Sequelae are not formally defined by any of the compensation Acts, nor is it a term used elsewhere within the text of those Acts. The term refers to medical conditions which represent a medical consequence of a previously accepted injury or disease, but is other than a simple worsening of that same condition. The main feature of sequelae is that they are different from the original condition (i.e. a sequela has a separate diagnosis). It is a new condition that has arisen out of the effects of that original condition.
Sequelae are not synonymous with aggravations. Read the Section 10.6 [2]. of this Handbook on aggravations. Basically, aggravations consist of a factor from the workplace affecting (worsening, accelerating etc.) a pre existing medical condition. A sequelae on the other hand, is where a compensable condition, of its own nature subsequently promotes or contributes to a new ailment (i.e. without the operation of other work related factors).
Note that, virtually by definition, sequelae are diseases (see part 10.5 [3]). They are natural progressions of a condition. They are not additional injuries which may have resulted from a further accident even if that further accident is said to have been contributed to by a disability residual from the original injury.
For example, development of osteoarthritis in a left knee joint which had previously suffered a split articular surface in a compensable fall would, if medical opinion established a causative link between the two, be a sequela of that original knee condition. Similarly, in that case, the right knee condition may also be accepted for compensation as a sequela of the left knee condition(s).
How can the Delegate be satisfied that a new injury was sustained as claimed? One possible way would be for the Delegate to seek a Statutory Declaration from the employee stating the exact circumstances and cause of the accident and the exact symptoms suffered following the accident (and injury). Similar Statutory Declaration(s) by any friend(s) or family member(s) would also be most helpful to the Delegate. While a Statutory Declaration is not of course 'evidence' of the matters to which it refers, we in policy consider that most employees' preparedness to complete such a declaration can reasonably be seen to be supportive of any assertions that are made in it.
Previously, an injury and its sequelae were often regarded as a single compensable unit, i.e. similar to the situation where multiple injuries are received in a single vehicle accident. However, this has changed since the High Court decision in Canute v Comcare which indicated that once a condition has been determined as an injury as defined by the Act, it is thereafter treated on its own merits. The importance of a sequelae is in the liability process – to link the sequalae to being service related – requires the delegate to look at a connection between the original accepted condition and the sequelae. If such a connection is established and liability can then be accepted for the sequelae it then essentially becomes a 'stand alone' condition for the purposes of compensation such as permanent impairment.
However, if liability for the original condition were to be revoked, for example there was clearly no evidence to link the original condition with service based on the evidence available to the delegate at the time and the decision was clearly wrong on the face of the record, then any sequalae conditions which had subsequently been decided may also require to be revoked. Care would need to be taken to ensure that the 'sequelae' condition did not on its own merits satisfy a connection to service irrespective of the original condition.
Links
[1] https://clik.dva.gov.au/user/login?destination=node/20398%23comment-form
[2] https://clik.dva.gov.au/military-compensation-srca-manuals-and-resources-library/liability-handbook/ch-10-injury-disease-or-aggravation/106-aggravation
[3] https://clik.dva.gov.au/military-compensation-srca-manuals-and-resources-library/liability-handbook/ch-10-injury-disease-or-aggravation/105-disease-date-effect-onafter-13-april-2007-s5b
[4] https://clik.dva.gov.au/user/login?destination=node/20384%23comment-form
[5] https://clik.dva.gov.au/user/login?destination=node/20083%23comment-form