After receiving radiotherapy and chemotherapy for a squamous cell carcinoma, 60 year-old John (not his real name) developed a cold sore on his lip.
Initially, the cold sore did not seem problematic, but in the day after contracting it, he developed a few vague symptoms. First a headache, then memory loss, followed by an episode of vacant staring.
Even though the behaviour was out of character for John, neither he nor his wife were particularly worried; but given his recent history, they decided to visit the emergency department. Here, he was assessed, treated symptomatically, and sent home.
Hours later and John took a turn for the worse, suffering an overnight seizure. He was rushed to emergency, where he received more tests – one of which showed his inflammatory markers were up. A CT scan did not identify anything.
John stayed in hospital, deteriorated and, after 24 hours, was given antibiotics. A second CT scan showed non-specific abnormalities.
After deteriorating further, a third cerebral CT revealed defined abnormalities on his temporal lobe.
Finally, John received a lumbar puncture (a spinal tap), where it was confirmed he had herpes encephalitis – potentially deadly infection of the brain, resulting from the herpes simplex virus.
Catastrophic outcomes
According to Professor William Rawlinson AM, Senior Medical Virologist at the University of NSW, this type of outcome is difficult to diagnose, but eminently treatable.
“It’s the sort of confusing case that doctors find difficult sometimes,” he said, ahead of the Medico Legal Congress.
“John was initially looking normal, and even though he had a fresh cold sore, this is not typically associated with herpes encephalitis. It is more likely he developed the encephalitis from a latent (resting) herpes simplex virus he acquired years, or even decades, ago.
“Latent herpes simplex are responsible for the vast majority of cases of severe herpes simplex encephalitis – and it is rare to see any kind of cold sore or lesion on the skin with this condition. John had both, which is highly unusual and confusing for the treating doctors.”
Complicating things further, Rawlinson highlights that approximately one in five patients with a diagnosis of herpes encephalitis will show no abnormalities on a lumbar puncture, particularly if it is performed early.
This often delays the diagnosis.
“I’ve seen medico legal cases where a child has had an essentially normal lumbar puncture, because it was done (as it should be) early in the condition, and the diagnosis has largely been ruled out on the basis of that.”
Likewise, performing a cerebral (brain) CT scan early can also miss abnormalities.
“If it is less than a couple of day since the onset of symptoms, you may miss herpes simplex encephalitis. It’s not until after a few days that you can definitely show it on CT scan. Even then, it may miss subtle evidence of the infection.”
Although early detection of herpes encephalitis is hard, early treatment is crucial, adding to the complexity of managing the condition, Rawlinson added.
“An untreated herpes encephalitis in an adult has about a 60 percent mortality rate and about a 90 percent rate of morbidity, or long term damage. In a child the statistics are even worse.
“This can be reduced to a mortality rate of 10 to 20 percent with treatment – still too high, but much better. So you really need that early diagnosis and treatment to avoid death or very severe long term outcomes.”
A complex medico legal scenario
In John’s scenario it was clear that medical staff should have made the diagnosis as soon as possible. It is also known that delaying treatment of this condition can be catastrophic.
Despite this, proving liability in this type of scenario can be complex, given a lack of scientific data, Rawlinson said.
“Intuitively, a plaintiff may be convinced that X has caused Y – for example, that a delayed antibiotic treatment led to osteomyelitis, a chronic bone infection.
“But since the deliberate delaying of antibiotic treatment for someone with a bone infection is not ethical in a clinical study, this hunch will often not have supporting laboratory and clinical data. Nor could the findings of studies in animals be used, since animals react differently to infections such as osteomyelitis and to antibiotic treatment.”
Ensuring good legal outcomes
In light of these challenges, Prof Rawlinson says it is important to remember an age-old industry phrase: evidence of absence does not mean absence of evidence.
“This is a catchy way to describe a common problem in the field: the inability to prove that X causes Y, because the hypothesis cannot be tested safely on humans, and animal findings do not translate,” he said.
Additionally, it pays to consider the cultural differences between medical and legal sectors.
“In the medical sector, we are very data driven. We cannot make conclusions without the backing of data and, even when we have data, we are cautious about how we report and use it. We talk about hypotheses being ‘supported’ rather than ‘proven’, for example, and often conclude research papers with recommendations for further research.
“In many ways this represents what the philosopher Karl Popper called falsification – the idea that scientific hypotheses can be proven wrong, but cannot truly be proved right.
“In contrast to medicine, the legal sector explores the merit of a single case, and that case might end up being definitive. Legal conclusions from a medical standpoint are also dichotomous and can be relatively concrete – e.g. did X cause Y, or not? – and, in that way, they are fundamentally different to the outcomes of clinical medicine.”
Further insight
Sharing more thoughts and insights on complex medico legal cases, Prof Rawlinson will present at the upcoming Medico Legal Congress, hosted by Informa.
This year’s event will be held 27-28 March at the Swissotel Sydney.
Learn more and register your tickets here.
About Professor Rawlinson
William (Bill) Rawlinson AM FAAHMS BSc (Med) MBBS PhD (Cantab) GCM FRACP FRCPA FASM FFSc is an infectious diseases clinician and molecular virologist, overseeing various diagnostic facilities.
A major contributor in the field of viral pathogenesis research, Bill has undertaken medico-legal reports for legal firms and government for over 30 years.
He is also known for establishing serology and virology clinical and research programs, statewide transplant donor screening, and national quality programs for serology and biosecurity.