1
Q
What are causes of false-positive and false-negative sweat tests?
A
- False-positive: adrenal insufficiency, nephrogenic diabetes insipidus, atopic dermatitis, familial cholestasis syndrome, Klinefelter’s, GSD, mucopolysaccharidosis, G6PD
- False-negative: oedema, malnutrition, mineralcorticosteroid use
2
Q
Describe the factors that affect oxygenation and ventilation?
A
- Oxygenation is primarily affected by:
FiO2
Mean airway pressure
Lung volume
- Ventilation (CO2) is primarily affected by: Minute volume (MV = TV x RR)
A higher minute volume will remove more CO2 and thus decrease the arterial CO2 concentration.
3
Q
At which stage of lung development is the earliest time when surfactant is produced?
A
Canalicular (week 16-24), type 1 and 2 pneumocytes formed
4
Q
Discuss pulmonary alveolar proteinosis
A
- Progressive accumulation of surfactant (lipid and protein)
due to insufficient surfactant clearance. - Surfactant homeostasis is maintained by balanced
production by T2 alveolar cells and
clearance by uptake and catabolism in alveolar macrophages - Reduction in PU.1 expression results in impaired AM
function. GM-CSF signaling is also impaired in PAP. - It is believed that PAP results from accumulation of
surfactant that is produced in normal quantity but is
unable to be catabolised and cleared by macrophages. - SOB, cough, exercise intolerance
- Pulmonary infiltrates on CXR, pink sputum with lipid at bottom
- Tx: lung lavage, not temporary solution
5
Q
Discuss surfactant production
A
- Surfactant is composed of lipids and proteins that are produced by alveolar type II pneumocytes
- Surfactant protein B deficiency is a
rare inherited disorder which is usually rapidly fatal
6
Q
Discuss the differences between:
- Congenital lobar emphysema
- Bronchogenic cyst
- CPAM
- Pulmonary sequestration
A
- CLE: hyperinflation due to obstruction of developing airway, usually LUL, air-filled, herniates across mediastinum, compression of contralateral lung, usually symptomatic neonate. Usually symptomatic. Associated CHD. Resect only if symptomatic
- Bronchogenic cyst: usually mediastinal but can be anywhere, fluid-filled, sharply marginated. Risk infections. Remnant of primitive foregut
- CPAM: abnormality of branching morphogenesis of the
lung, cystic and adenomatous elements, connection with tracheobronchial tree, can arise anywhere along it, blood supply from pulmonary circulation. Often asymptomatic, usually lower lobes. Resection as malignancy risk - Sequestration: non-functioning mass of lung tissue, lacks communication with tracheobronchial tree, receives arterial blood supply from systemic circulation, usually lower lobes, dull to percuss with decreased BS, predispose to recurrent infections. Usually asymptomatic at birth. May have have continuous or systolic murmur over back. Surg resection or coil embolisation
7
Q
Side effects of montelukast?
A
Headache, abdo pain, thirst, nightmares
8
Q
Main infections in CF and treatments
A
- Staph (augmentin/clindamycin)
- Burkholderia (cotrimoxazole)
- Pseudomonas (ciprofloxacin)
9
Q
Discuss the DLCO
A
- The diffusion capacity (DLCO) reflects the integrity of alveolar blood membrane.
- DLCO measures the diffusion of gas across alveoli which is in turn determined by the alveolar surface area and integrity of the alveoli and the pulmonary vascular network.
- DLCO is reduced in conditions where the diffusion surface area is reduced e.g. pulmonary fibrosis or emphysema
10
Q
Findings in bronchodilator and histamine challenges?
A
- FEV1 inc >12% or >200ml in bronchodilator challenge = +ve
- FEV1 dec by >20% in histamine challenge = +ve
11
Q
Methenamine silver nitrate is used to stain for?
A
- Fungi and Pneumocystis carinii. Pneumocystis is a genus of unicellular fungi.
- Also use toluidine blue stain
12
Q
How do you calculate compliance?
A
Compliance = change in volume / change in pressure
13
Q
What is the physiological dead space?
A
- The anatomical dead space + alveoli that aren’t involved.
