Causation: the importance of keeping the possibility of rare occurrences under consideration

TB (a protected party) v Bedford Hospital NHS Trust [14.10.19]


Kennedys were instructed to represent the Trust in relation to a claim for an alleged failure to diagnose a transient ischaemic attack (TIA) which, it was alleged, led to an avoidable stroke. The claimant established breach of duty, but failed to prove that a stroke she suffered was avoidable.


The claimant suffered a major stroke aged just 44, which left her with significant permanent disabilities. She attended Bedford Hospital in October 2009 and January 2010 and it was agreed, with the benefit of hindsight, she had suffered from TIAs. It was the claimant’s case that there was a breach of duty for failing to diagnose these. The defendant Trust’s position was that the claimant presented with highly unusual symptoms was very young to be suffering TIAs and it was therefore not negligent to fail to diagnose. 


Her Honour Judge Taylor found that the possibility of a TIA should have been considered as a differential diagnosis and failure to do so was a breach of duty. However, HHJ Taylor accepted the defendant Trust’s position that the claimant herself thought she had suffered from TIAs and indeed told her GP that she had suffered TIAs.  The claimant had a significant history of non-compliance with medication and advice. HHJ Taylor concluded that even if the claimant had been given:

a diagnosis of possible, probable or definite TIA, and advised of any necessary changes in her lifestyle in October 2009, on a balance of probabilities she would have been no more compliant with medication, stopping smoking, or losing weight for any more time than previously, nor in a way which would have made a difference. 

Further, the Judge found that the claimant “believed that she had had a TIA, knew of the family history of stroke, and was aware of her own medical risk factors.

The Judge also accepted the defendant Trust’s evidence that, even if the claimant had complied with advice and been prescribed medication, she had not succeeded in proving the cause of her stroke was atherosclerosis (which is the only potential cause that could potentially have been avoided with earlier/different treatment). Therefore the claimant failed to prove that the course could have been avoided and failed to establish causation and her claim was dismissed.


Causation of the stroke was complex requiring expert opinion to assist the court. The claimant was unable to establish, on the balance of probabilities, which of the potential causes had led to her stroke. Only one of these causes could have been prevented with earlier/different treatment. The claimant was unable to prove that the stroke was avoidable. Even in a hypothetical situation of her being compliant with advice and medication.