Transcript Aviation Medicine and Respiratory Disease

Aviation Medicine and Respiratory Disease
Diploma in Aviation Medicine Course No 44
Wg Cdr Gary Davies
RAF Consultant Advisor in Respiratory Medicine
Consultant Respiratory Physician, Chelsea &
Westminster Hospital
Introduction
• Commonest cause of morbidity and time
off work in general population
• 2nd most common medical cause of loss of
flying time
• Often thought to be incompatible with
flying
Diseases to be covered
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Asthma
Sarcoidosis
Pneumothorax
Pulmonary thrombo-embolic disease
Obstructive Sleep Apnoea
Interstitial Lung Disease
Bronchiectasis
COPD
Pulmonary Tuberculosis
Atypical Mycobacterium
Pulmonary Malignancies
Asthma
Asthma - Introduction
• Widespread airway obstruction of a
variable nature
• Variation – Spontaneous, stimulus
(allergic) or treatment
• Asthma and flying thought by some to be
incompatible
Asthma – Natural History
• Wide variety of clinical patterns
• 5-10% of UK adults
• Increasing prevelance
• Link with childhood asthma and adult
asthma
• Early treatment → better prognosis
Aviation Management Problems
• INDIVIDUAL
• Concerns
– Sudden Incapacitation
• At risk individuals
– Previous life-threatening attack
– Variable PEF on treatment
– Repeated admissions
Asthma - Symptoms
• Very variable
• Cough / wheeze / SOB / Nocturnal
wakening / chest tightness
• Look for stimuli
• History very important but use OBJECTIVE
assessments
Specific History
• Gestation and birth weight
• Recurrent respiratory or sinus infections
during childhood
• Whooping cough in young childhood
• Persistent symptoms after the age of 5
years
• Maternal smoking
Asthma - Investigation
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PEF diary
Basic Spirometry
Gas transfer and RV
Reversibility testing / Steroid challenge
Exercise spirometry
Methacholine (Histamine) challenge testing
Allergy testing
• Exhaled NO
• Breath condensate
Treatment
STEP 5
Add daily oral steroid or regular
booster courses of oral steroid
STEP 4
Add any or all of the following as determined by
empirical trial: increase inhaled steroid up
to  2000 μg/day, leukotriene receptor antagonist,
theophylline, cromone
STEP 3
Add long-acting β2-agonist
STEP 2
Add inhaled steroid:  800 μg/day adult  400 μg/day children
******** Symbicort SMART *********
STEP 1
Inhaled short-acting β2-agonist (or other bronchodilator)
Adapted from draft BTS /SIGN asthma guidelines
3. BTS/SIGN draft guidelines.
Treatment worries
• SABAs as regular solo treatment
 Fenoterol (NZ) 1980s – increased mortality
 Potential increased risk of hospitalisation or death 1 2
 Increase PEF variability and bronchial hyper-reactivity
• LABAs as regular solo treatment
 Salmeterol alone 3
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Potential mechanism
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Increased brain-derived neurotrophic factor (BDNF)
IL-6
cAMP response element (CRE)
1. Bronchodilator treatment and deaths from asthma: case control study. Anderson et al. BMJ 2005;330:117.
2. Excess mortality in patients with asthma on long acting β2-agonists. Hasford & Virchow. Eur Resp J 2006;28:900-2
3. Salmeterol Multicenter Asthma Research Trial (SMART). Nelson et al. Chest 2006; 129:15-26
4 mechanism of adverse effects of β2-agonists in asthma. Johnston & Edwards. Thorax 2009; 64:739-741
5. Adverse effects of salmeterol in asthma: a neuronal perspective. Lommatzsch et al. Thorax 2009; 64:763-769
New Specialist Treatment
• Steroid sparing agents
• IV Immunoglobulin
• Xolair (Omalizumab) – anti-IgE
• Bronchial thermoplasty
Disposition
• Pilot Recruits
– Exclusion criteria
• Currently on any treatment for asthma.
• Any asthmatic symptoms including nocturnal cough or
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exercise-induced wheezing.
Regular inhaled steroids for a period > 8 weeks in the 5
years before application.
