Thread by @prissanthemum, FUNCTIONAL NEURO DISORDERS (FND). since I peeked out of the woodland & [...]

FUNCTIONAL NEURO DISORDERS (FND). since I peeked out of the woodland & got some DMs, a thread. stories of "all tests run & normal (so it's you)" abound. without knowing details: sometimes a non-FND diagnosis is missed. other times, FNDs aren't considered/explained well. 1/26

IMPORTANT!

This is not medical advice. Googling "functional neurologist" results in chiropractors, who are NOT qualified for this. "Functional neuro" here = residency-trained MD/DO/MBBS/equivs in neuro w/ expertise in FNDs (many fellowship-trained in movement disorders). 2/26

so the brain is super complex. science still doesn't fully understand many aspects of the higher-order functions, like reason & memory. even the "simpler" things we know lots about like how the thought of moving translates to action likely involves more than we know. 3/26

as it is, these pathways are *nightmares* to memorize. here's two of them: if you're ever tested on these, look at them right before & draw as soon as you start! back to our key problem: 1) there's lots we don't know 2) we don't have tests for some of the things we do know. 4/26

the great news is that even with these unknowns, neurologic syndromes/diseases produce predictable patterns of functional impairment. neurologists rely on this knowledge, together with a great history & physical examination (and sometimes a few tests), to make a diagnosis. 5/26

which is why LISTENING IS THE MOST IMPORTANT PART. trainees are often told that if they have no idea what is going on after hearing the story, they better ask more questions until they do. physical exam findings & tests should confirm (or rule scary things out). 6/26

so let’s talk tests. there are basically only 5 types of tests for the nervous system. 1) imaging 2) EEG 3) EMG/NCS 4) LP 5) blood tests (ok, there's also 6) biopsies, but those are super rare for obvious reasons, and 7) assorted others which I won’t cover here.) 7/26

IMAGING: MRI/CT tell you about structure, from which you can sometimes infer function, but also sometimes not. There are people with half a brain (since the other half stroked & died in infancy) & have motor impairments, but are smarter than most of us. 8/26

Yet many with intellectual disability have a normal brain. fMRI and MR spectroscopy can tell *some* things about function & metabolism, but have limited use (mostly specialized/research cases, or predicting neuronal injury even if the structure of the brain looks normal). 9/26

EEG: brainwave test; sees you when you’re sleeping and knows when you’re awake. It can tell some things about function (mostly is the brain irritable/prone to seizures?), but not things like cognition. There are special cases: certain patterns can suggest certain diseases. 10/26

EMG: stabby needle electrode to listen to how muscles talk. NCS: electric shocks to see how fast nerves conduct. Together they assess function of the peripheral NS: if there’s a block somewhere in the nerve & signals can’t move quickly enough, it can cause weakness or pain. 11/26

LP: needle in your back (like an epidural) to measure the pressure around your brain & get a sample of your spinal fluid. Tests for nerve breakdown products that shouldn’t be there, antibodies that could be attacking your brain, or to measure levels of neurotransmitters. 12/26

Blood tests: more needles! Tests for muscle breakdown products that shouldn’t be there, antibodies, vitamin levels, how your body metabolizes energy. And genetic tests (an entirely different Pandora’s box for another day). 13/26

so how do we get to "they ran every test & everything was normal. nobody knows what's wrong"? in FNDs, what’s wrong is in pathways we don't have good tests for. when this is the case, your symptoms won’t outright kill you or cause irreparable damage if left undiagnosed. 14/26

of course, these functional impairments can cause severe physical deconditioning and pain, not to mention the psychosocial harm disabled people suffer. lost experiences & productivity, “it can’t be that bad”; worst of all: “you’re faking for attention” or “you’re crazy”. 15/26

to understand functional neuro symptoms, we have to understand the fight-or-flight response. if you come face-to-face with an angry bear, you have 2 choices: kill/disable or outrun. the body’s systems reflexively do things to give you the best chance of survival. 16/26

digesting food is useless now, so blood flow to your gut changes (this is why you get butterflies/stomach pain or nausea when you're nervous). keeping your fingers toasty is less important than blood flow to your heart & muscles (so you can feel clammy/jittery/tingly). 17/26

your heart beats faster & you breathe faster so you can oxygenate more blood to supply muscles for strength or running. your pupils dilate so you can see better. your brain focuses attention solely on danger, so it’s hard to concentrate on other things. 18/26

nobody would say these functional changes are real or made-up – we know these are physiological responses to danger. these days, the predators stalking us tend to be incorporeal (like our own thoughts), but the response of the body to this stress is exactly the same. 19/26

with FNDs, SOMETIMES it's a stressor we can identify. sometimes a physical injury triggers the symptoms & the body heals, but normal function doesn't return. sometimes an emotional stressor "overflows" to movement or sensory parts of the brain & triggers the impairment. 20/26

sometimes there's no obvious stressor, but something in that complex tangle of brain pathways that affect how we function changes. but once that cycle of functional impairment starts, it can be hard to stop. (chronic migraine also has this physiologic+overflow cycle, btw.) 21/26

so why are FNDs missed or underdiagnosed? 1) science & medicine, with good reason, are focused on empirical evidence: what’s measurable/observable/provable. I think it’s uncomfortable for many when the problem isn’t clearly so. 22/26

but a trained neuro with expertise in FNDs IS comfortable in this scenario AND with telling if it is a clear pattern of disease, so after listening to you, looking at records, & running other tests if needed, can make a firm diagnosis & plan treatment. 23/26

2) there’s a lot of stigma in our culture towards disabled people & mental illness. we need to break away from that. 3) conversion disorder & FNDs are often dismissed as “in your head”. I guess it all technically is, just as much as MS or a stroke is a problem in your head. 24/26

4) FNDs can be tricky to treat, because you need specialists who are all on the same page about the plan: neuro, psych, therapists, rehab, PT/OT, nurses, etc. AKA cat herding required. But if you find the right doc (or get yours in contact with one), THERE IS HOPE. 25/26

RESOURCES
1) NeuroSymptoms: https://neurosymptoms.org
2) FND Hope: https://fndhope.org/fnd-guide
3) FND docs: https://fndhope.org/living-fnd/managing-fnd-find-provider 26/26
#FNDaware #FND2021 #LetsTalkFND

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