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

2. 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

3. 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

4. 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

5. Asthma

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

7. 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

8. Aviation Management Problems • INDIVIDUAL • Concerns • Sudden Incapacitation • At risk individuals • Previous life-threatening attack • Variable PEF on treatment • Repeated admissions

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

10. 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

11. 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

12. 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.

13. 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 2005;330:117. 2. Excess mortality in patients with asthma on long acting β2-agonists. Hasford & Virchow. EurResp 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

14. New Specialist Treatment • Steroid sparing agents • IV Immunoglobulin • Xolair (Omalizumab) – anti-IgE • Bronchial thermoplasty

15. 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 > 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

16. 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

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

19. Sarcoidosis

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

21. 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

22. 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

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

24. Sarcoidosis – Treatment • None • Corticosteroids (Stage 2 +) • Azathioprine • Hydroxychloroquine • Methotrexate

25. Aviation Management Problems • Main risk - cardiac arrhythmia • Interference with operational effectiveness • Steroid treatment

26. 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

27. Pneumothorax

28. Pneumothorax – Natural History • Two peaks of incidence • Young adults • Old adults • Recurrence Rate • 30% after 1st • 50% after 2nd • 80% after 3rd

29. Pneumothorax - Investigation • CXR • Spirometry • Hi Res CT Thorax

30. Pneumothorax - Treatment • Aspiration / chest drain • Operative treatment • Open pleurectomy • Thoracoscopic pleurectomy • Chemical pleurodesis (NOT recommended)

31. Aviation Management Problems • Sudden incapacitation • Increasing with altitude

32. 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

33. Traumatic Pneumothorax • No associated bullous lung disease • Risk of recurrence – VERY small • No further treatment required after emergency treatment

34. Pulmonary thrombo-embolic disease

35. Pulmonary thrombo-embolic disease – Natural History • Variation from single life threatening event to insidious breathlessness • Causes • Short term risks • Malignancies • Clotting disorders

36. Pulmonary thrombo-embolic disease - Investigation • CXR • ECG • Arterial Blood Gases • CTPA • Ventilation/perfusion scan

37. 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

38. Aviation Management Problems • Risks of sudden incapacitation • Disabling breathlessness

39. 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

40. Obstructive Sleep Apnoea

41. 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

42. OSA - Investigation • Sleep study • Epworth Sleepiness Scale

43. OSA - Treatment • Address aggravating factors • CPAP • Jaw advancement splint • Surgery

44. Aviation Management Problems • Daytime somnolence leading to increased accidents and decreased performance • Treatment negates this risk

45. OSA - Disposition • Pilot Training • Disquallifying • Trained Aircrew • Grounded until response to treatment assessed • Effective treatment → full flying category • Help from specialist centre

46. Interstitial Lung Disease

47. 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.

49. ILD - Investigation • CXR (little use) • Hi res CT scan • Refer to specialist centre

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