- The volume of the lung that does not eliminate CO2
14
Q
Obstructive lung function tests
A
- Asthma, Bronchiectasis, Emphysema, Cystic Fibrosis
- FEV1/FVC < 80%
- FVC normal or decr
- FEF 25-75 decreased
- TLC normal or increased
15
Q
Restrictive lung funcion tests
A
- Interstitial Fibrosis, Scoliosis, Obesity, Lung Resection,
Neuromuscular diseases, Cystic Fibrosis - FEV1/FVC inc or normal, FVC decr, FEV1 decr
- TLC decr
- FEF 25-75 normal or decr
16
Q
Fixed upper airway obstruction
A
- Tracheal stenosis, bilateral vocal cord paralysis, goitre
‐ Inspiration and expiration are limited equally - Flattened curve on insp and exp
17
Q
Variable extrathoracic obstruction
A
‐ Limitation of inspiratory flow, flattened inspiratory loop
‐ e.g. Vocal cord paralysis, vocal cord dysfunction
‐ During expiration the vocal cords are passively blown aside
‐ During inspiration vocal cord moves passively with the inhalation and obstructs the glottis
18
Q
Variable intrathoracic obstruction
A
‐ Flattening of expiratory limb
‐ e.g. Tracheomalacia
‐ During expiration there is loss of support resulting in resulting in a narrow trachea and reduced flow
‐ During forced inspiration the negative pleural pressure holds the floppy trachea open
19
Q
Causes of decreased DLCO
A
- Too few alveolar/capillary units
- Thickened membranes or interstitial space
- also affected by Hb level, cardiac shunting, alveolar volume
- measure of severity of ILD
20
Q
What is the KCO?
A
DLCO corrected for alveolar volume
21
Q
Cause of low DLCO in obstructive disease?
A
Bronchiolitis obliterans, CF
22
Q
DLCO in restrictive lung disease - low and normal causes?
A
- DLCO helps in differential diagnosis of restrictive lung disease
- Low DLCO with reduced lung volumes suggests ILD, sarcoid, pneumonitis, pulm fibrosis
- Normal DLCO associated with low volumes is consistent with extrapulmonary cause of restriction – pleural effusion, obesity, neuromuscular weakness, kyphoscoliosis
23
Q
What can result in a high DLCO?
A
- Pulmonary hemorrhage (Extra blood in lungs to absorb CO)
- Asthma
24
Q
Causes of low DLCO with normal pulmonary function tests
A
- Vasculitis - Wegners, MPA
- CHF
- Pulmonary emboli
- Pulmonary hypertension
- SLE
- Early ILD
25
What is the FeNO, and causes of low and high tests?
- Fractional exhaled nitric oxide
- Positive test suggests eosinophilic inflammation
- Positive >35ppb = asthma, eosinophilic bronchitis, allergic rhinitis, eczema
- Lower: smokers, neutrophilic asthma
26
Nasal nitric oxide - causes of low results
- Screening tool before ciliary brushing or biopsy taken
- Low NO = primary ciliary dyskinesia and cystic fibrosis
- Abnormal <250, true PCD <100
27
Positive exercise challenge
Fall of FEV1 >10% from baseline
28
Discuss the different CFTR genes in CF
- Class I (3%) - no protein e.g. G542X. Stop mutation, nonsense, short protein which is deleted, therefore no function.
- Class II (90%) - no traffic e.e F508del. Abnormal folding, trafficking defect, therefore no traffic to cell membrane.
- Class III (5%) - no function. e.g. G551D. Gating defect, protein can get to cell wall but Cl- cannot get out of cell.
- Class IV - less function
- Class V - less protein
- Class VI - less stable
29
Modulator drugs in CF
- Class I (G542X) - nil
- Class II (F508) - orkambi (lumacaftor and ivacaftor) >2yo in Aus, tricaftor (3 drugs, very new), symdeco (>12yo)
- Class III (G551D) - ivacaftor - allows chloride through. >2yo in Aus. Can be used on homozygotes and heterozygotes.
