Disentangling symptoms and their causes
Tuffin v University Hospitals Coventry and Warwickshire NHS Trust [2024] EWHC 3318 (KB)
Background
In Tuffin, the Claimant underwent elective spinal surgery in 2015. In breach of duty, the Defendant failed to administer Clexane (a medication to prevent blood clots) post-surgery. This resulted in the Claimant suffering from a deep vein thrombosis (DVT) and post thrombotic syndrome (PTS). There was no dispute that the DVT and PTS were caused by the Defendant’s negligent failure to administer Clexane.
After the surgery, it was also clear the Claimant may have also been suffering from symptoms indicative of complex regional pain syndrome (CRPS). Consequently, in 2018, the Claimant had her left leg amputated.
Issues
The preliminary issue before HHJ Dight was whether the negligence of the Defendant caused or materially contributed to the Claimant’s amputation. A range of causes were advanced in relation to the reason for amputation: allodynia, ulceration, and inversion deformity. The parties disagreed as to whether these were caused by the negligence or CRPS.
On the applicable test for causation, HHJ Dight cited the well-known paragraph from Bailey v MOD [2008] EWCA Civ 883 at [46]:
“…If the evidence demonstrates that ‘but for’ the contribution of the tortious cause the injury would probably not have occurred, the claimant will (obviously) have discharged the burden. In a case where medical science cannot establish the probability that ‘but for’ an act of negligence the injury would not have happened but can establish that the contribution of the negligent cause was more than negligible, the ‘but for’ test is modified, and the claimant will succeed.”
The Claimant’s primary case was that the complications from the DVT and PTS caused the amputation. In particular, allodynia, ulceration, and the inversion deformity were all caused by the negligence. In the alternative, if the court could not disentangle whether the symptoms were caused by the Defendant’s negligence or the CRPS, then causation was made out on the basis of material contribution.
The Defendant’s case, on the other hand, was that the amputation was caused by symptomatic CRPS and not by the negligence. On a careful analysis of the symptoms leading to the amputation, there was no basis for finding that the symptoms leading to the amputation were caused by DVT or PTS. Furthermore, there was no basis for finding that CRPS was caused by DVT or PTS.
Judgment
The judge agreed with the evidence of the Defendant’s experts. In particular, the Defendant’s pain management expert, Dr Simpson, was able to disentangle and show how the various symptoms were not caused by the negligence and instead were a consequence of the CRPS. Cogent reasons were provided, drawing on Dr Simpson’s own expertise, the Claimant’s previous medical history, and the literature, as to why the symptoms were not caused by the negligence. Further, Dr Simpson made clear that DVT and PTS would not cause CRPS. As the judge said at [119]: “Dr Simpson was able, in my judgment, to disentangle the symptoms and their causes.”
Therefore, the judge found that the symptoms which caused the Claimant to undergo the amputation were attributable to CRPS, which occurred irrespective of the negligence. Material contribution did not arise in circumstances where there was no good evidence to prove that the negligence materially contributed to the symptoms.
Comment
As the judge held that there was no evidence that the negligence caused the symptoms, a potentially interesting discussion on material contribution did not arise. However, Tuffin does highlight an important point about the court’s approach to expert evidence. Mere reliance on anecdotal evidence by an expert, especially where it is at odds with the experience of other experts, will not provide a sufficient basis for proving causation. The judge stated at [145]: “there was no good medical evidence before me in either the literature or the experience of the experts to support anything other than an anecdotal connection, which is not a sound basis, for concluding that the CRPS was caused by the DVT” (emphasis added).
Relatedly, the case will be of benefit to Defendants facing a material contribution argument. In particular, Tuffin shows that the court will be alert to the risk of concluding that because a pathology arose in close proximity to negligence it was therefore caused by it.
