Temple v South Manchester Health Authority

In a medical negligence claim involving uncertain scientific causation, the claimant must prove on the balance of probabilities that the negligent treatment caused the injury. It is insufficient to show that the treatment was regarded as unsafe, that it could have caused the injury, or that the injury followed it in time.

The exceptional increased-risk approach applies where the facts fall within the principles in Bonnington Castings or McGhee. It does not apply where several possible causes may have operated independently or cumulatively, as in Wilsher. Appellate courts should show appropriate deference to a trial judge’s assessment of conflicting expert evidence.

The claimant, a child, developed cerebral oedema and permanent brain injury while being treated for diabetic ketoacidosis at the respondent health authority’s hospital. The first-instance judge found negligence in the management of the treatment, including the use of hypotonic fluids and inadequate monitoring, but dismissed the claim because causation was not proved on the balance of probabilities.

The claimant appealed. The central issue was whether the negligent administration of hypotonic fluids had probably caused the cerebral oedema, notwithstanding the limited medical knowledge, competing expert evidence and other possible causes.

1. Appeal dismissed. The first-instance judge was entitled to find that the claimant had not established a relevant causal link between the negligent treatment and the cerebral oedema.
2. The fact that cerebral oedema followed the negligent treatment did not establish that the treatment probably caused it. The medical evidence and literature showed several possible causes, including the severity and duration of the underlying illness, which could operate independently or cumulatively.
3. The claimant therefore had to prove, on the balance of probabilities, that the administration of hypotonic fluids triggered the cerebral oedema. It was not enough to establish a physically plausible mechanism, a possible association, or a possible increased risk.
4. The exceptional approach in Bonnington Castings Ltd v Wardlaw and McGhee v National Coal Board did not apply. Those cases involved materially different circumstances. The present case resembled Wilsher v Essex Area Health Authority, where other non-negligent factors could also have caused the injury.
5. The judge was not bound by the experts’ conclusions and was required to assess legal probability rather than scientific certainty. Nevertheless, in a complex technical dispute, substantial weight was properly given to the trial judge’s opportunity to hear and evaluate the experts. His criticisms could not undermine his positive assessment of the respondent’s expert evidence.
6. Lord Justice Schiemann agreed. He added that the claimant would at least have needed to show that the treatment significantly increased the risk of cerebral oedema for a group of which he was a member. The evidence did not establish that proposition.

• Court of Appeal (Civil Division): The appeal from the judgment of Mr Brian Leveson QC, sitting as a deputy judge of the Queen’s Bench Division, was dismissed. The claim had been dismissed at first instance on the ground that causation was not proved.