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Diagnosis and Post-mortems in asbestosis cases

Diagnosis and Post-mortems in asbestosis cases. Daniel Easton Partner, Leigh Day & Co APIL Occupational Health SIG, 24 November 2010. Helsinki Criteria. Asbestos, Asbestosis, and cancer: the Helsinki criteria for attribution and diagnosis Scand J Work Environ Health, 1997 23:311-6

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Diagnosis and Post-mortems in asbestosis cases

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  1. Diagnosis and Post-mortemsin asbestosis cases Daniel Easton Partner, Leigh Day & Co APIL Occupational Health SIG, 24 November 2010

  2. Helsinki Criteria Asbestos, Asbestosis, and cancer: the Helsinki criteria for attribution and diagnosis Scand J Work Environ Health, 1997 23:311-6 “Asbestosis is defined as diffuse interstitial fibrosis of the lung as a consequence of exposure to asbestos dust…” • History of significant exposure to asbestos dust; or • Detection of asbestos fibres or bodies in the lung

  3. Helsinki Criteria Significant exposure? = 25 fibre-years 1 year of heavy exposure manufacture of asbestos products asbestos spraying lagging) 5-10 years of moderate exposure construction shipbuilding “Extremely high exposure” can be sufficient with exposure of less than 1 year Dock workers?

  4. Helsinki Criteria Asbestos fibres or bodies = histology 2+ asbestos bodies in a section area of 1 cm² 2m amphibole fibres (>5 um) per gram of dry lung tissue 5m amphibole fibres (>1 um) per gram of dry lung tissue 5,000 to 15,000 asbestos bodies per gram of dry tissue 5 to 15 asbestos bodies per millilitre of bronchoalveolar lavage fluid lung fibre burden within the range recorded for asbestosis in the same laboratory

  5. The Updated Helsinki Criteria Pathology of Asbestosis: An Update of the Diagnostic Criteria Arch Pathol Lab Med – Vol 134, March 2010 “Asbestosis is defined as diffuse pulmonary fibrosis caused by the inhalation of excessive amounts of asbestos fibers”

  6. The Updated Helsinki Criteria “diagnosis is usually based on the exposure history, clinical findings, and radiographic features. Biopsy is seldom required, but it may be helpful when differential diagnostic considerations cannot be resolved on clinical or radiographic grounds alone.”

  7. “Differential Diagnosis” • Clinical features are essentially identical to idiopathic pulmonary fibrosis (IPF / CFA) • Fibrosis • Symptoms of breathlessness • Indicators? • Heavier exposure = shorter latency period ~ 15-20 year latency is less likely to be asbestosis • IPF progresses quicker • IPF median survival is 2.5 years • Asbestosis typically 10+ years (possibly 5+ years) • Widespread shadowing on x-ray more likely to be IPF, asbestosis is more concentrated

  8. Evidential burden • Expert medical evidence needed • Chest physicians • Radiologists? • Detailed witness statements • clear evidence of duration, hours, weeks etc • Engineering evidence • Look carefully at historical med recs • Consider onset of symptoms and breathlessness • Any signs on old x-rays? • Family evidence – signs of ‘aging’

  9. Fibre count • Fibre Count = “gold standard” • Types of asbestos fibre counts • Light microscopy = counting asbestos bodies • Electron microscopy = counting asbestos fibres • Dr Roggli, Duke University, America • Dr Gibbs / Attenoos, Llandough Hospital, Cardiff • See Sabin v BRB (Residuary) Ltd[2010] EWHC 267 • Mrs Justice Swift • background cases from population with higher incidental asbestos exposure, hence less difference between the samples sent to them and background population, so less likely to diagnose asbestosis

  10. Reliability of fibre counts? • Fibres are not spread evenly in the lung • room for error in the count between different samples • can be as much as tenfold • Clearance can affect the count • count at death will be less than at the time the exposure • “clearance” of asbestos fibres from the lungs (e.g. by scavenger cells, fibres coughed up, fibres dissolving etc) • Shorter fibres are cleared more easily, as are certain types, e.g. chrysotile. • Which laboratory? • Lab range can affect whether the fibre count is deemed sufficient to have caused asbestosis (see Sabin) • Can be technical problems with the fibre counting • Can have “false negative” result (but see case of Treble)

  11. Weaver –v- Contract Services Division Ltd • Mr Weaver lorry driver 1960-65 • Unloads and transports asbestos for D • Claim issued 26 September 2008 • Dies 25 October 2008 • Post mortem on 29 October 2008 • “occasional asbestos bodies” • Pulmonary fibrosis + pleural plaques • Tissue blocks retained for histology • 28 January 2009 • Family ask if they can destroy tissue • Solicitor agrees despite “defendants might object” • March 2009 directions given re histological evidence

  12. Weaver –v- Contract Services Division Ltd Application to strike out CPR 3.4(b) Abuse of court process; or Otherwise likely to obstruct just disposal of proceedings Solicitors actions Advised client to destroy samples Try to argue religious grounds Then reveal attendance notes at lunchtime

  13. Weaver –v- Contract Services Division Ltd 2009 (Lawtel), Master Whitaker Considers Three Arrows Nominees v Blackledge & Ors [2001] BCC 591 “Defendant deprived of admissible, relevant and highly persuasive evidence” “trial would have to proceed on the basis of a fiction” Defendant not able to test victim’s evidence Engineers can only produce reports based on untested evidence Substantial risk that there cannot be a fair trial

  14. C –v- Rio Tinto PLC & Ors George C laggers mate with Dicks Asbestos for “a couple of months” in 1950/51; engineer in the Merchant Navy from 1954 to 1960; stevedore at London docks unloading asbestos cargos for 8-12 days between 1960 and 1966

  15. C –v- Rio Tinto PLC & Ors • Pre-issue defendants are given • Witness evidence • Medical evidence • Copy medical records • Permission to examine claimant • Proceedings • Issued 29 January 2010 • Served 2 February 2010 • Exposure & causation disputed • Mr C dies 14 April 2010 • No automatic post-mortem in Australia • PM requested by defs day after death • Widow refused

  16. C –v- Rio Tinto PLC & Ors Application to strike out - the arguments C argues D wasted 3 chances to obtain evidence Witness – could have asked for deposition Medical – could have examined C PM – could have asked Mr C before he died D relies on Weaver –v- Contract Services Three Arrows Nominees Logicrose Limited vs Southend United Football Club Limited Landauer Limited vs Comins and Co Treble –v- ISC Ltd [2008] Asbestosis diagnosis in lifetime Negative fibre count at post-mortem

  17. C –v- Rio Tinto PLC & Ors 2010, unreported, Master Eastman the loss of the Defendant’s chance of obtaining histopathological evidence, caused a substantial risk that the case will not be dealt with justly the just disposal of these proceedings has been substantially put at risk Case struck out under CPR rule 3.4(2)(b) Permission to appeal

  18. Where are we now? • Progress asbestosis cases asap • Lifetime diagnosis primarily relies on • Diffuse pulmonary fibrosis • Evidence of significant asbestos exposure • Post-mortem in every case? • Yes if diagnosis not accepted • Raise difficult issues with client in lifetime • Or ask defs to agree…

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