In order to constitute "injury" within section 4 of the 1987 Act there must be a "sudden or identifiable pathological change": Castro v State Transit Authority (NSW) (2000) 19 NSWCCR 496).
personal injury: To distinguish from injury to other property. Does not embrace damages to artificial aids: McCawley v Storey  WCR 41, 48 SR (NSW) 474, but see s 74. Mills notes the phrase would comprehend disease except for its context: Slazengers (Aust) PL v Burnett  AC 13 (PC).
Injury as disease is limited to such disease contracted in the course of employment, and to which disease the employment is a contributing factor: Darling Island Stevedoring & Lighterage Co Ltd v Hussey (1959) 102 CLR 482.
Per McClemens J in Commissioner for Railways v Coates  WCR 88: "... categorise injury as trauma due to one or a series of happenings, or as trauma aggravating or accelerating disease, or as a disease contracted in the course of the employment and to which the employment was a contributing factor ": Mills p41.
Mills reservedly notes Anderson Meat Packing Co PL v Giacomantonio  WCR 3 where a majority of the NSW Court of Appeal found personal injury satisfied by mental shock causing physiological effect greater than mere emotional impulse.
Mason P at  in Fletcher International Exports PL v Barrow & Anor  NSWCA 244: Disease is the failure of an area of the body to cope with repeated stress imposed upon it, leading to pain and loss of function is capable of being found to be a disease process: see generally Armao v Ladue Holdings PL (1992) 8 NSWCCR 440; Perry v Tanine PL t/as Ermington Hotel (1998) 16 NSWCCR 253.
arising out of or in the course of employment The phrase originated in the England Workmen's Compensation Act 1897: Boulter p26.