawtooth pattern between FEF 25%-75% (quite commonly seen in children with OSA)
50
Staccato cough and persistent eosinophilia in a neonate?
Chlamydia trachomatis
- first sign is usually conjunctivitis, can end up with pneumonia if not treated
- onset usually insidious and children do not usually have a fever or seem unwell
- biggest risk factor is lack of antenatal care
- treat with prolonged course of erythromycin or azithromycin
51
Methenamine silver nitrate is used to stain for which organisms?
PCP (pneumocystis)
- pneumocystis pneumonia most often observed when CD4+ T helper cell counts fail
52
In a patient with respiratory depression following an opiate overdose, what is the most important step prior to treatment of the overdose?
Increase ventilation rate - normalise the carbon dioxide level prior to giving naloxone.
This is important as opiate antagonists and hypercapnia stimulate the SNS, and a sudden rise in adrenaline concentration could result in ventricular arrhythmias and other issues such as APO, asystole and seizures
53
Presentation of a mycoplasma pneumonia?
Can be abrupt onset
Often gradual onset of headache, malaise, fever and sore throat, followed by lower respiratory symptoms (hoarseness, cough)
Fine creps are a prominent sign.
Treatment: roxithromycin / erythromycin / clarithromycin / azithromycin
54
The role of Vitamin D in the pathogenesis of pulmonary disease?
- improves type 2 pneumocyte maturation and therefore increases surfactant synthesis
- deficiency is associated with reduced lung volume
- maternal deficiency in pregnancy is associated with recurrent wheezing in children/higher rates of asthma
- deficiency has been associated with a lower mean FEV1
55
Mechanism of action of palivizumab?
Humanised monoclonal antibody (IgG) that prevents the replication of a virus within the host cell
- used to prevent RSV, but is not a vaccine, as it works to neutralise and inhibit the fusion of RSV within the host cell therefore preventing replication
56
Mechanism of action of live attenuated vaccines?
Induces antibody creation and cytotoxic T-cell mediated response
57
Mechanism of action of mRNA vaccines?
Nucleic acid vaccination that carries antigen-encoding mRNA to antigen presenting cells
58
Definition of chylothorax?
Presence of lymphatic fluid in the pleural space secondary to leakage from the thoracic duct or one of its main tributaries
- most commonly a complication of cardio thoracic surgery
- initial therapy includes low fat or medium chain TG, high protein diet or TPN
59
When are gamma release assays not useful?
In children <2 years old (results can be indeterminate in this age group)
60
Spirometry findings in mild obstructive disease?
FEV1 65-80% = mild obstruction
FEV1 50-65% = moderate obstruction
FEV1 <50% = severe obstruction
61
What is the drug class of montelukast?
Leukotriene receptor antagonist
- neuropsychiatric side effects are common in children
62
Rationale behind nebulised adrenaline for treatment of croup?
Neb adrenaline provides rapid improvement of upper airway obstruction.
Adrenaline works by adrenergic stimulation, constricts pre capillary arterioles in upper airway mucosa and decreases capillary hydrostatic pressure, leading to fluid resorption and improvement in airway oedema.
Beta-2 adrenergic activity leads to smooth muscle relaxation and bronchodilation
Improvements are transient therefore patients should also be treated with oral dexamethasone
63
Where is reactivation tuberculosis most likely to occur?
Most common form is an infiltrate or cavity in the apex of the upper lobes where oxygen tension and blood flow are great
64
Overview of Wegener granulomatosis
= necrotising granulomatous inflammation involving the respiratory tract affecting small to medium sized vessels.
- necrotising GN is common
- diagnosis suspected with severe sinusitis, granulomas involving the upper airway, pulmonary haemorrhage and renal findings consistent with nephritis
- diagnosis confirmed by presence of anti PR3-ANCA (which is absent in other granulomatous disorders)
65
Overview of Churg Strauss syndrome?
Usually associated with asthma, and can be both cANCA and pANCA positive
66
Overview of pulmonary sequestration
Nonfunctioning mass of lung tissue that lacks normal communication with the trachelbronchial tree, and receives its arterial supply from the systemic circulation
- mostly occur in lower lobes
- dull to percussion with reduced breath sounds
- immediate surgical intervention required if respiratory distress present
67
Features of epiglottitis?
Acute onset of fever, respiratory symptoms and drooling, stridor is a late sign
Most commonly caused by Haemophilus influenza B
Thumb print sign on lateral neck XR
68
What is the predominant investigation finding suggestive of pertussis infection?
An overall leukocytosis resulting from lymphocytosis (the absolute lymphocyte count is often >10,000 lymphocytes per microL
69
What condition is associated with a false negative sweat chloride result?
Oedema
70
What conditions are associated with a false positive sweat chloride test result?
