New Invasive and non-Invasive Diagnostic Methods in Paediatric Respiratory Diseases

New Invasive and non-Invasive Diagnostic

Methods in Paediatric Respiratory Diseases

Andrew Bush MD FRCP FRCPCH

Imperial School of Medicine &Royal Brompton Hospital

Email: [email protected]

New Methods In Paediatric Respiratory Diseases

Ethical Issues in using Innovative Methods

Measuring Inflammation: General Measuring Inflammation: Non-

invasive Measuring Inflammation: Invasive Summary and Conclusions

Paediatric Ethical issues:General Principles

Must do adult studies before children Research in children only if unavoidable Risks are not permitted without benefit Adults cannot consent to risk their children Bribery is not allowed Children can be altruistic, and this should be permitted

Paediatric Ethical issues:General Principles

Testing involves not just the child, but the extended family - consent issues for all

Should a child be tested for carrier status?

Should a child be tested for an incurable condition?

Should DNA from a child be stored?



Measuring Inflammation: General

Measuring Inflammation: Non-invasive

Measuring Inflammation: Invasive Summary and Conclusions

Lungs

•Airway wall andlumen

•Lung parenchyma

•Intravascularevents

Bone marrow

EBCExhaled breathSputumFOB, BAL, Bx

Adhesion moleculesBone marrow signals

Blood sampleUrine tests

Biopsy

TBB

Tests to Assess Different Aspects of Inflammation

The Perfect “Inflammometer”

Cheap Easy to maintain and calibrate Completely non-invasive Easy to use, no co-operation needed Direct measurement of all relevant

aspects of inflammation Rapid availability of answers

Facets of Inflammation Cellular mechanisms

Resident cells – epithelial, fibroblasts, myofibroblasts

Invading cells – eosinophil, neutrophil, mixed

Chemical mechanisms Cytokines, chemokines Lipid mediators, e.g.leukotrienes Oxidative stress

Neurogenic mechanisms NANC system

How to Measure Inflammation

Invasive FOB, BAL, Bronchial

biopsy, (TBB)

(Blood tests)

Non-invasive Exhaled breath (eNO)

Induced sputum

Exhaled breath condensate

(BHR)

Mechanisms vs. Individuals

Statistically significant differences between groups

May help predict mechanisms (beware guilt by association)

No use for clinic decisions

Measurement of exhaled nitric oxide

Alveolar and Airway NO Measure eNO and hence NO production

at multiple flow rates Slope of line gives airway production Extrapolated intercept gives alveolar

production Still needs to be evaluated in children

JAP 1999; 87: 1532-42BlueJ 2001; 163: 1557-61

eNO – What does it mean? Measurement conditions crucial

Good for looking at group mechanisms

Variable relationship with airway eosinophilia

MAY be useful in monitoring asthma, but at best indirect

Multiple flow rate measurements need further work

Collection of exhaled breath condensate

EBC – What does it Mean? Many molecules can be measured

Assay more important than collection methods

No value monitoring inhaled steroid reduction

Still unclear if any PRACTICAL value

Sputum induction

A dosimeter is usedto administer ameasured quantity ofhypertonic saline

Induced sputum sample – DTT treated

Inflammation in Severe Asthma

Sputum induction (3.5% saline) in 40 children, symptomatic despite > 1 mg FP/day

Two excluded as FEV1 < 65%; all given β-2 agonist prior to procedure

28/38 (74%) sample obtained


0

2

4

6

8

10

12

14

16

18

NO+,E+ NO+,E- NO-,E- NO-,E+

Nos.

Conclusion: eosinophilic inflammation overcalled by eNO


7/38 symptomatic during induction, only 3 Δ FEV1 > -20%

Only 9/28 had persistent inflammation

6 eosinophilic (eosins > 2.5%) 3 non-eosinophilic (neutrophils > 54%)

Conclusion: inflammation apparently not that common

Can FENO measurements be used to diagnose asthma?

Diagnosing asthma: role of exhaled nitric oxide Smith et al. AJRCCM., 2004

Consecutive patients referred by GP ?asthma

Diagnostic work-up over three study visits: twice-daily peak flow measurements (7days) spirometry bronchodilator response (FEV1) bronchial challenge testing (AHR) induced sputum analysis response (peak flows and FEV1) to pred 30 mg/day

for 2 weeks

Exhaled NO and sputum eosinophil results

Asthma(n=17)

Non-asthma(n=30)

p

FENO (ppb) 52.0(35.3, 68.6)

15.7(10.9, 20.4)

<0.001

Sputum eosinophils (%)

13.8(8.6, 19.1)

1.8(0, 3.7)