Hospital attendance, including A&E, for asthma or
wheezing in the 5 years before application.
Required oral steroids for asthma within the 5 years
before application.
Required admission to an intensive care unit for asthma
at any time in their life.
Required a hospital admission > 24 hours for asthma or
wheeze since the age of 5
Disposition
• Pilot Recruits
– Objective testing
• Normal full pulmonary function tests
– (spirometry and reversibility, lung volumes and transfer factor).
• Methacholine challenge test.
– > 16mg/ml
– Research
• Exhaled nitric oxide level.
• Allergy skin prick (basic allergen panel)
– house dust mite, grass, tree pollen and aspergillus
– further tests may be required if the history suggests other potential
allergen.
• Total IgE.
• Eosinophil count
Disposition
• Trained Aircrew (At present)
– Can continue with Restricted flying category if
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Resting Lung Function, exercise testing normal on treatment
Treatment not > step 2 BTS guidelines
Dual crew aircraft
Normal bronchial hyper-responsiveness
Infrequent exacerbations
Sarcoidosis
Sarcoidosis - Introduction
• Multi-system granulomatous disease of
unknown aetiology
• More common than thought
• Often incidental finding on routine medical
Sarcoidosis – Natural History
• Most commonly – asymptomatic BHL
• → Asymptomatic pulmonary infiltrates
• Erythema Nodosum
• If shadowing persists > 1 year, ↑ risk of
fibrosis
• Extra thoracic often more chronic and
indolent
Sarcoidosis – Natural History (2)
• Stage 1 – BHL only
• Stage 2 – BHL + Pulmonary Infiltrates
• Stage 3 – Pulmonary Infiltrates only
• Stage 4 – Irreversible fibrosis
• Cardiac involvement irrespective of
staging
Sarcoidosis - Investigation
• Bronchoscopy
– BAL and Trans-bronchial biopsies
• Urine and blood calcium
• Biopsy of nodes
• Echocardiogram
• Serum ACE level
Sarcoidosis – Treatment
• None
• Corticosteroids (Stage 2 +)
• Azathioprine
• Hydroxychloroquine
• Methotrexate
Aviation Management Problems
• Main risk - cardiac arrhythmia
• Interference with operational effectiveness
• Steroid treatment
Sarcoidosis - Disposition
• Pilot Training
– Any History → Unfit (risk cardiac sarcoidosis)
• Trained Aircrew
– Grounded until fully investigated
– If no cardiac involvement and asymptomatic and no treatment
• As or with co-pilot initially
• Upgrade to solo after 1 year
– On treatment
• Grounded until above
– Asymptomatic pulmonary infiltrates
• REFER RESPIRATORY PHYSICIAN
Pneumothorax
Pneumothorax – Natural History
• Two peaks of incidence
– Young adults
– Old adults
• Recurrence Rate
– 30% after 1st
– 50% after 2nd
– 80% after 3rd
Pneumothorax - Investigation
• CXR
• Spirometry
• Hi Res CT Thorax
Pneumothorax - Treatment
• Aspiration / chest drain
• Operative treatment
– Open pleurectomy
– Thoracoscopic pleurectomy
– Chemical pleurodesis (NOT recommended)
Aviation Management Problems
• Sudden incapacitation
• Increasing with altitude
Pneumothorax – Disposition
• Pilot Training
– > 2 years ago or following definitive treatment
specialist referral to investigate possible underlying
disease
• Trained Aircrew
– Pleurectomy → 3 months
• VATS procedure or mini-thoracotomy preferably
– If no pleurectomy - Grounding 18 months minimum
– Investigation
Traumatic Pneumothorax
• No associated bullous lung disease
• Risk of recurrence – VERY small
• No further treatment required after
emergency treatment
Pulmonary thrombo-embolic disease
Pulmonary thrombo-embolic
disease – Natural History
• Variation from single life threatening event
to insidious breathlessness
• Causes
– Short term risks
– Malignancies
– Clotting disorders
Pulmonary thrombo-embolic
disease - Investigation
• CXR
• ECG
• Arterial Blood Gases
• CTPA
• Ventilation/perfusion scan
Pulmonary thrombo-embolic
disease - Treatment
• LMW heparin + warfarin followed by 3 - 6
months of warfarin for first event.