- Best results seen in tricaftor and ivacaftor - improved FEV1 > 10% (but inhaled TOBI also inc by 12%)
30
Newborn screening process for CF
- Immunoreactive trypsinogen - picks up to 1% levels (pancreatic duct blocked so enzymes cannot get into GIT therefore absorbed into bloodstream)
- CF gene panel
- > for 5 positive screens, 1 has true CF. 8% CF is missed (either IRT not in top 1% or has other gene mutations)
- Sweat test: normal <30, abnormal >60, indeterminate 30-60
31
Diagnosis of CF?
Two CF causing genetic mutations +/- positive chloride sweat test (>60)
32
Cystic fibrosis screen positive, inconclusive diagnosis
- 2 CF genes but negative sweat test
- 1 or no genes and indeterminate sweat test
- Indeterminate sweat test and genes of uncertain pathogenic significance
33
Treatment of pseudomonas for first time in CF patient
- If unwell: admission to hospital for intravenous antibiotics
- If well: oral ciprofloxacin & nebulized TOBI
34
Most common CF pathogens in paeds population
- Staph > haemophilus > pseudomonas > MRSA > st. maltophilia
- Pseudomonas increases through lifespan
- MRSA increasing Aus > NZ
35
CF most common chronic infection in a) early childhood and b) later childhood?
- A = staph aureus. Not yet routine prophylaxis in NZ. MRSA ~15%, increasing.
- B = pseudomonas aeruginosa.
- If well then use PO ciprofloxacin + inhaled tobramycin
- If unwell then use IV ceftazidime (NZ) or meropenem and tobramycin (Aus).
- Causes intense inflammation, develops biofilm, difficult to eradicate. Associated with poorer prognosis and lower survival.
- If chronic pseudomonas (>50% samples of 4/year) then use azithromycin Mon/Wed/Fri
36
Discuss bronchiolitis obliterans
- After an insult to the lower respiratory tract and leads to chronic obstructive lung disease from fibrosis of the small airways
- Post viral: adenovirus, mycoplasma or inflammatory disease (e.g. JIA, SLE) or graft vs. host disease or lung transplant
- Chronic cough, SOB, sputum production and wheeze. Hypoxemia and crackles
- CXR: variable, hyperlucency and patchy infiltrates. - PFTS: obstructive, variable response to salbutamol
- Tx: supportive, treat infections, O2, may require steroid course, immunosuppressants (tacrolimus, cyclosporine, macrolide antibiotics)
37
Type 1 vs type 2 pneumocytes
- Type 1 - squamous, cover 95%, involved in gas exchange
| - Type 2 - cuboidal, cover 5%, secrete surfactant
38
Discuss Burkholderia treatment
- Gram -ve bacteria
- Innate antibiotic resistance, biofilms, resistant to colistin
- Associated with poor prognosis, 10yr reduction median survival
- IV ceftazidime/meropenem + tobramycin + cotrimox + inhaled TOBI
39
Discuss non-TB mycobacterium treatment
- 10% of CF patients
- MAC (avium) in 70%, abscessus 16%
- Only a proportion develop non-TB mycobacterium disease - nodular changes on CT chest
- May not require treatment, only if abscess, severe lung disease, anticipated transplant
- 6w IV antibiotics + 12m PO antibiotics, often stopped due to ADRs (hearing loss, renal and liver dysfunction)
- Need to rule out NTM before starting azithromycin as develops resistance
40
Discuss CF-related diabetes
- Will develop with time
- Often deterioration in lung function associated
- Decreased insulin production + insulin resistance + normal effect of insulin reduced
- Screen with OGTT and HbA1c (unreliable) and confirm with continuous glucose monitoring
- Some will require small amount of insulin
41
Treatment of ABPA?
Steroids and antifungal (itraconazole or voriconazole)
42
Airway clearance in CF
- Pulmozyme - recombinant human deoxyribonuclease I - an enzyme which cleaves DNA, reduces sputum viscoelasticity, improves lung function and reduces exacerbations
- Hypertonic saline nebs 7% - draws water into airways and thins secretions, improves FEV1 and reduces exacerbations
- Physio
- Exercise
43
Poor prognostic factors in CF?
- Malnutrition
- Pseudomonas
- B. cepacia
- CF-related diabetes
- Frequent exacerbations
- Female, especially teenage
44
Most common chronic infection in bronchiectasis?
