Aviation Medicine and Respiratory Disease Diploma in Aviation Medicine Course No 44

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Aviation Medicine and Respiratory DiseaseDiploma
in Aviation Medicine Course No 44

• Wg Cdr Gary Davies
• RAF Consultant Advisor in Respiratory Medicine
• Consultant Respiratory Physician, Chelsea
  Westminster Hospital

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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

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Diseases to be covered

• Asthma
• Sarcoidosis
• Pneumothorax
• Pulmonary thrombo-embolic disease
• Obstructive Sleep Apnoea
• Interstitial Lung Disease
• Bronchiectasis
• COPD
• Pulmonary Tuberculosis
• Atypical Mycobacterium
• Pulmonary Malignancies

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Asthma
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Asthma - Introduction

• Widespread airway obstruction of a variable
  nature
• Variation Spontaneous, stimulus (allergic) or
  treatment
• Asthma and flying thought by some to be
  incompatible

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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

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Aviation Management Problems

• INDIVIDUAL
• Concerns
• Sudden Incapacitation
• At risk individuals
• Previous life-threatening attack
• Variable PEF on treatment
• Repeated admissions

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Asthma - Symptoms

• Very variable
• Cough / wheeze / SOB / Nocturnal wakening / chest
  tightness
• Look for stimuli
• History very important but use OBJECTIVE
  assessments

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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

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Asthma - Investigation

• PEF diary
• Basic Spirometry
• Gas transfer and RV
• Reversibility testing / Steroid challenge
• Exercise spirometry
• Methacholine (Histamine) challenge testing
• Allergy testing
• Exhaled NO
• Breath condensate

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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 ß2-agonist
STEP 2 Add inhaled steroid ? 800 µg/day adult ?
400 µg/day children Symbicort SMART

STEP 1 Inhaled short-acting ß2-agonist (or other
bronchodilator)
Adapted from draft BTS /SIGN asthma guidelines
3. BTS/SIGN draft guidelines.
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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
• Potential mechanism 4 5
• 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
  2005330117.
• 2. Excess mortality in patients with asthma on
  long acting ß2-agonists. Hasford Virchow. Eur
  Resp J 200628900-2
• 3. Salmeterol Multicenter Asthma Research Trial
  (SMART). Nelson et al. Chest 2006 12915-26
• 4 mechanism of adverse effects of ß2-agonists in
  asthma. Johnston Edwards. Thorax 2009
  64739-741
• 5. Adverse effects of salmeterol in asthma a
  neuronal perspective. Lommatzsch et al. Thorax
  2009 64763-769

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New Specialist Treatment

• Steroid sparing agents
• IV Immunoglobulin
• Xolair (Omalizumab) anti-IgE
• Bronchial thermoplasty

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Disposition

• Pilot Recruits
• Exclusion criteria
• Currently on any treatment for asthma.
• Any asthmatic symptoms including nocturnal cough
  or exercise-induced wheezing.
• Regular inhaled steroids for a period gt 8 weeks
  in the 5 years before application.
• Hospital attendance, including AE, 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 gt 24 hours for
  asthma or wheeze since the age of 5

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Disposition

• Pilot Recruits
• Objective testing
• Normal full pulmonary function tests
• (spirometry and reversibility, lung volumes and
  transfer factor).
• Methacholine challenge test.
• gt 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

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Disposition

• Trained Aircrew (At present)
• Can continue with Restricted flying category if
• Resting Lung Function, exercise testing normal on
  treatment
• Treatment not gt step 2 BTS guidelines
• Dual crew aircraft
• Normal bronchial hyper-responsiveness
• Infrequent exacerbations

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Sarcoidosis
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Sarcoidosis - Introduction

• Multi-system granulomatous disease of unknown
  aetiology
• More common than thought
• Often incidental finding on routine medical

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Sarcoidosis Natural History

• Most commonly asymptomatic BHL
• ? Asymptomatic pulmonary infiltrates
• Erythema Nodosum
• If shadowing persists gt 1 year, ? risk of
  fibrosis
• Extra thoracic often more chronic and indolent

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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