• Life-long warfarin for recurrent events
• Thrombolysis in life-threatening events
Aviation Management Problems
• Risks of sudden incapacitation
• Disabling breathlessness
Pulmonary thrombo-embolic
disease - Disposition
• Pilot Training
– Cause unknown or recurrent episodes
→ Disqualifying
– Recognised cause
→ Individual -> referral
• Trained Aircrew
– Grounded while on warfarin
– Single episode with defined cause and normal pro-coagulation
screen → upgraded after treatment
– Recurrent episodes / malignancy / clotting disorder →
permanent grounding
Obstructive Sleep Apnoea
Obstructive Sleep Apnoea –Natural
History
• Collapse of upper airway during sleep leading to apnoea
• Overweight, middle aged men most commonly
• Hypoxia and hypercapnia
• Hypersomnolence
• Increased risks of cardiac disease if untreated
OSA - Investigation
• Sleep study
• Epworth Sleepiness Scale
OSA - Treatment
• Address aggravating factors
• CPAP
• Jaw advancement splint
• Surgery
Aviation Management Problems
• Daytime somnolence leading to increased
accidents and decreased performance
• Treatment negates this risk
OSA - Disposition
• Pilot Training
– Disquallifying
• Trained Aircrew
– Grounded until response to treatment
assessed
– Effective treatment → full flying category
– Help from specialist centre
Interstitial Lung Disease
Interstitial Lung Disease – Natural
History
• Characterised by diffuse parenchymal lung
disease distal to the terminal bronchiole.
• Large number of different disorders
• Progression is dependant on specific
cause.
ILD - Investigation
• CXR (little use)
• Hi res CT scan
• Refer to specialist centre
ILD - Treatment
• Complex and related to cause and pattern
of disease.
• Mainstay treatment involving
– Oral / iv steroids
– Azathioprine
– Cyclophosphamide
• May require transplantation
Aviation Management Problems
• Breathlessness and difficulty completing
duties
• Risks of side-effects of treatment
ILD - Disposition
• Pilot Training
– Disqualifying
• Trained Aircrew
– Permanent grounding
Bronchiectasis
Bronchiectasis – Natural History
• Chronic dilatation of one or more bronchi
• Large multitude of causes
• Major variation of symptoms and
progression
Bronchiectasis - Investigation
• CXR
• Hi Res CT scan
• Investigation of underlying cause
• Lung function testing
Bronchiectasis - Treatment
• Regular Physiotherapy
• Prompt treatment of infections
• Treat any underlying airway inflammation
– Bronchodilators and inhaled corticosteroids
• Treat any underlying cause
Aviation Management Problems
• Recurrent respiratory tract infections
• Possibility of sudden incapacitation
Bronchiectasis - Disposition
• Pilot Training
– Disqualifying except
• Following surgery for limited disease (not
recommended)
– REFER TO RESPIRATORY PHYSICIAN
• Trained Aircrew
– Limited – limited flying duties
– More severe – permanent grounding
COPD
• Pilot Training
– Full respiratory assessment
– Unlikely to be accepted
• Trained Aircrew
– Mild disease, No bullous disease, normal lung function
→ unrestricted flying (regular assessments)
– Moderate disease → limited flying
– Severe disease / recurrent exacerbations →
permanent grounding
Pulmonary Tuberculosis
• Pilot Training
– Appropriate chemotherapy with no lung damage
(radiologically and lung function) → accepted for
training
• Trained Aircrew
– Active disease or on treatment → temporally unfit
flying duties
– Residual lung damage → Individual (refer to
respiratory specialist)
Atypical Mycobacterium
• Pilot Training
– Disqualified
• Trained Aircrew
– Permanent downgrading
Pulmonary Malignancy
• Pilot Training
– Disqualifying
– Benign tumour – refer Respiratory Physician
• Trained Aircrew
– Permanent grounding
– Benign tumour – refer Respiratory Physician
Questions ?
The swedish
concept
Lars-Gunnar Hök M.D.