Causation is the connection between the breach of duty of care and the damage/injury that a person suffers. Unless the casual connection can be drawn between the two, a person cannot maintain a claim for damages.
In medical negligence cases the casual connection is not always clear. Sometimes it is possible to have breach of duty but no causal connection to the injuries.
An example of the complexity of causation in medical negligence cases is as follows:-
A patient presents to a hospital for a biopsy of a breast tumour. The biopsy results confirm that the tumour is cancerous, however the results are not provided to the patient or his or her treatment providers for a period of 6 months. This is clearly a breach of duty of care, as the results should have been provided earlier.
Upon receipt of the results the patient receives the relevant surgery to remove the tumour without complication. 3 months later the patient, in a routine check up is diagnosed with having a separate lung cancer, which has now spread to her bones.
Can it be argued that but for the delay in providing the biopsy results of the breast cancer this patients lung cancer has spread?
The answer is no: There is no doubt that the patient has suffered damage with the spread of her lung cancer, however the spread of cancer has not eventuated as a result of any breach of duty by the doctors.