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Sarcoidosis - Investigation

• Bronchoscopy
• BAL and Trans-bronchial biopsies
• Urine and blood calcium
• Biopsy of nodes
• Echocardiogram
• Serum ACE level

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Sarcoidosis Treatment

• None
• Corticosteroids (Stage 2 )
• Azathioprine
• Hydroxychloroquine
• Methotrexate

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Aviation Management Problems

• Main risk - cardiac arrhythmia
• Interference with operational effectiveness
• Steroid treatment

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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

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Pneumothorax
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Pneumothorax Natural History

• Two peaks of incidence
• Young adults
• Old adults
• Recurrence Rate
• 30 after 1st
• 50 after 2nd
• 80 after 3rd

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Pneumothorax - Investigation

• CXR
• Spirometry
• Hi Res CT Thorax

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Pneumothorax - Treatment

• Aspiration / chest drain
• Operative treatment
• Open pleurectomy
• Thoracoscopic pleurectomy
• Chemical pleurodesis (NOT recommended)

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Aviation Management Problems

• Sudden incapacitation
• Increasing with altitude

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Pneumothorax Disposition

• Pilot Training
• gt 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

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Traumatic Pneumothorax

• No associated bullous lung disease
• Risk of recurrence VERY small
• No further treatment required after emergency
  treatment

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Pulmonary thrombo-embolic disease
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Pulmonary thrombo-embolic disease Natural
History

• Variation from single life threatening event to
  insidious breathlessness
• Causes
• Short term risks
• Malignancies
• Clotting disorders

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Pulmonary thrombo-embolic disease - Investigation

• CXR
• ECG
• Arterial Blood Gases
• CTPA
• Ventilation/perfusion scan

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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

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Aviation Management Problems

• Risks of sudden incapacitation
• Disabling breathlessness

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Pulmonary thrombo-embolic disease - Disposition

• Pilot Training
• Cause unknown or recurrent episodes
• ? Disqualifying
• Recognised cause
• ? Individual -gt 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

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Obstructive Sleep Apnoea
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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

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OSA - Investigation

• Sleep study
• Epworth Sleepiness Scale

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OSA - Treatment

• Address aggravating factors
• CPAP
• Jaw advancement splint
• Surgery

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Aviation Management Problems

• Daytime somnolence leading to increased accidents
  and decreased performance
• Treatment negates this risk

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OSA - Disposition

• Pilot Training
• Disquallifying
• Trained Aircrew
• Grounded until response to treatment assessed
• Effective treatment ? full flying category
• Help from specialist centre

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Interstitial Lung Disease
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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.

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ILD - Investigation

• CXR (little use)
• Hi res CT scan
• Refer to specialist centre

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ILD - Treatment

• Complex and related to cause and pattern of
  disease.
• Mainstay treatment involving
• Oral / iv steroids
• Azathioprine
• Cyclophosphamide
• May require transplantation

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Aviation Management Problems

• Breathlessness and difficulty completing duties
• Risks of side-effects of treatment

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ILD - Disposition

• Pilot Training
• Disqualifying
• Trained Aircrew
• Permanent grounding

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Bronchiectasis
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Bronchiectasis Natural History

• Chronic dilatation of one or more bronchi
• Large multitude of causes
• Major variation of symptoms and progression

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Bronchiectasis - Investigation

• CXR
• Hi Res CT scan
• Investigation of underlying cause
• Lung function testing

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Bronchiectasis - Treatment

• Regular Physiotherapy
• Prompt treatment of infections
• Treat any underlying airway inflammation
• Bronchodilators and inhaled corticosteroids
• Treat any underlying cause

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Aviation Management Problems

• Recurrent respiratory tract infections
• Possibility of sudden incapacitation

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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

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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

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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)

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Atypical Mycobacterium

• Pilot Training
• Disqualified
• Trained Aircrew
• Permanent downgrading

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Pulmonary Malignancy

• Pilot Training
• Disqualifying
• Benign tumour refer Respiratory Physician
• Trained Aircrew
• Permanent grounding
• Benign tumour refer Respiratory Physician

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Questions ?
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