Functional Neurological Disorder – Pushing the boundaries of medical credibility?
31st May 2022
Whilst doing my ward round I came across a patient who was being attended to by one of the junior doctors, a 12 year old boy who had been admitted with “seizures”, a relatively common condition which most paediatric trainees should feel comfortable in managing. The patient, let’s call him Peter (not his name), had a previous diagnosis of “functional neurological disorder” (FND for short) and my junior was about to discharge this patient home despite the fact that the parents had brought their child to hospital because of the severity of his symptoms, because they were desperate and had been desperate for the past three years with a child who was house bound, unable to function on a day to day basis, unable to attend school and unable to experience a normal childhood. The patient raised my curiosity but before I discuss the management let’s take a look at FND, what it is and how the term came into being.
To fully understand FND we need to go back to Hippocrates who in 400 BC coined the term “hysteria” to describe unusual symptoms in patients which he felt were due to the uterus wondering around the body (hysteria is Greek for womb). This term was used to describe patients with unusual neurological or psychiatric symptoms that could not be explained by conventional medicine. Fast forward to the 19th century and we meet Jean-Martin Charcot, often described as the father of neurology who worked at the Salpetriere hospital in Paris. Charcot performed autopsies on the brains of patients who had been diagnosed with hysteria and who had subsequently died, despite his efforts he did not find any anatomical abnormalities that could explain the symptoms that these patients had experienced. This was at a time when the battle between those who believed in the disorders of the mind versus those who believed in a physical or organic explanation of patients symptoms were particularly fervent. put in modern terms this was the battle between the molecule and the mind. One of Charcot’s pupils was Gilles de la Tourette who went on to describe Tourette’s syndrome following encouragement from Charcot.
In the twentieth century the baton was picked up by Joseph Babinski, Pierre Janet and Sigmund Freud. Freud championed the idea that hysterical symptoms (ie those symptoms that could not be explained by conventional medicine) were likely to be due to repressed trauma, abuse or other disturbing events and hence the term “conversion disorder” was coined. This led to a movement of patients with “hysteria” away from neurology to psychiatry. Over the next few decades Freud’s influence diminished and so did the number of cases of conversion disorder. Conversion disorder was seen as a disease of the Victorian era.
Conversion disorder fell out of favour until 2013 when a group of physicians were concerned that the concept of conversion disorder would not be accepted in modern society. They therefore lobbied for a new term “functional neurological disorder” to be included in the DSM-5 catalogue (this is an indexing system that ascribes a code to a medical condition allowing it to be monitored but also giving it credibility).
So we now have functional neurological disorder (FND) to help assign a label to complex symptoms in patients who do not fit conventional medical explanations but just how useful is it? Some of my juniors joke that FND=finding no diagnosis. It would be funny if it wasn’t for the tragedy associated with this condition. Protagonists of FND recommend a “bio-psychosocial” approach to manage these patients with input from CAMHS and the use of CBT etc etc. This unfortunately is not the real world where patients are often waiting months or years for a CAMHS review and even if they are reviewed they are often directed to self-help websites on parenting skills. As one of my colleagues put it: “I have yet to meet a patient who has benefitted from receiving a diagnosis of FND”. My concern is that once a child receives a diagnosis of FND, the diagnostic process stops and people stop being inquisitive.
So let’s go back to Peter, a 12 year old boy with tics, obsessive compulsive behaviours and a strange seizure like phenomenon that occurs 200 times a day. The seizures are unusual in that he cannot respond during an attack, his limbs go into a foetal position with rhythmical beating and his eyes deviate to one side. Occasionally he can hear what is going around him but cannot respond. The build up to a seizure is cumulative with a sudden drop, something I have termed a “capacitance effect” because it is like a capacitor discharging its charge. He had been investigated with an EEG and MRI but both returned normal and he was subsequently given a diagnosis of FND. I had seen this before so I asked my junior to run some tests and then started some treatment. Peter’s symptoms improved by 80% within two weeks, he was able to function normally and started to attend school.
This was not a case of functional neurological disorder, conversion syndrome, non-organic disease or hysteria but rather an immune mediated behavioural change that could have been detected if the right tests had been requested and the right treatment started, I would estimate that there are at least another 20 cases around the UK right now which are like Peter and most of whom have previously been given a diagnosis of FND. As one of my juniors put it, “you only know what you know”. The battle between those that subscribe to the molecule versus those that subscribe to the mind will continue for now, our job as doctors is to try our very best to ensure that the patients we encounter are met not only by doctors with experience but also by doctors who have the humility to consider diagnoses beyond their own specialisations only then can we effectively treat those patients who sit on the boundaries of conventional medicine.
Dr Tim Ubhi