Adrenal insufficiency
Nephrogenic DI
Atopic dermatitis
Familial cholestasis
71
Overview of laryngomalacia
Flaccidity of supraglottic structures leading to collapse into the airway
Accounts for 60-70% of congenital stridor
Usually presents soon after birth, and worsen over the next 8 months, maximum at 9-12 months then gradually resolve by 2 yrs
May be intermittent symptoms (present when feeding or crying, worse during sleep)
Cry is normal and strong, may have feeding difficulties but FTT is rare
72
Overview of lingual cyst
Not a specific disease, could be a thyroglossal duct cyst, or a salivary gland cyst, or dermoid/epidermoid cyst
Any of the former can cause stridor or dyspnoea
73
Overview of sublottic haemangioma
More common in girls
Grows from 2-12 months onwards, signs occur at 3-6 months and regress by 1 year
Biphasic stridor
Can have barking cough (may present with croup)
50% associated with cutaneous lesions
74
Overview of a vascular ring
A number of anatomic variations of abnormal development of the aortic arch leading to a ring around the trachea and oesophagus causing compression of those structures
Can present in infancy with stridor, worse with feeding/URTI
Can also present later with swallowing difficulties
75
Overview of vocal cord lesions
Bilateral lesions result in progressive airway obstruction (high pitched stridor, worsens with distress, voice quality reasonable)
Usually idiopathic
May be secondary to central lesion e.g. myelomeningocele, Arnold-Chiari malformation, hydrocephalus
May be secondary to surgical correction of cardiac defects, TOF
76
Overview of bronchiectasis
= irreversible abnormal dilatation of part of the bronchial tree. Involved bronchi are dilated, inflamed and easily collapsible, resulting in airflow obstruction and impaired secretion clearance
77
Causes of bronchiectasis?
CF is one of the most common
PCD, immune deficiency and some infections (pertussis, measles, TB) can also be associated
78
Clinical features of bronchiectasis?
Most common complaint is cough with copious purulent sputum production
Haemoptysis is not uncommon
Crackles, wheeze and digital clubbing may be found on exam
Fevers during infective exacerbations
79
Investigation findings in bronchiectasis?
CXR: parallel line opacities (tram tracks) due to dilated bronchi, ring opacities or cystic spaces as large as 2cm in diameter resulting from cystic bronchiectasis (sometimes with air-fluid levels), tubular opacities caused by dilated fluid-filled bronchi, increased size and loss of definition of the pulmonary vessels, crowding of pulmonary vascular markings from loss of volume
80
Overview of CCAM/CPAM
Abnormality of lung development
Cystic area within the lung that stems from abnormal embryogenesis, a hamartomatous or dysplastic lung tissue mixed with more normal lung
Large lesions can result in hydrops fetalis in 40%, due to IVC compression
Also associated with pulmonary hypoplasia, can have recurrent chest infections in later life
Surgical resection at <1 year is generally the treatment of choice
81
Pressure swings at alveolar level will be smallest during what method of ventilation?
High frequency oscillatory ventilation
82
Describe Type C TOF?
Proximal oesophageal pouch and a distal TOF (accounts for 85% of cases)
83
CT findings in bronchiolitis obliterans?
Mosaic hyperinflation
Central bronchiectasis
Vascular attenuation
84
Which part of the lung is most affected by CLD in school age children?
CLD (otherwise known as bronchopulmonary dysplasia) tends to affect the bronchioles and acini of school-age children
85
What is eventuation?
Congenital eventration = incomplete muscularisation of the diaphragm, which is instead replaced by a thin membrane which stretches over time and does not contract normally, results in compensatory work of breathing
86
Triad of haemolytic uraemic syndrome?
Haemolytic anaemia
Acute renal failure (uraemia)
Thrombocytopenia
87
Strep pneumoniae associated HUS
5% of cases of HUS
Bacteria produce neuraminidase which damages endothelial cells, and bacteria remove N-acetylneuraminic acid from cell-surface glycoproteins and expose the normally hidden T-antigen on erythrocytes / platelets / glomeruli.
Serum has anti-T immunoglobulin M (IgM) which can react with the antigen and cause damage to RBCs and the kidneys.
88
Spirometry features of tracheomalacia?
Dynamic collapse of the trachea, most lesions are intrathoracic, therefore airway collapse tends to occur during expiration (obstructive pattern during expiration)
89
What is the most appropriate test for children under 6 to culture for mycobacterium tuberculosis?
Gastric aspirate culture
90
Risk factors for chronic lung disease?
Prematurity is the most important
Others include barotrauma, fluid overload, infection, oxygen toxicity
91
What is the maximum allowable variation on repeat testing of flow volume curves in 6-12 year old children?
5% or 100ml (the larger of the two)
92
Specific lung compliance is standardised by measuring lung compliance at which of the following lung volumes?
Functional residual capacity
93
Definition of lung compliance?
Compliance = rate of change of volume in response to pressure
- anything that reduces the outward mobility of the chest wall reduces its compliance
Fibrosis: stiff lungs, poorly compliant
Emphysema: floppy lungs, highly compliant
94
Order of five phases of lung development?
Embryonic -> pseudo glandular -> canalicular -> saccular -> alveolar
95
Cause of worsening hypoxaemia despite administration of B2 agonists with air?
V/Q mismatch
(Salbutamol also increases cardiac output)
96
Common clinical features of bronchiolitis obliterans?
Cough, fever, cyanosis, dyspnoea, chest pain, respiratory distress then initial improvement.
Then progresses to chronic cough, wheeze, worsening dyspnoea, crackles
Can be infective (commonly adeno) or inflammatory
97
Physiological basis for grunting?
Generation of positive end-expiratory pressure
- uniquely seen in infants
- represents a form of self-induced auto-PEEP which allows infants to keep their smaller airways and alveoli open
98
Benefit of macrolide antibodies in CF?
Modulation of airway inflammation
99
Most common pathogen associated with protracted bacterial bronchitis in children?
Non-typeable haemophilus influenzae (47%)
Then strep (35%), and Moraxella (26%)
100
Infectious causes of bronchiolitis obliterans?
Adenovirus (47%)
Influenza, parainfluenza, mycoplasma and RSV are also known causes (but less commonly than adenovirus)
101
Increased FEV1/FVC ratio is suggestive of?
Restrictive lung disease (normal is 75-80%)