<0.001

Conventional testsTest

* Recommended values from current guidelines

Positive tests

Asthma

(n=17)

Non-asthma(n=30)

Sensitivity

(%)

Specificity

(%)

Positive AHR 15 0 - -Positive bronchodilator response

7 0 - -

FEV1 <80% predicted * 5 0 29 100

FEV1/VC ratio <70% * 6 0 35 100

Peak flow variation >20% *

0 0 0 100

15% improvement in PEFR with steroid *

4 0 24 100

15% improvement in FEV1 with steroid *

2 0 12 100

Results:FENO and sputum eosinophils

Test Positive tests

Asthma Non-asthma

Sensitivity

(%)

Specificity

(%)

FENO > 20ppb 14/16 6/28 88 79

Sputum eosinophils > 3%

12/14 3/26 86 89

ROC Curves for eNO As Diagnostic Test: Comparisons Between Studies

Berkman et alMalmberg et al

eNO

eNO

Dupont et al

eNO

eNO

PC20 methacholine

Smith et al

Deykin et al

eNO (42ml/sec) eNO

(500ml/sec)

eNO

Can non-invasive measurements be used to manage asthma?

BlueJ 1999; 159: 1043-51

Managing asthma by normalisingsputum eosinophils in adults

Lancet 2002; 360: 1715-21

Non-invasive Markers to Monitor Steroid Reduction

BlueJ 2005; 171: 1077-82

Non-invasive Markers to Monitor Steroid Reduction

me

an

PD

20

me

tha

cho

line

(u

g)

2000

1000900800700

600

500

400

300

200

100Visit

6543210

ICS

do

se (

mic

rog

ram

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1050

950

850

750

650

GROUP

2,00

1,00

Titrating Steroids on Exhaled Nitric Oxide in Asthmatic Children: a Randomized Controlled Trial. Pijnenburg et al. AJRCCM, 2005

85 atopic asthmatic children. ICS dose in FENO group: increase if >30ppb; no change if <30ppb and symptoms still present; decrease if <30ppb and reduced symptoms.

A a a a

FENO

FENO

Symptoms

Symptoms

Changes in PD20 methacholine Changes in ICS dose (micrograms)

P = 0.04 P = NS




invasive Measuring Inflammation:

Invasive Summary and Conclusions

The Difficult Asthma Protocol

Visit two: FOBAssess reversible factorsAssess symptoms, use of rescue medicationSpirometry, PC20, reversibilityInduced sputum, eNOFOB, BAL, biopsy

Visit three: Decision timeAssess symptoms, diary card, and use of rescue medication Spirometry, PC20, reversibilityInduced sputum, eNOSerum cortisol assay

IntramuscularTriamcinolone

4-6 weeks

Visit one: MDT AssessmentDrug delivery deviceHome visit: environmentSchool visit: bullying?Assess compliancePsychological assessment

1-2 months

Endobronchial Biopsy

1 10 1000.1

1.0

10.0

100.0

FENO (ppb)

Eosinophilscore (%)

r = 0.67p = 0.001

Evidence of adherence

Adherence unknown

Correlation between FENO and eosinophils in biopsy

Phenotype Specific Asthma Treatment

Steroid sensitive (eosinophilic) inflammation

Normal lung function

No BHR No inflammation on

visit 2 biopsy

Treatment approach

Wean steroids (Cyclosporin A if

intolerable side-effects)


Steroid resistant eosinophilic

inflammation

Symptomatic Eosinophilic biopsy on

visit 2 (steroid receptor

abnormalities) Adherence to oral

steroids

Treatment approach

Cyclosporin A Other steroid

sparing agent


Neutrophilic inflammation

Symptomatic Neutrophilic

inflammation on visit 2 biopsy

Treatment approach

Theophyllines (neutrophil apoptosis)

Macrolides (reduced epithelial IL-8)

5-Lipoxygenase inhibitor (LTB4) or LTB4 receptor antagonist

Smoking??


BHR, no inflammation

Symptomatic Marked PF

variability and reversibility

No inflammation on visit 2 biopsy

Treatment approach

Subcutaneous terbutaline infusion

(Increase dose of LABs)


Fixed airflow obstruction

Symptomatic Obstructive

spirometry, no reversibility

No inflammation on visit 2 biopsy

Treatment approach

Reduce treatment until evidence of reversibility appears

Overall Conclusions No one ideal “inflammometer” May be helpful in looking at

mechanisms – individual vs. group differences

May be useful to improve monitoring of asthma

May be useful in planning treatment

New Invasive and non-Invasive Diagnostic Methods in Paediatric Respiratory Diseases

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