Subdural haemorrhages—a way out?

Cases involving subdural haemorrhages are notoriously difficult to defend and, quite frankly, to understand, but as the proud recipient of a 'C' at A-level Biology, I can’t think of anyone more qualified to write about such a thing.

The anatomy bit

The brain is covered by three membranes. The first is a thin film called the pia mater, which is impervious to fluid. Above that is the subarachnoid space topped by the arachnoid mater, with the final thicker dura mater just below the skull. Passing between these layers are blood vessels. Recently, in an effort at trying to explain to me in words of as few syllables as possible, a neurosurgeon, Peter Richards, used a pictorial analogy. A bemused judge and equally bemused lawyers were invited to consider the brain as a sausage, the pia as the sausage skin, the arachnoid as the cling film around the sausage and the dura as the sandwich bag around that. He didn’t go so far, but I suppose the skull would be the lunchbox and presumably the rucksack it is put in would be the hat?

The injury bit

In ordinary life there is no reason for there to be fluid in the subdural space. The subarachnoid space contains clear cerebrospinal fluid, and again, in ordinary life, no blood. The existence of fluid ie blood in the subdural space is almost always due to some form of infection or trauma. We, as lawyers, will only become involved where the suggestion is that a child has suffered some inflicted trauma. This will have shown up on an MRI or CT scan as fluid in the subdural or subarachnoid space. This has happened because the blood vessels which cross the layers have been torn as a result of the application of force in what is often described as a 'to and fro' fashion. This causes blood to leak into the subdural or subarachnoid layers and will almost always have had an impact on the health of the child which could include the most serious of consequences. In the absence of any other explanation, the existence of such a bleed will inevitably result in the parents finding themselves in the pool of potential perpetrators.

The way out bit? 

Those who have dealt with these sorts of cases before will know how difficult they are to deal with. We are lawyers, not radiologists nor brain surgeons. My grade C doesn’t exactly qualify me!

How do we create a useful line of questioning for experts? It is important to remember that the reality is you probably won’t have that 'Columbo' moment where 'just one last thing' unravels the case and causes the previously certain witness to change their mind. It may be that the best we can do is mitigate the level of inflicted injury to the extent that the relevant parent/intervener remains a viable carer within the proceedings.

The most effective questioning may be the most simple, such as inviting the experts to consider what evidence isn’t present in any given case, such as:

  • often subdural haemorrhages go hand-in-hand with retinal haemorrhages
  • associated fractures and swellings can be seen, particularly in respect of ribs
  • encephalopathy (an interruption of the brain function or damage to the brain) is often seen
  • hypoxia (lack of oxygen) causing damage to the brain is thought to be a direct result of such inflicted injury; and
  • bleeding down the spinal cord can occur

The alternative course is to determine what the experts don’t know:

  • there has never been clinical trial to determine what happens to children who are shaken—all assertions are based on a limited test pool of those that present for medical attention
  • similarly, medical examination of children only occurs if there is some reason to do so ie there is no controlled variable to compare against; and
  • there is no known association between the extent of the injury and the extent of force. Indeed, the reality is that the same force inflicted on two identical children could have vastly differing consequences ranging from nothing to death

The third course is the internet

With carefully chosen search terms (particularly carefully chosen if it’s a work computer...) there is no excuse nowadays for not being able to find medical journals or research papers. Medical science is always changing. As part of his 'Ten Commandments', Mr Justice Baker has made it clear (most notably in Re L and M [2013] EWHC 1569, quoting Dame Butler-Sloss) that: 'The judge in care proceedings must never forget that today’s medical certainty may be discarded by the next generation of experts or that scientific research would throw into light corners that are currently dark.' Again, the reality is that experts may well be more up to speed with such developments than us, but we must remember all we are doing is seeking to put doubt in the mind of the court.

The changing medical evidence bit, an example

This article came about as a result of a case in which I and another member of chambers were involved. It seemed as good an example as any to try to pull together all the points above. In this case, a ten-month-old girl had been rushed into hospital with a subdural bleed over the left side of the brain, which ultimately caused a seizure and collapse. (Fortunately, within two weeks she had been discharged with a good prognosis). The case was 'straightforward' in so far as the mother and partner were the only carers of the child in the preceding 24 hours and the medical evidence seemed to be clear about non-accidental injury. However, tucked away in only one of the seven reports which had been commissioned, was that the child in question had what were described as 'prominent subarachnoid spaces'. Medical interpretation of ever advancing scanning technology has developed so much over the last 15-20 years that the prominence of these spaces would most likely not have been noted by either the radiologist or any of the experts who rely on those scans. In relatively recent years the existence of 'benign enlarged subarachnoid spaces' or 'BESS' has become more and more of a feature of supposed shaken baby cases. In simple terms, it occurs where the space between the 'sausage skin' and the 'cling film' is abnormally large causing the blood vessels that bridge that gap to be stretched. The thinking is that this makes the child more vulnerable to the tearing of these blood vessels at a lower force, or perhaps even spontaneously. This could either rule out the mechanism of any subdural bleed being a deliberate shake or at least mitigate it to some perfectly acceptable level of force.

It is difficult for medical experts to say what percentage of children have such enlarged spaces because many children will never be diagnosed with it, or even know about it. One article I have read considers at least 17% of children under the age of two may have them. As stated in generalities above, predominantly only those children who have had the clinical need for radiology will have been tested and therefore seen to have the condition. There appears to be no accepted thinking as to how large a space constitutes BESS, though 5mm from brain to skull seems to be the minimum. It is not clear whether a space marginally less than that could at least be a contributory factor sufficient to bring at least the level of force into question.

There is a wealth of articles on the subject, some of which consider the relevance of retinal haemorrhages and at least one of which considers that retinal haemorrhages 'could' come about as a result of raised intracranial pressure associated with the enlarged spaces. All of this gives at least a line of questioning which could lead to sufficient doubt as to mechanism of injury from a judicial standpoint. Commandment number 8 (per Baker J) tells us that: 'It is important to remember that the roles of the court and the expert are distinct and it is the court that is in the position to weigh up the expert evidence against its findings on the other evidence. It is the judge who makes the final decision'. To put it another way, even if the expert has little doubt, the court might.

In this case, ultimately, the experts were as confident as they could be that there was no contributory factor borne by the prominent spaces and indeed that is what the judge found. However, if the 17% is right, it is something that is going to appear in any number of allegations of shaken baby. The conclusions drawn in that case may well be different.

Sadly, one conclusion to be drawn from this is that, there may well have been cases 15 or so years ago, in which experts confidently stated that a subdural bleed could only have been inflicted when in fact, it could well have been caused by BESS.

I wonder what my old biology teacher would make of this.

James Cranfield is a barrister at Albion Chambers. This blog post was first published in the May issue of Albion Chambers family newsletter. 

The views expressed by our Legal Analysis interviewees are not necessarily those of the proprietor.

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