- Haemophilus influenzae. Note: staph is rare, therefore if present need to check for CF
- Moraxella and strep pneumoniae intermittent
45
Bronchiectasis management
- Prolonged azithromycin + nebulised antibiotics not recommended unless frequent exacerbations, chronic PsA infection
- Hypertonic saline - short term improvements, not routine
- Pulmozyme is bad in bronchiectasis - more deaths, inc exacerbations
- Inhalers only if co-existent asthma
46
Effects of isolated LABA use
- Not recommended for isolated use in children due to reduction of B2 receptor density -> therefore difficulty in treating acute exacerbation leading to high risk mortality
47
Immune process involved in asthma?
- Th2, IL-5, B cells, humoral response, IgE dominant and eosinophilic inflammation
48
Th1 immune response
- Th1 via IL-2 and IFN gamma, IgG dominant response, interacts with T cells, cell mediated immune response
49
Discuss the steps of asthma therapy
- 1: SABA (salbutamol)
- 2: SABA + low dose ICS (fluticasone, flixotide)
- 3: <5y - leukotrine receptor antagonist (montelukast)
>5y - SABA + ICS + LABA (seretide, salmeterol)
>12y - SMART therapy with symbicort (budesonide/formeterol)
- 4: increase ICS dose, add montelukast >5y
- 5: increase ICS dose
-> always check compliance, spacer, lung function tests
- LABA monotherapy unsafe. Not used <4y
50
Discuss the emryological lung stages
- Embryonic (26 days to 6 weeks gestation)
- Pseudoglandular (6-16 weeks) - major lung elements, except for those required for gas exchange (e.g. alveoli) have appeared.
- Canalicular (16-26 weeks) - bronchial lumens enlarge and lung tissue becomes vascularised. Bronchioles and alveolar ducts develop from terminal bronchioles.
- Saccular (26 weeks to birth) - specialised cells appear (type 1 and type II alveolar cells) and produces surfactant.
- Alveolar (birth to 3 years) - terminal saccules, alveolar ducts, and alveoli increase in number.
51
Diagnostic findings in primary ciliary dyskinesia?
- Abnormal cilia - absent dynein arms, translocation of central tubules
- Ciliary beat frequency low
- Low exhaled nasal nitric oxide
52
Use of osteltamivir
- Neuraminidase inhibitor
- For influenza
- Reduces viral spread in airways if given in first 48 hours of symptoms
53
Defects in IF-gamma and IL-12 pathways predisposes to?
TB
54
Hypersensitivity reactions associated with TB?
Erythema nodosum, nodular conjunctivitis
55
Mantoux cut-off values
- >15mm positive in everyone
- >10mm if recent immigrant, children <4y, high risk
- >5mm if HIV, recent TB contact, abnormal CXR
- False negatives in young, immune deficiency, HIV/flu/measles
- T-cell mediated reaction
56
Treatment of TB
- Chemoprophylaxis in infection - isoniazid 6m +/- rifampicin 3m
- Chemotherapy (disease) - isoniazid + rifampicin for 6m + pyrazinamide + ethambutol for first 2m
- Total 12m if meningitis.
