The Causation Issue in Medical Malpractice Cases

Article by: Kathryn Griffin, Student-at-Law

Just because you were injured by the negligence of a doctor, it does not necessarily mean that you will have a successful medical malpractice case. Your medical malpractice lawyer would also tell you that you have to prove that the negligence caused the injury.

For example, let’s say a patient regularly goes into see their family doctor and is consistently told that they are healthy. Six months later the patient finds out from another doctor that they have had cancer for the last six months and the family doctor failed to follow proper procedure and negligently failed to diagnose that the patient had cancer. The doctor’s actions were obviously below the standard of care and he acted negligently. On its face, this seems like a pretty clear cut case.

Unfortunately, in medical malpractice cases it is not enough to prove that a doctor was negligent. On top of proving that your doctor fell below the standard of care, your medical malpractice lawyer must also clear the much more difficult (and complex) hurdle of “causation”.

Causation is the connection between the damages suffered and the negligent actions of the wrongdoer. It is the ability to prove that the at-fault party was responsible for the damage. You must show that the negligence of the doctor actually caused the injury and that the injury would not have happened if it were not for the actions of the doctor. This can be especially difficult in medical malpractice because the doctor, as the expert, often has much more knowledge of the procedure and the injury than the patient.

There are a few ways to prove causation in medical malpractice cases. The first is to show that “but for” the actions of the doctor, your injury would not have occurred.

For example, in our cancer scenario the patient would have to prove that the misdiagnosis caused them to suffer an injury. They would have to show that an earlier diagnosis and treatment would have led to a better result or that the misdiagnosis caused the symptoms to be greater. If the patient dies from the cancer, their loved ones would have to prove that an earlier diagnosis and treatment would have saved the patient’s life. Given the treatment options, the variety of cancers, and the individual characteristics that can affect a person’s recovery, this is not always an easy feat.

In cases like this the defence will always argue that earlier treatment would not have changed anything; that the patient’s chances of survival would not have been affected by an earlier diagnosis. As plaintiff counsel, and as your medical malpractice lawyers, it is our job to find our own expert witnesses to help us prove that it would have been more likely than not that the patient would have survived had they received earlier treatment. However, the experts must be able to show that there was a greater than 50% chance that the patient would have survived. In Canada there is generally no such thing as a “loss of chance”. It is not enough to show that the patient may have stood a better chance of survival. The Plaintiff must show that it was more likely than not that the misdiagnosis resulted in a worse outcome.

Another way to show causation is to show that the Doctor “materially contributed” to the injuries you suffered. This test is used when there are multiple possible causes of the injury. For example, lets say a plaintiff is in a car accident and then goes to the hospital for leg surgery which is performed negligently. If plaintiff looses all feeling in the leg the doctor could argue that the car accident was completely responsible for the leg injury. On the other hand, the driver of the car could argue that the Doctor’s negligence was responsible for the injury. As Plaintiffs we would have to find expert evidence to show that the negligent surgery materially contributed to the risk of injury and, therefore, the doctor should be held responsible. To prove material contribution, it must be impossible for the plaintiffs to prove causation and the Plaintiff must be able to prove that by breaching the standard of care the doctor exposed the Plaintiff to an unreasonable risk of injury.

A final way to prove causation is in cases where there is no clear expert evidence to show how the injury happened. For example, what happens if a patient goes in for an eye surgery and suffers an unexpected bleed that causes the patient to lose sight in his eye? The doctor and the Plaintiff have no clear evidence of what caused the bleed but it is clear that it occurred around the time of the surgery. In cases like this, where there is no clear expert evidence, the Court may draw a “common sense” inference based on the facts of the case. This means that the court will use common sense to weigh the circumstances of the case and determine what caused the injury.

In short, causation can be shown in a number of ways but it is a very complex and difficult process. This is why Robinson LLP is here to help you by having our medical malpractice lawyers in Edmonton navigate the pitfalls of causation and help you prove your medical malpractice claim.