- 6-8 weeks corticosteroids if meningitis/pericarditis/miliary TB
- Need sputum culture of gastric aspirates prior to starting therapy
- AFB, Ziehl Neelsen stain
57
Side effects of TB meds
Peripheral neuropathy, liver derangements, orange urine/tears (rifampicin), visual disturbance (ethambutol)
58
Discuss pneumocystis jiroveci
- Tachypnoea, resp distress, fever, bilat crackles, hypoxia
- CXR: bilat interstitial and alveolar shadowing, ground glass/crazy paving on CT
- Yeast-like fungus
- Dx: bronchoalveolar lavage, blue/silver stain
- Causes: SCID, HIV, DiGeorge, hyper IgM, oncology
- Tx: high dose cotrimoxazole (causes pancytopenia, fever, rash), +/- steroids, surfactant if I+V, prophylaxis post treatment
- Can get dual infection with CMV as cause of pneumonitis
59
Discuss lymphocytic interstital pneumonitis
- Seen in HIV or immunodeficiency, EBV
- Marked lymphadenopathy, parotid hyperplasia, HSM, falling CD40 count, chronic cough, hypoxia, clubbing, ILD
- Tx: nil if well, may respond to steroids
60
Discuss pulmonary haemosiderosis
- Triad of iron-deficiency anemia, hemoptysis, and multiple alveolar infiltrates on chest radiographs
- Repeated pulm haemorrhage leads to accumulation of hemosiderin in alveoli
- Can have haemoptysis, episodic fever, SOB, wheeze
- CXR: normal or patchy
- Diagnosis via BAL - hemosiderin-laden macrophages
- Tx: acute O2, transfusion. Chronic - steroids, hydroxychloroquine, immunosuppression
- Can be associated with SLE, GPA, Goodpasture's, cardiac abnormalities, or be idiopathic
- Can be associated with Cow's milk hypersensitivity
61
Discuss the changes seen on sleep study in:
- Awake eyes open
- Awake eyes closed
- N2
- N3
- REM
- Awake with eyes open - big chin EMG, EEG active ++
- Awake with eyes shut - med chin EMG, EEG rhythmic alpha occipital leads
- N2 light sleep - med chin EMG, quiet EEG, K complex and spindles
- N3 deep sleep - small chin EMG, EEG big slow waves (+Ks + spindles)
- REM - smallest chin EMG, EEG quiet, eye move ++, partial paralysis, vivid dreams, irregular breathing
62
What stage of sleep does OSA worsen in?
REM - irregular breathing, inc upper airways resistance, low tone, decreased tidal volume
63
When do parasomnias occur?
- Partial awakening from N3 deep sleep
- Usually 60-90 min after going to sleep
- 1 or 2 per night
- Usually +ve family history
64
Treatment of periodic limb movement?
- Associated with partial iron deficiency in CNS - treat with iron to keep systemic ferritin >50-75 to force iron into brain
65
Periodic limb movements vs. restless legs
- PLMD: repetitive (usually every 20 to 40 sec) twitching or kicking of legs or arms during sleep. Interrupted nocturnal sleep or excessive daytime sleepiness.
- RLS: irresistible urge to move the legs, arms, or, body, usually accompanied by paresthesias +/- pain. Inc when sedentary, evening time. To relieve symptoms, patients move the affected extremity by stretching, kicking, or walking. Difficulty falling asleep, repeated nocturnal awakenings, or both.
66
Discuss narcolepsy
- Primary hypersomnia
- Due to deficiency of hypocretin (orexin) which normally stimulates the cortex to be awake
- Associated with cataplexy, sleep paralysis, hypnagogic hallucinations
- Ix: decreased hypocretin-1 levels in CSF, DQB10602 +ve
- Tx: routine scheduled naps and sleeps, stimulants, tricyclics or SSRIs for cataplexy
67
What are causes of secondary hypersomnia
- Lack of sleep is most common cause
- OSA
- Delayed sleep phase
- Meds
- Substance abuse esp cannabis
- Psych - anxiety, depression, pain
- CNS tumours (esp hypothalamic tumours)
68
Discuss congenital hypoventilation syndrome
- Ondine's curse
- Presents in infancy with apnoea and cyanosis
- Hypoventilation, worse in sleep
- Absent response to hypercarbia and hypoxia when awake and asleep
- Decreased tidal volume
- Ventilation better awake and in REM (opp. from usual)
- PHOX2B mutation
- Usually require trache-ventilation (older can have NIV)
- Developmental delay if recurrent hypoxia
- Also associated with: failure to develop fever, sudden death (arrhythmia), neural crest tumours, Hirschsprung
Paediatrics RACP written exam
flashcards
Decks in class (18)
# Cards
-
Cardiology185
-
Oncology/Haematology236
-
Gastroenterology228
-
Neurology216
-
Respiratory68
-
Emergency Medicine96
-
Endocrinology52
-
Immunology162
-
Rheumatology/dermatology53
-
Genetics216
-
Psychiatry55
-
Metabolic118
-
Neonatology175
-
Statistics36
-
Infectious Disease92
-
Nephrology219
-
Pharmacology20
-
General Paediatrics18
